Question 1

Which of the following best describes the role of ATP hydrolysis in coupling endergonic and exergonic reactions within the cell?

Accepted Answer

ATP hydrolysis releases free energy that can be used to drive endergonic reactions by coupling, making the overall process exergonic.

Question 2

A cell is exposed to a toxin that irreversibly inhibits the active site of an essential enzyme. Which of the following best describes the effect of this toxin?

Accepted Answer

The enzyme will be permanently inactivated, preventing substrate binding and catalysis.

Question 3

Which of the following statements about the fluid mosaic model of biological membranes is correct?

Accepted Answer

Membrane proteins and lipids can move laterally within the bilayer, contributing to membrane fluidity.

Question 4

A red blood cell is placed in a hypertonic solution. What will happen to the cell, and why?

Accepted Answer

The cell will shrink because water leaves the cell to balance solute concentrations.

Question 5

Which of the following best explains why saturated fatty acids decrease membrane fluidity compared to unsaturated fatty acids?

Accepted Answer

Saturated fatty acids pack tightly together, reducing movement of phospholipids.

Question 6

Which equation correctly represents the relationship between free energy change ($\Delta G$), enthalpy change ($\Delta H$), entropy change ($\Delta S$), and temperature ($T$)?

Accepted Answer

$\Delta G = \Delta H - T\Delta S$

Question 7

During glycolysis, which molecule acts as the primary electron acceptor, and what is the fate of the electrons in the absence of oxygen?

Accepted Answer

NAD+; electrons are transferred to pyruvate or its derivatives during fermentation.

Question 8

Which of the following best describes the function of the Na$^+$/K$^+$ ATPase pump in animal cells?

Accepted Answer

It uses ATP hydrolysis to move Na$^+$ out of the cell and K$^+$ into the cell, maintaining electrochemical gradients.

Question 9

A mutation causes a cell to produce a nonfunctional SNARE protein. Which cellular process would be most directly affected?

Accepted Answer

Fusion of vesicles with target membranes during exocytosis

Question 10

Which of the following is a key difference between competitive and noncompetitive enzyme inhibitors?

Accepted Answer

Competitive inhibitors bind to the active site, while noncompetitive inhibitors bind to an allosteric site.

Question 11

Which process is responsible for the majority of ATP production during aerobic cellular respiration?

Accepted Answer

Oxidative phosphorylation via the electron transport chain and ATP synthase

Question 12

A cell is exposed to a drug that blocks the function of COP proteins. Which process will be most directly impaired?

Accepted Answer

Formation of vesicle coats for intracellular transport

Question 13

Which of the following best describes the role of the 3' polyadenylation of mRNA in eukaryotic cells?

Accepted Answer

It increases mRNA stability and aids in export from the nucleus.

Question 14

Which of the following is a direct output of the light reactions of photosynthesis?

Accepted Answer

NADPH

Question 15

A scientist wants to measure the membrane potential of a neuron. Which equation should they use to calculate the equilibrium potential for a single ion?

Accepted Answer

Nernst equation

Question 16

Which of the following best explains why the TCA (Krebs) cycle is considered amphibolic?

Accepted Answer

It functions in both the breakdown (catabolism) and synthesis (anabolism) of biomolecules.

Question 17

Which of the following is a characteristic feature of apoptosis but NOT necrosis?

Accepted Answer

DNA fragmentation and membrane blebbing

Question 18

Which of the following best describes the function of G-protein coupled receptors (GPCRs) in cell signaling?

Accepted Answer

They activate intracellular signaling cascades by exchanging GDP for GTP on the G-protein.

Question 19

Which of the following best explains why enzymes are highly specific for their substrates?

Accepted Answer

The three-dimensional shape of the active site is complementary to the substrate.

Comprehensive Study Guide for Cell Biology Final Exam

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