BIO301L Homework Questions

What is the meaning of the statement "correlation does not imply causation"?

A. Just because two variables vary in a similar pattern does not mean that changing one variable causes a change in the other.
B. It is not possible to demonstrate a correlation between two variables.
C. When a change in one variable causes a change in another variable, the two variables are not necessarily related to each other in any way.
D. It is not possible to prove the cause of any naturally occurring phenomenon.
E. Just because two variables vary in a similar pattern does not mean that they have any relationship to each other.

A. Just because two variables vary in a similar pattern does not mean that changing one variable causes a change in the other.

Which of the following issues would be least helped by application of the scientific method?

A. developing more effective high school curricula
B. evaluating the relationship between violence in videogames and criminal behavior in teens
C. determining the most effective safety products for automobiles
D. formulating public policy on euthanasia
E. comparing the effectiveness of two potential antibiotics

D. formulating public policy on euthanasia

A relationship between phenomena that has been established based on large amounts of observational and experimental data is referred to as:

A. a theory.
B. a fact.
C. an assumption.
D. a conjecture.
E. a hypothesis.

A. a theory.

Anecdotal evidence:

A. is a more efficient method for understanding the world than the scientific method.
B. tends to be more reliable than data based on observations of large numbers of diverse individuals.
C. is a necessary part of the scientific method.
D. is often the only way to prove important causal links between two phenomena.
E. can seem to reveal links between two phenomena, but the links may not actually exist.

E. can seem to reveal links between two phenomena, but the links may not actually exist.

Statistical methods make it possible to:

A. prove any hypothesis is true.
B. determine how likely it is that certain results have occurred by chance.
C. unambiguously learn the truth.
D. reject any hypothesis.
E. test non-falsifiable hypotheses.

B. determine how likely it is that certain results have occurred by chance.

An independent variable:

A. can cause a change in a dependent variable.
B. is generally less variable than a dependent variable.
C. is plotted on the y-axis in a line graph.
D. can be controlled less well than a dependent variable.
E. is typically of greater interest to the experimenter than a dependent variable.

A. can cause a change in a dependent variable.

You hear the males of a particular bird species calling in their natural environment and question why they call. You design an experiment to try to answer your question. You cage one male bird and record his calling rate in response to four treatments, varying the number of conspecific (of the same species) males and the number of conspecific females that the male subject can see. The treatments are: no conspecific birds; 10 conspecific males; 10 conspecific females; 5 conspecific males and 5 conspecific females. Your results are: the rate at which the male subject calls is the same across all four treatments. Which of the following is a null hypothesis that your experimental design could reject?

A. Males of the species do not call.
B. Males of the species call more often than do females.
C. Males of the species call at a rate that is independent of the sex composition of the audience.
D. Males of the species call less often than do females.
E. Males of the species call when called to.

C.Males of the species call at a rate that is independent of the sex composition of the audience.

If a researcher collects data by using the same experimental setup as in another study, but using different research subjects, the process is considered:

A. an uncontrolled experiment.
B. intuitive reasoning.
C. extrapolation.
D. replication.
E. exploration.

D. replication.

A _____________ is a pill that looks identical to a pill that contains the active ingredient in a scientific trial, but contains no active ingredient itself.

A. tablet
B. barbiturate
C. placebo
D. capsule
E. treatment

C. placebo

Some have claimed that the herb echinacea reduces the likelihood of catching the common cold. In many hundreds of studies, this claim has been refuted. Assuming these studies were properly conducted, which of the following is a scientifically responsible claim that an echinacea advocate could make in support of further research on this subject.

A. The effective dosage of echinacea was outside the range of the dosages given in the scientific studies.
B. The investigators were paid off by the drug companies.
C. The effective length of time needed for taking echinacea is longer than that provided in any of the scientific studies.
D. All of the above are scientifically responsible claims that an echinacea advocate could make in support of further research on this subject.
E. Only a) and c) are scientifically responsible claims that an echinacea advocate could make in support of further research on this subject.

E. Only a) and c) are scientifically responsible claims that an echinacea advocate could make in support of further research on this subject.

Which of the following is the BEST way to state the relationship between "data" and "results"?

A. "Data" are the facts you collect from your experiment, while "results" are your interpretation of what the data mean.
B. Any two scientists reporting the same "results" must have been using the same "data."
C. "Data" and "results" are two names for the same thing.
D. The "data" section should always come before the "results" section in a scientific paper.
E. Any two scientists examining the same "data" would draw the same "results."

A. "Data" are the facts you collect from your experiment, while "results" are your interpretation of what the data mean.

Scientific theories do not represent speculations or guesses about the natural world. Rather they are hypotheses—proposed explanations for natural phenomena—that have been:

A. found to be statistically significant.
B. used to support the political stances of the scientists that have developed them.
C. validated by the International Board of Scientific Theories.
D. verified by at least one critical experiment.
E. so strongly and persuasively supported by empirical observation that the scientific community views them as unlikely to be altered by new evidence.

E. so strongly and persuasively supported by empirical observation that the scientific community views them as unlikely to be altered by new evidence.

In controlled experiments:

A. one variable is manipulated while others are held constant.
B. all variables are held constant.
C. all critical variables are manipulated.
D. all variables are dependent on each other.
E. all variables are independent of each other.

A. one variable is manipulated while others are held constant.

In a randomized, controlled, double-blind study:

A. experimental subjects are blind-folded when given the experimental treatment.
B. individuals will be assigned to an experimental or control group depending on whether they took part in a pilot study.
C. all experimental variables are held constant.
D. neither the experimenter nor the subject know whether the subject is in a control group or an experimental group.
E. All of the above.

D. neither the experimenter nor the subject know whether the subject is in a control group or an experimental group.

An experimental condition applied to research subjects is called a:

A. control.
B. treatment.
C. variable.
D. randomization.
E. placebo.

B. treatment.

Which of the following is the BEST description of a control group in an experiment?

A. The control group is identical to each test group except for one variable.
B. The control group is a test group that is chosen at random.
C. There should be more than one control group in any experiment.
D. The control group and the test groups may have several differences between them.
E. There can be more than one difference between the control group and test groups, but not several differences or else the experiment is invalid.

A. The control group is identical to each test group except for one variable.

In a scientific study, the dependent variable is:

A. a measurable entity whose value can be changed and set at the start of an experiment.
B. an entity that cannot be measured directly; it must be calculated based on the value of another variable.
C. a measurable entity whose value always fluctuates up and down, closely following changes in another variable.
D. a measurable, non-controllable entity whose value is created by the process being observed.
E. a variable in a study that is kept constant.

C. a measurable entity whose value always fluctuates up and down, closely following changes in another variable.

In a line graph, the value of the independent variable is:

A. represented as long lines extending from the right side of the graph.
B. represented on the x-axis.
C. represented on the y-axis.
D. represented as "slices in a pie."
E. represented as bars extending from the y-axis.

B. represented on the x-axis.

Visual displays, such as graphs, are used in scientific presentations because:

A. they obscure embarrassing errors and mistakes in the data.
B. they are the form in which data is recorded during an actual experiment.
C. they allow for easier comparisons between data sets than do data tables.
D. they condense large amounts of information into an easily digested form.
E. Both c) and d) are correct.

E. Both c) and d) are correct.

If a report states, "the female subjects in the study are 5 feet 6 inches ± 3 inches," this indicates that:

A. 90% of the women are between 5 feet 3 inches and 5 feet 9 inches.
B. the variation among all women is 3 inches in height.
C. all of the women are between 5 feet 3 inches and 5 feet 9 inches.
D. two thirds of the women are between 5 feet 3 inches and 5 feet 9 inches.
E. the investigator is unsure of her data.

D. two thirds of the women are between 5 feet 3 inches and 5 feet 9 inches.

The set of analytical and mathematical tools designed to help researchers gain understanding from the data they gather is called:

A. experimentation.
B. statistics.
C. geometry.
D. genetics.
E. biology.

B. statistics.

If you toss a coin and it comes up tails on eight consecutive tosses, what is the likelihood it will come up heads on the ninth toss?

A. 1
B. 1/2
C. 0
D. 5/9
E. 4/9

B. 1/2

In a series of studies, researchers found a statistically significant positive correlation between the number of fire fighters present at a fire and the amount of damage that the fire does. Which of the following is the BEST conclusion to be drawn from these studies?

A. Statistical data must be put in its proper context to be understood.
B. To more accurately estimate the effect of the number of fire fighters on the amount of damage, we would need to compare the amount of damage from fires of different sizes that are fought by similar numbers of fire fighters.
C. Fire fighters make fires worse.
D. Causation is not correlation.
E. Fire fighters are effective in fighting fires.

A. Statistical data must be put in its proper context to be understood.

The atomic number of carbon is 6. Its nucleus must contain:

A. 6 neutrons and 6 protons.
B. 3 protons and 3 neutrons.
C. 6 neutrons and no electrons.
D. 6 protons and no electrons.
E. 6 protons and 6 electrons.

A. 6 neutrons and 6 protons.

The second orbital shell of an atom can hold ___ electrons.

A. 2
B. 3
C. 4
D. 6
E. 8

E. 8

A covalent bond is formed when:

A. two non-polar molecules associate with each other in a polar environment.
B. a positively charged particle is attracted to a negatively charged particle.
C. one atom gives up electrons to another atom.
D. two atoms share electrons.
E. two polar molecules associate with each other in a non-polar environment.

D. two atoms share electrons.

An element:

A. is a substance that cannot be broken down chemically into any other substance.
B. is an atom that has lost either a proton or an electron.
C. must occur naturally on earth somewhere.
D. is a component of an atom.
E. All of the above are true.

