HESI A2
HESI A2 Biology 2024
1. 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.
2. In a phospholipid molecule, the head:
- A. Is hydrophilic
- B. Is hydrophobic
- C. Is on the inner side of the layer
- D. Both A and C
Correct answer: D
Rationale: The head of a phospholipid is hydrophilic (water-loving) and is located on the outer side of the lipid bilayer, interacting with water molecules. This arrangement positions the hydrophobic tails inward, away from water. Therefore, the correct answer is D. Choice A is incorrect because the head is hydrophilic, not hydrophobic. Choice B is incorrect as the head is on the outer side, not the inner side of the layer.
3. Humans, or Homo sapiens, are part of the family ___________.
- A. Animalia
- B. Hominidae
- C. Mammalia
- D. Chordata
Correct answer: B
Rationale: Humans, or Homo sapiens, are part of the family Hominidae, which includes great apes such as gorillas, chimpanzees, and orangutans. This family belongs to the order Primates within the class Mammalia. Choice A (Animalia) refers to the animal kingdom, not the family of humans. Choice C (Mammalia) is the class to which the family Hominidae belongs, not the family itself. Choice D (Chordata) is the phylum to which humans and other animals with a notochord belong, not the specific family.
4. Which bacteria are spherical in shape?
- A. Clostridia
- B. Bacilli
- C. Spirilla
- D. Cocci
Correct answer: D
Rationale: The correct answer is D, Cocci. Bacteria that are spherical in shape are known as cocci. They can be found in various arrangements such as clusters, chains, or pairs. Examples of cocci bacteria include Staphylococcus aureus and Streptococcus pneumoniae. Choice A, Clostridia, consists of rod-shaped bacteria. Choice B, Bacilli, refers to rod-shaped bacteria as well. Choice C, Spirilla, are spiral-shaped bacteria, not spherical.
5. From which component do RNA and DNA derive their names?
- A. From the sugar each contains
- B. From the structure of their nucleotides
- C. From the information they transfer
- D. From their formative processes
Correct answer: A
Rationale: RNA and DNA derive their names from the sugar each contains. RNA stands for Ribonucleic Acid, with 'ribo' indicating the ribose sugar in its structure. DNA stands for Deoxyribonucleic Acid, with 'deoxyribo' referring to the deoxyribose sugar in its structure. The sugars in RNA and DNA molecules distinguish them and are the basis for their names. Choices B, C, and D are incorrect as they do not accurately explain how RNA and DNA derive their names.
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