cells that line the inner or outer surfaces of organs or body cavities are often linkedt ogether by intimate physical connections these connections ar

HESI A2

Biology HESI A2 Practice Test

1. Cells that line the inner or outer surfaces of organs or body cavities are often linked together by intimate physical connections. These connections are referred to as ______.

A. Separate desmosomes
B. Ronofilaments
C. Tight junctions
D. Fascia adherens

Correct answer: C

Rationale: The correct answer is C: Tight junctions. Tight junctions, also known as zonula occludens, are the intimate physical connections between cells that line the inner or outer surfaces of organs or body cavities. These junctions form a virtually impermeable barrier to fluid, creating a tight seal between the cells. This helps in maintaining the integrity and function of the tissue as well as regulating the movement of substances across the cell layer. Choice A, Separate desmosomes, are cell structures that provide strong adhesion between cells but do not create a barrier to fluid. Choice B, Ronofilaments, is not a term used to describe the connections between cells. Choice D, Fascia adherens, are another type of cell junction involved in cell adhesion, but they are different from tight junctions in terms of their structure and function.

2. What are the three main events of the haploid cell cycle?

A. DNA replication, mitosis, and cytokinesis
B. DNA replication, meiosis, and cytokinesis
C. DNA replication, cytokinesis, and degradation
D. Mitosis, meiosis, and apoptosis

Correct answer: A

Rationale: In the haploid cell cycle, the three main events are DNA replication, where the cell's genetic material is duplicated; mitosis, which is the division of the nucleus to ensure each daughter cell receives a complete set of chromosomes; and cytokinesis, the division of the cell cytoplasm to separate the two daughter cells. Meiosis is not part of the haploid cell cycle as it occurs in diploid cells to produce haploid gametes. Apoptosis is a process of programmed cell death and is not a routine event in the cell cycle. Therefore, the correct answer is A. Choices B, C, and D are incorrect as meiosis and apoptosis are not part of the haploid cell cycle, and degradation is not a typical event in the cell cycle.

3. In an example of a male with hemophilia and a female carrier, what percentage of the offspring is predicted to be carriers only?

A. 0%
B. 25%
C. 50%
D. 100%

Correct answer: C

Rationale: In this scenario, the male offspring will inherit the X chromosome with the hemophilia gene from the mother, as males have one X chromosome inherited from their mother. The female offspring will inherit one normal X chromosome from the father and one X chromosome with the hemophilia gene from the mother, making them carriers of the hemophilia trait. Therefore, 50% of the offspring will be carriers only. Option A (0%) is incorrect as female offspring will inherit the X chromosome with the hemophilia gene from the mother. Option B (25%) is incorrect as the female offspring will not be unaffected. Option D (100%) is incorrect as not all offspring will be carriers, only the female offspring.

4. Which of the following is true of heterozygous traits?

A. They are haploid
B. They are denoted AA
C. They are denoted aa
D. They are denoted Aa

Correct answer: D

Rationale: Heterozygous traits are denoted by having two different alleles for a particular gene, represented as Aa. This means that they are not haploid (A), not denoted AA (B), and not denoted aa (C). Therefore, the correct answer is D, as heterozygous traits are represented as Aa.

5. What provides the cell with the ability to move and propel?

A. Microfilaments
B. Microtubules
C. Flagella
D. Cilia

Correct answer: B

Rationale: Microtubules are the cellular structures responsible for cell movement and propulsion. Microtubules are part of the cytoskeleton and play a crucial role in various cellular processes, including cell motility and intracellular transport. While microfilaments also contribute to cell movement by enabling muscle contraction and cell shape changes, they are not primarily responsible for propelling the cell. Flagella and cilia are cellular appendages involved in cell movement, but they are composed of microtubules, making them the structures that move due to the actions of microtubules.