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What is the purpose of using PCR (polymerase chain reaction) in the laboratory?

A. To separate DNA fragments by size.

B. To amplify specific regions of DNA.

C. To sequence DNA fragments.

D. To analyze protein expression levels.

Answer Explanation:

The correct answer is choice B.

To amplify specific regions of DNA.

PCR (polymerase chain reaction) is a laboratory technique used to make many copies of a specific region of DNA.

The goal of PCR is to make enough of the target DNA region that it can be analyzed or used in some other way.

PCR has many research and practical applications, including DNA cloning, medical diagnostics, and forensic analysis of DNA.

Choice A is incorrect because PCR does not separate DNA fragments by size. Choice C is incorrect because PCR does not sequence DNA fragments.

Choice D is incorrect because PCR does not analyze protein expression levels.

Therefore, the Correct Answer is B.

Q #1: A patient with a history of heart failure is prescribed a medication that increases urine output to reduce fluid buildup. Which of the following statements best describes the mechanism of action of the prescribed medication?

A. Inhibits the renin-angiotensin-aldosterone system.

B. Blocks beta receptors.

C. Increases sodium and water reabsorption.

D. Enhances glomerular filtration rate.

Answer Explanation

The correct answer is choice D - Enhances glomerular filtration rate.

The medication prescribed to the patient is a diuretic, which removes water and electrolytes from the body by increasing urination 1.

This helps reduce fluid buildup in the body.

Choice A, Inhibits the renin-angiotensin-aldosterone system, is not the correct answer because it describes a different mechanism of action.

Choice B, Blocks beta receptors, is not the correct answer because it describes a different mechanism of action.

Choice C, Increases sodium and water reabsorption, is not the correct answer because it would have the opposite effect of reducing fluid buildup.
Q #2: Which of the following is a mechanism that the body uses to regulate blood pH levels?

A. Increased respiration rate to remove excess CO2.

B. Decreased respiration rate to retain CO2.

C. Increased water intake to dilute the blood.

D. Decreased water intake to concentrate the blood.

Answer Explanation

The correct answer is choice A.

Increased respiration rate to remove excess CO2.

The body regulates blood pH through several mechanisms, including chemical buffers, the respiratory system, and the urinary system.

The respiratory system can adjust blood pH by changing the rate of respiration to remove or retain CO2.

When there is excess acid in the blood, the respiratory rate increases to remove more CO2, which helps to raise blood pH.

Choice B is incorrect because decreasing the respiration rate would retain CO2, which would lower blood pH.

Choice C is incorrect because increased water intake would not directly affect blood pH levels.

Choice D is incorrect because decreased water intake would not directly affect blood pH levels.
Q #3: What is the name of the process in which an atom loses or gains electrons to form an ion?

A. Ionization

B. Oxidation

C. Reduction

D. Isotopic decay

Answer Explanation

Ionization is the process in which an atom loses or gains electrons to form an ion.

An ion is an atom or molecule that has a net electrical charge due to the loss or gain of one or more electrons.

Choice B is not the best answer because oxidation refers to the loss of electrons from an atom or molecule.

Choice C is not the best answer because reduction refers to the gain of electrons by an atom or molecule.

Choice D is not the best answer because isotopic decay refers to the process in which an unstable atomic nucleus loses energy by emitting radiation

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