HESI A2 Biology Practice Test 2024

Correct Answer: B

Rationale: The main function of ribosomes is protein synthesis. Ribosomes are responsible for translating the genetic information encoded in mRNA into proteins. This process involves decoding the mRNA sequence and linking amino acids together to form a protein. Ribosomes do not participate in DNA replication (Choice A), lipid breakdown (Choice C), or cell division (Choice D). DNA replication occurs in the nucleus, lipid breakdown is carried out by enzymes in the cytoplasm, and cell division involves processes such as mitosis and cytokinesis. Therefore, the correct answer is B because ribosomes are directly involved in protein synthesis.

Correct Answer: B

Rationale: The correct answer is B: Active Transport. Active transport moves substances across the cell membrane against the concentration gradient, requiring energy (usually in the form of ATP). This process is crucial for maintaining cellular homeostasis and allowing the cell to accumulate essential molecules. Passive transport (A) does not require energy and moves substances along the concentration gradient. Facilitated diffusion (C) is a type of passive transport that involves the use of transport proteins to move specific molecules across the membrane. Osmosis (D) is the movement of water across a selectively permeable membrane, also considered a type of passive transport.

Correct Answer: A

Rationale: Mitosis is the correct answer because it is the process of cell division in which a single cell divides into two daughter cells that are genetically identical to the parent cell. This process involves several stages such as prophase, metaphase, anaphase, and telophase, where the genetic material is replicated and evenly distributed to the daughter cells. Meiosis, on the other hand, results in four daughter cells with genetic variation, not identical genetic material. Binary fission is a form of asexual reproduction in prokaryotic cells, not eukaryotic cells like mitosis. Budding is a type of asexual reproduction seen in some organisms where a new individual develops as an outgrowth of the parent cell, not resulting in two daughter cells with identical genetic material.

Correct Answer: C

Rationale: The correct answer is C: 4. Mitosis consists of four phases: prophase, metaphase, anaphase, and telophase. In prophase, chromosomes condense. In metaphase, chromosomes align at the cell equator. In anaphase, sister chromatids separate and move to opposite poles. In telophase, the nuclear envelope reforms. Choices A, B, and D are incorrect because mitosis is a complex process that involves more than 2 or 3 phases.

Correct Answer: A

Rationale: The correct answer is A: ATP. ATP (adenosine triphosphate) is the primary molecule responsible for providing energy to the cell. It stores and transfers energy within cells for various cellular processes. ATP releases energy when the third phosphate group is cleaved off, forming ADP (adenosine diphosphate). DNA (B) is responsible for storing genetic information, not energy. ADP (C) is a product of ATP hydrolysis and not the primary energy molecule itself. Glycogen (D) is a polysaccharide stored in cells for energy reserves, but it is not the primary molecule responsible for providing energy to the cell.