Biology HESI A2 2024

Correct Answer: A

Rationale: The correct answer is A because chlorophyll appears green due to its absorption spectrum. It absorbs light most efficiently in the blue and red regions of the spectrum, while reflecting or transmitting green light. This selective absorption of light wavelengths results in chlorophyll appearing green to our eyes. Choice B is incorrect because chlorophyll does not primarily absorb green light. Choice C is incorrect as chlorophyll actually does absorb green light, just not as efficiently as blue and red light. Choice D is incorrect because chlorophyll primarily absorbs red and blue light, not red light alone.

Correct Answer: D

Rationale: In a lysosome, enzymes break down food particles through the process of digestion. This process helps to recycle nutrients and eliminate waste materials. Ribosomes are not made in lysosomes, as they are responsible for protein synthesis. Lysosomes do not produce food but rather break it down. Water storage does not occur in lysosomes. Therefore, the correct answer is D - food is digested in a lysosome.

Correct Answer: C

Rationale: The correct answer is C because yeast carries out fermentation, producing ethanol and carbon dioxide. During fermentation, yeast breaks down sugars in the dough into ethanol and carbon dioxide gas. The carbon dioxide gas gets trapped in the dough, causing it to rise. Choice A is incorrect because yeast does not engage in photosynthesis. Choice B is incorrect because yeast does not carry out photosynthesis at all. Choice D is incorrect because yeast primarily produces carbon dioxide through fermentation, not aerobic respiration.

Correct Answer: B

Rationale: During interphase, the cell prepares for division by replicating its DNA, including the chromosomes. This occurs before the actual cell division stages of mitosis or meiosis. Prophase is the stage where chromosomes condense, not replicate. Anaphase is when sister chromatids separate, and telophase is the final stage where chromosomes de-condense. Therefore, the correct answer is B (Interphase) as it is the specific phase where chromosome replication occurs.

Correct Answer: C

Rationale: The correct answer is C: thymine. In DNA, adenine always pairs with thymine through two hydrogen bonds. This is a fundamental principle known as Chargaff's rule, where A pairs with T and C pairs with G. Thymine is a pyrimidine base, complementing adenine, which is a purine base. Therefore, thymine is the most suitable choice for adenine in a DNA strand. Choices A, B, and D are incorrect because adenine does not pair with cytosine (A), uracil (B), or guanine (D) in DNA.