HESI A2
Biology HESI A2 Practice Test
1. The mixture of gases surrounding a planet is referred to as its ______.
- A. Atmosphere
- B. Stratosphere
- C. Biosphere
- D. Troposphere
Correct answer: A
Rationale: The mixture of gases surrounding a planet is referred to as its atmosphere. The atmosphere plays a crucial role in supporting life on Earth by providing oxygen, regulating carbon dioxide levels, and shielding the planet from harmful radiation. While the stratosphere, troposphere, and other layers are part of the atmosphere, the term 'atmosphere' encompasses the entire gaseous envelope surrounding a planet. The stratosphere, troposphere, mesosphere, thermosphere, and exosphere are specific layers within the atmosphere, each with distinct characteristics and functions.
2. Bacillus subtilis may be described as ___________.
- A. spiral
- B. globular
- C. rod-shaped
- D. grape-like clusters
Correct answer: C
Rationale: Bacillus subtilis is a rod-shaped bacterium. Its name "Bacillus" refers to its rod-like shape, which is a characteristic feature of this bacteria.
3. The fur color in a population of dogs is controlled by two alleles: black (B) and tan (b). The black allele exhibits complete dominance. If the phenotype of the dog is tan fur, what is its genotype?
- A. BB
- B. Bb
- C. bb
- D. Not enough information
Correct answer: C
Rationale: The correct answer is C: "bb." Since tan fur is the recessive trait controlled by the allele 'b,' the only possible genotype for a dog with tan fur is 'bb.' If a dog had the genotype 'BB' or 'Bb,' the dominant trait (black fur) would be expressed, not tan fur. Choice D, 'Not enough information,' is incorrect because based on the information provided, we can deduce the genotype of a dog with tan fur.
4. How should a researcher test the hypothesis that practicing yoga reduces blood pressure?
- A. Record the blood pressure of one male and one female participant before and after participating in a yoga class.
- B. Divide 30 female participants into two groups with similar average blood pressure; test each participant’s blood pressure after participating in a yoga class.
- C. Divide 30 female participants into two groups with similar average blood pressure; have one group watch television for an hour while the other takes a yoga class, record each participant’s blood pressure after the hour. Repeat daily for two weeks.
- D. Start with 15 men and 15 women; have the men watch television for an hour while the women take a yoga class, record each participant’s blood pressure after the hour. Reverse, having the men take a yoga class while the women watch television.
Correct answer: B
Rationale: Option B is the most appropriate way to test the hypothesis that practicing yoga reduces blood pressure. By dividing 30 female participants into two groups with similar average blood pressure levels and testing each participant's blood pressure after participating in a yoga class, the researcher can effectively evaluate the impact of yoga on blood pressure. This design allows for a comparison between the two groups, helping to isolate the effects of yoga practice on blood pressure. Option A only involves one male and one female participant, which may not provide a representative sample. Option C introduces an additional variable of watching television, which could confound the results. Option D lacks consistency in the experimental design by switching the activities between men and women, making it difficult to attribute any observed changes solely to yoga practice.
5. 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.
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