HESI A2 Biology Practice Test 2024

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: 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.

Correct Answer: B

Rationale: The correct answer is B: Golgi Apparatus. The Golgi Apparatus is responsible for packaging, processing, and shipping proteins and lipids produced by the endoplasmic reticulum. It modifies these molecules and packages them into vesicles for transport within the cell or secretion outside the cell. The other choices are incorrect because: A: The nucleus contains genetic material and is responsible for regulating cell activities, not packaging and shipping. C: The endoplasmic reticulum is involved in protein synthesis and lipid metabolism, but it is the Golgi Apparatus that processes and packages these molecules. D: Ribosomes are responsible for protein synthesis, not packaging and shipping.

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: B

Rationale: The correct answer is B: Ribosomes. Ribosomes are the organelles responsible for protein synthesis. They are either free-floating in the cytoplasm or attached to the endoplasmic reticulum. Ribosomes read the mRNA and assemble amino acids into proteins during the process of translation. The other choices (A: Endoplasmic Reticulum, C: Lysosomes, D: Vacuoles) are incorrect because the endoplasmic reticulum is involved in protein processing and transport, lysosomes are involved in digestion and waste removal, and vacuoles are involved in storage and maintaining cell structure, not protein synthesis.