A. is a substance that cannot be broken down chemically into any other substance.

The nucleus of an atom is usually made up of:

A. protons, neutrons, and proteins that hold them together.
B. protons, which have a positive electrical charge, and proteins, which hold them together.
C. neutrons, which have no electrical charge.
D. neutrinos, which have no electrical charge.
E. protons, which a positive charge, and neutrons, which have no electrical charge.

E. protons, which a positive charge, and neutrons, which have no electrical charge.

Relative to protons:

A. electrons have approximately the same mass.
B. electrons have a significantly stronger positive charge.
C. electrons have significantly greater mass.
D. electrons have significantly less mass.
E. None of the above; electrons have no mass.

D. electrons have significantly less mass.

The four most abundant elements in living organisms are:

A. sodium, nitrogen, carbon, and silicon.
B. carbon, nitrogen, oxygen, and calcium.
C. carbon, hydrogen, nitrogen, and phosphorus.
D. carbon, nitrogen, potassium, and oxygen.
E. hydrogen, nitrogen, oxygen, and carbon.

E. hydrogen, nitrogen, oxygen, and carbon.

All matter on earth, both living and non-living, is made up of:

A. carbohydrates.
B. atoms.
C. DNA.
D. cells.
E. phospholipids.

B. atoms.

Some atoms of an element contain more neutrons or fewer neutrons than the most commonly found "version" of the atoms for that element. These "alternate versions" of the standard atom are called:

A. radioactive elements.
B. atomic variants.
C. decayed nuclei.
D. isotopes.
E. analogs.

D. isotopes.

Which of the following elements have four electrons in their outer shells?

A. carbon and silicon
B. nitrogen and phosphorus
C. fluorine and chlorine
D. oxygen and sulfur
E. boron and aluminum

A. carbon and silicon

An atom can be changed into an ion by adding or removing:

A. a neutron.
B. an orbital shell.
C. an electron.
D. a proton.
E. an isotope.

C. an electron.

Helium is not a reactive molecule because:

A. its first-level shell is full with two protons.
B. its second-level shell is full with two electrons.
C. its first-level shell is full with two neutrons.
D. its first-level shell is full with two electrons.
E. Helium is a reactive molecule.

D. its first-level shell is full with two electrons.

Which of the following molecules is NOT formed by covalent bonding?

A. NaCl
B. H2
C. H2O
D. CH4
E. O2

A. NaCl

One important difference between covalent and ionic bonds is that:

A. in covalent bonds two atoms share electrons while in ionic bonds two atoms of opposite charge are attracted to each other.
B. ionic bonds only occur among water-soluble elements.
C. in ionic bonds two atoms share electrons, while in covalent bonds one atom gives one or more electrons to the other atom.
D. in ionic bonds both protons and electrons can be shared while in covalent bonds only electrons can be shared.
E. ionic bonds are much stronger than covalent bonds.

A. in covalent bonds two atoms share electrons while in ionic bonds two atoms of opposite charge are attracted to each other.

Water molecules form which type of bond with other water molecules?

A. disulfide bridges
B. ionic bonds
C. hydrogen bonds
D. covalent bonds
E. atomic bonds

C. hydrogen bonds

The tendency of molecules to stick together, called cohesion, is stronger in water than in other liquids because:

A. the polarity of water allows an oxygen atom from one water molecule to form a hydrogen bond with the oxygen atom of another water molecule.
B. the polarity of water allows a hydrogen atom from one water molecule to form a hydrogen bond with the oxygen atom of another water molecule.
C. the polarity of water allows a hydrogen atom from one water molecule to form an ionic bond with the oxygen atom of another water molecule.
D. the polarity of water allows a hydrogen atom from one water molecule to form a hydrogen bond with the hydrogen atom of another water molecule.
E. the polarity of water allows a hydrogen atom from one water molecule to form a covalent bond with the oxygen atom of another water molecule.

B. the polarity of water allows a hydrogen atom from one water molecule to form a hydrogen bond with the oxygen atom of another water molecule.

The most abundant molecule in the cell is:

A. cellulose.
B. oxygen.
C. water.
D. carbohydrate.
E. carbon dioxide.

C. water.

Why do coastal areas have milder, less variable climates than inland areas?

A. Because water is a good solvent, it is able to dissolve the photons in light, reducing their ability to heat or cool the land.
B. Large bodies of water have high salt concentrations and salt absorbs a large proportion of the light energy that would have warmed the land.
C. Coastal areas are concentrated near the equator, which varies less than other parts of the globe in the angle at which the sun's light hits it.
D. Large bodies of water, especially oceans, can absorb huge amounts of heat from the sun during warm times of the year, reducing temperature increases on the land. Similarly, during cold times of year the ocean slowly cools, giving off heat that reduces the temperature drop on shore.
E. None of the above. No one knows why coastal areas have milder, less variable climates than inland areas.

D. Large bodies of water, especially oceans, can absorb huge amounts of heat from the sun during warm times of the year, reducing temperature increases on the land. Similarly, during cold times of year the ocean slowly cools, giving off heat that reduces the temperature drop on shore.

Which of the following is NOT a property of water?

A. It is less dense when frozen than when it's a liquid.
B. It is a good solvent because both polar and nonpolar molecules dissolve in it.
C. It takes a lot of energy to raise the temperature of water.
D. Water molecules stick to each other.
E. A lot of energy must be withdrawn from water in order to lower its temperature.

B. It is a good solvent because both polar and nonpolar molecules dissolve in it.

Which of the following statements BEST explains the observation that there are more autism cases now than in the past?

A. There are more parents who neglect their children, which is a cause of autism, now than in the past.
B. Autism has been selected for in recent generations by natural selection.
C. The vaccine for measles, mumps, and rubella has been established as a significant cause of autism.
D. Doctors are more aware of the condition and have better techniques for diagnosing and reporting it.
E. All of the above are equally good explanations for the observation that there are more autism cases now than in the past.

D. Doctors are more aware of the condition and have better techniques for diagnosing and reporting it.

All of the following are branches of biology EXCEPT:

A. ecology.
B. evolution.
C. geology.
D. genetics.
E. behavior.

C. geology.

Which of the following areas is NOT heavily influenced by biology?

A. environmental issues
B. agriculture
C. criminology
D. behavioral issues
E. Biology heavily influences ALL of these areas.

E. Biology heavily influences ALL of these areas.

Which of the following is NOT of central importance to the study of biology?

A. evolution
B. the hierarchical organization of life
C. the scientific method
D. the technical application of research findings
E. All of the above are of central importance to the study of biology.

D. the technical application of research findings

Carbohydrates:

A. act as a relatively quickly available source of fuel.
B. serve as carbon skeletons that can be rearranged to form other molecules that are essential for biological structures and functions like nucleic acids.
C. in the form of oligosaccharides are often covalently bonded to proteins and lipids on the outer cell surface, where they serve as cell recognition signals.
D. are a good source of sustained energy when they come in the form of polysaccharides.
E. All of the above.

D. are a good source of sustained energy when they come in the form of polysaccharides.

Which of the following are all monosaccharides?

A. glucose, fructose, and galactose
B. starch, cellulose, and glycogen
C. fructuse and cellulose
D. glucose and maltose
E. glycogen and glucose

A. glucose, fructose, and galactose

Glucose that circulates in your blood has one of three fates: it is used to fuel cellular activities, it can be converted into fat, or it can _______.

A. be stored temporarily as glycogen
B. be converted into starch
C. be converted into fructose and linked together
D. serve as a buffer
E. be broken down into simple sugars

A. be stored temporarily as glycogen

Glycogen belongs in the class of molecules known as:

A. amino acids.
B. monosaccharides.
C. proteins.
D. polysaccharides.
E. nucleic acids.

D. polysaccharides.

Sucrose (table sugar) and lactose (the sugar found in milk) are examples of:

A. simple sugars.
B. polyunsaccharide sugars.
C. disaccharides.
D. monosaccharides.
E. naturally occurring enzymes.

C. disaccharides.

All lipids are:

A. polymers of fatty acids.
B. not soluble in water.
C. triglycerides.
D. polar.
E. hydrophilic.

B. not soluble in water.

An unsaturated fatty acid is one in which:

A. carbon-carbon double bonds are present in the hydrocarbon chain.
B. not all of the carbons in the hydrocarbon chain are bonded to hydrogen atoms.
C. there are an odd number of subunits in the hydrocarbon chain.
D. there are an even number of subunits in the hydrocarbon chain.
E. carbon-carbon double bonds are not present in the hydrocarbon chain.

A. carbon-carbon double bonds are present in the hydrocarbon chain.

Which statement about phospholipids is FALSE?

A. They are hydrophilic at one end.
B. They contain glycerol linked to fatty acids.
C. They are a major constituent of cell membranes.
D. They are hydrophobic on one end.
E. Because their phosphate groups repel each other, they are used as organisms' chief form of short-term energy.

E. Because their phosphate groups repel each other, they are used as organisms' chief form of short-term energy.

Which of the following is a common role that sterols play in the human body?

A. They are used as energy storage molecules.
B. They are important components of cell membranes.
C. They are used as primary fuel molecules for cellular metabolism.
D. When eaten in the diet, they help prevent heart disease by lowering blood pressure.
E. None of the above is true about sterols.

E. None of the above is true about sterols.

All of the following are roles played by protein in the body EXCEPT:

A. structural support.
B. muscular contraction.
C. protection against invading organisms.
D. oxygen transport.
E. transmission of electrical impulses.

E. transmission of electrical impulses.

All of the following are components of a single amino acid EXCEPT:

A. an alpha carbon.
B. a variable side chain.
C. a nitrogen-containing amino group.
D. a carboxyl group.
E. All of the above are components of a single amino acid.

