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The primary elements making up living organisms are
A. carbon, hydrogen, oxygen, and calcium.
B. carbon, oxygen, iron, and chlorine.
C. carbon, hydrogen, iron, and calcium.
D. carbon, hydrogen, oxygen, and nitrogen.
E. carbon, oxygen, sulfur, and calcium.
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D. carbon, hydrogen, oxygen, and nitrogen
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The atomic number of an atom or element is
A. the number of neutrons in the nucleus.
B. the number of electrons in the nucleus.
C. the number of protons in the nucleus.
D. the number of neutrons in the orbitals.
E. the number of protons in the orbitals.
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C. the number of protons in the nucleus.
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An ion is
A. an atom that has gained electrons.
B. an atom that has a positive charge.
C. an atom that has lost electrons.
D. an atom that has a negative charge.
E. All answers are correct.
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E. All answers are correct.
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The mass number of an atom is defined as
A. the total number of protons, neutrons, and electrons of an atom.
B. the total number of protons and electrons of an atom.
C. the total number of protons and neutrons of an atom.
D. the total number of neutrons and electrons of an atom.
E. the total number of protons of an atom
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C. the total number of protons and neutrons of an atom.
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Isotopes of the same element are different from one another in that
A. they have a different number of protons.
B. they have a different number of neutrons.
C. they have a different number of electrons.
D. they are a different element.
E. only one of the isotopes is matter.
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B. they have a different number of neutrons.
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The first energy shell of an atom contains a maximum of
A. one electron.
B. two electrons.
C. four electrons.
D. eight electrons.
E. sixteen electrons.
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B. two electrons.
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If an atom has a valence shell that is full, then it
A. is highly reactive.
B. is chemically unstable.
C. is highly likely to combine with other atoms.
D. is found only in a gas form.
E. is inert.
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E. is inert.
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The second energy shell of an atom contains a maximum of
A. eight electrons.
B. two electrons.
C. four electrons.
D. one electron.
E. sixteen electrons.
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A. eight electrons.
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In a covalent bond
A. atoms share electrons.
B. atoms of opposite charges attract each other.
C. atoms share protons.
D. atoms share neutrons.
E. atoms are repelled by each other.
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A. atoms share electrons.
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An ionic bond is a bond in which
A. atoms share electrons.
B. atoms share protons.
C. atoms of opposite charges attract each other.
D. atoms share neutrons.
E. atoms are repelled by each other.
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C. atoms of opposite charges attract each other.
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In the example of ionic bond formation between sodium and chlorine, which of the following is a false statement?
A. Na is the chemical symbol for sodium.
B. Chlorine donates an electron.
C. Chlorine becomes negatively charged.
D. Sodium becomes positively charged.
E. The bond that is formed is a strong bond.
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C. Chlorine becomes negatively charged.
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In the example of ionic bond formation between sodium and chlorine
A. Na is the chemical symbol for chlorine.
B. sodium accepts an electron.
C. chlorine accepts an electron.
D. chlorine becomes positively charged.
E. both sodium and chlorine accept electrons.
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C. chlorine accepts an electron.
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If a covalent bond is polar
A. electrons are not shared by atoms.
B. protons are shared by atoms.
C. it will not form in living organisms.
D. electronegativity of atoms is unequal in their pull on electrons.
E. the bond is weak in strength.
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D. electronegativity of atoms is unequal in their pull on electrons.
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A hydrogen bond
A. is generally a very strong bond.
B. does not occur in living organisms.
C. does not require electron transfer.
D. forms between atoms having the same electronegativity.
E. is a specialized type of covalent bond.
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C. does not require electron transfer.
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Evaporation is
A. the conversion of a liquid into a vapor.
B. the conversion of a solid into a vapor.
C. the conversion of a vapor into a liquid.
D. the conversion of a vapor into a solid.
E. All answers are correct.
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A. the conversion of a liquid into a vapor.
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Ice floats on liquid water because
A. the molecules are closer together in ice than in liquid water.
B. the molecules are farther apart in ice than in liquid water.
C. ice is denser than liquid water.
D. convection currents caused by temperature differences push upwards on the ice.
E. water vapor is less dense than liquid water.
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B. the molecules are farther apart in ice than in liquid water.
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An acid
A. has a value above seven on the pH scale.
B. is a chemical that takes hydrogen ions from a solution.
C. has a value of seven on the pH scale.
D. is a chemical that adds hydrogen ions to a solution.
E. All answers are correct.
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D. is a chemical that adds hydrogen ions to a solution.
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A base
A. has a value of 7 on the pH scale.
B. is a chemical that adds hydrogen ions to a solution.
C. is a chemical that absorbs hydrogen ions from a solution.
D. has a value below 7 on the pH scale.
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C. is a chemical that absorbs hydrogen ions from a solution.
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A substance with a pH of 2 is
A. neutral.
B. a weak acid.
C. a weak base.
D. a strong base.
E. a strong acid.
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E. a strong acid.
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A substance with a pH of 6 is
A. a weak acid.
B. neutral.
C. a weak base.
D. a strong acid.
E. a strong base.
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A. a weak acid.
