HESI A2 Biology 2024

Correct Answer: C

Rationale: The correct answer is C because counting birds at the same feeder at two different times (noon and 6:00 P.M.) provides a more accurate representation of bird activity throughout the day. This method allows the student to observe any variations in bird populations at different times, capturing potential fluctuations in activity levels. Choice A (counting birds at one feeder every 6 hours) may miss out on important changes in bird presence during different times of the day. Choice B (counting birds at three feeders at noon and 6:00 P.M.) increases the complexity and potential for errors in data collection. Choice D (counting birds at three feeders every 6 hours) may lead to redundancy and a lack of focus on specific feeding areas.

Correct Answer: A

Rationale: Hydrolysis is the correct term for the breakdown of glycogen into glucose subunits. During hydrolysis, a water molecule is used to break the bonds between glucose molecules in glycogen, resulting in the release of individual glucose units. This process is catalyzed by enzymes like glycogen phosphorylase. Reduction is the gain of electrons, not relevant here. Metabolism is a broad term encompassing all chemical reactions in the body, not specific to glycogen breakdown. Transpiration is the loss of water vapor from plants, not related to the breakdown of glycogen.

Correct Answer: A

Rationale: The correct answer is A: From the sugar each contains. RNA and DNA derive their names from the type of sugar molecule they contain. RNA stands for Ribonucleic Acid, where "ribo" refers to the sugar ribose, and DNA stands for Deoxyribonucleic Acid, where "deoxyribo" refers to the sugar deoxyribose. This naming convention is based on the specific type of sugar present in each nucleic acid. Summary: - B: From the structure of their nucleotides: While the structure of nucleotides is important in understanding RNA and DNA, it is not the basis for their names. - C: From the information they transfer: While RNA and DNA do transfer genetic information, this is not the primary reason for their names. - D: From their formative processes: The naming of RNA and DNA is not based on their formative processes but rather on the type of sugar they contain.

Correct Answer: C

Rationale: Rationale: 1. The Krebs cycle produces ATP (A), CO2 (B), and NADH (D) as products. 2. Glucose (C) is not directly produced by the Krebs cycle; glucose is the starting molecule that enters glycolysis before the Krebs cycle. Summary: A, B, and D are products of the Krebs cycle, while glucose (C) is not directly produced by the Krebs cycle but is a substrate for glycolysis.

Correct Answer: B

Rationale: The correct answer is B: Virus. A virus is a structure composed of a core of nucleic acid (either RNA or DNA) surrounded by a protein coat. This structure allows viruses to infect host cells and replicate. Blue-green algae (option C) are photosynthetic organisms composed of cells with chlorophyll. RNA (option A) is a type of nucleic acid but does not necessarily have a protein coat. Saprophytes (option D) are organisms that obtain nutrients from decaying organic matter and do not typically have a core of nucleic acid surrounded by a protein coat.