E. All of the above are components of a single amino acid.

In dietary terms, a "complete" protein is one that:

A. contains all 20 amino acids.
B. contains all of the essential amino acids.
C. can serve in a variety of cellular functions, like as an enzyme, oxygen transporter, etc.
D. contains carbohydrates, lipids, and nucleic acids as well.
E. stays intact as it travels through your digestive system.

B. contains all of the essential amino acids.

Which of the following statements is NOT true of amino acids?

A. They come in polar, non-polar, and electrically charged forms.
B. They combine to form polypeptides.
C. They combine to form proteins.
D. They are organic molecules possessing both carboxyl and amino groups.
E. They are distinguished from each other by variation in their carboxyl groups.

E. They are distinguished from each other by variation in their carboxyl groups.

A polypeptide chain is a linear polymer of amino acids. Peptide bonds are present between which of the two following groups?

A. the carbon atom of the carboxyl group and the oxygen atom double-bonded to it
B. the carbon atom of the carboxyl group and the adjacent carbon atom of the chain's backbone
C. the carbon atom of the carboxyl group and the nitrogen atom of the amino group
D. the carbon atom of the carboxyl group and the OH bound to it
E. All of the above are true.

C. the carbon atom of the carboxyl group and the nitrogen atom of the amino group

The secondary structure of a protein refers to:

A. the linear assembly of amino acids into a chain.
B. the way two or more polypeptides bind to each other.
C. the twisting of the amino acid chain into a corkscrew-like shape or into a zigzag folding pattern.
D. the configuration of the folded protein when bound to other proteins.
E. None of the above is correct.

C. the twisting of the amino acid chain into a corkscrew-like shape or into a zigzag folding pattern.

Enzymes:

A. catalyze reactions that release energy, but not those that consume energy.
B. sometimes increase the amount of energy necessary to initiate a reaction.
C. reduce the energy released by a reaction by one of four different mechanisms.
D. are always consumed by catalyzing a reaction.
E. increase the rate at which a reaction occurs.

E. increase the rate at which a reaction occurs.

Which of the following statements about enzymes is NOT true?

A. Enzymes are permanently changed when they take place in a chemical reaction.
B. Enzymes are proteins.
C. Enzymes speed up chemical reactions.
D. Enzymes often induce shape changes in the molecules to which they bind.
E. Enzymes help initiate chemical reactions.

A. Enzymes are permanently changed when they take place in a chemical reaction.

Phosphate groups are important components of:

A. triglycerides.
B. nucleic acids.
C. amino acids.
D. structural polysaccharides.
E. All of the above are correct.

B. nucleic acids.

DNA is made of:

A. nucleotides.
B. four interconnected carbon rings.
C. amino acids.
D. glucose molecules.
E. fatty acids.

A. nucleotides.

An amino acid is to a polypeptide as:

A. testosterone is to a steroid hormone.
B. a nucleotide is to a nucleic acid.
C. triglycerides are to fats.
D. a phospholipid is to a plasma membrane.
E. glycogen is to glucose.

B. a nucleotide is to a nucleic acid.

Which type of macromolecule is an informational molecule?

A. DNA
B. fatty acid
C. protein
D. polysaccharide
E. monosaccharide

A. DNA

Which of the following nucleotide bases are present in equal amounts in DNA?

A. thymine and cytosine
B. adenine and guanine
C. adenine and cytosine
D. thymine and guanine
E. adenine and thymine

E. adenine and thymine

Phenylketonuria is an inherited disorder. Affected individuals have a defective enzyme called phenylalanine hydroxylase. The substance these individuals cannot break down is a(n):

A. protein.
B. carbohydrate.
C. nucleic acid.
D. lipid.
E. amino acid.

E. amino acid.

Which of the following would influence the rate of an enzyme catalyzed reaction?

A. substrate concentration
B. temperature
C. pH
D. presence of inhibitors or activators
E. All of the above influence enzymatic rate.

E. All of the above influence enzymatic rate.

Which of the following is NOT true of ALL cells?

A. They eliminate wastes.
B. They assimilate nutrients.
C. They move by means of flagella or cilia.
D. They have DNA as their genetic material.
E. They synthesize new cellular material.

C. They move by means of flagella or cilia.

Which statement is NOT part of modern cell theory?

A. All living organisms consist of one or more cells.
B. The first cell arrived on earth from outer space.
C. Cellular reactions include both energy-releasing and biosynthetic types.
D. Cells contain hereditary information that passes from one generation of cells to the next.
E. Cells arise from other cells.

B. The first cell arrived on earth from outer space.

Which of the following is found in both prokaryotic and eukaryotic cells?

A. Golgi apparatus
B. ribosome
C. centriole
D. lysosome
E. peroxisome

B. ribosome

Prokaryotic organisms lack:

A. replicator molecules (DNA or RNA).
B. cell membranes.
C. metabolism.
D. organelles.
E. All of the above.

D. organelles.

What are the two distinct "faces" of the phospholipids that make up the surface membrane of a cell?

A. a hydrophilic head and a hydrophobic tail
B. a hydrophobic head and a hydrophilic tail
C. a phosphate group head and two fatty acid tails
D. Both a) and c) are correct.
E. Both b) and c) are correct.

D. Both a) and c) are correct.

Which cellular structure makes it possible for a cell to differ structurally and biochemically from its surroundings?

A. nucleolus
B. nucleus
C. plasma membrane
D. cell wall
E. endoplasmic reticulum

C. plasma membrane

Beta-blockers do all of the following EXCEPT:

A. block signaling through adrenaline receptors.
B. reduce outward symptoms of anxiety.
C. bind to the cytoplasmic side of a receptor protein.
D. reduce high blood pressure.
E. reduce the effects of adrenaline on the heart.

C. bind to the cytoplasmic side of a receptor protein.

Which of the following is the most important factor governing a cell's particular type of interaction with other cells

A. the type of animal the cell came from
B. the location of the cell within an organism
C. whether the cell is either an animal cell or a plant cell
D. the pattern of proteins on the cell's surface
E. whether the cell is either eukaryotic or prokaryotic

D. the pattern of proteins on the cell's surface

The net movement of molecules from locally concentrated regions to uniform distributions is best described as:

A. active transport.
B. passive transport.
C. diffusion.
D. enthalpy.
E. concentration gradient.

C. diffusion.

Which of the following BEST defines diffusion?

A. net movement of particles between cells
B. net movement of fluids from the environment into and out of an organism
C. net movement of particles from a cell into the extracellular matrix
D. net movement of particles from areas of low concentration to areas of high concentration
E. net movement of particles from areas of high concentration to areas of low concentration

E. net movement of particles from areas of high concentration to areas of low concentration

In aquatic environments, water moves _____________.

A. down the water-concentration scale
B. against the water-concentration gradient
C. up the water-concentration scale
D. down the water-concentration gradient
E. up the water-concentration gradient

D. down the water-concentration gradient

You are bored at a lunch meeting and surreptitiously place a raisin in your glass of water. The raisin swells to twice its original size. Relative to the water, the raisin must have been:

A. hypertonic.
B. isotonic.
C. hypotonic.
D. mesotonic.
E. osmotic.

A. hypertonic.

You measure the concentration of a polar molecule inside and outside of a cell. You find that the concentration is high and gradually increasing inside the cell. You also measure the ATP concentration inside the cell and find that it is dropping. What would be your best hypothesis for the process that is occurring?

A. facilitated diffusion
B. active transport
C. endocytosis
D. passive transport
E. simple diffusion

A. facilitated diffusion

Photosynthesis is the process by which plants, some bacteria, and some protistans use the energy from sunlight to produce sugar, which _______________ converts to ATP, the "fuel" used by all living things.

A. speciation
B. adaptation
C. denaturation
D. cellular respiration
E. eutrophication

D. cellular respiration

Life gains most of its energy from:

A. water.
B. sunlight.
C. sugar molecules.
D. oxygen.
E. carbohydrate molecules.

B. sunlight.

A cyclist rides her bike up a very steep hill. Pick from the following choices the one that properly describes this example in energetic terms.

A. Potential energy in food is converted to kinetic energy as muscles push the cyclist up the hill.
B. Kinetic energy is highest when the cyclist is at the crest of the hill.
C. The cyclist produces the most potential energy as she cruises down the hill's steep slope.
D. Gravity provides a source of potential energy.
E. Both a) and d) are correct.

E. Both a) and d) are correct.

Within the study of thermodynamics, a closed system is defined as a system in which energy does not come in and energy does not go out. Which of the following is considered a closed system?

A. the universe
B. the earth
C. an ocean
D. a living organism's body
E. All of the above are examples of closed systems.

A. the universe

Each ATP molecule is composed of three separate subunits. Which of the following is NOT a proper description of one of these subunits?

A. three carbon-nitrogen rings
B. an adenine
C. a five-carbon sugar
D. a triphosphate group
E. a ribose

A. three carbon-nitrogen rings

The phosphate groups in ATP:

A. are covalently bonded to each other.
B. represent a significant source of stored energy.
C. are negatively charged.
D. release energy when separated from the rest of the molecule.
E. All of the above are correct.

E. All of the above are correct.

Which of the following is NOT a product of photosynthesis?

A. glucose
B. oxygen
C. sugars
D. carbon dioxide
E. None of the above; all are products of photosynthesis.

D. carbon dioxide

A green plant can carry out photosynthesis if given nothing more than:

A. water.
B. light.
C. water, light, and air.
D. water and light.
E. air.

C. water, light, and air.

Which by-product of photosynthesis was important in altering the atmosphere of the earth so that aerobic organisms could evolve?

