A&P 1 Practice Exam 3

Forms part of the protein synthesis site in the cytoplasm.

ribosomal RNA

Act as "interpreter" molecules that recognize specific amino acids and nucleotide base sequences.

transfer RNA

Attaches the correct amino acid to its transfer RNA.

Synthetase enzymes

Provides the energy needed for synthesis reactions.

ATP

Found in the cytoplasm, this structure specifies the exact sequence of amino acids of the protein to be made.

messenger RNA

May be attached to the ER or scattered in the cytoplasm.

ribosomal RNA

Chromosomes decoil to form chromatin.

telophase

Chromosomal centromeres split and chromosomes migrate to opposite ends of the cell.

anaphase

Nuclear membrane and nucleolus disintegrate.

late prophase

Chromosomes align on the spindle equator.

metaphase

Centrioles move to opposite ends of the cell.

early prophase

Plays a role in the synthesis of steroid-based hormones and proteins.

Endoplasmic reticulum

The actual site of protein synthesis.

ribosomes

Hollow cytoskeletal elements that act as organizers for the cytoskeleton.

microtubules

Dense spherical bodies in the nucleus that are the synthesis site for ribosomal RNA.

nucleoli

Houses DNA and RNA.

nucleus

The cell (plasma) membrane normally contains substantial amounts of cholesterol.

true

Each daughter cell resulting from mitotic cell division has exactly as many chromosomes as the parent cell.

true

Apoptosis is programmed cell suicide, but cancer cells fail to undergo apoptosis.

true

The spindle is formed by the migration of the chromatin.

false

Final preparation for cell division is made during the cell life cycle subphase called G2.

true

Chromatin consists of DNA and RNA.

false

In osmosis, movement of water occurs toward the solution with the lower solute concentration.

false

The genetic information is coded in DNA by the regular alternation of sugar and phosphate molecules.

false

A process by which large particles may be taken into the cell for food, protection of the body, or for disposing of old or dead cells is called phagocytosis.

true

The orderly sequence of the phases of mitosis is prophase, metaphase, anaphase, and telophase.

true

Diffusion is always from areas of greater to areas of lesser concentration.

true

Facilitated diffusion always requires a carrier protein.

false

Pressure caused by gravity is necessary for any filtration pressure to occur in the body.

false

DNA transcription is another word for DNA replication.

false

The glycocalyx is often referred to as the "cell coat," which is somewhat fuzzy and sticky with numerous cholesterol chains sticking out from the surface of the cell membrane.

false

In their resting state, all body cells exhibit a resting membrane potential ranging from -50 to about +50 millivolts.

false

Microfilaments are thin strands of the contractile protein myosin.

false

Interstitial fluid represents one type of extracellular material.

true

Hyperplasia generally means that an organ will increase in size due to the excessive formation of extracellular fluids.

false

A chemical that inhibits DNA synthesis has yet to be found in aging cells.

false

Aquaporins are believed to be present in red blood cells and kidney tubules, but very few other cells in the body.

false

Most organelles are bounded by a membrane that is quite different in structure from the lipid bilayer of the plasma membrane.

false

Only one cell type in the human body has a flagellum.

true

Microtubules are hollow tubes made of subunits of the protein tubulin.

true

Telomeres are the regions of chromosomes that code for the protein ubiquitin.

false

Nitric oxide may act as a biological messenger.

true

In certain kinds of muscle cells, calcium ions are stored ________.

in the smooth ER

Which of the following is true regarding the generation of a membrane potential?

Both potassium and sodium ions can "leak" through the cell membrane due to diffusion.

Transcytosis is ________.

transporting an endosome from one side of a cell to the other and releasing the contents by exocytosis

The RNA responsible for bringing the amino acids to the "factory" site for protein formation is the ________.

tRNA

A red blood cell placed in pure water would ________.

swell and burst

The plasma membrane is ________.

the phospholipid bilayer surrounding the cell

Which of these is NOT a function of the plasma membrane?
A) It acts as a site of cell-to-cell interaction and recognition.
B) It encloses the cell contents.
C) It is selectively permeable.
D) It prevents potassium ions from leaking out and sodium ions from crossing into the cell.

D) It prevents potassium ions from leaking out and sodium ions from crossing into the cell.

Which structures are fingerlike projections that greatly increase the absorbing surface of cells?

microvilli

Which of the following statements is correct regarding diffusion?
A) The lower the temperature, the faster the diffusion rate.
B) The greater the concentration of gradient, the faster the rate of diffusion.
C) Molecular weight of a substance does not affect the rate of diffusion.
D) The rate of diffusion is independent of temperature.

B) The greater the concentration of gradient, the faster the rate of diffusion.

Cell junctions that promote the coordinated activity of cells by physically binding them together into a cell community include all of the following except ________.
A) gap junctions
B) tight junctions
C) desmosomes
D) peroxisomes

D) peroxisomes

If cells are placed in a hypertonic solution containing a solute to which the membrane is impermeable, what could happen?

