HESI A2 Practice Test Biology

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: C

Rationale: The correct answer is C: Synthesize proteins. Ribosomes are responsible for protein synthesis in the cell by translating mRNA into specific amino acid sequences. They are composed of rRNA and protein subunits. Ribosomes do not break down cellular waste (A), organize cellular division (B), or provide cellular structure (D). Cellular waste breakdown is typically performed by lysosomes, cellular division is organized by the centrosome, and cellular structure is maintained by the cytoskeleton.

Correct Answer: C

Rationale: The correct answer is C: four. DNA is composed of four different types of nucleotides: adenine (A), thymine (T), cytosine (C), and guanine (G). Each nucleotide consists of a nitrogenous base, a sugar (deoxyribose), and a phosphate group. These four nucleotides form complementary base pairs, which are essential for DNA replication and protein synthesis. The other choices are incorrect because DNA is made up of multiple nucleotides with specific base pairings, not just one or two types. Therefore, the correct answer is C: four.

Correct Answer: C

Rationale: The correct answer is C: Supply electrons in the light reactions. In photosynthesis, water molecules are split during the light reactions of photosynthesis, releasing electrons that are used to drive the electron transport chain. This process generates ATP and NADPH, which are essential for the synthesis of glucose in the Calvin cycle. Water does not combine with carbon dioxide (A), absorb light energy (B), or transport hydrogen ions in the dark reactions (D) during photosynthesis.

Correct Answer: D

Rationale: The correct answer is D because DNA controls the synthesis of enzymes, which are essential for carrying out metabolic activities in the cell. Enzymes are biological catalysts that regulate chemical reactions in the cell. DNA contains the genetic information needed to produce specific enzymes through the process of transcription and translation. Enzymes play a crucial role in breaking down nutrients, synthesizing molecules, and regulating metabolic pathways. A: DNA does not initiate cellular mitosis; that is controlled by other molecules. B: DNA is not responsible for providing cell wall stability; that is primarily the role of the cell wall structure itself. C: DNA is not directly involved in increasing glucose absorption; that is regulated by other mechanisms such as insulin signaling.