A. air
B. methane gas
C. nitrogen
D. carbon dioxide
E. oxygen

E. oxygen

Carotenoids:

A. are primary pigments in certain plants and algae chloroplasts that fix carbon in place of chlorophyll.
B. are the organelles in a leaf cell in which photosynthesis occurs.
C. are the stacks of thylakoid membranes in a chloroplast.
D. are the organelles in a leaf cell in which respiration occurs.
E. are accessory pigments in chloroplasts that protect the chlorophyll by absorbing excessive light energy.

E. are accessory pigments in chloroplasts that protect the chlorophyll by absorbing excessive light energy.

Chlorophyll b and the carotenoids are important as receptors of light energy because they:

A. can absorb green light.
B. transform this energy into chemical energy.
C. respond to wavelengths different from the wavelengths that chlorophyll a responds to.
D. can respond to infrared and ultraviolet light.
E. have their own photosystems.

C. respond to wavelengths different from the wavelengths that chlorophyll a responds to.

The most effective portion(s) of the visible spectrum in driving photosynthesis is (are):

A. the violet-blue portion.
B. the yellow-green portion.
C. the red-orange portion.
D. Both a) and b) are correct.
E. Both a) and c) are correct.

E. Both a) and c) are correct.

Biologically speaking, a pigment:

A. is a molecule that absorbs carbon dioxide.
B. is a cell that fixes carbon.
C. is a molecule that absorbs a photon.
D. is a molecule that releases oxygen.
E. is a cell that absorbs a photon.

C. is a molecule that absorbs a photon.

During photosynthesis, visible light has enough energy to directly:

A. excite electrons.
B. synthesize NADPH.
C. convert ADP into ATP.
D. reflect light in the red spectrum.
E. split a water molecule into hydrogen and oxygen.

A. excite electrons.

What are the resulting products of the splitting of water in photosynthesis?

A. electrons, oxygen, and hydroxide ions
B. electrons, carbon dioxide, and hydrogen ions
C. electrons and oxygen only
D. electrons, oxygen, and photons
E. electrons, oxygen, and hydrogen ions

E. electrons, oxygen, and hydrogen ions

Oxygen gas produced during photosynthesis originates as:

A. oxygen atoms are released by the metabolism of carbohydrates.
B. oxygen atoms contained in carbon dioxide are released when the carbon is fixed.
C. a by-product of nitrogen-fixing bacteria.
D. a molecule of chlorophyll oxidized by a photon.
E. oxygen atoms contained in water molecules.

E. oxygen atoms contained in water molecules.

The carbon dioxide needed for photosynthesis enters the plant through the:

A. stroma.
B. stomata.
C. grana.
D. thylakoid.
E. roots.

B. stomata.

Cellular respiration is the process by which:

A. oxygen is produced during metabolic activity.
B. light energy is converted into kinetic energy.
C. oxygen is used to transport chemical energy throughout the body.
D. energy from the chemical bonds of food molecules is captured by an organism.
E. ATP molecules are converted into water and sugar.

D. energy from the chemical bonds of food molecules is captured by an organism.

An inherited disease results from abnormal mitochondria passed from mother to child. Using your knowledge of the function of mitochondria within human cells, which of the following is the most likely description of the symptoms of this disease?

A. extreme sensitivity to UV light, resulting in skin cancer at a very young age
B. fragile bones and arthritis
C. extreme muscle weakness
D. color blindness
E. inability to absorb iron, resulting in extreme anemia

C. extreme muscle weakness

Cellular respiration is an efficient process that captures approximately 35% of the energy in glucose. From 1 molecule of glucose, it yields:

A. 3 to 4 ATP, depending on the tissue and organism.
B. 10 to 12 ATP, depending on the tissue and organism.
C. exactly 40 ATP, in every tissue and organism.
D. 30 to 32 ATP, depending on the tissue and organism.
E. exactly 35 ATP, in every tissue and organism.

D. 30 to 32 ATP, depending on the tissue and organism.

A person's unique DNA is carried within some of the cells and tissues of their body. These include all of the following EXCEPT:

A. intestines
B. blood.
C. skin cells.
D. saliva.
E. All of the above contain a person's DNA.

E. All of the above contain a person's DNA.

Double-stranded DNA that contains a high G-C content requires a higher temperature in order to separate the two DNA strands. This is because:

A. G-C base pairing involves three hydrogen bonds while A-T pairing involves only two.
B. high G-C content makes the DNA less flexible.
C. DNA with a high G-C content forms a tighter double helix.
D. All of the above are correct.
E. Only a) and b) are correct.

A. G-C base pairing involves three hydrogen bonds while A-T pairing involves only two.

Most genes come in alternative forms called:

A. chromosomes.
B. gametes.
C. dominants.
D. alleles.
E. recessives.

D. alleles.

In order for translation to occur:

A. the nuclear membrane must dissolve.
B. transcription must be occurring simultaneously.
C. a cell must contain a cell wall to which translational protein receptors are bound.
D. there must be large numbers of free amino acids present in the cytosol.
E. the DNA must produce large numbers of free amino acids.

D. there must be large numbers of free amino acids present in the cytosol.

The term "gene expression" refers to:

A. which amino acid is "called for" by a particular codon
B. the role and function of the protein coded for by a gene
C. the total number of genes in an organisms
D. the presence or absence of genes in a particular cell
E. None of the above describes what "gene expression" means.

E. None of the above describes what "gene expression" means.

A frameshift mutation:

A. leaves the amino acid sequence unchanged.
B. results from an insertion or deletion in a DNA sequence.
C. substitutes a purine for a pyrimidine only.
D. is the result of an unequal crossing-over.
E. substitutes a pyrimidine for a purine, or vice versa.

B. results from an insertion or deletion in a DNA sequence.

A mutation that involves the addition, subtraction, or substitution of a single base is known as

A. an inversion.
B. polypoloidy.
C. a chromosomal aberration.
D. a basic mutation.
E. a point mutation.

E. a point mutation.

Animal cells have "counters" that keep track of how many times a cell has divided. These counters are called:

A. odometers.
B. telomeres.
C. chromosomes.
D. nuclei.
E. centromeres.

B. telomeres.

In DNA replication, when the DNA molecule separates into two strands:

A. it is possible to reconstruct perfectly all the information on the missing strand because one strand carries all the information needed to construct its complementary strand.
B. the rebuilding process begins, in which an enzyme connects the appropriate complementary base to the exposed base.
C. the mitotic phase begins.
D. All of the above are correct.
E. Only a) and b) are correct.

E. Only a) and b) are correct.

Somatic cells can include:

A. kidney cells.
B. heart cells.
C. sperm cells.
D. All of the above are correct.
E. Both a) and b) are correct.

E. Both a) and b) are correct.

The rate at which mitosis occurs varies dramatically for different types of cells. The most rapid cell division occurs:

A. in the blood and the heart.
B. on the skin.
C. in the blood and the cells lining the various tissues of organs.
D. in the gametes.
E. in the heart and the brain.

C. in the blood and the cells lining the various tissues of organs.

Mitosis results in:

A. daughter cells with the same number of chromosomes but different combinations of alleles.
B. gametes.
C. daughter cells with the same number and composition of chromosomes.
D. daughter cells with twice as much genetic material and a unique collection of alleles.
E. eight daughter cells.

C. daughter cells with the same number and composition of chromosomes.

In order for a eukaryotic cell to undergo reproduction and divide, certain steps must be successfully completed. Which of the following choices is NOT one of these necessary steps?

A. There must be proper packaging and segregation of the replicated DNA.
B. There must be proper reshuffling of the genetic material in order to provide diversity within the gametes.
C. There must be replication of the DNA within the nucleus.
D. There must be proper division of the cytoplasm.
E. All of the choices above are necessary steps in eukaryotic cellular replication.

B. There must be proper reshuffling of the genetic material in order to provide diversity within the gametes.

Chemotherapy is one common treatment for cancer. Which of the following are aspects of chemotherapy?

A. Drugs that interfere with cell division are administered to the patient.
B. Chemotherapy drugs circulate throughout the entire body.
C. Chemotherapy drugs disrupt normal systems that rely on the rapid and constant production of new cells.
D. All of the above are correct.
E. Only a) and c) are correct.

D. All of the above are correct.

Cancer cells are different from other cells in that they have lost their "contact inhibition." "Contact inhibition" means:

A. DNA replication in most cells stops when the double helix comes in contact with particular enzymes.
B. most cells stop dividing when they have reached 50 cell divisions.
C. DNA replication in most cells doesn't begin until the double helix comes in contact with particular enzymes.
D. most cells stop dividing when they bump up against other cells or collections of cells.
E. most cells don't begin to divide until they bump up against other cells or collections of cells.

D. most cells stop dividing when they bump up against other cells or collections of cells.

Which of the following are features that distinguish cancer cells from normal cells?

A. Normal cells undergo cytokinesis; cancer cells do not undergo cytokinesis.
B. Normal cells have contact inhibition; cancer cells have no contact inhibition.
C. Normal cells metastasize; cancer cells do not metastasize.
D. Normal cells can divide a finite number of times; cancer cells can divide indefinitely.
E. Both b) and d) are correct.

E. Both b) and d) are correct.

In humans, the haploid number, n, equals:

A. 2n.
B. 44.
C. 23.
D. 46.
E. n.

C. 23.

During meiosis, chromatin:

A. reduces the incidence of crossing over.
B. unwinds to allow synapsis between homologous pairs of chromatids.
C. condenses, becoming more tightly coiled.
D. binds to the metaphase plate, enabling chromosome division.
E. unwinds to allow tetrads to form.

