Biology HESI A2 2024

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: D

Rationale: The correct answer is D: Carbohydrates. Glucose is a type of simple sugar and a carbohydrate. Carbohydrates are composed of carbon, hydrogen, and oxygen in a 1:2:1 ratio, which is the molecular formula of glucose (C6H12O6). Proteins (choice A) are composed of amino acids, lipids (choice B) are composed of fatty acids and glycerol, and nucleic acids (choice C) are composed of nucleotides. Therefore, only carbohydrates, specifically glucose, contain the specific molecular structure that characterizes glucose.

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.

Correct Answer: B

Rationale: The correct answer is B: Both are prokaryotes. Rationale: 1. Bacteria and blue-green algae lack a true nucleus, membrane-bound organelles, and have a simpler cellular structure, indicating they are prokaryotes. 2. Prokaryotes are distinct from eukaryotes, which have a true nucleus and membrane-bound organelles. 3. Gymnosperms (choice A) are seed-producing plants, not related to bacteria or blue-green algae. 4. Autotrophs (choice C) can include plants, algae, and some bacteria, but not all bacteria are autotrophs. 5. Pathogens (choice D) are disease-causing agents, not a characteristic that defines the classification of bacteria and blue-green algae.

Correct Answer: A

Rationale: The correct answer is A: Stamen. The stamen is the male reproductive organ of a flower, producing pollen containing male gametes. The pistil, stigma, and style are all parts of the female reproductive system, involved in receiving pollen and supporting the development of seeds. Therefore, the stamen is of a different "gender" than the others, making it the correct choice. Stigma and style are specifically part of the pistil, which is the female organ of the flower.