which of the following is necessary for cell diffusion

HESI A2

HESI A2 Practice Test Biology

1. Which of the following is necessary for cell diffusion?

A. water
B. membrane
C. ATP
D. gradient

Correct answer: D

Rationale: The correct answer is 'gradient.' In cell diffusion, substances move from an area of high concentration to an area of low concentration, driven by the concentration gradient. This process does not require water, membrane, or ATP specifically. Water can aid in the movement of substances, but it is not necessary for diffusion itself. The membrane is involved in regulating diffusion but is not a requirement for the process. ATP is not directly involved in simple diffusion processes; instead, it is more related to active transport mechanisms. Therefore, the concentration gradient is essential for cell diffusion to occur.

2. Which cell organelle functions to transport materials from the endoplasmic reticulum throughout the cell?

A. Ribosome
B. Golgi apparatus
C. Lysosome
D. Vacuole

Correct answer: B

Rationale: The Golgi apparatus is the correct answer because it functions to transport materials from the endoplasmic reticulum throughout the cell. Ribosomes are responsible for protein synthesis, not transportation of materials. Lysosomes contain enzymes for digestion and waste removal, not for transporting materials. Vacuoles are primarily involved in storage, waste disposal, and maintaining turgor pressure, not in transporting materials from the endoplasmic reticulum.

3. Select the strand of DNA that would match this segment: ACTTGCA

A. TGAACGT
B. GACCATG
C. ACTTGCA
D. None of the above

Correct answer: A

Rationale: The correct match for the DNA segment ACTTGCA is TGAACGT. In DNA, adenine (A) always pairs with thymine (T), and cytosine (C) always pairs with guanine (G). Therefore, the complementary strand to ACTTGCA should be TGAACGT, making choice A the correct answer. Choice B (GACCATG) does not follow the base pairing rules; hence, it is incorrect. Choice C (ACTTGCA) is the original segment, not its complementary strand. Choice D is incorrect as well because a matching strand does exist.

4. Which organelle organizes protein synthesis?

A. mitochondrion
B. nucleus
C. ribosome
D. vacuole

Correct answer: C

Rationale: Ribosomes are the organelles responsible for organizing protein synthesis. They are the protein factories of the cell, where amino acids are linked together to form proteins. Mitochondria are known as the powerhouse of the cell, responsible for energy production. The nucleus contains the cell's genetic material but does not directly organize protein synthesis. Vacuoles are responsible for storage and maintaining the cell's turgidity.

5. Why is polarity the most important characteristic of water?

A. the results of the polarity are hydrogen bonding, a high specific heat value, and its versatile solvent properties
B. the results of the polarity are covalent bonding, a low specific heat value, and its versatile solvent properties
C. the results of the polarity are ionic bonding, a high specific heat value, and its versatile solvent properties
D. the results of the polarity are hydrogen bonding, a low specific heat value, and its versatile solvent properties

Correct answer: A

Rationale: Polarity is the most important characteristic of water because it results in hydrogen bonding, a high specific heat value, and its versatile solvent properties. These unique properties enable water to form hydrogen bonds with other substances, resist temperature changes, and dissolve a wide variety of solutes, making it essential for life processes. Choice B is incorrect because water exhibits hydrogen bonding, not covalent bonding. Choice C is incorrect as water does not form ionic bonds. Choice D is incorrect because water has a high, not low, specific heat value, which is vital for its role in temperature regulation.