C. condenses, becoming more tightly coiled.

BIO301L Homework Questions - Subjecto.com

BIO301L Homework Questions

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What is the meaning of the statement "correlation does not imply causation"?

A. Just because two variables vary in a similar pattern does not mean that changing one variable causes a change in the other.
B. It is not possible to demonstrate a correlation between two variables.
C. When a change in one variable causes a change in another variable, the two variables are not necessarily related to each other in any way.
D. It is not possible to prove the cause of any naturally occurring phenomenon.
E. Just because two variables vary in a similar pattern does not mean that they have any relationship to each other.

A. Just because two variables vary in a similar pattern does not mean that changing one variable causes a change in the other.

Which of the following issues would be least helped by application of the scientific method?

A. developing more effective high school curricula
B. evaluating the relationship between violence in videogames and criminal behavior in teens
C. determining the most effective safety products for automobiles
D. formulating public policy on euthanasia
E. comparing the effectiveness of two potential antibiotics

D. formulating public policy on euthanasia

A relationship between phenomena that has been established based on large amounts of observational and experimental data is referred to as:

A. a theory.
B. a fact.
C. an assumption.
D. a conjecture.
E. a hypothesis.

A. a theory.

Anecdotal evidence:

A. is a more efficient method for understanding the world than the scientific method.
B. tends to be more reliable than data based on observations of large numbers of diverse individuals.
C. is a necessary part of the scientific method.
D. is often the only way to prove important causal links between two phenomena.
E. can seem to reveal links between two phenomena, but the links may not actually exist.

E. can seem to reveal links between two phenomena, but the links may not actually exist.

Statistical methods make it possible to:

A. prove any hypothesis is true.
B. determine how likely it is that certain results have occurred by chance.
C. unambiguously learn the truth.
D. reject any hypothesis.
E. test non-falsifiable hypotheses.

B. determine how likely it is that certain results have occurred by chance.

An independent variable:

A. can cause a change in a dependent variable.
B. is generally less variable than a dependent variable.
C. is plotted on the y-axis in a line graph.
D. can be controlled less well than a dependent variable.
E. is typically of greater interest to the experimenter than a dependent variable.

A. can cause a change in a dependent variable.

You hear the males of a particular bird species calling in their natural environment and question why they call. You design an experiment to try to answer your question. You cage one male bird and record his calling rate in response to four treatments, varying the number of conspecific (of the same species) males and the number of conspecific females that the male subject can see. The treatments are: no conspecific birds; 10 conspecific males; 10 conspecific females; 5 conspecific males and 5 conspecific females. Your results are: the rate at which the male subject calls is the same across all four treatments. Which of the following is a null hypothesis that your experimental design could reject?

A. Males of the species do not call.
B. Males of the species call more often than do females.
C. Males of the species call at a rate that is independent of the sex composition of the audience.
D. Males of the species call less often than do females.
E. Males of the species call when called to.

C.Males of the species call at a rate that is independent of the sex composition of the audience.

If a researcher collects data by using the same experimental setup as in another study, but using different research subjects, the process is considered:

A. an uncontrolled experiment.
B. intuitive reasoning.
C. extrapolation.
D. replication.
E. exploration.

D. replication.

A _____________ is a pill that looks identical to a pill that contains the active ingredient in a scientific trial, but contains no active ingredient itself.

A. tablet
B. barbiturate
C. placebo
D. capsule
E. treatment

C. placebo

Some have claimed that the herb echinacea reduces the likelihood of catching the common cold. In many hundreds of studies, this claim has been refuted. Assuming these studies were properly conducted, which of the following is a scientifically responsible claim that an echinacea advocate could make in support of further research on this subject.

A. The effective dosage of echinacea was outside the range of the dosages given in the scientific studies.
B. The investigators were paid off by the drug companies.
C. The effective length of time needed for taking echinacea is longer than that provided in any of the scientific studies.
D. All of the above are scientifically responsible claims that an echinacea advocate could make in support of further research on this subject.
E. Only a) and c) are scientifically responsible claims that an echinacea advocate could make in support of further research on this subject.

E. Only a) and c) are scientifically responsible claims that an echinacea advocate could make in support of further research on this subject.

Which of the following is the BEST way to state the relationship between "data" and "results"?

A. "Data" are the facts you collect from your experiment, while "results" are your interpretation of what the data mean.
B. Any two scientists reporting the same "results" must have been using the same "data."
C. "Data" and "results" are two names for the same thing.
D. The "data" section should always come before the "results" section in a scientific paper.
E. Any two scientists examining the same "data" would draw the same "results."

A. "Data" are the facts you collect from your experiment, while "results" are your interpretation of what the data mean.

Scientific theories do not represent speculations or guesses about the natural world. Rather they are hypotheses—proposed explanations for natural phenomena—that have been:

A. found to be statistically significant.
B. used to support the political stances of the scientists that have developed them.
C. validated by the International Board of Scientific Theories.
D. verified by at least one critical experiment.
E. so strongly and persuasively supported by empirical observation that the scientific community views them as unlikely to be altered by new evidence.

E. so strongly and persuasively supported by empirical observation that the scientific community views them as unlikely to be altered by new evidence.

In controlled experiments:

A. one variable is manipulated while others are held constant.
B. all variables are held constant.
C. all critical variables are manipulated.
D. all variables are dependent on each other.
E. all variables are independent of each other.

A. one variable is manipulated while others are held constant.

In a randomized, controlled, double-blind study:

A. experimental subjects are blind-folded when given the experimental treatment.
B. individuals will be assigned to an experimental or control group depending on whether they took part in a pilot study.
C. all experimental variables are held constant.
D. neither the experimenter nor the subject know whether the subject is in a control group or an experimental group.
E. All of the above.

D. neither the experimenter nor the subject know whether the subject is in a control group or an experimental group.

An experimental condition applied to research subjects is called a:

A. control.
B. treatment.
C. variable.
D. randomization.
E. placebo.

B. treatment.

Which of the following is the BEST description of a control group in an experiment?

A. The control group is identical to each test group except for one variable.
B. The control group is a test group that is chosen at random.
C. There should be more than one control group in any experiment.
D. The control group and the test groups may have several differences between them.
E. There can be more than one difference between the control group and test groups, but not several differences or else the experiment is invalid.

A. The control group is identical to each test group except for one variable.

In a scientific study, the dependent variable is:

A. a measurable entity whose value can be changed and set at the start of an experiment.
B. an entity that cannot be measured directly; it must be calculated based on the value of another variable.
C. a measurable entity whose value always fluctuates up and down, closely following changes in another variable.
D. a measurable, non-controllable entity whose value is created by the process being observed.
E. a variable in a study that is kept constant.

C. a measurable entity whose value always fluctuates up and down, closely following changes in another variable.

In a line graph, the value of the independent variable is:

A. represented as long lines extending from the right side of the graph.
B. represented on the x-axis.
C. represented on the y-axis.
D. represented as "slices in a pie."
E. represented as bars extending from the y-axis.

B. represented on the x-axis.

Visual displays, such as graphs, are used in scientific presentations because:

A. they obscure embarrassing errors and mistakes in the data.
B. they are the form in which data is recorded during an actual experiment.
C. they allow for easier comparisons between data sets than do data tables.
D. they condense large amounts of information into an easily digested form.
E. Both c) and d) are correct.

E. Both c) and d) are correct.

If a report states, "the female subjects in the study are 5 feet 6 inches ± 3 inches," this indicates that:

A. 90% of the women are between 5 feet 3 inches and 5 feet 9 inches.
B. the variation among all women is 3 inches in height.
C. all of the women are between 5 feet 3 inches and 5 feet 9 inches.
D. two thirds of the women are between 5 feet 3 inches and 5 feet 9 inches.
E. the investigator is unsure of her data.

D. two thirds of the women are between 5 feet 3 inches and 5 feet 9 inches.

The set of analytical and mathematical tools designed to help researchers gain understanding from the data they gather is called:

A. experimentation.
B. statistics.
C. geometry.
D. genetics.
E. biology.

B. statistics.

If you toss a coin and it comes up tails on eight consecutive tosses, what is the likelihood it will come up heads on the ninth toss?

A. 1
B. 1/2
C. 0
D. 5/9
E. 4/9

B. 1/2

In a series of studies, researchers found a statistically significant positive correlation between the number of fire fighters present at a fire and the amount of damage that the fire does. Which of the following is the BEST conclusion to be drawn from these studies?

A. Statistical data must be put in its proper context to be understood.
B. To more accurately estimate the effect of the number of fire fighters on the amount of damage, we would need to compare the amount of damage from fires of different sizes that are fought by similar numbers of fire fighters.
C. Fire fighters make fires worse.
D. Causation is not correlation.
E. Fire fighters are effective in fighting fires.

A. Statistical data must be put in its proper context to be understood.

The atomic number of carbon is 6. Its nucleus must contain:

A. 6 neutrons and 6 protons.
B. 3 protons and 3 neutrons.
C. 6 neutrons and no electrons.
D. 6 protons and no electrons.
E. 6 protons and 6 electrons.

A. 6 neutrons and 6 protons.

The second orbital shell of an atom can hold ___ electrons.

A. 2
B. 3
C. 4
D. 6
E. 8

E. 8

A covalent bond is formed when:

A. two non-polar molecules associate with each other in a polar environment.
B. a positively charged particle is attracted to a negatively charged particle.
C. one atom gives up electrons to another atom.
D. two atoms share electrons.
E. two polar molecules associate with each other in a non-polar environment.

D. two atoms share electrons.

An element:

A. is a substance that cannot be broken down chemically into any other substance.
B. is an atom that has lost either a proton or an electron.
C. must occur naturally on earth somewhere.
D. is a component of an atom.
E. All of the above are true.

