HESI A2 Biology 2024

Correct Answer: B

Rationale: During glycolysis, glucose is broken down into molecules of pyruvic acid through a series of enzymatic reactions. This process occurs in the cytoplasm of cells and is the first step in cellular respiration. Pyruvic acid can then enter the citric acid cycle (Kreb's cycle) to further generate ATP. Choice A is incorrect because glucose's energy is not entirely lost but rather partially captured in the form of ATP. Choice C is incorrect as glucose is not stored in NADH but rather NADH is generated during glycolysis. Choice D is incorrect as glucose does not join with molecules of citric acid during glycolysis but rather pyruvic acid is the end product.

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 because it involves testing the impact of radiation from a single cell phone on the temperature of water in a test tube in a controlled manner. By letting the phone ring for two minutes and recording the temperature before and after, the researcher can isolate the effects of radiation. Choice B introduces additional variables by varying the ringing time, making it difficult to determine the specific impact of radiation. Choice C introduces the factor of different cell phone brands, which may have varying radiation levels and could confound the results. Choice D also introduces multiple variables by using different ringing times and phone brands, making it challenging to attribute any temperature changes solely to radiation from the cell phones. Therefore, choice A is the most appropriate as it ensures a controlled experiment to directly test the hypothesis regarding the impact of cell phone radiation on water temperature.

Correct Answer: B

Rationale: The correct answer is B (25%). When two heterozygous parents (Hh) with Huntington's disease reproduce, they can produce offspring with genotypes HH, Hh, or hh. The only genotype that results in the disease is HH. Therefore, 25% of the offspring are predicted to be disease-free (hh), as they would inherit the recessive allele from both parents. The other choices are incorrect because 0% is not possible since the parents are heterozygous, 50% would mean all offspring are disease-free which is not the case, and 100% would mean all offspring have the disease, which is also not true.

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.