HESI A2
Biology HESI A2 Practice Test
1. Which system maintains the body's balance through the release of hormones directly into the bloodstream?
- A. The gastrointestinal system
- B. The endocrine system
- C. The digestive system
- D. The endocrine system
Correct answer: D
Rationale: The correct answer is D: The endocrine system. The endocrine system maintains the body's balance through the release of hormones directly into the bloodstream. Hormones produced by glands in the endocrine system regulate various bodily functions such as metabolism, growth, and reproduction. This system plays a crucial role in maintaining homeostasis by releasing hormones that help control and coordinate different processes in the body. Choices A, C, and B are incorrect. The gastrointestinal system is responsible for digestion, absorption of nutrients, and excretion of waste; the digestive system includes the gastrointestinal system and other accessory organs; and choice B is a duplicate of the correct answer.
2. Which of the following arrangement is seen in the plasma membrane?
- A. Lipids with embedded proteins
- B. An outer lipid layer and an inner lipid layer
- C. Proteins embedded in lipid bilayer
- D. Altering protein and lipid layers
Correct answer: C
Rationale: The correct arrangement seen in the plasma membrane is proteins embedded in the lipid bilayer. The plasma membrane is composed of a lipid bilayer with embedded proteins. These proteins perform various functions such as transport, signaling, and structural support within the cell membrane. This arrangement allows for the selective permeability of the membrane and facilitates communication between the cell and its environment. Choices A, B, and D are incorrect because the primary arrangement in the plasma membrane involves proteins being embedded in the lipid bilayer, not lipids with embedded proteins, an outer and inner lipid layer, or altering protein and lipid layers.
3. Which of the following is false?
- A. Animal cells use lysosomes to break down old cells
- B. Animal cells use chloroplasts to gain energy
- C. Plant cells have a cell wall to maintain structure
- D. All of the above are true
Correct answer: B
Rationale: The statement "B. Animal cells use chloroplasts to gain energy" is false. Chloroplasts are only present in plant cells and certain algae, where they are responsible for photosynthesis to generate energy from sunlight. Animal cells rely on other organelles, such as mitochondria, for energy production. Choice A is true because animal cells use lysosomes to break down old cells and cellular waste. Choice C is true as plant cells have a cell wall composed of cellulose that provides structural support and protection.
4. 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.
5. How does an enzyme work on a chemical reaction that occurs in a substrate?
- A. An enzyme slows down the chemical reaction.
- B. An enzyme speeds up the chemical reaction.
- C. An enzyme has no effect on the chemical reaction.
- D. An enzyme stops most chemical reactions.
Correct answer: B
Rationale: Enzymes are biological catalysts that facilitate chemical reactions by lowering the activation energy required for the reaction to occur. This allows the reaction to proceed more quickly and efficiently. Enzymes do not change the overall outcome of the reaction, but they significantly increase the rate at which it takes place. Therefore, choice B, 'An enzyme speeds up the chemical reaction,' is the correct answer. Choices A, C, and D are incorrect because enzymes do not slow down, have no effect, or stop chemical reactions; instead, they accelerate the process by lowering the activation energy.
Similar Questions
Access More Features
HESI A2 Basic
$89/ 30 days
- 3,000 Questions with answers
- 30 days access
HESI A2 Premium
$129.99/ 90 days
- Actual HESI A2 Questions
- 3,000 questions with answers
- 90 days access