A. is a substance that cannot be broken down chemically into any other substance.

The nucleus of an atom is usually made up of:

A. protons, neutrons, and proteins that hold them together.
B. protons, which have a positive electrical charge, and proteins, which hold them together.
C. neutrons, which have no electrical charge.
D. neutrinos, which have no electrical charge.
E. protons, which a positive charge, and neutrons, which have no electrical charge.

E. protons, which a positive charge, and neutrons, which have no electrical charge.

Relative to protons:

A. electrons have approximately the same mass.
B. electrons have a significantly stronger positive charge.
C. electrons have significantly greater mass.
D. electrons have significantly less mass.
E. None of the above; electrons have no mass.

D. electrons have significantly less mass.

The four most abundant elements in living organisms are:

A. sodium, nitrogen, carbon, and silicon.
B. carbon, nitrogen, oxygen, and calcium.
C. carbon, hydrogen, nitrogen, and phosphorus.
D. carbon, nitrogen, potassium, and oxygen.
E. hydrogen, nitrogen, oxygen, and carbon.

E. hydrogen, nitrogen, oxygen, and carbon.

All matter on earth, both living and non-living, is made up of:

A. carbohydrates.
B. atoms.
C. DNA.
D. cells.
E. phospholipids.

B. atoms.

Some atoms of an element contain more neutrons or fewer neutrons than the most commonly found "version" of the atoms for that element. These "alternate versions" of the standard atom are called:

A. radioactive elements.
B. atomic variants.
C. decayed nuclei.
D. isotopes.
E. analogs.

D. isotopes.

Which of the following elements have four electrons in their outer shells?

A. carbon and silicon
B. nitrogen and phosphorus
C. fluorine and chlorine
D. oxygen and sulfur
E. boron and aluminum

A. carbon and silicon

An atom can be changed into an ion by adding or removing:

A. a neutron.
B. an orbital shell.
C. an electron.
D. a proton.
E. an isotope.

C. an electron.

Helium is not a reactive molecule because:

A. its first-level shell is full with two protons.
B. its second-level shell is full with two electrons.
C. its first-level shell is full with two neutrons.
D. its first-level shell is full with two electrons.
E. Helium is a reactive molecule.

D. its first-level shell is full with two electrons.

Which of the following molecules is NOT formed by covalent bonding?

A. NaCl
B. H2
C. H2O
D. CH4
E. O2

A. NaCl

One important difference between covalent and ionic bonds is that:

A. in covalent bonds two atoms share electrons while in ionic bonds two atoms of opposite charge are attracted to each other.
B. ionic bonds only occur among water-soluble elements.
C. in ionic bonds two atoms share electrons, while in covalent bonds one atom gives one or more electrons to the other atom.
D. in ionic bonds both protons and electrons can be shared while in covalent bonds only electrons can be shared.
E. ionic bonds are much stronger than covalent bonds.

A. in covalent bonds two atoms share electrons while in ionic bonds two atoms of opposite charge are attracted to each other.

Water molecules form which type of bond with other water molecules?

A. disulfide bridges
B. ionic bonds
C. hydrogen bonds
D. covalent bonds
E. atomic bonds

C. hydrogen bonds

The tendency of molecules to stick together, called cohesion, is stronger in water than in other liquids because:

A. the polarity of water allows an oxygen atom from one water molecule to form a hydrogen bond with the oxygen atom of another water molecule.
B. the polarity of water allows a hydrogen atom from one water molecule to form a hydrogen bond with the oxygen atom of another water molecule.
C. the polarity of water allows a hydrogen atom from one water molecule to form an ionic bond with the oxygen atom of another water molecule.
D. the polarity of water allows a hydrogen atom from one water molecule to form a hydrogen bond with the hydrogen atom of another water molecule.
E. the polarity of water allows a hydrogen atom from one water molecule to form a covalent bond with the oxygen atom of another water molecule.

B. the polarity of water allows a hydrogen atom from one water molecule to form a hydrogen bond with the oxygen atom of another water molecule.

The most abundant molecule in the cell is:

A. cellulose.
B. oxygen.
C. water.
D. carbohydrate.
E. carbon dioxide.

C. water.

Why do coastal areas have milder, less variable climates than inland areas?

A. Because water is a good solvent, it is able to dissolve the photons in light, reducing their ability to heat or cool the land.
B. Large bodies of water have high salt concentrations and salt absorbs a large proportion of the light energy that would have warmed the land.
C. Coastal areas are concentrated near the equator, which varies less than other parts of the globe in the angle at which the sun’s light hits it.
D. Large bodies of water, especially oceans, can absorb huge amounts of heat from the sun during warm times of the year, reducing temperature increases on the land. Similarly, during cold times of year the ocean slowly cools, giving off heat that reduces the temperature drop on shore.
E. None of the above. No one knows why coastal areas have milder, less variable climates than inland areas.

D. Large bodies of water, especially oceans, can absorb huge amounts of heat from the sun during warm times of the year, reducing temperature increases on the land. Similarly, during cold times of year the ocean slowly cools, giving off heat that reduces the temperature drop on shore.

Which of the following is NOT a property of water?

A. It is less dense when frozen than when it’s a liquid.
B. It is a good solvent because both polar and nonpolar molecules dissolve in it.
C. It takes a lot of energy to raise the temperature of water.
D. Water molecules stick to each other.
E. A lot of energy must be withdrawn from water in order to lower its temperature.

B. It is a good solvent because both polar and nonpolar molecules dissolve in it.

Which of the following statements BEST explains the observation that there are more autism cases now than in the past?

A. There are more parents who neglect their children, which is a cause of autism, now than in the past.
B. Autism has been selected for in recent generations by natural selection.
C. The vaccine for measles, mumps, and rubella has been established as a significant cause of autism.
D. Doctors are more aware of the condition and have better techniques for diagnosing and reporting it.
E. All of the above are equally good explanations for the observation that there are more autism cases now than in the past.

D. Doctors are more aware of the condition and have better techniques for diagnosing and reporting it.

All of the following are branches of biology EXCEPT:

A. ecology.
B. evolution.
C. geology.
D. genetics.
E. behavior.

C. geology.

Which of the following areas is NOT heavily influenced by biology?

A. environmental issues
B. agriculture
C. criminology
D. behavioral issues
E. Biology heavily influences ALL of these areas.

E. Biology heavily influences ALL of these areas.

Which of the following is NOT of central importance to the study of biology?

A. evolution
B. the hierarchical organization of life
C. the scientific method
D. the technical application of research findings
E. All of the above are of central importance to the study of biology.

D. the technical application of research findings

Carbohydrates:

A. act as a relatively quickly available source of fuel.
B. serve as carbon skeletons that can be rearranged to form other molecules that are essential for biological structures and functions like nucleic acids.
C. in the form of oligosaccharides are often covalently bonded to proteins and lipids on the outer cell surface, where they serve as cell recognition signals.
D. are a good source of sustained energy when they come in the form of polysaccharides.
E. All of the above.

D. are a good source of sustained energy when they come in the form of polysaccharides.

Which of the following are all monosaccharides?

A. glucose, fructose, and galactose
B. starch, cellulose, and glycogen
C. fructuse and cellulose
D. glucose and maltose
E. glycogen and glucose

A. glucose, fructose, and galactose

Glucose that circulates in your blood has one of three fates: it is used to fuel cellular activities, it can be converted into fat, or it can _______.

A. be stored temporarily as glycogen
B. be converted into starch
C. be converted into fructose and linked together
D. serve as a buffer
E. be broken down into simple sugars

A. be stored temporarily as glycogen

Glycogen belongs in the class of molecules known as:

A. amino acids.
B. monosaccharides.
C. proteins.
D. polysaccharides.
E. nucleic acids.

D. polysaccharides.

Sucrose (table sugar) and lactose (the sugar found in milk) are examples of:

A. simple sugars.
B. polyunsaccharide sugars.
C. disaccharides.
D. monosaccharides.
E. naturally occurring enzymes.

C. disaccharides.

All lipids are:

A. polymers of fatty acids.
B. not soluble in water.
C. triglycerides.
D. polar.
E. hydrophilic.

B. not soluble in water.

An unsaturated fatty acid is one in which:

A. carbon-carbon double bonds are present in the hydrocarbon chain.
B. not all of the carbons in the hydrocarbon chain are bonded to hydrogen atoms.
C. there are an odd number of subunits in the hydrocarbon chain.
D. there are an even number of subunits in the hydrocarbon chain.
E. carbon-carbon double bonds are not present in the hydrocarbon chain.

A. carbon-carbon double bonds are present in the hydrocarbon chain.

Which statement about phospholipids is FALSE?

A. They are hydrophilic at one end.
B. They contain glycerol linked to fatty acids.
C. They are a major constituent of cell membranes.
D. They are hydrophobic on one end.
E. Because their phosphate groups repel each other, they are used as organisms’ chief form of short-term energy.

E. Because their phosphate groups repel each other, they are used as organisms’ chief form of short-term energy.

Which of the following is a common role that sterols play in the human body?

A. They are used as energy storage molecules.
B. They are important components of cell membranes.
C. They are used as primary fuel molecules for cellular metabolism.
D. When eaten in the diet, they help prevent heart disease by lowering blood pressure.
E. None of the above is true about sterols.

E. None of the above is true about sterols.

All of the following are roles played by protein in the body EXCEPT:

A. structural support.
B. muscular contraction.
C. protection against invading organisms.
D. oxygen transport.
E. transmission of electrical impulses.

E. transmission of electrical impulses.

All of the following are components of a single amino acid EXCEPT:

A. an alpha carbon.
B. a variable side chain.
C. a nitrogen-containing amino group.
D. a carboxyl group.
E. All of the above are components of a single amino acid.

