HESI A2 Practice Test Biology

Correct Answer: B

Rationale: The correct answer is B: Ribosome. Ribosomes are responsible for organizing protein synthesis by translating mRNA into protein. They are the cellular machinery where protein synthesis occurs. The nucleus (A) houses the genetic material but does not directly participate in protein synthesis. Lysosomes (C) are responsible for cellular waste digestion, not protein synthesis. Vacuoles (D) are primarily storage organelles and do not play a direct role in organizing protein synthesis. In summary, the ribosome is the correct answer as it is the key organelle directly involved in protein synthesis within the cell.

Correct Answer: A

Rationale: The correct answer is A: Transcription. During protein synthesis, transcription is the process where an RNA strand is synthesized using DNA as a template. This RNA strand is complementary to the DNA template and serves as a messenger to carry genetic information from the DNA to the ribosomes for translation. Explanation for incorrect choices: B: Translation is the process where the information carried by the mRNA is decoded to produce a protein, not to produce a complementary DNA strand. C: Transfer synthesis is not a recognized term in protein synthesis processes. D: Codon synthesis is not a correct term for the process of producing a complementary DNA strand using an RNA template.

Correct Answer: B

Rationale: The correct answer is B: hemoglobin. Hemoglobin is a protein because it is composed of amino acids linked together in a specific sequence to form a complex structure that carries oxygen in red blood cells. Cellulose (choice A) is a carbohydrate, estrogen (choice C) is a hormone, and ATP (choice D) is a nucleotide that serves as a source of energy in cells. Hemoglobin's role in oxygen transport and its structural composition as a sequence of amino acids classify it as a protein.

Correct Answer: B

Rationale: The correct answer is B: Golgi apparatus. The Golgi apparatus is responsible for modifying, sorting, and packaging proteins and lipids from the endoplasmic reticulum for transport throughout the cell. It receives materials from the ER, processes them, and then directs them to their final destinations. Ribosomes (choice A) are responsible for protein synthesis, lysosomes (choice C) are involved in digestion and waste removal, and vacuoles (choice D) are storage organelles. Therefore, B is the correct answer as it specifically functions in the transportation of materials within the cell.

Correct Answer: D

Rationale: The correct answer is D: gradient. A concentration gradient is necessary for cell diffusion to occur, as it drives the movement of particles from an area of higher concentration to an area of lower concentration. This process does not require ATP (choice C) as it is a passive transport mechanism. While water (choice A) is essential for life and plays a role in cell diffusion, it is not the sole requirement. The presence of a membrane (choice B) is important for regulating the diffusion process but is not the direct driving force behind it. Therefore, the concentration gradient is the critical factor necessary for cell diffusion to take place.