homeostasis is necessary because

HESI A2

Biology HESI A2 Practice Test

1. Why is homeostasis necessary?

A. It maintains temperature
B. It maintains pH
C. It maintains glucose levels
D. All of the above

Correct answer: D

Rationale: Homeostasis is necessary because it ensures the maintenance of a stable, relatively constant internal environment. This includes regulating various factors such as temperature, pH levels, and glucose levels to support optimal bodily functions and overall health. Choices A, B, and C are all correct as they represent key aspects of homeostasis that contribute to maintaining the body's internal balance.

2. Tundra, savannas, grasslands, deserts, and rainforests are examples of what?

A. Biomasses
B. Biospheres
C. Biodiversity
D. Biomes

Correct answer: D

Rationale: Tundra, savannas, grasslands, deserts, and rainforests are examples of biomes. A biome is a large geographical area with similar climatic conditions and distinct flora and fauna. Each biome has its unique characteristics, such as temperature, precipitation levels, and types of vegetation, which define the ecosystem within that region. Biomasses refer to the total mass of living organisms in a given area, biospheres are the global ecological system integrating all living beings and their relationships, and biodiversity represents the variety of life forms in a specific habitat.

3. During protein synthesis, what process creates a complementary strand of RNA from a DNA template?

A. Transcription
B. Translation
C. Transformation
D. Replication

Correct answer: A

Rationale: The correct answer is 'Transcription.' During protein synthesis, transcription is the process that creates a complementary RNA strand from a DNA template. This process involves the synthesis of mRNA using DNA as a template. Choice B, 'Translation,' is incorrect as it is the process where the genetic code carried by mRNA is decoded to produce a specific polypeptide chain. Choice C, 'Transformation,' is not related to the synthesis of RNA from a DNA template. Choice D, 'Replication,' is the process of copying DNA to produce an identical DNA molecule, not RNA.

4. 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.

5. Which is a byproduct of fermentation in muscle cells?

A. Ethanol
B. Pyruvic acid
C. Lactic acid
D. Oxygen

Correct answer: C

Rationale: Lactic acid is a byproduct of fermentation in muscle cells. During intense exercise or when oxygen is limited, muscle cells use anaerobic respiration to generate energy. This process breaks down glucose into lactic acid, which can cause muscle fatigue and soreness. Choice A, Ethanol, is not produced in muscle cells during fermentation. Choice B, Pyruvic acid, is an intermediate product in glucose metabolism but is not a byproduct of fermentation in muscle cells. Choice D, Oxygen, is not a byproduct of fermentation but a reactant in aerobic respiration.