HESI A2 Practice Test Biology

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.

Correct Answer: D

Rationale: The correct answer is D: DNA. DNA is not directly involved in translation. Translation is the process of synthesizing proteins from mRNA using tRNA and ribosomes. DNA serves as the template for transcription, where mRNA is synthesized. Once mRNA is formed, it carries the genetic information from DNA to the ribosome for translation. tRNA brings in amino acids based on the codons on the mRNA, and the ribosome facilitates the assembly of amino acids into a polypeptide chain. Therefore, DNA is not directly involved in the actual process of translation, making it the correct answer.

Correct Answer: C

Rationale: The correct answer is C, fermentation and cellular respiration, because both are catabolic pathways that lead to cellular energy production. Fermentation occurs in the absence of oxygen, producing a small amount of ATP. Cellular respiration, on the other hand, occurs in the presence of oxygen and is a more efficient process, producing a significantly higher amount of ATP. Choices A, B, and D are incorrect because internal respiration, external respiration, and anaerobic respiration do not directly lead to cellular energy production through catabolic pathways.

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: B

Rationale: The correct answer is B: ATP. ATP (adenosine triphosphate) is the primary molecule responsible for storing and transferring energy in cells through its high-energy phosphate bonds. Glucose (choice A) is a source of energy but not a storage molecule. Fatty acids (choice C) are primarily used for long-term energy storage. Starch (choice D) is a polysaccharide used for energy storage in plants, but ATP is the main energy currency in all cells for immediate use.