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A substance with a pH of 7 is
A. a weak acid.
B. a weak base.
C. neutral.
D. a strong acid.
E. a strong base
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C. neutral.
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A substance with a pH of 8 is
A. neutral.
B. a weak base.
C. a weak acid.
D. a strong acid.
E. a strong base.
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B. a weak base.
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A substance with a pH of 13 is
A. a weak acid.
B. a weak base.
C. neutral.
D. a strong acid.
E. a strong base.
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E. a strong base.
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Organic molecules are defined as chemical compounds that contain
A. hydrophilic solutions.
B. no carbon.
C. ionically bonded atoms.
D. negative hydrogen ions.
E. carbon and hydrogen.
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E. carbon and hydrogen.
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The four major groups of organic compounds are
A. fats, waxes, carbohydrates, and amino acids.
B. carbohydrates, lipids, steroids, and monosaccharides.
C. lipids, fats, waxes, and steroids.
D. carbohydrates, lipids, proteins, and nucleic acids.
E. carbohydrates, proteins, amino acids, and nucleic acids.
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D. carbohydrates, lipids, proteins, and nucleic acids.
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A process by which cells build large molecules from monomers is
A. hydrolysis.
B. reproduction.
C. dehydration synthesis.
D. hydrolysis and dehydration synthesis.
E. unrelated to chemical bonds.
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C. dehydration synthesis.
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A process by which cells break polymers down into smaller units is
A. hydrolysis.
B. dehydration synthesis.
C. reproduction.
D. hydrolysis and dehydration synthesis.
E. unrelated to chemical bonds.
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A. hydrolysis.
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Examples of monosaccharides are
A. cellulose and sucrose.
B. lactose and sucrose.
C. glucose and fructose.
D. glucose and cellulose.
E. None of the answers are correct.
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C. glucose and fructose.
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The primary building block (monomer) of proteins is
A. a glucose molecule.
B. a fatty acid.
C. a nucleotide.
D. an amino acid.
E. four interconnected rings.
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D. an amino acid.
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An amino acid contains
A. three R groups and a glycerol.
B. nitrogen, carbon, and an R group.
C. multiple saccharide rings.
D. carbon and phosphorus monomers.
E. carbon and phosphorus
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B. nitrogen, carbon, and an R group
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A peptide bond
A. is an ionic bond in proteins.
B. is a covalent bond in carbohydrates.
C. is a covalent bond in proteins.
D. is an ionic bond in carbohydrates.
E. is a hydrogen bond in nucleic acids.
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C. is a covalent bond in proteins.
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The primary building block (monomer) of nucleic acids is
A. a nucleotide.
B. a glucose molecule.
C. a fatty acid.
D. an amino acid.
E. legos.
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A. a nucleotide.
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The three major components in a nucleotide are
A. glucose, a nitrogen base, and a phosphate group.
B. glucose, a fatty acid, and glycerol.
C. a nitrogen base, a carboxyl group, and an R group.
D. a nitrogen base, a five-carbon sugar, and a phosphate group.
E. a carboxyl group, an R group, and an amino group.
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D. a nitrogen base, a five-carbon sugar, and a phosphate group.
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The four nitrogenous bases found in RNA are
A. glycerol, phosphate, adenine, and glucose.
B. adenine, cytosine, guanine, and uracil.
C. adenine, thymine, cytosine, and uracil.
D. thymine, cytosine, guanine, and uracil.
E. adenine, thymine, guanine, and cytosine.
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B. adenine, cytosine, guanine, and uracil.
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Water is best described as which of the following?
A. an ion
B. a non-polar molecule
C. an atom
D. a polar molecule
E. an element
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D. a polar molecule
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Individual water molecules bind to each other with
A. covalent bonds.
B. ionic bonds.
C. hydrogen bonds.
D. hydrophobic bonds.
E. peptide bonds.
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C. hydrogen bonds.
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Within a single molecule of water, ____ bonds are formed between oxygen and hydrogen.
A. ionic
B. covalent
C. hydrogen
D. hydrophobic
E. nuclear
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B. covalent
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What do a lemon, a baseball and sand grains have in common?
A. All are composed of matter.
B. All are alive.
C. All are composed of organic molecules.
D. All are acidic.
E. All are basic.
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A. All are composed of matter.
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You can painlessly wade into a pool, but doing a belly flop off of the high diving board hurts because of ______.
A. water’s high density
B. adhesion of your molecules with the water molecules
C. water’s high boiling point
D. a neutral pH
E. cohesion of the water molecules
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E. cohesion of the water molecules
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Trees are able to transport water hundreds of feet up from the roots because of
A. water’s high density.
B. cohesion of the water molecules.
C. water’s high boiling point.
D. dispersion of the water molecules.
E. a neutral pH.
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B. cohesion of the water molecules.
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Sugars dissolve well in water and are therefore called ______ substances.
