Question 1

Which of the following best describes the main function of the light reactions in photosynthesis?

Accepted Answer

To generate ATP and NADPH by using light energy to split water and transfer electrons

Question 2

A plant is exposed to intense heat, causing its stomata to close. What is the most likely immediate consequence for photosynthesis?

Accepted Answer

Increased photorespiration as O$$_2$$ builds up and Rubisco incorporates O$$_2$$ instead of CO$$_2$$

Question 3

Which process directly produces molecular oxygen (O$$_2) $$during photosynthesis?

Accepted Answer

Splitting of water by Photosystem II

Question 4

In the Calvin cycle, which enzyme catalyzes the initial fixation of CO$$_2 to $$RuBP?

Accepted Answer

Rubisco

Question 5

Which of the following best explains why C$$_4$$ and CAM plants are more efficient than C$$_3$$ plants in hot, dry environments?

Accepted Answer

They pump CO$$_2 to $$Rubisco, reducing photorespiration

Question 6

Which of the following is an example of a secondary messenger in cell signaling?

Accepted Answer

cAMP

Question 7

A mutation causes a cell to produce a nonfunctional cyclin-dependent kinase (CDK). Which cell cycle process is most directly affected?

Accepted Answer

Progression through cell cycle checkpoints

Question 8

Which of the following events occurs during anaphase of mitosis?

Accepted Answer

Sister chromatids are separated and pulled to opposite poles

Question 9

A researcher observes a cell with a cell plate forming at its center during division. This cell is most likely:

Accepted Answer

A plant cell undergoing cytokinesis

Question 10

Which of the following best describes the difference between meiosis I and meiosis II?

Accepted Answer

Meiosis I reduces chromosome number by half; meiosis II separates sister chromatids

Question 11

In Mendel’s monohybrid cross, what is the expected genotypic ratio in the F$$_2$$ generation?

Accepted Answer

$$1:2:1$$

Question 12

A woman with type AB blood and a man with type O blood have a child. What are the possible blood types of their child?

Accepted Answer

A or B

Question 13

Which of the following is an example of incomplete dominance?

Accepted Answer

A pink snapdragon flower resulting from a cross between red and white parents

Question 14

Which of the following best illustrates the concept of epistasis?

Accepted Answer

One gene masking or altering the expression of another gene, such as coat color in mice

Question 15

Which of the following is NOT a source of genetic variation in sexually reproducing organisms?

Accepted Answer

Replication of DNA during S phase

Question 16

A cell receives a signal molecule that binds to a G-protein coupled receptor. Which sequence best describes the resulting signal transduction pathway?

Accepted Answer

Signal binds receptor → G-protein activated → secondary messenger produced → cellular response

Question 17

Which of the following best describes the role of feedback regulation in cell signaling?

Accepted Answer

It terminates or modulates the cellular response to prevent overstimulation

Question 18

A scientist observes a pedigree in which a trait appears in every generation and affects both males and females equally. Which inheritance pattern is most likely?

Accepted Answer

Autosomal dominant

Question 19

Which of the following best explains why a test cross is used in genetics?

Accepted Answer

To determine whether an individual with a dominant phenotype is homozygous or heterozygous

Question 20

Which of the following is an example of pleiotropy?

Accepted Answer

A single gene causing both sickle-shaped red blood cells and resistance to malaria

Photosynthesis, Cell Communication, Cell Cycle, and Mendelian Genetics: Core Concepts in Biology

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