Question 1

If non-kinetochore microtubules are prevented from elongating during mitosis, what is the most likely consequence for the dividing eukaryotic cell?

Accepted Answer

The centrosomes will not be physically separated, impairing the elongation of the cell during anaphase.

Question 2

What is the normal function of the p53 protein when a cell detects severe DNA damage during interphase?

Accepted Answer

It triggers apoptosis or cell cycle arrest to prevent propagation of mutations.

Question 3

Why does the loss of p53 protein function significantly increase a patient's risk for developing cancer?

Accepted Answer

Cells with DNA damage can continue to divide unchecked, accumulating mutations.

Question 4

Why can't DNA polymerase synthesize both the leading and lagging strands continuously in the same direction away from the replication fork?

Accepted Answer

DNA polymerase can only add nucleotides to the 3' end, so one strand must be synthesized discontinuously as Okazaki fragments.

Question 5

How does the accumulation of a metabolic pathway's final product prevent overproduction and conserve cellular resources?

Accepted Answer

By inhibiting the first enzyme through feedback inhibition.

Question 6

The sodium-potassium pump is considered 'electrogenic' because:

Accepted Answer

It moves three sodium ions out and two potassium ions in, creating a net negative charge inside the cell.

Question 7

If a mutation prevents a G-protein from hydrolyzing GTP to GDP, what is the most likely effect on second messenger production such as cAMP?

Accepted Answer

Second messenger production will be continuously active, leading to excessive signaling.

Question 8

During intense exercise when oxygen is scarce, why do human muscle cells switch to fermentation rather than stopping glycolysis?

Accepted Answer

Fermentation allows glycolysis to continue by regenerating NAD	extsuperscript{+}.

Question 9

How does increasing substrate concentration affect reaction rates in the presence of a competitive inhibitor compared to a non-competitive inhibitor?

Accepted Answer

It can overcome competitive inhibition but not non-competitive inhibition.

Question 10

Using the concept of free water concentration, why does a cell placed in a hypertonic solution lose water?

Accepted Answer

Water moves from an area of higher free water concentration (inside the cell) to lower free water concentration (outside) via osmosis.

Question 11

What is the fundamental difference between homologous chromosomes and sister chromatids?

Accepted Answer

Homologous chromosomes come from different parents and have different alleles; sister chromatids are identical copies formed during DNA replication.

Question 12

A species has a diploid chromosome number of $$2n = 50. $$How many chromosomes and DNA molecules are present in a single gamete after meiosis?

Accepted Answer

25 chromosomes and 25 DNA molecules

Question 13

If DNA Polymerase I is completely inactive during replication, what structural flaw remains in the newly synthesized DNA strands?

Accepted Answer

RNA primers are not removed and replaced with DNA.

Question 14

How does a cell drive an endergonic reaction forward?

Accepted Answer

By coupling it with an exergonic reaction, such as ATP hydrolysis: $$\Delta G_{	ext{total}} = \Delta G_{	ext{endergonic}} + \Delta G_{	ext{exergonic}} \u003c 0$$

Question 15

Which of the following best describes the three primary stages of cell signaling and what occurs during the initial stage?

Accepted Answer

Reception: the cell detects a signaling molecule; Transduction: the signal is relayed and amplified; Response: the cell changes its activity.

Question 16

During which phase of meiosis does crossing over occur, and why is this process important for populations?

Accepted Answer

Crossing over occurs during prophase I, increasing genetic diversity by exchanging genetic material between non-sister chromatids.

Question 17

A patient is found to have a mutation that causes their G-proteins to remain permanently bound to GTP. Which of the following is a likely cellular consequence?

Accepted Answer

Continuous activation of downstream signaling pathways, such as persistent cAMP production.

Question 18

A scientist adds a competitive inhibitor to an enzyme-catalyzed reaction and then increases the substrate concentration. What is the expected effect on reaction rate?

Accepted Answer

The reaction rate will increase and may approach the rate without inhibitor.

Question 19

Which of the following best explains why the sodium-potassium pump contributes to the negative membrane potential of animal cells?

Accepted Answer

It moves more positive charges out (3 Na	extsuperscript{+}) than in (2 K	extsuperscript{+}), resulting in a net export of positive charge.

General Biology Module 3 Study Guide – Step-by-Step Guidance

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드