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. Enzymes are typically _ _.
- A. Fats
- B. Proteins
- C. Sugars
- D. Neurons
Correct answer: B
Rationale: Enzymes are typically proteins that act as biological catalysts, speeding up chemical reactions in living organisms. While most enzymes are made of proteins, a few exceptions, known as ribozymes, are made of RNA. Proteins are composed of amino acids arranged in specific sequences that give enzymes their unique shape and functionality. Choice A, 'Fats,' is incorrect as enzymes are not typically composed of fats. Choice C, 'Sugars,' is incorrect as enzymes are not typically composed of sugars. Choice D, 'Neurons,' is incorrect as neurons are a type of cell in the nervous system, not typically associated with enzymes.
3. Why can animal cells use a contractile ring but plant cells cannot?
- A. Plant cells can use both methods to divide
- B. Animal cells divide faster, requiring them to pinch apart
- C. Plant cells are too rigid to use a contractile ring
- D. N/A
Correct answer: C
Rationale: Plant cells have a rigid cell wall surrounding them, which prevents them from using a contractile ring for cell division. The rigid cell wall requires plant cells to form a cell plate during cell division instead of pinching apart like animal cells with a contractile ring. Choice A is incorrect because plant cells cannot use a contractile ring due to their rigid cell wall. Choice B is incorrect as the speed of cell division is not the primary reason for the difference in cell division mechanisms between plant and animal cells. Choice D is not applicable as plant cells indeed have a specific limitation in using a contractile ring for cell division.
4. What takes place in a lysosome?
- A. Ribosomes are made.
- B. Food is produced.
- C. Water is stored.
- D. Food is digested.
Correct answer: D
Rationale: In a lysosome, food particles are digested through the action of enzymes. Lysosomes are membrane-bound organelles containing digestive enzymes that break down large molecules into smaller ones, allowing the cell to utilize the nutrients for energy and other processes. Choices A, B, and C are incorrect because ribosomes are not made in lysosomes, food is not produced in lysosomes, and lysosomes do not store water.
5. Which organelle is responsible for organizing protein synthesis?
- A. Nucleus
- B. Ribosome
- C. Lysosome
- D. Vacuole
Correct answer: B
Rationale: The correct answer is B: Ribosome. Ribosomes are responsible for organizing protein synthesis by assembling amino acids. They are the cellular machinery where proteins are synthesized. The other choices, such as the nucleus, lysosome, and vacuole, do not directly participate in protein synthesis. The nucleus contains DNA and controls cell activities, the lysosome is involved in digestion and waste removal, and the vacuole is responsible for storage and maintaining cell turgor pressure.
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