Gropper, Jack Smith, Timothy Carr
Answers At The End Of Each Chapter
Chapter_01_The_Cell A_Microcosm_of_Life
Indicate whether the statement is true or false.
1. Most of the metabolic energy produced in cells is made in the mitochondria.
a. True
b. False
2. An increase in the concentration of a substrate will increase the rate of the enzyme-catalyzed reaction.
a. True
b. False
3. Polysomes function to transcribe mRNA into proteins.
a. True
b. False
4. If two enzymes (e.g., pyruvate dehydrogenase and pyruvate carboxylase) compete for the same substrate (pyruvate), the
one with the higher Km has less affinity and will be more active when pyruvate concentrations are high.
a. True
b. False
5. Transcription of DNA cannot be altered.
a. True
b. False
6. The nuclear envelope is a single membrane structure that helps to isolate the nucleus from the rest of the cell.
a. True
b. False
7. The lipid bilayer determines the function of the plasma membrane, while the proteins are primarily responsible for the
structure of the membrane.
a. True
b. False
8. When discussing enzyme kinetics, Km refers to the substrate concentration at which the enzyme is saturated and
functioning at maximal velocity.
a. True
b. False
9. Peripheral proteins are involved in cell-cell recognition, whereas integral proteins function primarily as
receptors/transporters.
a. True
b. False
10. The various components within a cell (e.g., mitochondria) are not “free-floating” in the cytosol, but rather, are held in
place by the cytoskeleton.
a. True
b. False
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Chapter_01_The_Cell A_Microcosm_of_Life
11. Different cells express different proteins because they contain different sequences of DNA in the nucleus.
a. True
b. False
12. Oncosis results from cell injury and is associated with cellular swelling and swelling of the mitochondrial nucleus.
a. True
b. False
13. Allosteric regulation of enzymes is carried out by modulators, other proteins that bind to the enzyme to inhibit its
activity.
a. True
b. False
14. Most cellular reactions are irreversible because the same enzyme that catalyzes the conversion cannot catalyze the
reverse reaction.
a. True
b. False
15. The plasma membrane is a sheet-like structure composed solely of lipids.
a. True
b. False
Indicate the answer choice that best completes the statement or answers the question.
16. Most receptor proteins are most likely which type?
a. peripheral proteins
b. internal proteins
c. integral proteins
d. glycoproteins
17. MicroRNAs are small noncoding RNAs that .
a. enhance gene expression by activating mRNA expression
b. silence gene expression by binding to mRNA to inhibit translation
c. modify gene expression by replacing specific nucleotides in mRNA
d. mediate DNA production in a reverse direction
18. All components of the electron transport chain are embedded in the .
a. mitochondrial inner membrane
b. mitochondrial outer membrane
c. mitochondrial matrix
d. cytoplasmic matrix
19. The smooth endoplasmic reticulum (SER) is associated with .
a. lipid synthesis
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Chapter_01_The_Cell A_Microcosm_of_Life
b. protein synthesis
c. the calcium ion pump necessary for the contractile process
d. ribosomes and cytochrome P450 enzymes
20. In the cell structure, the provides support and controls the movement of cell organelles.
a. endoplasmic reticulum
b. mitochondrion
c. cytoskeleton
d. matrix space
21. What is released when nutrient molecules are oxidized?
a. oxygen
b. potential (or free) energy
c. kinetic energy
d. hydrogen
22. The cell organelle responsible for the initiation and regulation of most cellular activity is the .
a. cytoplast
b. nucleus
c. mitochondrion
d. nucleolus
23. What is the role of cholesterol in plasma membrane structure?
a. to produce bile
b. to regulate fluidity and permeability
c. to reduce stability
d. to produce hormones
24. Which organelle is composed of an extensive network of membranous channels that connects the nuclear membrane,
the Golgi apparatus, and the plasma membrane?
a. the lysosome
b. the nucleolus
c. the centrioles
d. the endoplasmic reticulum
25. Which are highly specialized membrane proteins that modify the cell's response to its environment?
a. transport proteins
b. enzymes
c. receptors
d. peroxisomes
26. Elongation is the process by which .
a. the mRNA strand is formed
b. peptide bonds are formed between aligned amino acids after the amino acids are positioned
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Chapter_01_The_Cell A_Microcosm_of_Life
c. amino acids are activated by ATP at their carboxyl end
d. activated amino acids are transferred to their specific tRNAs that contain the anticodon complementary to each
amino acid’s codon
27. One trigger of apoptosis is .
a. overexpression of Bcl-2
b. inactivation of Casp-9
c. swelling of the cell
d. release of mitochondrial cytochrome c
28. What is the major route for ATP production?
a. oxidative phosphorylation
b. hydrolysis
c. peroxidation
d. transformation
29. Cyclic AMP activates which enzymes?
a. protein kinases
b. restriction endonucleases
c. allosteric enzymes
d. adenyl (adenylyl) cyclases
30. Which organelle is capable of performing both fission and fusion?
a. Golgi apparatus
b. mitochondria
c. rough endoplasmic reticulum
d. nucleus
31. Enzymes of metabolic pathways within the cytoplasmic matrix are often oriented so that the product of one enzyme is
released in close proximity to the next enzyme for which it is a substrate, to facilitate the velocity of the overall pathway.
This arrangement includes enzymes of .
a. beta-oxidation
b. glycolysis
c. ketone production
d. the Krebs cycle
32. In addition to the mitochondria, which organelle possesses an inner and outer membrane?
a. lysosome
b. lysosome
c. Golgi apparatus
d. nucleus
33. Constitutive enzymes are .
a. uninfluenced by external stimuli
b. influenced by external stimuli