HESI A2 Biology Practice Test 2024

Correct Answer: B

Rationale: The correct answer is B: Mitochondria. Mitochondria are known as the powerhouse of the cell as they produce energy through the process of respiration. They contain enzymes responsible for converting nutrients into ATP, the energy currency of the cell. The nucleus (A) is responsible for storing genetic material, Golgi Apparatus (C) is involved in protein processing and packaging, and Chloroplasts (D) are responsible for photosynthesis in plant cells, not respiration.

Correct Answer: B

Rationale: The genetic information in a eukaryotic cell is stored in the nucleus. This is because the nucleus contains the cell's DNA, which carries the genetic instructions for the cell's functions. The DNA is organized into chromosomes within the nucleus, where it is protected and regulated. The other choices, mitochondria, Golgi Apparatus, and cytoplasm, do not house the cell's genetic information. Mitochondria have their own separate DNA but do not store the cell's overall genetic information. Golgi Apparatus is involved in processing and packaging proteins, while cytoplasm is a fluid-filled space where organelles are located, but neither of them stores the cell's genetic information. Thus, the correct answer is B: Nucleus, as it is the specific organelle where the genetic information of a eukaryotic cell is stored.

Correct Answer: B

Rationale: The correct answer is B: Glycolysis. This is the initial step in the metabolism of food to cellular energy because it involves the breakdown of glucose to produce ATP, the cell's energy currency. Glycolysis occurs in the cytoplasm and does not require oxygen. The Citric Acid Cycle (A) and Electron Transport Chain (C) occur after glycolysis in cellular respiration. Photosynthesis (D) is the process by which plants convert light energy into chemical energy, not the metabolism of food for cellular energy.

Correct Answer: C

Rationale: The correct answer is C: Cytoskeleton. The cytoskeleton provides structural support to the cell, helps maintain its shape, and allows it to adapt to external stimuli. It is composed of microfilaments, intermediate filaments, and microtubules. Microfilaments (choice A) play a role in cell movement but are not primarily responsible for maintaining cell shape. Cytoplasm (choice B) is the gel-like substance within the cell where organelles are suspended, but it does not directly contribute to maintaining cell shape. Centrioles (choice D) are involved in cell division and organization of microtubules, but they do not primarily help the cell maintain its shape and adapt.

Correct Answer: B

Rationale: The slide is typically placed on the stage of a microscope. The stage is the platform where the slide sits for observation. Placing the slide on the stage allows for easy movement and adjustment to focus on different areas of the specimen. The eyepiece is where you look through to view the specimen, the focus knob is used to adjust the focus, and the objective lens magnifies the specimen. The stage is the correct answer because it is where the slide is physically positioned for examination.