Which of the following actions allows for repolarization of a neuron?
A. The inhibition of sodium and potassium pumps, stopping all ion movement into the neuron
B. The opening of sodium channels, allowing sodium to enter the neuron
C. The closing of both sodium and potassium channels to restrict movement of ions into and out of the neuron
D. The opening of potassium channels allowing potassium to leave the neuron
D. The opening of potassium channels allowing potassium to leave the neuron
The correct answer is d. The opening of potassium channels allowing potassium to leave the neuron. Repolarization of a neuron occurs after an action potential, when the neuron's membrane potential returns to its resting state. This is achieved by the opening of potassium channels, which allows potassium ions to flow out of the neuron. This movement of positively charged ions out of the neuron helps to restore the negative membrane potential.
A. The inhibition of sodium and potassium pumps would not allow for repolarization because these pumps are necessary for maintaining the resting membrane potential.
B. The opening of sodium channels would cause depolarization, not repolarization.
C. The closing of both sodium and potassium channels would restrict ion movement, but it would not allow for repolarization.
Therefore, the Correct Answer is D.
More Questions on TEAS 7 Science
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Q #1: Which of the following is the process in which an ovarian follicle matures and releases a reproductive egg?
A. Oogenesis
B. Menstruation
C. Ovulation
D. Fertilization
Answer Explanation
Ovulation is the process in which an ovarian follicle matures and releases a reproductive egg. During ovulation, the egg is released from the ovary and travels down the fallopian tube where it may be fertilized by sperm.
The other options are not processes in which an ovarian follicle matures and releases a reproductive egg. Oogenesis is the process of egg cell formation, menstruation is the shedding of the uterine lining, and fertilization is the fusion of an egg and sperm to form a zygote.
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Q #2: Which of the following growth curves shows a population that is at its carrying capacity?
A. B
B. C
C. A
D. D
Answer Explanation
A population is said to be at its carrying capacity when it has reached the maximum number of individuals that can be sustained in a particular environment over a prolonged period of time, given the available resources and the prevailing environmental conditions.
In other words, carrying capacity refers to the maximum population size that a given ecosystem can support without being depleted of resources or experiencing environmental degradation. Once a population reaches its carrying capacity, its growth rate slows down and stabilizes, as individuals start to compete more intensely for resources such as food, water, and shelter, and mortality rates increase.
Carrying capacity is an important concept in ecology and population biology because it helps to explain the dynamics of natural populations and how they are influenced by changes in the environment, such as climate change, habitat loss, and human activities.
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Q #3: Which of the following best describes the result of using a catalyst in a chemical reaction?
A. A more desirable product is often formed.
B. The reaction is completed in a shorter amount of time.
C. A greater amount of heat energy is released by the reaction.
D. The yield of product is increased.
Answer Explanation
The result of using a catalyst in a chemical reaction is that the reaction is completed in a shorter amount of time ¹. A catalyst is a chemical substance that affects the rate of a chemical reaction by altering the activation energy required for the reaction to proceed ¹. This process is called catalysis ¹. A catalyst provides an alternative pathway for the reaction, one that has a lower activation energy than the uncatalyzed pathway .
The other options are not correct because they do not accurately describe the result of using a catalyst in a chemical reaction. A more desirable product is not necessarily formed, a greater amount of heat energy is not necessarily released by the reaction, and the yield of product is not necessarily increased as a result of using a catalyst.
