HESI A2 Biology 2024

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: B

Rationale: The correct answer is B because it involves testing the hypothesis in a controlled manner. By dividing participants into two groups with similar average blood pressure, any observed changes can be more confidently attributed to the yoga practice. Testing each participant's blood pressure after participating in a yoga class allows for individual assessment and comparison within the groups. This design helps isolate the effect of yoga on reducing blood pressure by controlling for other variables. Option A lacks a control group for comparison, making it difficult to determine if the changes in blood pressure are solely due to yoga practice. Option C introduces an additional variable (watching television) in one group, which could confound the results. Option D introduces gender as a variable, which could also affect the results. By eliminating these potential confounding factors, option B provides a more valid and reliable test of the hypothesis.

Correct Answer: A

Rationale: During anaphase, the correct answer is A because it is the phase where chromosomes move to opposite ends of the spindle. This separation ensures that each new cell receives a complete set of chromosomes. Choice B is incorrect because nuclear membrane and nucleoli disintegrate during prophase, not anaphase. Choice C is incorrect as chromatids line up at the center of the spindle during metaphase. Choice D is incorrect as the nuclear membrane and nucleoli do not form during anaphase but rather re-form during telophase.

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: 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.