Question 1

Which of the following best explains why sickle cell anemia persists in certain human populations, despite its negative health effects?

Accepted Answer

It provides resistance to malaria, demonstrating natural selection where heterozygotes have a survival advantage.

Question 2

A eukaryotic cell is missing its mitochondria. Which process would be most directly affected?

Accepted Answer

Production of ATP through aerobic cellular respiration

Question 3

Which of the following best describes the role of actin filaments in cell division?

Accepted Answer

They form the contractile ring during cytokinesis, helping to separate the cytoplasm.

Question 4

A cell increases in size from a radius of $$2\ \mu m to$$ $$4\ \mu m. $$How does its surface area to volume ratio change?

Accepted Answer

It decreases, making transport of materials less efficient.

Question 5

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

Accepted Answer

Na$$^+$$ ions

Question 6

During which step of cellular respiration is the majority of ATP produced, and what is the main mechanism?

Accepted Answer

Electron transport chain via chemiosmosis

Question 7

A herbicide inhibits photosystem II in plants. What is the most immediate effect on photosynthesis?

Accepted Answer

No oxygen is produced and ATP synthesis is reduced.

Question 8

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

Accepted Answer

Active transport requires energy (ATP) to move substances against their concentration gradient, while passive transport does not.

Question 9

Which of the following mutations would most likely result in a shortened, nonfunctional protein?

Accepted Answer

Nonsense mutation

Question 10

Which process is responsible for the conversion of DNA to mRNA, and which enzyme is primarily involved?

Accepted Answer

Transcription; RNA polymerase

Question 11

Which of the following best explains why alternative splicing increases protein diversity in eukaryotes?

Accepted Answer

It allows a single gene to code for multiple proteins by including or excluding different exons.

Question 12

A scientist uses gel electrophoresis to analyze DNA samples. What property of DNA allows this technique to separate DNA fragments?

Accepted Answer

DNA fragments are separated based on size, with smaller fragments moving further through the gel.

Question 13

Which of the following best describes the role of feedback inhibition in cellular respiration?

Accepted Answer

It prevents the overproduction of ATP by inhibiting enzymes in the pathway when ATP levels are high.

Question 14

Which of the following is true regarding 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 15

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

Accepted Answer

They cut DNA at specific sequences, allowing for DNA manipulation and analysis.

Question 16

Which of the following is an example of codominance in genetics?

Accepted Answer

A person with AB blood type expressing both A and B antigens equally.

Question 17

Which of the following best describes the role of the Calvin cycle in photosynthesis?

Accepted Answer

It uses ATP and NADPH to convert CO$$_2$$ into carbohydrates.

Question 18

Which of the following statements about enzyme structure and function is correct?

Accepted Answer

Enzyme activity depends on the three-dimensional structure, which can be disrupted by changes in temperature or pH.

Question 19

Which of the following best describes the difference between a tumor suppressor gene and a proto-oncogene?

Accepted Answer

A tumor suppressor gene prevents uncontrolled cell division, while a proto-oncogene promotes cell division when activated.

Question 20

Which of the following is a correct statement about the scientific method?

Accepted Answer

A hypothesis is a testable explanation for an observation that can be supported or refuted by experimentation.

Comprehensive Study Guide: Key Concepts in College Biology

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