HESI A2
Biology HESI A2 2024
1. Why do we perceive chlorophyll as green?
- A. It absorbs yellow and blue light.
- B. It primarily absorbs green light.
- C. It fails to absorb green light.
- D. It primarily absorbs red light.
Correct answer: A
Rationale: Chlorophyll appears green to us because it primarily absorbs yellow and blue light while reflecting green light. The wavelengths of yellow and blue light are absorbed by chlorophyll for photosynthesis, which results in the green color we perceive. Choice B is incorrect because chlorophyll absorbs yellow and blue light, not green light. Choice C is incorrect because chlorophyll does absorb green light, but it also absorbs other wavelengths, primarily yellow and blue. Choice D is incorrect because chlorophyll primarily absorbs yellow and blue light, not red light.
2. Cytosine and thymine are known as:
- A. Purines
- B. Pyrimidines
- C. Both
- D. None of the above
Correct answer: B
Rationale: Cytosine and thymine are known as pyrimidines because they have a single carbon ring structure. Purines, on the other hand, have a double-ring structure. Choice A ('Purines') is incorrect because purines have a double-ring structure, unlike cytosine and thymine. Choice C ('Both') is incorrect as it implies they are both purines and pyrimidines, which is not true. Choice D ('None of the above') is incorrect because cytosine and thymine are indeed pyrimidines.
3. What kind of symbiosis exists between a pneumonia bacterium and a human?
- A. Mutualism
- B. Parasitism
- C. Commensalism
- D. Competition
Correct answer: B
Rationale: In the case of a pneumonia bacterium and a human, the relationship is best described as parasitism. The bacterium benefits by causing harm to the human host, while the human is negatively affected by the presence of the bacterium, leading to illness or infection. This is a classic example of a parasitic relationship where one organism benefits at the expense of the other. Mutualism (Choice A) is a type of symbiotic relationship where both organisms benefit from each other. Commensalism (Choice C) is a symbiotic relationship where one organism benefits, and the other is neither helped nor harmed. Competition (Choice D) refers to a relationship where both organisms are negatively affected by each other as they compete for resources.
4. Where is the genetic information of a eukaryotic cell stored?
- A. Mitochondria
- B. Nucleus
- C. Golgi Apparatus
- D. Cytoplasm
Correct answer: B
Rationale: The correct answer is B: Nucleus. In eukaryotic cells, genetic information (DNA) is stored in the nucleus. This organelle acts as the control center of the cell, housing the DNA and regulating gene expression. Choices A, C, and D are incorrect because the genetic information is not stored in the mitochondria, Golgi Apparatus, or cytoplasm. The mitochondria are responsible for energy production, the Golgi Apparatus is involved in protein processing and packaging, and the cytoplasm is where various cellular activities take place, but none of these organelles store the genetic information.
5. Why do high-salt content foods not require refrigeration to prevent spoilage?
- A. Osmosis
- B. Diffusion
- C. Active transport
- D. Passive transport
Correct answer: A
Rationale: Osmosis is the natural process that prevents high-salt content foods from spoiling without the need for refrigeration. Osmosis involves the movement of water across a semi-permeable membrane from an area of lower solute concentration (water) to an area of higher solute concentration (salt). In high-salt content foods, the salt acts as a preservative by drawing moisture out of bacteria or other microorganisms, making it difficult for them to survive and spoil the food. This process helps in preserving the food and preventing spoilage even without refrigeration. Choices B, C, and D are incorrect because they do not involve the specific mechanism of water movement in response to the salt concentration in high-salt content foods.
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