which part of cellular respiration produces the greatest amount of atp

HESI A2

Biology HESI A2 Practice Test

1. Which part of cellular respiration produces the greatest amount of ATP?

A. electron transport chain
B. glycolysis
C. citric acid cycle
D. fermentation

Correct answer: A

Rationale: The electron transport chain (ETC) produces the greatest amount of ATP during cellular respiration. This process occurs in the inner mitochondrial membrane and involves the transfer of electrons through a series of protein complexes, creating a proton gradient that drives the synthesis of ATP. By utilizing the energy from the electron carriers NADH and FADH2 produced in earlier stages of cellular respiration, the ETC can generate a large amount of ATP efficiently through oxidative phosphorylation. Glycolysis only produces a small amount of ATP in comparison to the ETC. The citric acid cycle generates some ATP but not as much as the ETC. Fermentation does not produce ATP through oxidative phosphorylation and yields a much smaller amount of ATP compared to the ETC.

2. How should a researcher test the hypothesis that eating chocolate leads to acne in teenagers?

A. Take 100 teenagers and feed each one a different amount of chocolate daily for 60 days; then test for acne.
B. Take 100 teenagers and feed 50 two bars of chocolate daily for 60 days while the other 50 eat no chocolate; then test for acne.
C. Take 1 teenager and feed him or her two bars of chocolate for 30 days and no chocolate for 30 days; then test for acne.
D. Take 100 teenagers and feed them no chocolate for 30 days and two bars of chocolate apiece for 30 days; then test for acne.

Correct answer: B

Rationale: Option B is the correct approach to test the hypothesis that eating chocolate leads to acne in teenagers. This method involves having a control group (50 teenagers not consuming chocolate) and an experimental group (50 teenagers consuming two bars of chocolate daily), which allows for comparison. By having two distinct groups, researchers can assess the impact of chocolate consumption on acne development. Option A lacks a control group for comparison, making it harder to attribute any observed effects specifically to chocolate consumption. Option C only involves a single subject, which limits the generalizability of the results. Option D, where all teenagers experience both conditions, does not allow for a direct comparison between chocolate consumption and acne development, as all subjects are exposed to both conditions.

3. In a strand of DNA, you would expect to see adenine paired with ___________.

A. cytosine
B. uracil
C. thymine
D. guanine

Correct answer: C

Rationale: In a strand of DNA, adenine always pairs with thymine through two hydrogen bonds. This pairing is a fundamental aspect of DNA structure, where adenine and thymine complement each other in the double helix. Choice A (cytosine) is incorrect because adenine does not pair with cytosine in DNA. Choice B (uracil) is incorrect as uracil is found in RNA, not DNA. Choice D (guanine) is incorrect as guanine pairs with cytosine, not adenine, in DNA.

4. Which of the following statements about the respiratory system is true?

A. The respiratory system consists of all the organs involved in breathing
B. Organs included in the respiratory system are the nose, pharynx, larynx, trachea, bronchi, and lungs
C. The respiratory system conveys oxygen into our bodies and removes carbon dioxide from our bodies
D. All of the Above

Correct answer: D

Rationale: The correct answer is D. The respiratory system consists of all the organs involved in breathing, including the nose, pharynx, larynx, trachea, bronchi, and lungs. Additionally, the respiratory system is responsible for conveying oxygen into our bodies and removing carbon dioxide from our bodies. Therefore, all the statements provided are true, making option D the correct choice. Options A, B, and C are all accurate statements about the respiratory system, reinforcing the correctness of choosing option D.

5. Which organelle is the site of energy production?

A. Mitochondrion
B. Vacuole
C. Cell membrane
D. Ribosome

Correct answer: A

Rationale: The correct answer is A: Mitochondrion. The mitochondrion is the site of energy production in a cell. It is often referred to as the powerhouse of the cell because it is where cellular respiration occurs, generating energy in the form of adenosine triphosphate (ATP) through processes like the citric acid cycle and oxidative phosphorylation. The other organelles listed play different roles in the cell - vacuoles store materials, the cell membrane regulates the movement of substances in and out of the cell, and ribosomes are involved in protein synthesis.