Biology HESI A2 Practice Test

Correct Answer: C

Rationale: Correct Answer: C Rationale: 1. Sexual reproduction involves two cells (sperm and egg) contributing genetic material to offspring, leading to genetic variation. 2. Greater genetic variation in offspring helps in adapting to changing environments and enhances species survival. 3. Asexual reproduction involves a single parent cell dividing to produce genetically identical offspring. 4. Option A is incorrect as sexual reproduction does not result in half of the cells being identical to the original cell. 5. Option B is incorrect as asexual reproduction does not result in greater variation, it produces genetically identical offspring. 6. Option D is incorrect as sexual reproduction involves two cells contributing genetic material, leading to variation.

Correct Answer: C

Rationale: The correct answer is C. Antibiotics do not cause more bacteria to grow; in fact, they aim to kill or inhibit the growth of bacteria. Antibiotics interfere with the bacteria's ability to survive by targeting specific processes essential for their growth and reproduction (A). They can affect how bacteria multiply by inhibiting cell wall synthesis, protein synthesis, or DNA replication (B). Lastly, antibiotics specifically target bacteria and do not work on viruses or fungi (D). Therefore, choice C is the only statement that is not true about antibiotics.

Correct Answer: C

Rationale: The correct answer is C: Uracil. DNA bases consist of Adenine, Thymine, Cytosine, and Guanine, whereas Uracil is only found in RNA. DNA uses Thymine, while RNA uses Uracil as one of its bases. Therefore, Uracil is not a part of DNA bases. Adenine, Thymine, and Cytosine are all essential components of DNA.

Correct Answer: C

Rationale: Exocytosis is the process by which cells expel waste products out of the cell. It is essential for maintaining cellular homeostasis and preventing the accumulation of toxic substances. Through exocytosis, cells can remove waste such as by-products of metabolism or harmful substances. This process helps keep the cell environment clean and functional. A: Cells obtain energy through processes like cellular respiration, not exocytosis. B: Cells defend against invaders through immune responses, not exocytosis. D: Cell division occurs through processes like mitosis, not exocytosis.

Correct Answer: B

Rationale: The correct answer is B: mitochondria. Heart muscle cells require a significant amount of energy to constantly contract and pump blood, making mitochondria crucial for energy production through aerobic respiration. Mitochondria are abundant in heart muscle cells to meet their high energy demands. Lysosomes (A) are involved in cellular waste disposal, mRNA (C) carries genetic information, and ribosomes (D) are involved in protein synthesis, but they are not expected to be unusually high in heart muscle cells.