HESI A2 Practice Test Biology

Correct Answer: B

Rationale: The correct answer is B: Sexual reproduction and asexual reproduction. Sexual reproduction involves the fusion of gametes from two parents to create offspring with genetic variation. Asexual reproduction involves a single parent producing genetically identical offspring. Option A is incorrect because binary fission is a form of asexual reproduction, not sexual reproduction. Option C is incorrect because binary fission is a specific type of asexual reproduction, not the only category. Option D is incorrect because mitosis is a cell division process within asexual reproduction, but it is not a category of cell reproduction on its own.

Correct Answer: D

Rationale: The correct answer is D: gradient. A concentration gradient is necessary for cell diffusion to occur, as it drives the movement of particles from an area of higher concentration to an area of lower concentration. This process does not require ATP (choice C) as it is a passive transport mechanism. While water (choice A) is essential for life and plays a role in cell diffusion, it is not the sole requirement. The presence of a membrane (choice B) is important for regulating the diffusion process but is not the direct driving force behind it. Therefore, the concentration gradient is the critical factor necessary for cell diffusion to take place.

Correct Answer: A

Rationale: The correct answer is A: two diploid cells. During mitosis in humans, a single diploid cell divides into two identical diploid cells. This process ensures that each new cell receives a complete set of chromosomes, maintaining the same genetic information. This is essential for growth, repair, and maintenance of tissues in the body. Choices B, C, and D are incorrect because mitosis results in the production of genetically identical diploid cells, not haploid cells or additional copies of diploid cells. Haploid cells are produced through meiosis, not mitosis.

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: Hydrogen. Water molecules are bonded to each other through hydrogen bonds. In a water molecule, oxygen is more electronegative than hydrogen, creating a partial negative charge on oxygen and a partial positive charge on hydrogen. These opposite charges allow hydrogen bonding to occur between water molecules, where the partially positive hydrogen atom of one molecule is attracted to the partially negative oxygen atom of another molecule. This type of bond is weaker than covalent bonds but crucial for the unique properties of water, such as high surface tension and cohesion. Summary of other choices: A: Ionic - Water molecules do not form ionic bonds with each other. B: Covalent - While water molecules are held together by covalent bonds within the molecule itself, they are not bonded to each other through covalent bonds. D: Molecular - This choice is vague and does not accurately describe the specific type of bonding between water molecules.