why is dna important for metabolic activities of the cell

HESI A2

HESI A2 Practice Test Biology

1. Why is DNA important for metabolic activities of the cell?

A. It controls the synthesis of enzymes.
B. It stabilizes the cell wall.
C. It initiates cell division.
D. It prevents diffusion of nutrients.

Correct answer: A

Rationale: The correct answer is A. DNA plays a crucial role in metabolic activities by controlling the synthesis of enzymes. Enzymes are the biological catalysts that regulate and facilitate metabolic reactions within the cell. Choice B is incorrect because DNA is not involved in stabilizing the cell wall; that role is usually associated with other components like the cell membrane. Choice C is incorrect as cell division is primarily regulated by different processes and molecules, not directly by DNA. Choice D is incorrect because DNA is not related to preventing the diffusion of nutrients; instead, it is involved in coding for proteins that aid in various cellular functions.

2. Select the word that makes the following sentence grammatically correct. The flock huddles against the wind that ruffles ___________ feathers.

A. its
B. their
C. it's
D. they're

Correct answer: A

Rationale: In this sentence, the word 'flock' is singular, so the pronoun that follows should also be singular. Therefore, the correct choice is 'its,' which refers back to the singular noun 'flock.' Choice B ('their') is incorrect because it is a plural pronoun and does not agree in number with the singular noun 'flock.' Choices C ('it's') and D ('they're') are both incorrect contractions that do not fit grammatically in this context.

3. Which type of muscle tissue is found in the walls of hollow organs?

A. Skeletal muscle
B. Cardiac muscle
C. Smooth muscle
D. Striated muscle

Correct answer: C

Rationale: Smooth muscle tissue is found in the walls of hollow organs such as the intestines, blood vessels, and bladder. It contracts involuntarily, allowing for functions like peristalsis in the intestines and regulation of blood flow in blood vessels. Skeletal muscle (Choice A) is attached to bones, cardiac muscle (Choice B) is found in the heart, and striated muscle (Choice D) refers to both skeletal and cardiac muscles due to their striped appearance, but neither of these types are typically found in the walls of hollow organs.

4. What part of the eye is responsible for focusing light on the retina?

A. Cornea
B. Lens
C. Retina
D. Pupil

Correct answer: B

Rationale: The lens of the eye is responsible for focusing light on the retina. When light enters the eye, it first passes through the cornea, which helps in bending the light, and then the lens further refracts and focuses the light onto the retina at the back of the eye. The retina contains photoreceptor cells that convert light into neural signals, which are then sent to the brain for visual processing. The cornea is the transparent outermost layer of the eye that helps in focusing light, but the main responsibility lies with the lens. The retina is the layer at the back of the eye that receives the focused light and initiates the process of vision. The pupil is the opening in the center of the iris that controls the amount of light entering the eye and is not directly involved in focusing light on the retina.

5. Select the meaning of the underlined word in the following sentence. What is the prognosis for those accident victims?

A. Expected outcome
B. Treatment option
C. Fabrication
D. Fabrication

Correct answer: A

Rationale: In this sentence, the word 'prognosis' refers to the expected outcome or forecast for the accident victims. It indicates what is likely to happen in terms of their recovery or overall condition following the accident. Therefore, the correct meaning of the underlined word is the expected outcome, which is option A. Choices B, C, and D are incorrect because 'prognosis' does not refer to a treatment option or fabrication.