Question 1

Which of the following best explains why the Florida beach mouse population evolved lighter fur coloration compared to inland populations?

Accepted Answer

A mutation for lighter fur occurred, and because it was heritable and provided a survival advantage in sandy environments, it increased in frequency due to natural selection.

Question 2

Which of the following statements about prokaryotic and eukaryotic cells is correct?

Accepted Answer

Eukaryotic cells have compartmentalized organelles, which increases efficiency of cellular processes, while prokaryotic cells lack these compartments.

Question 3

A pancreatic cell is specialized for producing and secreting insulin, a protein hormone. Which organelle would you expect to be especially abundant in these cells, and why?

Accepted Answer

Rough endoplasmic reticulum, because it is the site of protein synthesis and processing.

Question 4

Which of the following best describes the effect of increasing cell size on the surface area to volume ratio, and the consequence for cellular function?

Accepted Answer

As cell size increases, the surface area to volume ratio decreases, which can limit the rate of exchange of materials and reduce efficiency.

Question 5

Which of the following molecules would most likely require a transport protein to cross the plasma membrane?

Accepted Answer

Glucose, because it is a large, polar molecule.

Question 6

A cell is placed in a solution and begins to swell. Which type of solution is the cell in, and what is the direction of water movement?

Accepted Answer

The cell is in a hypotonic solution; water moves into the cell.

Question 7

Which of the following best describes the process of chemiosmosis in cellular respiration?

Accepted Answer

A proton gradient is established across the inner mitochondrial membrane, and ATP is synthesized as protons flow through ATP synthase.

Question 8

A herbicide inhibits photosystem II in plant cells. Which of the following would be the most immediate effect?

Accepted Answer

The electron transport chain would be disrupted, decreasing ATP and NADPH production.

Question 9

Which of the following best explains why lactase persistence is more common in populations with a history of dairy farming?

Accepted Answer

A genetic mutation allowing lactase production into adulthood provided a selective advantage in populations that relied on dairy, increasing its frequency through natural selection.

Question 10

Which of the following best describes the role of DNA polymerase during DNA replication?

Accepted Answer

It adds nucleotides to the growing DNA strand in the 5’ to 3’ direction.

Question 11

A mutation changes a codon from $$UAC ($$tyrosine) to $$UAA ($$stop codon). What type of mutation is this, and what is its likely effect on the protein?

Accepted Answer

Nonsense mutation; results in premature termination of translation.

Question 12

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

Accepted Answer

Homologous chromosomes are pairs of chromosomes with the same genes but possibly different alleles; sister chromatids are identical copies formed during DNA replication.

Question 13

Which of the following is an example of polygenic inheritance?

Accepted Answer

Height in humans, which is influenced by multiple genes

Question 14

Which of the following best describes the function of restriction enzymes in molecular biology?

Accepted Answer

They cut DNA at specific nucleotide sequences.

Question 15

A scientist is testing the effect of a new drug on cell growth. What is the independent variable in this experiment?

Accepted Answer

The concentration of the drug administered

Question 16

Which of the following best explains why enzymes are sensitive to changes in temperature and pH?

Accepted Answer

Changes in temperature and pH can disrupt the hydrogen and ionic bonds in the enzyme's three-dimensional structure, affecting its function.

Question 17

Which of the following best describes the role of feedback inhibition in metabolic pathways?

Accepted Answer

The end product of a pathway inhibits an enzyme involved early in the pathway, preventing overproduction.

Question 18

During which phase of meiosis does crossing over occur, and what is its significance?

Accepted Answer

Prophase I; it increases genetic diversity by exchanging genetic material between homologous chromosomes.

Question 19

Which of the following best describes the difference between active and passive transport across the plasma membrane?

Accepted Answer

Active transport requires energy input (usually ATP) to move substances against their concentration gradient, while passive transport does not require energy and moves substances down their concentration gradient.

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