Nursing Elites

1. What type of genetic variation is caused by changes in the DNA sequence?

• A. Epigenetic variation
• B. Phenotypic variation
• C. Genotypic variation
• D. Behavioral variation

Correct answer: C

Rationale: A) Epigenetic variation refers to changes in gene expression that do not involve alterations in the DNA sequence itself. These changes can be influenced by environmental factors. B) Phenotypic variation refers to differences in observable traits or characteristics of an organism, which can be influenced by both genetic and environmental factors. C) Genotypic variation is caused by changes in the DNA sequence, such as mutations or genetic recombination. These changes directly impact the genetic information carried by an organism. D) Behavioral variation refers to differences in behavior among individuals of the same species, which can be influenced by genetic, environmental, and experiential factors.

2. How many grams of solid CaCO3 are needed to make 600 mL of a 35 M solution? The atomic masses for the elements are as follows: Ca = 40.1 g/mol; C = 12.01 g/mol; O = 16.00 g/mol.

• A. 18.3 g
• B. 19.7 g
• C. 21.0 g
• D. 24.2 g

Correct answer: B

Rationale: 1. First, calculate the molar mass of CaCO3 by adding the atomic masses of Ca, C, and 3 O atoms: 40.1 + 12.01 + (3 * 16.00) = 100.13 g/mol. 2. Calculate the number of moles in 600 mL of a 35 M solution: 600 mL * 35 mol/L = 21,000 mmol. 3. Convert moles to grams using the molar mass of CaCO3: 21,000 mmol * (100.13 g/mol / 1000 mmol/mol) = 2,102.73 g. 4. Therefore, you would need 19.7 g of solid CaCO3 to make 600 mL of a 35 M solution.

3. What structure in plant cells provides rigidity and support?

• A. Cell membrane
• B. Golgi apparatus
• C. Plastid
• D. Cell wall

Correct answer: D

Rationale: The correct answer is D, the cell wall. The cell wall is the structure in plant cells that provides rigidity and support. It is a tough, rigid structure located outside the cell membrane. Composed primarily of cellulose, the cell wall offers structural support to the cell, helping it maintain its shape and protect it from damage. The other choices, such as the cell membrane (choice A), Golgi apparatus (choice B), and plastid (choice C) do not provide rigidity and support to plant cells. The cell membrane is a selectively permeable barrier, the Golgi apparatus is involved in processing and packaging proteins, and plastids are organelles responsible for functions like photosynthesis and storage, but they do not provide the structural support that the cell wall does.

4. Which type of immune cell does the human immunodeficiency virus (HIV) target and destroy?

• A. Neutrophils
• B. Macrophages
• C. Helper T cells
• D. Memory B cells

Correct answer: C

Rationale: HIV targets and destroys Helper T cells, which are vital for coordinating the immune response against infections. The destruction of Helper T cells weakens the immune system, leading to acquired immunodeficiency syndrome (AIDS). Neutrophils (Choice A) are primarily involved in acute inflammatory responses and fighting bacterial infections. Macrophages (Choice B) play a role in phagocytosis and antigen presentation but are not the primary target of HIV. Memory B cells (Choice D) are responsible for mounting a quicker and more robust antibody response upon re-exposure to a pathogen, but they are not the main target of HIV infection.

5. What is the cycle of infection?

• A. Reservoir host, means of exit, means of transmission, means of entrance, susceptible host
• B. Entry point, transmission, replication, exit, susceptible host
• C. Susceptible host, replication, transmission, entry, exit
• D. Transmission, replication, entry, exit, susceptible host

Correct answer: A

Rationale: The correct answer is A: 'Reservoir host, means of exit, means of transmission, means of entrance, susceptible host.' This cycle of infection involves the pathogen starting in a reservoir host, exiting through a means, being transmitted to another host, entering the new host through a means, and ultimately infecting the susceptible host. Choices B, C, and D are incorrect because they do not follow the correct sequence of events in the cycle of infection.

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