HESI A2 Biology Practice Test 2024

Correct Answer: B

Rationale: The correct answer is B: DNA. DNA, or deoxyribonucleic acid, is the molecule that stores the genetic code for each person. It is located in the cell nucleus and organized into structures called chromosomes. DNA contains the instructions for building and maintaining an organism, including traits and characteristics. RNA (choice A) is involved in protein synthesis but does not store the complete genetic information. The nucleus (choice C) is the cellular organelle where DNA is located, not the genetic code itself. Chromosomes (choice D) are made up of DNA and proteins and contain the genetic material in a condensed form. Therefore, the correct choice is DNA as it is the primary storage location for the genetic code.

Correct Answer: B

Rationale: Passive transport is the term for the movement of ions and other molecular substances across cell membranes without the need for energy. This process relies on the concentration gradient to drive molecules from an area of high concentration to an area of low concentration. Unlike active transport (choice A), which requires energy, passive transport does not involve energy consumption. Diffusion (choice C) is a type of passive transport where molecules move freely across the membrane. Osmosis (choice D) is a specific type of passive transport involving the movement of water molecules across a selectively permeable membrane.

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: B

Rationale: The correct answer is B: Chloroplasts. Chloroplasts are the organelles responsible for photosynthesis in plant cells. They contain chlorophyll, the pigment that captures sunlight for photosynthesis. Mitochondria (A) are involved in cellular respiration, not photosynthesis. Ribosomes (C) are responsible for protein synthesis, not photosynthesis. Endoplasmic Reticulum (D) is involved in protein and lipid synthesis, not photosynthesis. Therefore, the correct answer is B because chloroplasts are specifically designed for photosynthesis in plant cells.

Correct Answer: B

Rationale: The correct answer is B: Cell. Cells are the fundamental unit of life because they are the basic building blocks of all living organisms. Cells carry out essential functions such as metabolism, growth, and reproduction. Tissues (C) are made up of cells, organs (D) are made up of tissues, and atoms (A) are the smallest unit of matter and are not considered the fundamental unit of life. Therefore, the correct choice is B as it represents the starting point of all living organisms.