Q: Which of the following best illustrates the central dogma of molecular biology?

$$\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}$$

Question 1

Which of the following best explains why oxygen ($$O_2) is $$essential for efficient ATP production during cellular respiration in human cells?

Accepted Answer

Oxygen is the final electron acceptor in the electron transport chain, allowing for the generation of a proton gradient used to produce ATP.

Question 2

A plant is exposed to a toxin that specifically inhibits the function of Photosystem II (PSII). Which of the following outcomes would you expect?

Accepted Answer

The plant will not produce $$O_2$$ and ATP production in the light reactions will decrease.

Question 3

Which of the following best describes the role of second messengers such as cAMP in cell signaling?

Accepted Answer

They amplify the signal from the cell surface receptor, allowing for a rapid and widespread cellular response.

Question 4

A mutation causes a cell to lose its G1 checkpoint control. Which of the following is the most likely consequence?

Accepted Answer

The cell may begin uncontrolled division, increasing the risk of cancer.

Question 5

Which process increases genetic variation during meiosis?

Accepted Answer

Crossing over between homologous chromosomes during prophase I.

Question 6

A woman is a carrier for a recessive X-linked disorder. If she has a child with a man who does not have the disorder, what is the probability that their son will have the disorder?

Accepted Answer

$$50\%$$

Question 7

Which of the following statements about DNA replication is correct?

Accepted Answer

The lagging strand is synthesized in short fragments called Okazaki fragments.

Question 8

Which of the following best illustrates the central dogma of molecular biology?

Accepted Answer

$$	ext{DNA} ightarrow 	ext{RNA} ightarrow 	ext{Protein}$$

Question 9

A mutation changes a codon from $$UAC ($$tyrosine) to $$UAA ($$stop codon). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 10

In the lac operon of E. coli, what happens when lactose is present?

Accepted Answer

The repressor is inactivated, allowing RNA polymerase to transcribe the operon.

Question 11

Which of the following is a direct product of the Calvin cycle in photosynthesis?

Accepted Answer

G3P (glyceraldehyde-3-phosphate)

Question 12

A cell with 8 chromosomes undergoes mitosis. How many chromosomes will each daughter cell have after cytokinesis?

Accepted Answer

8

Question 13

Which of the following best describes the difference between benign and malignant tumors?

Accepted Answer

Benign tumors do not spread to other tissues, while malignant tumors can invade and metastasize.

Question 14

Which of the following events occurs during anaphase of mitosis?

Accepted Answer

Sister chromatids are pulled apart toward opposite poles.

Question 15

A diploid cell ($$2n = 6) $$undergoes meiosis. What is the chromosome number in each resulting gamete?

Accepted Answer

3

Question 16

Which of the following is a function of G-protein coupled receptors in cell signaling?

Accepted Answer

They activate intracellular G-proteins, which then trigger downstream signaling pathways.

Question 17

Which scientist(s) provided evidence for the semiconservative model of DNA replication?

Accepted Answer

Meselson and Stahl

Question 18

Which of the following is a source of genetic variation unique to sexual reproduction?

Accepted Answer

Crossing over during meiosis

Question 19

Which of the following best describes epigenetic regulation of gene expression?

Accepted Answer

Chemical modifications to DNA or histones that affect gene expression without changing the DNA sequence.

Question 20

A patient has a mutation in a tumor suppressor gene. What is the most likely effect of this mutation?

Accepted Answer

The risk of uncontrolled cell division and cancer increases.

Comprehensive Study Notes: Cellular Respiration, Photosynthesis, Cell Communication, Cell Cycle, Genetics, and Molecular Biology

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