The cells will lose water and shrink.

Which of the following is not a subcellular structure?
A) membranes
B) intercellular material
C) organelles
D) cytoplasm

B) intercellular material

Once solid material is phagocytized and taken into a vacuole, which of the following statements best describes what happens?
A) A lysosome combines with the vacuole and digests the enclosed solid material.
B) A ribosome enters the vacuole and uses the amino acids in the "invader" to form new protein.
C) Nitrogen enters the vacuole and "burns" the enclosed solid material.
D) The vacuole remains separated from the cytoplasm and the solid material persists unchanged.

A) A lysosome combines with the vacuole and digests the enclosed solid material.

Riboswitches are folded RNAs that act as switches to turn protein synthesis on or off in response to _________.

B) changes in the environment

Which of the following is a function of a plasma membrane protein?
A) oxygen transport
B) molecular transport through the membrane
C) forms a lipid bilayer
D) circulating antibody

B) molecular transport through the membrane

Which of the following statements is correct regarding RNA?
A) There is exactly one specific type of mRNA for each amino acid.
B) Messenger RNA, transfer RNA, and ribosomal RNA play a role in protein synthesis.
C) If the base sequence of DNA is ATTGCA, the messenger RNA template will be UCCAGU.
D) rRNA is always attached to the rough ER.

B) Messenger RNA, transfer RNA, and ribosomal RNA play a role in protein synthesis.

Which of the following would NOT be a constituent of a plasma membrane?
A) glycolipids
B) phospholipids
C) messenger RNA
D) glycoproteins

C) messenger RNA

Mitosis ______.

produces nucleus replication

The electron microscope has revealed that one of the components within the cell consists of microtubules arranged to form a hollow tube. This structure is ______.

centriole

Which of these is an inclusion, NOT an organelle?
A) cilia
B) melanin
C) microtubule
D) lysosome

B) melanin

Hyperplasia means __________.

accelerated growth

If the nucleotide or base sequence of the DNA strand used as a template for messenger RNA synthesis is ACGTT, then the sequence of bases in the corresponding mRNA would be ________.

UGCAA

Which of the following is true regarding cells in humans?
A) Cells can be as long as 1 meter.
B) All cells of an adult have a very short life span.
C) Organelles are independent life forms.
D) Maximum cell diameter is limited to 2 micrometers.

A) Cells can be as long as 1 meter.

Phospholipids ________.
A) are both hydrophilic and hydrophobic in nature
B) form the lipid bilayer, with tails directed to the outside
C) are exclusively hydrophilic molecules
D) contain polar tails and nonpolar head groups

A) are both hydrophilic and hydrophobic in nature

Passive membrane transport processes include_____.

movement of a substance down its concentration gradient

Enzymes called _________ destroy the cell’s DNA and cytoskeleton, producing a quick death to the cell.

caspases

Mitochondria ________.
A) are always the same shape
B) contain some of the DNA and RNA code necessary for their own function
C) synthesize proteins for use outside the cell
D) are single-membrane structures involved in the breakdown of ATP

B) contain some of the DNA and RNA code necessary for their own function

Ribosomes, endoplasmic reticulum, and the Golgi apparatus functionally act in sequence to synthesize and modify proteins for secretory use (export) only, never for use by the cell. This statement is ________.

false; integral cell membrane proteins are also synthesized this way

Peroxisomes ________.
A) are able to detoxify substances by enzymatic action
B) also called microbodies, contain acid hydrolases
C) sometimes function as secretory vesicles
D) function to digest particles ingested by endocytosis

A) are able to detoxify substances by enzymatic action

DNA replication ________.

takes place during interphase of the cell cycle

Which statement is the most correct regarding transcription/translation?
A) The nucleotide sequence in a mRNA codon is an exact copy of the DNA triplet that coded for it.
B) The nucleotide sequence in a tRNA anticodon is an exact copy of the DNA triplet that coded for it.
C) The nucleotide sequence in a tRNA anticodon is an exact copy of the DNA triplet that coded for it except that uracil is substituted for thymine.
D) The nucleotide sequence in a mRNA codon is an exact copy of the DNA triplet that coded for it except that uracil is substituted for thymine.

C) The nucleotide sequence in a tRNA anticodon is an exact copy of the DNA triplet that coded for it except that uracil is substituted for thymine.

In the maintenance of the cell resting membrane potential ________.

extracellular sodium levels are high

Which of the following is a concept of the cell theory?
A) Only higher organisms are composed of cells.
B) The subcellular organelle is the basic unit of life.
C) Simple cells can arise spontaneously from rotting vegetation.
D) A cell is the basic structural and functional unit of living organisms.

D) A cell is the basic structural and functional unit of living organisms.

Cells are composed mainly of ________.

carbon, hydrogen, nitrogen, oxygen

Which of the following is a principle of the fluid mosaic model of cell membrane structure?
A) Phospholipids consist of a polar head and a nonpolar tail made of three fatty acid chains.
B) Phospholipids form a bilayer that is largely impermeable to water-soluble molecules.
C) All proteins associated with the cell membrane are contained in a fluid layer on the outside of the cell.
D) The lipid bilayer is a solid at body temperature, thus protecting the cell.

