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.
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.
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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.
More Questions on TEAS 7 Science
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Q #1: A nurse is caring for a patient who has suffered a traumatic brain injury after falling from a height. The nurse knows that the severity of the injury depends on the speed at which the patient hit the ground. Which of the following factors affects the terminal velocity of a falling object?
A. The shape and surface area of the object.
B. The mass and volume of the object.
C. The acceleration and momentum of the object.
D. The height and distance of the fall.
Answer Explanation
The correct answer is choice A.
The shape and surface area of the object.
The terminal velocity of an object falling through a fluid is affected by several factors, including its mass and shape.
Objects with large surface areas will often experience a large amount of air resistance when they move.
Choice B is incorrect because the volume of the object does not affect its terminal velocity.
Choice C is incorrect because the acceleration and momentum of the object do not affect its terminal velocity.
Choice D is incorrect because the height and distance of the fall do not affect the terminal velocity of a falling object.
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Q #2: Which process involves the fusion of male and female gametes resulting in the formation of a zygote?
A. Oogenesis.
B. Fertilization.
C. Meiosis.
D. Mitosis.
Answer Explanation
Fertilization.
Fertilization is the process by which male and female gametes fuse to form a zygote.
Oogenesis (choice A) is the process by which female gametes, or eggs, are produced.
Meiosis (choice C) is a type of cell division that results in the formation of gametes.
Mitosis (choice D) is a type of cell division that results in the formation of two identical daughter cells.
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Q #3: 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.