E. All of the above are components of a single amino acid.

In dietary terms, a "complete" protein is one that:

A. contains all 20 amino acids.
B. contains all of the essential amino acids.
C. can serve in a variety of cellular functions, like as an enzyme, oxygen transporter, etc.
D. contains carbohydrates, lipids, and nucleic acids as well.
E. stays intact as it travels through your digestive system.

B. contains all of the essential amino acids.

Which of the following statements is NOT true of amino acids?

A. They come in polar, non-polar, and electrically charged forms.
B. They combine to form polypeptides.
C. They combine to form proteins.
D. They are organic molecules possessing both carboxyl and amino groups.
E. They are distinguished from each other by variation in their carboxyl groups.

E. They are distinguished from each other by variation in their carboxyl groups.

A polypeptide chain is a linear polymer of amino acids. Peptide bonds are present between which of the two following groups?

A. the carbon atom of the carboxyl group and the oxygen atom double-bonded to it
B. the carbon atom of the carboxyl group and the adjacent carbon atom of the chain’s backbone
C. the carbon atom of the carboxyl group and the nitrogen atom of the amino group
D. the carbon atom of the carboxyl group and the OH bound to it
E. All of the above are true.

C. the carbon atom of the carboxyl group and the nitrogen atom of the amino group

The secondary structure of a protein refers to:

A. the linear assembly of amino acids into a chain.
B. the way two or more polypeptides bind to each other.
C. the twisting of the amino acid chain into a corkscrew-like shape or into a zigzag folding pattern.
D. the configuration of the folded protein when bound to other proteins.
E. None of the above is correct.

C. the twisting of the amino acid chain into a corkscrew-like shape or into a zigzag folding pattern.

Enzymes:

A. catalyze reactions that release energy, but not those that consume energy.
B. sometimes increase the amount of energy necessary to initiate a reaction.
C. reduce the energy released by a reaction by one of four different mechanisms.
D. are always consumed by catalyzing a reaction.
E. increase the rate at which a reaction occurs.

E. increase the rate at which a reaction occurs.

Which of the following statements about enzymes is NOT true?

A. Enzymes are permanently changed when they take place in a chemical reaction.
B. Enzymes are proteins.
C. Enzymes speed up chemical reactions.
D. Enzymes often induce shape changes in the molecules to which they bind.
E. Enzymes help initiate chemical reactions.

A. Enzymes are permanently changed when they take place in a chemical reaction.

Phosphate groups are important components of:

A. triglycerides.
B. nucleic acids.
C. amino acids.
D. structural polysaccharides.
E. All of the above are correct.

B. nucleic acids.

DNA is made of:

A. nucleotides.
B. four interconnected carbon rings.
C. amino acids.
D. glucose molecules.
E. fatty acids.

A. nucleotides.

An amino acid is to a polypeptide as:

A. testosterone is to a steroid hormone.
B. a nucleotide is to a nucleic acid.
C. triglycerides are to fats.
D. a phospholipid is to a plasma membrane.
E. glycogen is to glucose.

B. a nucleotide is to a nucleic acid.

Which type of macromolecule is an informational molecule?

A. DNA
B. fatty acid
C. protein
D. polysaccharide
E. monosaccharide

A. DNA

Which of the following nucleotide bases are present in equal amounts in DNA?

A. thymine and cytosine
B. adenine and guanine
C. adenine and cytosine
D. thymine and guanine
E. adenine and thymine

E. adenine and thymine

Phenylketonuria is an inherited disorder. Affected individuals have a defective enzyme called phenylalanine hydroxylase. The substance these individuals cannot break down is a(n):

A. protein.
B. carbohydrate.
C. nucleic acid.
D. lipid.
E. amino acid.

E. amino acid.

Which of the following would influence the rate of an enzyme catalyzed reaction?

A. substrate concentration
B. temperature
C. pH
D. presence of inhibitors or activators
E. All of the above influence enzymatic rate.

E. All of the above influence enzymatic rate.

Which of the following is NOT true of ALL cells?

A. They eliminate wastes.
B. They assimilate nutrients.
C. They move by means of flagella or cilia.
D. They have DNA as their genetic material.
E. They synthesize new cellular material.

C. They move by means of flagella or cilia.

Which statement is NOT part of modern cell theory?

A. All living organisms consist of one or more cells.
B. The first cell arrived on earth from outer space.
C. Cellular reactions include both energy-releasing and biosynthetic types.
D. Cells contain hereditary information that passes from one generation of cells to the next.
E. Cells arise from other cells.

B. The first cell arrived on earth from outer space.

Which of the following is found in both prokaryotic and eukaryotic cells?

A. Golgi apparatus
B. ribosome
C. centriole
D. lysosome
E. peroxisome

B. ribosome

Prokaryotic organisms lack:

A. replicator molecules (DNA or RNA).
B. cell membranes.
C. metabolism.
D. organelles.
E. All of the above.

D. organelles.

What are the two distinct "faces" of the phospholipids that make up the surface membrane of a cell?

A. a hydrophilic head and a hydrophobic tail
B. a hydrophobic head and a hydrophilic tail
C. a phosphate group head and two fatty acid tails
D. Both a) and c) are correct.
E. Both b) and c) are correct.

D. Both a) and c) are correct.

Which cellular structure makes it possible for a cell to differ structurally and biochemically from its surroundings?

A. nucleolus
B. nucleus
C. plasma membrane
D. cell wall
E. endoplasmic reticulum

C. plasma membrane

Beta-blockers do all of the following EXCEPT:

A. block signaling through adrenaline receptors.
B. reduce outward symptoms of anxiety.
C. bind to the cytoplasmic side of a receptor protein.
D. reduce high blood pressure.
E. reduce the effects of adrenaline on the heart.

C. bind to the cytoplasmic side of a receptor protein.

Which of the following is the most important factor governing a cell’s particular type of interaction with other cells

A. the type of animal the cell came from
B. the location of the cell within an organism
C. whether the cell is either an animal cell or a plant cell
D. the pattern of proteins on the cell’s surface
E. whether the cell is either eukaryotic or prokaryotic

D. the pattern of proteins on the cell’s surface

The net movement of molecules from locally concentrated regions to uniform distributions is best described as:

A. active transport.
B. passive transport.
C. diffusion.
D. enthalpy.
E. concentration gradient.

C. diffusion.

Which of the following BEST defines diffusion?

A. net movement of particles between cells
B. net movement of fluids from the environment into and out of an organism
C. net movement of particles from a cell into the extracellular matrix
D. net movement of particles from areas of low concentration to areas of high concentration
E. net movement of particles from areas of high concentration to areas of low concentration

E. net movement of particles from areas of high concentration to areas of low concentration

In aquatic environments, water moves _____________.

A. down the water-concentration scale
B. against the water-concentration gradient
C. up the water-concentration scale
D. down the water-concentration gradient
E. up the water-concentration gradient

D. down the water-concentration gradient

You are bored at a lunch meeting and surreptitiously place a raisin in your glass of water. The raisin swells to twice its original size. Relative to the water, the raisin must have been:

A. hypertonic.
B. isotonic.
C. hypotonic.
D. mesotonic.
E. osmotic.

A. hypertonic.

You measure the concentration of a polar molecule inside and outside of a cell. You find that the concentration is high and gradually increasing inside the cell. You also measure the ATP concentration inside the cell and find that it is dropping. What would be your best hypothesis for the process that is occurring?

A. facilitated diffusion
B. active transport
C. endocytosis
D. passive transport
E. simple diffusion

A. facilitated diffusion

Photosynthesis is the process by which plants, some bacteria, and some protistans use the energy from sunlight to produce sugar, which _______________ converts to ATP, the "fuel" used by all living things.

A. speciation
B. adaptation
C. denaturation
D. cellular respiration
E. eutrophication

D. cellular respiration

Life gains most of its energy from:

A. water.
B. sunlight.
C. sugar molecules.
D. oxygen.
E. carbohydrate molecules.

B. sunlight.

A cyclist rides her bike up a very steep hill. Pick from the following choices the one that properly describes this example in energetic terms.

A. Potential energy in food is converted to kinetic energy as muscles push the cyclist up the hill.
B. Kinetic energy is highest when the cyclist is at the crest of the hill.
C. The cyclist produces the most potential energy as she cruises down the hill’s steep slope.
D. Gravity provides a source of potential energy.
E. Both a) and d) are correct.

E. Both a) and d) are correct.

Within the study of thermodynamics, a closed system is defined as a system in which energy does not come in and energy does not go out. Which of the following is considered a closed system?

A. the universe
B. the earth
C. an ocean
D. a living organism’s body
E. All of the above are examples of closed systems.

A. the universe

Each ATP molecule is composed of three separate subunits. Which of the following is NOT a proper description of one of these subunits?

A. three carbon-nitrogen rings
B. an adenine
C. a five-carbon sugar
D. a triphosphate group
E. a ribose

A. three carbon-nitrogen rings

The phosphate groups in ATP:

A. are covalently bonded to each other.
B. represent a significant source of stored energy.
C. are negatively charged.
D. release energy when separated from the rest of the molecule.
E. All of the above are correct.

E. All of the above are correct.

Which of the following is NOT a product of photosynthesis?

A. glucose
B. oxygen
C. sugars
D. carbon dioxide
E. None of the above; all are products of photosynthesis.

D. carbon dioxide

A green plant can carry out photosynthesis if given nothing more than:

A. water.
B. light.
C. water, light, and air.
D. water and light.
E. air.

C. water, light, and air.

Which by-product of photosynthesis was important in altering the atmosphere of the earth so that aerobic organisms could evolve?

