HESI A2 Biology Practice Test

Correct Answer: C

Rationale: The correct answer is C because plant cells have a rigid cell wall that prevents them from forming a contractile ring during cell division. The cell wall provides structural support, making it challenging for plant cells to constrict and pinch apart like animal cells. This rigidity limits the flexibility needed for the contractile ring to form and function effectively. Plant cells primarily rely on other mechanisms such as cell plate formation for division. Choices A and B are incorrect as they do not address the specific structural difference between plant and animal cells. Choice D is incorrect as it does not provide any relevant information on the topic.

Correct Answer: D

Rationale: Step-by-step rationale: 1. Diploid organisms can be multicellular or unicellular, so A is not universally true. 2. Diploid cells can be somatic or germ cells, so B is not always true. 3. Diploid cells always have two sets of homologous chromosomes, making C true. 4. Since C is true and A and B are not always true, the correct answer is D.

Correct Answer: D

Rationale: The correct answer is D: They are denoted Aa. Heterozygous traits refer to the presence of different alleles at a specific gene locus. In this case, A and a represent two different alleles for the same trait. When an individual is heterozygous, one allele is dominant (A) and the other is recessive (a). Therefore, the correct notation for a heterozygous trait is Aa. Option A is incorrect because heterozygous traits are not haploid (having one set of chromosomes), but diploid (having two sets). Option B is incorrect as it denotes a homozygous dominant genotype. Option C is incorrect as it denotes a homozygous recessive genotype.

Correct Answer: D

Rationale: The correct answer is D because all the statements mentioned in choices A, B, and C are true. A: The respiratory system consists of all organs involved in breathing, including the nose, pharynx, larynx, trachea, bronchi, and lungs. B: Organs included in the respiratory system are the nose, pharynx, larynx, trachea, bronchi, and lungs. C: The respiratory system conveys oxygen into our bodies and removes carbon dioxide from our bodies. Therefore, as all three statements are true, the correct answer is D - All of the Above. The other choices are incorrect because they do not encompass all the organs involved in the respiratory system or the functions it performs.

Correct Answer: A

Rationale: The correct answer is A: It controls the substances entering and leaving the cell. The cell membrane acts as a selective barrier, regulating the passage of molecules in and out of the cell. It does this through various mechanisms such as protein channels and pumps. This function is crucial for maintaining cellular homeostasis and ensuring the cell's survival. Summary: - B: It maintains the cell's shape: The cell membrane does contribute to the cell's shape but this is not its primary function. - C: It controls the substances entering the cell: This is partially correct, but the cell membrane also controls substances leaving the cell. - D: It supports the cell's structures: While the cell membrane provides some structural support, its main function is controlling the movement of substances.