HESI A2 Biology Practice Test

Correct Answer: A

Rationale: The correct answer is A because water is a raw material for the light reactions in photosynthesis, specifically in the process of photolysis where water is split to release electrons for the photosystems. Without enough water, this process is hindered, leading to a drop in photosynthetic rate. Choice B is incorrect because carbon dioxide availability affects the Calvin cycle, not the light reactions. Choice C is incorrect as carbon atoms for sugar come from carbon dioxide, not water. Choice D is incorrect because fermentation is not directly related to the availability of water in photosynthesis.

Correct Answer: D

Rationale: The correct answer is D because mitosis is essential for the growth and repair of body tissues. During mitosis, a cell divides to produce two identical daughter cells with the same genetic information as the parent cell. This process is crucial for replacing damaged or dead cells, allowing for growth and tissue repair. A is incorrect because mitosis does not involve the fusion of male and female gametes, which is a process called fertilization. B is incorrect because mitosis actually maintains genetic consistency within a species by producing genetically identical cells. C is incorrect because mitosis typically produces cells that are very similar to the parent cell, ensuring the preservation of genetic information and function.

Correct Answer: A

Rationale: The correct answer is A: A segment of DNA. Genes are segments of DNA that contain the instructions for building proteins and controlling various processes in an organism. DNA is the genetic material that carries hereditary information and is passed down from parents to offspring. Option B is incorrect because genes are not bead-like structures on chromosomes but are located within chromosomes. Option C is incorrect because genes are not protein molecules themselves but may code for proteins. Option D is incorrect because genes are not made up of RNA but rather DNA.

Correct Answer: B

Rationale: The correct answer is B: Create energy. Mitochondria are known as the powerhouse of the cell because they produce ATP, the primary energy source for cellular functions. They do this through a process called cellular respiration. Option A is incorrect as the nucleus controls the cell. Option C is incorrect as protein synthesis occurs in the ribosomes. Option D is incorrect as waste packaging is typically done by lysosomes.

Correct Answer: C

Rationale: The correct answer is C: Prometaphase. This phase of mitosis is characterized by the disintegration of the nuclear envelope. During prometaphase, the breakdown of the nuclear envelope allows the spindle fibers to access the chromosomes. This is crucial for the proper alignment and separation of the chromosomes during mitosis. In prophase (choice A), the nuclear envelope starts to break down but is not fully disintegrated. In metaphase (choice D), the nuclear envelope is already broken down, and the chromosomes are aligned at the metaphase plate. Therefore, prometaphase is the specific phase where the nuclear envelope completely disintegrates, making it the correct answer.