HESI A2 Biology 2024

Correct Answer: A

Rationale: The correct order of taxonomic categories from least to most specific is Kingdom, Phylum, Class, Order. This is because taxonomy categorizes organisms based on their shared characteristics, starting from broader groups to more specific ones. Kingdom is the broadest category, followed by phylum, which further narrows down the classification. Class is more specific than phylum, and order is the next level of specificity after class. Therefore, the correct answer is A: Kingdom, phylum, class, order. Choices B, C, and D are incorrect because they do not follow the hierarchical structure of taxonomy. Choice B has the order and class positions switched, choice C has the order and phylum positions switched, and choice D has the class and order positions switched. These alternative choices do not adhere to the principles of taxonomy where classification moves from broader to more specific categories.

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: D

Rationale: The correct answer is D: Fragmentation. Fragmentation is the form of asexual reproduction where an organism breaks into fragments, and each fragment can develop into a new individual. In this scenario, ocean waves tearing sponges into pieces allows each piece to grow into a new sponge, demonstrating fragmentation. A: Budding involves the formation of a new organism from a small outgrowth on the parent organism. This process does not involve breaking the parent organism into pieces. B: Vegetative propagation is a method of asexual reproduction in plants where new individuals are formed from vegetative parts like stems or roots. This does not apply to sponges. C: Binary fission is a form of reproduction seen in single-celled organisms where the cell divides into two identical cells. This process is not applicable to sponges, which are multicellular organisms.

Correct Answer: B

Rationale: The correct answer is B: Amino acids bond. In the final step of protein synthesis, amino acids bond together to form a polypeptide chain. This process occurs on the ribosomes, where transfer RNA delivers the specific amino acids according to the codons on the messenger RNA. DNA unzipping (A) happens during transcription, while transfer RNA bonding to messenger RNA (C) is part of the initiation step of translation. Messenger RNA moving to ribosomes (D) is essential for protein synthesis but is not the final step where amino acids bond.

Correct Answer: B

Rationale: The correct answer is B: Green. Chlorophyll, the pigment responsible for photosynthesis, absorbs light most efficiently in the red and blue regions of the spectrum. Green light is reflected, making it least effective. Violet, orange, and red lights are more readily absorbed by chlorophyll, enhancing photosynthesis. This is due to the specific absorption spectrum of chlorophyll, where green light is least absorbed.