Question 1

Which of the following best describes the difference between anabolic and catabolic pathways in cellular metabolism?

Accepted Answer

Anabolic pathways build complex molecules from simpler ones, requiring energy input, while catabolic pathways break down molecules to release energy.

Question 2

During cellular respiration, which molecule is the final electron acceptor in the electron transport chain?

Accepted Answer

Oxygen ($$O_2)$$

Question 3

Which of the following equations correctly represents the net reaction of glycolysis?

Accepted Answer

$$C_6H_{12}O_6$ + 2 NAD^+ + 2 ADP + 2 P_i \rightarrow 2 C_3H_4O_3 + 2 NADH + 2 ATP + 2 H_2O$$

Question 4

Which of the following is NOT a condition that affects enzyme activity?

Accepted Answer

Molecular weight of the enzyme

Question 5

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the active site and preventing substrate binding

Question 6

Which statement best explains why fermentation is important for cells under anaerobic conditions?

Accepted Answer

Fermentation regenerates $$NAD^+$$, allowing glycolysis to continue producing ATP.

Question 7

In photosynthesis, what is the role of Rubisco in the Calvin cycle?

Accepted Answer

Rubisco catalyzes the carboxylation of ribulose-1,5-bisphosphate ($$RuBP) $$with $$CO_2.$$

Question 8

Which of the following best describes the difference between C3 and C4 photosynthetic pathways?

Accepted Answer

C3 plants fix $$CO_2$$ directly via Rubisco, while C4 plants initially fix $$CO_2$$ into a four-carbon compound before entering the Calvin cycle.

Question 9

Which of the following is a correct sequence of events in the cell cycle?

Accepted Answer

G1 $$\rightarrow S$$ $$\rightarrow G2$$ $$\rightarrow$$ Mitosis $$\rightarrow$$ Cytokinesis

Question 10

Which of the following best describes the function of cyclins and CdKs in the cell cycle?

Accepted Answer

Cyclins and CdKs regulate progression through cell cycle checkpoints by phosphorylating target proteins.

Question 11

Which of the following mechanisms contributes to genetic variation during meiosis?

Accepted Answer

All of the above

Question 12

A human karyotype shows 46 chromosomes. How many pairs are autosomes?

Accepted Answer

22 pairs

Question 13

Which of the following best describes the difference between homologous chromosomes and sister chromatids?

Accepted Answer

Homologous chromosomes are similar but not identical, each inherited from a different parent; sister chromatids are identical copies formed during DNA replication.

Question 14

Which of the following is a correct description of the law of thermodynamics as it applies to cellular metabolism?

Accepted Answer

Energy is transferred and transformed, but the total amount remains constant.

Question 15

Which of the following is a function of cofactors in enzyme activity?

Accepted Answer

Cofactors are required for some enzymes to achieve their active conformation and catalyze reactions.

Question 16

A patient is diagnosed with lactic acidosis after intense exercise. Which metabolic pathway is most likely responsible for the accumulation of lactic acid?

Accepted Answer

Anaerobic fermentation in muscle cells

Question 17

Which of the following best explains the importance of density-dependent inhibition in normal cell growth?

Accepted Answer

It prevents cells from dividing when they are in contact with neighboring cells, helping regulate tissue growth.

Question 18

Which evolutionary mechanism is most directly responsible for the genetic variation observed in sexually reproducing populations?

Accepted Answer

Meiosis and sexual reproduction, which shuffle alleles through independent assortment and crossing over

Question 19

A cell is observed to have 23 chromosomes, each consisting of a single chromatid. This cell is most likely:

Accepted Answer

A human gamete after meiosis II

Core Concepts in Cell Biology: Metabolism, Respiration, Photosynthesis, Cell Cycle, Meiosis, and Evolution

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