B) Phospholipids form a bilayer that is largely impermeable to water-soluble molecules.

Which of the following statements is most correct regarding the intracellular chemical signals known as "second messengers"?
A) Second messengers act through receptors called K-proteins.
B) Second messengers usually act to remove nitric oxide (NO) from the cell.
C) Second messengers usually inactivate protein kinase enzymes.
D) Cyclic AMP and calcium may be second messengers.

D) Cyclic AMP and calcium may be second messengers.

The main component of the cytosol is ________.

water

Lysosomes ________.
A) maintain a highly alkaline internal environment
B) are the major site of protein synthesis
C) contain acid hydrolases that are potentially dangerous to the cell
D) are always used for the cell to "commit suicide"

C) contain acid hydrolases that are potentially dangerous to the cell

The endomembrane system is ________.

an interactive system of organelles whose membranes are physically or functionally connected

The functions of centrioles include ________.

organizing the mitotic spindle in cell division

A gene can best be defined as ________.

a segment of DNA that carries the instructions for one polypeptide chain

Extracellular matrix is ________.

the most abundant extracellular material

Crenation is likely to occur in ________.

blood cells in a hypertonic solution

Some hormones enter cells via ________.

receptor-mediated endocytosis

If a tRNA had an AGC anticodon, it could attach to a(n) ____ mRNA codon.

UCG

The basic structural and functional unit of life and the continuity of life has a cellular basis is

The cell theory

The Fluid Mosaic Model is a

that the cell membrane is a double bilayer of lipids with imbedded, dispersed proteins

Which of these is gap junction?
A) a place between two cells far apart across the range of cells
B) a nexus that allows chemical substances to pass between cells
C) an anchoring junction scattered along the sides of cells
D) an impermeable junction that encircles the cell

B) a nexus that allows chemical substances to pass between cells

Which of these is a method to transport substances by binding them to carrier proteins or pass them through protein channels?
A) Simple diffusion
B) Tight diffusion
C) Facilitated diffusion
D) Osmosis
E) Active diffusion

C) Facilitated diffusion

Which of these is a method to pass water across a semipermeable membrane?
A) Active diffusion
B) Tight diffusion
C) Simple diffusion
D) Facilitated diffusion
E) Osmosis

E) Osmosis

Which of these is the passage of water and solutes through a membrane by hydrostatic pressure?
A) Filtration
B) Active diffusion
C) Facilitated transport
D) Osmolarity
E) Tonicity

A) Filtration

Which of these is isotonic?
A) solutions with the same solute concentration as that of the cytosol
B) Solvation
C) solutions having lesser solute concentration than that of the cytosol
D) solutions having greater solute concentration than that of the cytosol

A) solutions with the same solute concentration as that of the cytosol

Which below is secondary active transport?
A) hydrolysis of ATP phosphorylates the transport protein causing conformational change
B) Dr. Sweet is the trickster, all of these are wrong
C) two substances are moved across a membrane in opposite directions
D) two substances are moved across a membrane in the same direction
E) use of an exchange pump (such as the Na+-K+ pump) indirectly to drive the transport of other solutes

E) use of an exchange pump (such as the Na+-K+ pump) indirectly to drive the transport of other solutes

Which type of vesicular transport moves substance from the cell interior to the extracellular space?
A) vesicular trafficking
B) phagocytosis
C) transcytosis
D) exocytosis
E) endocytosis

D) exocytosis

Which organelle below is the ribosome?
A) Large organelle that manufactures all secreted proteins
B) Selectively permeable double membrane barrier containing pores which mRNA can pass through
C) Dark-staining spherical bodies within the nucleus that is the site of ribosome synthesis
D) Small barrel-shaped organelles located in the centrosome
E) Small non-membranous organelle that is involved in synthesis of protein

E) Small non-membranous organelle that is involved in synthesis of protein

Which organelle below is the nucleus?
A) Stacked and flattened membranous sacs that functions as the UPS of the cell
B) Contains nuclear envelope, nucleoli, chromatin, and distinct compartments rich in specific protein sets
C) Whiplike, motile cellular extensions on exposed surfaces of certain cells
D) Membranous sacs containing oxidases and catalases
E) Spherical membranous bags containing digestive enzymes

B) Contains nuclear envelope, nucleoli, chromatin, and distinct compartments rich in specific protein sets

Which organelle below is the mitochondrion?
A) Whiplike, motile cellular extensions on exposed surfaces of certain cells
B) Long single cellular structure that moves the sperm
C) Membranous sacs containing oxidases and catalases
D) Contains nuclear envelope, nucleoli, chromatin, and distinct compartments rich in specific protein sets
E) Produces lots of ATP: the powerhouse of the cell

B) Long single cellular structure that moves the sperm