A. air
B. methane gas
C. nitrogen
D. carbon dioxide
E. oxygen

E. oxygen

Carotenoids:

A. are primary pigments in certain plants and algae chloroplasts that fix carbon in place of chlorophyll.
B. are the organelles in a leaf cell in which photosynthesis occurs.
C. are the stacks of thylakoid membranes in a chloroplast.
D. are the organelles in a leaf cell in which respiration occurs.
E. are accessory pigments in chloroplasts that protect the chlorophyll by absorbing excessive light energy.

E. are accessory pigments in chloroplasts that protect the chlorophyll by absorbing excessive light energy.

Chlorophyll b and the carotenoids are important as receptors of light energy because they:

A. can absorb green light.
B. transform this energy into chemical energy.
C. respond to wavelengths different from the wavelengths that chlorophyll a responds to.
D. can respond to infrared and ultraviolet light.
E. have their own photosystems.

C. respond to wavelengths different from the wavelengths that chlorophyll a responds to.

The most effective portion(s) of the visible spectrum in driving photosynthesis is (are):

A. the violet-blue portion.
B. the yellow-green portion.
C. the red-orange portion.
D. Both a) and b) are correct.
E. Both a) and c) are correct.

E. Both a) and c) are correct.

Biologically speaking, a pigment:

A. is a molecule that absorbs carbon dioxide.
B. is a cell that fixes carbon.
C. is a molecule that absorbs a photon.
D. is a molecule that releases oxygen.
E. is a cell that absorbs a photon.

C. is a molecule that absorbs a photon.

During photosynthesis, visible light has enough energy to directly:

A. excite electrons.
B. synthesize NADPH.
C. convert ADP into ATP.
D. reflect light in the red spectrum.
E. split a water molecule into hydrogen and oxygen.

A. excite electrons.

What are the resulting products of the splitting of water in photosynthesis?

A. electrons, oxygen, and hydroxide ions
B. electrons, carbon dioxide, and hydrogen ions
C. electrons and oxygen only
D. electrons, oxygen, and photons
E. electrons, oxygen, and hydrogen ions

E. electrons, oxygen, and hydrogen ions

Oxygen gas produced during photosynthesis originates as:

A. oxygen atoms are released by the metabolism of carbohydrates.
B. oxygen atoms contained in carbon dioxide are released when the carbon is fixed.
C. a by-product of nitrogen-fixing bacteria.
D. a molecule of chlorophyll oxidized by a photon.
E. oxygen atoms contained in water molecules.

E. oxygen atoms contained in water molecules.

The carbon dioxide needed for photosynthesis enters the plant through the:

A. stroma.
B. stomata.
C. grana.
D. thylakoid.
E. roots.

B. stomata.

Cellular respiration is the process by which:

A. oxygen is produced during metabolic activity.
B. light energy is converted into kinetic energy.
C. oxygen is used to transport chemical energy throughout the body.
D. energy from the chemical bonds of food molecules is captured by an organism.
E. ATP molecules are converted into water and sugar.

D. energy from the chemical bonds of food molecules is captured by an organism.

An inherited disease results from abnormal mitochondria passed from mother to child. Using your knowledge of the function of mitochondria within human cells, which of the following is the most likely description of the symptoms of this disease?

A. extreme sensitivity to UV light, resulting in skin cancer at a very young age
B. fragile bones and arthritis
C. extreme muscle weakness
D. color blindness
E. inability to absorb iron, resulting in extreme anemia

C. extreme muscle weakness

Cellular respiration is an efficient process that captures approximately 35% of the energy in glucose. From 1 molecule of glucose, it yields:

A. 3 to 4 ATP, depending on the tissue and organism.
B. 10 to 12 ATP, depending on the tissue and organism.
C. exactly 40 ATP, in every tissue and organism.
D. 30 to 32 ATP, depending on the tissue and organism.
E. exactly 35 ATP, in every tissue and organism.

D. 30 to 32 ATP, depending on the tissue and organism.

A person’s unique DNA is carried within some of the cells and tissues of their body. These include all of the following EXCEPT:

A. intestines
B. blood.
C. skin cells.
D. saliva.
E. All of the above contain a person’s DNA.

E. All of the above contain a person’s DNA.

Double-stranded DNA that contains a high G-C content requires a higher temperature in order to separate the two DNA strands. This is because:

A. G-C base pairing involves three hydrogen bonds while A-T pairing involves only two.
B. high G-C content makes the DNA less flexible.
C. DNA with a high G-C content forms a tighter double helix.
D. All of the above are correct.
E. Only a) and b) are correct.

A. G-C base pairing involves three hydrogen bonds while A-T pairing involves only two.

Most genes come in alternative forms called:

A. chromosomes.
B. gametes.
C. dominants.
D. alleles.
E. recessives.

D. alleles.

In order for translation to occur:

A. the nuclear membrane must dissolve.
B. transcription must be occurring simultaneously.
C. a cell must contain a cell wall to which translational protein receptors are bound.
D. there must be large numbers of free amino acids present in the cytosol.
E. the DNA must produce large numbers of free amino acids.

D. there must be large numbers of free amino acids present in the cytosol.

The term "gene expression" refers to:

A. which amino acid is "called for" by a particular codon
B. the role and function of the protein coded for by a gene
C. the total number of genes in an organisms
D. the presence or absence of genes in a particular cell
E. None of the above describes what "gene expression" means.

E. None of the above describes what "gene expression" means.

A frameshift mutation:

A. leaves the amino acid sequence unchanged.
B. results from an insertion or deletion in a DNA sequence.
C. substitutes a purine for a pyrimidine only.
D. is the result of an unequal crossing-over.
E. substitutes a pyrimidine for a purine, or vice versa.

B. results from an insertion or deletion in a DNA sequence.

A mutation that involves the addition, subtraction, or substitution of a single base is known as

A. an inversion.
B. polypoloidy.
C. a chromosomal aberration.
D. a basic mutation.
E. a point mutation.

E. a point mutation.

Animal cells have "counters" that keep track of how many times a cell has divided. These counters are called:

A. odometers.
B. telomeres.
C. chromosomes.
D. nuclei.
E. centromeres.

B. telomeres.

In DNA replication, when the DNA molecule separates into two strands:

A. it is possible to reconstruct perfectly all the information on the missing strand because one strand carries all the information needed to construct its complementary strand.
B. the rebuilding process begins, in which an enzyme connects the appropriate complementary base to the exposed base.
C. the mitotic phase begins.
D. All of the above are correct.
E. Only a) and b) are correct.

E. Only a) and b) are correct.

Somatic cells can include:

A. kidney cells.
B. heart cells.
C. sperm cells.
D. All of the above are correct.
E. Both a) and b) are correct.

E. Both a) and b) are correct.

The rate at which mitosis occurs varies dramatically for different types of cells. The most rapid cell division occurs:

A. in the blood and the heart.
B. on the skin.
C. in the blood and the cells lining the various tissues of organs.
D. in the gametes.
E. in the heart and the brain.

C. in the blood and the cells lining the various tissues of organs.

Mitosis results in:

A. daughter cells with the same number of chromosomes but different combinations of alleles.
B. gametes.
C. daughter cells with the same number and composition of chromosomes.
D. daughter cells with twice as much genetic material and a unique collection of alleles.
E. eight daughter cells.

C. daughter cells with the same number and composition of chromosomes.

In order for a eukaryotic cell to undergo reproduction and divide, certain steps must be successfully completed. Which of the following choices is NOT one of these necessary steps?

A. There must be proper packaging and segregation of the replicated DNA.
B. There must be proper reshuffling of the genetic material in order to provide diversity within the gametes.
C. There must be replication of the DNA within the nucleus.
D. There must be proper division of the cytoplasm.
E. All of the choices above are necessary steps in eukaryotic cellular replication.

B. There must be proper reshuffling of the genetic material in order to provide diversity within the gametes.

Chemotherapy is one common treatment for cancer. Which of the following are aspects of chemotherapy?

A. Drugs that interfere with cell division are administered to the patient.
B. Chemotherapy drugs circulate throughout the entire body.
C. Chemotherapy drugs disrupt normal systems that rely on the rapid and constant production of new cells.
D. All of the above are correct.
E. Only a) and c) are correct.

D. All of the above are correct.

Cancer cells are different from other cells in that they have lost their "contact inhibition." "Contact inhibition" means:

A. DNA replication in most cells stops when the double helix comes in contact with particular enzymes.
B. most cells stop dividing when they have reached 50 cell divisions.
C. DNA replication in most cells doesn’t begin until the double helix comes in contact with particular enzymes.
D. most cells stop dividing when they bump up against other cells or collections of cells.
E. most cells don’t begin to divide until they bump up against other cells or collections of cells.

D. most cells stop dividing when they bump up against other cells or collections of cells.

Which of the following are features that distinguish cancer cells from normal cells?

A. Normal cells undergo cytokinesis; cancer cells do not undergo cytokinesis.
B. Normal cells have contact inhibition; cancer cells have no contact inhibition.
C. Normal cells metastasize; cancer cells do not metastasize.
D. Normal cells can divide a finite number of times; cancer cells can divide indefinitely.
E. Both b) and d) are correct.

E. Both b) and d) are correct.

In humans, the haploid number, n, equals:

A. 2n.
B. 44.
C. 23.
D. 46.
E. n.

C. 23.

During meiosis, chromatin:

A. reduces the incidence of crossing over.
B. unwinds to allow synapsis between homologous pairs of chromatids.
C. condenses, becoming more tightly coiled.
D. binds to the metaphase plate, enabling chromosome division.
E. unwinds to allow tetrads to form.

C. condenses, becoming more tightly coiled.

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