HESI A2 Biology 2024

Correct Answer: D

Rationale: The correct answer is D (46). Humans have 23 pairs of homologous chromosomes, totaling 46 chromosomes. Each pair consists of one chromosome from each parent. Choices A (13), B (23), and C (26) are incorrect as they do not represent the total number of pairs of homologous chromosomes in humans. A and C do not reflect the correct total number of chromosomes, while B only specifies the number of individual chromosomes, not pairs. Therefore, option D is the correct choice because it accurately represents the total number of homologous chromosome pairs in humans.

Correct Answer: C

Rationale: The correct answer is C (50%). In this scenario, the male offspring will inherit the X chromosome with the hemophilia gene from the mother, making him a hemophiliac. The female offspring will inherit one X chromosome with the hemophilia gene, making her a carrier. Therefore, 50% of the offspring are predicted to be carriers only. Option A (0%) is incorrect as carriers will be present. Option B (25%) is incorrect because only male offspring will have hemophilia. Option D (100%) is incorrect as not all offspring will be carriers.

Correct Answer: A

Rationale: The correct answer is A. When messenger RNA reaches the cytoplasm, it attaches to a ribosome for protein synthesis. Ribosomes are the cellular machinery responsible for translating the genetic code carried by mRNA into proteins. Option B is incorrect as mRNA does not "unzip" in the cytoplasm. Option C is incorrect because mRNA does not pair with DNA bases in the cytoplasm; it pairs with ribosomes. Option D is incorrect as mRNA does not "pull free" of the DNA strand in the cytoplasm; it has already been transcribed from DNA in the nucleus.

Correct Answer: D

Rationale: The correct answer is D: Decomposer. Decomposers have the greatest energy efficiency among the given choices because they obtain energy by breaking down organic matter into simpler substances. This process requires less energy compared to the consumption and digestion processes in herbivores, carnivores, and omnivores. Decomposers play a vital role in recycling nutrients in ecosystems. Herbivores, carnivores, and omnivores have lower energy efficiency as they need to expend energy in hunting, digesting, and metabolizing food sources.

Correct Answer: A

Rationale: The correct answer is A: Golgi apparatus. Protists are eukaryotic organisms, so they have membrane-bound organelles like the Golgi apparatus. Monerans, which are prokaryotic organisms, lack membrane-bound organelles. The Golgi apparatus is essential for processing and packaging proteins for secretion or for use within the cell. Chromosomes (B) are found in both protists and monerans, as they contain genetic material. Cytoplasm (C) is a basic component of all cells, found in both protists and monerans. Cell membrane (D) is also present in both protists and monerans, as it is essential for maintaining cell structure and regulating the movement of substances in and out of the cell.