HESI A2 Practice Test Biology

Correct Answer: A

Rationale: The correct answer is A because tRNA carries amino acids to the ribosome during protein synthesis. Firstly, tRNA molecules bind to specific amino acids through their anticodon region. Secondly, tRNA recognizes the mRNA codon at the ribosome, ensuring the correct amino acid is added to the growing polypeptide chain. This process is crucial for translating the genetic code into proteins. Choices B, C, and D are incorrect because tRNA does not link nucleotides together, copy DNA sequences, or replicate genetic material during protein synthesis.

Correct Answer: B

Rationale: The correct answer is B: red blood cell. Red blood cells do not have a nucleus because during their maturation process, they eject their nucleus to make more space for hemoglobin which carries oxygen. Without a nucleus, red blood cells have more space to efficiently transport oxygen throughout the body. Platelets (A), white blood cells (C), and phagocytes (D) all have nuclei as they are involved in various cellular functions that require genetic material and the ability to replicate.

Correct Answer: C

Rationale: The correct answer is C: Binary fission. This is because binary fission is a form of asexual reproduction in bacteria where the cell divides into two identical daughter cells. This process does not involve the formation of gametes or genetic recombination, which are characteristics of meiosis. Mitosis is a process seen in eukaryotic cells, not prokaryotic bacteria. Cytokinesis is the final stage of cell division where the cytoplasm divides, which is a part of binary fission but not the overall process of bacterial reproduction.

Correct Answer: B

Rationale: The correct answer is B: Sexual reproduction and asexual reproduction. Sexual reproduction involves the fusion of gametes from two parents to create offspring with genetic variation. Asexual reproduction involves a single parent producing genetically identical offspring. Option A is incorrect because binary fission is a form of asexual reproduction, not sexual reproduction. Option C is incorrect because binary fission is a specific type of asexual reproduction, not the only category. Option D is incorrect because mitosis is a cell division process within asexual reproduction, but it is not a category of cell reproduction on its own.

Correct Answer: A

Rationale: The correct answer is A because DNA contains the genetic information needed for the synthesis of enzymes, which are crucial for metabolic activities in the cell. Enzymes are proteins that catalyze chemical reactions within the cell, allowing essential metabolic processes to occur. DNA serves as a template for the production of specific enzymes through the process of transcription and translation. Choices B, C, and D are incorrect because DNA does not directly play a role in stabilizing the cell wall, initiating cell division, or preventing diffusion of nutrients. These processes are regulated by other cellular components and mechanisms.