A. covalent
B. ionic
C. hydrogen
D. hydrophobic
E. hydrophilic
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E. hydrophilic
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Blood pH is closely maintained at a pH of 7.4. A patient whose blood pH drops below 7.35 is suffering from metabolic acidosis and can go into a coma. What happens to the concentration of H+ ions in a patient with a blood pH of 6.4?
A. H+ concentration is decreased 10-fold.
B. H+ concentration is decreased 2-fold.
C. H+ concentration is increased 2-fold.
D. H+ concentration is decreased 4-fold.
E. H+ concentration is increased 10-fold.
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C. H+ concentration is increased 2-fold.
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The most common isotope of carbon is 12C. The isotope 14C has ____ than 12C.
A. more protons
B. more neutrons
C. fewer neutrons
D. fewer protons
E. more electrons
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B. more neutrons
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Hydrogen, nitrogen, carbon, and oxygen account for 96% of the human body’s make-up. These elements are
A. also the main elements in organic molecules.
B. rare in non-human organisms.
C. rare on Earth.
D. always bonded by hydrogen bonds.
E. All answers are correct.
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A. also the main elements in organic molecules.
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Many digestive enzymes are hydrolases which carry out hydrolysis. What do these enzymes have in common?
A. They use water to form bonds between monomers.
B. They use water to break bonds in monomers.
C. They use water to break bonds in polymers.
D. They use water to form bonds between polymers.
E. They release water in forming bonds between monomers.
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C. They use water to break bonds in polymers.
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____ bonds are formed between monomers to form a polymer.
A. Ionic
B. Covalent
C. Hydrogen
D. Hydrophobic
E. Nuclear
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B. Covalent
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Hydrogen has 1 proton, 0 neutrons, and 1 electron. Which of the following is correct about hydrogen?
A. Hydrogen has an atomic number of 1.
B. Hydrogen has an atomic number of 2.
C. Hydrogen has an atomic mass of 2.
D. Hydrogen has an atomic number and atomic mass of 2.
E. The hydrogen atom mentioned in the question is an ion.
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A. Hydrogen has an atomic number of 1.
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Saturated fats have long straight tails of fatty acids, while unsaturated fats have kinks in their tails created by the double bonds. The kinks prevent the fatty acids from packing together as tightly. Ectothermic (cold blooded) animals need to keep their membranes fluid at cooler temperature and thus contain ______ their membranes.
A. mostly unsaturated fats in
B. mostly saturated fats in
C. no fatty acids in
D. a cell wall around
E. no lipids in
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B. mostly saturated fats in
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Saturated fats have long straight tails of fatty acids, while unsaturated fats have kinks in their tails created by the double bonds. The kinks prevent the fatty acids from packing together as tightly. Hydrogenated vegetable oils have hydrogens added back to the double bonds and thus behave like ____.
A. unsaturated fats
B. waxes
C. carbohydrates
D. protein
E. saturated fats
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E. saturated fats
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Two hydrogen atoms and an oxygen atom bonded together form
A. a molecule, but not a compound.
B. a compound, but not a molecule.
C. a molecule and a compound.
D. an atom and a molecule.
E. an atom, but not a molecule or compound.
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A. a molecule, but not a compound.
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A nucleotide contains which of the following?
A. amino acid and nitrogenous bases
B. saturated and unsaturated fatty acids
C. sugar, nitrogenous base, and phosphate
D. amino acid and saccharide
E. fatty acid, glycerol, and phosphate
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C. sugar, nitrogenous base, and phosphate
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How are the monomers in proteins joined?
A. phosphodiester bonds between amino acids
B. peptide bonds between amino acids
C. peptide bonds between nucleotides
D. phosphodiester bonds between nucleotides
E. peptide bonds between carbohydrates
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B. peptide bonds between amino acids
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How are the monomers in nucleic acids joined?
A. peptide bonds between carbohydrates
B. peptide bonds between amino acids
C. phosphodiester bonds between amino acids
D. peptide bonds between nucleotides
E. phosphodiester bonds between nucleotides
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D. peptide bonds between nucleotides
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A peptide bond is a covalent bond formed between amino acids.
A. True B. False
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A. True
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Cohesion is a property of water in which water molecules tend to stick together.
A. True B. False
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A. True
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A substance in which other substances dissolve is called a solute.
A. True B. False
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B. False
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Ice is less dense than liquid water, allowing organisms in ponds to live underneath the ice at the surface of the water, instead of trapped in the ice at the bottom of the pond.
A. True B. False
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A. True
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A fatty acid is unsaturated if there is at least one double bond between the carbon atoms in the hydrocarbon chains.
A. True B. False
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A. True
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The primary function of hemoglobin is to regulate the level of sugar in the blood.
True False
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False
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If a protein is denatured, its structure has changed enough to make the protein nonfunctional.
A. True B. False
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A. True
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Proteins store the genetic information of the cell and transmit it to the next generation.
A. True B. False
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A. True
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It is biologically important that pure water has a neutral pH, so that it does not alter the internal pH of organisms or pH of ecosystems.
A. True B. False
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A. True
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Nucleic acids are to nucleotides like amino acids are to proteins and monosaccharides are to carbohydrates.
A. True B. False
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A. True
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