which neurotransmitter is responsible for stimulat 6720627

ATI TEAS 7

TEAS 7 science practice

1. Which neurotransmitter is responsible for stimulating muscle contraction?

A. Dopamine
B. Acetylcholine
C. Serotonin
D. Norepinephrine

Correct answer: B

Rationale: Acetylcholine is the neurotransmitter responsible for stimulating muscle contraction at the neuromuscular junction. When an action potential reaches the end of a motor neuron, acetylcholine is released into the synaptic cleft and binds to receptors on the muscle cell membrane, leading to muscle contraction. Dopamine, serotonin, and norepinephrine are neurotransmitters that have different functions in the nervous system and are not directly involved in stimulating muscle contraction. Dopamine is involved in reward and pleasure pathways, serotonin regulates mood and behavior, and norepinephrine is involved in the 'fight or flight' response.

2. Which type of cells make up the myelin sheaths?

A. Glial cells.
B. Dendrites.
C. Melanocytes.
D. Squamous cells.

Correct answer: A

Rationale: The correct answer is A: Glial cells. Glial cells are responsible for producing the myelin sheaths that surround and insulate nerve cells in the central and peripheral nervous systems. Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system are types of glial cells that form the myelin sheaths. Choice B, dendrites, are not involved in forming myelin sheaths; they are extensions of neurons that receive signals. Choice C, melanocytes, are cells responsible for producing melanin, not myelin. Choice D, squamous cells, are flat epithelial cells found in various tissues but are not involved in myelin sheath formation.

3. Molecular clocks utilize the accumulation of mutations in DNA sequences to estimate the evolutionary divergence time between species. This method relies on the assumption that:

A. The rate of mutation is constant across all genes and all species.
B. Species with more morphological similarities diverged more recently.
C. Mutations are always beneficial and contribute to increased fitness.
D. The fossil record provides the most accurate estimates of evolutionary relationships.

Correct answer: A

Rationale: A molecular clock is a method used to estimate the time of divergence between species by measuring the accumulation of mutations in DNA sequences. This method relies on the assumption that mutations occur at a relatively constant rate over time. If the rate of mutation were not constant, it would be challenging to accurately estimate the evolutionary divergence time between species. Therefore, option A is the most appropriate choice as it aligns with the fundamental principle underlying the molecular clock hypothesis. Option B is incorrect because the assumption that species with more morphological similarities diverged more recently does not directly relate to the concept of molecular clocks and the accumulation of mutations in DNA sequences. Option C is incorrect because mutations are not always beneficial and do not always contribute to increased fitness. Mutations can be neutral or deleterious as well, and their accumulation is what is used to estimate evolutionary di

4. Anna is planning a trip to Bretagne, or Brittany, in the northwestern part of France. Since she knows very little about it, she is hoping to find information about hiking trails, beaches, restaurants, and accommodations. Which of the following guides will be the best for her to review?

A. The Top Ten Places to Visit in Brittany, published by a non-profit organization in Bretagne aiming to attract tourism to the region
B. Getting to Know Nantes: Eating, Staying, and Sightseeing in Brittany's Largest City, published by the French Ministry of Tourism
C. Hiking Through Bretagne: The Best Trails for Discovering Northwestern France, published by a company specializing in travel for those wanting to experience the outdoors
D. The Complete Guide to Brittany, published by a travel book company that provides guides for travel throughout Europe

Correct answer: C

Rationale: The best guide for Anna to review would be 'Hiking Through Bretagne: The Best Trails for Discovering Northwestern France,' published by a company specializing in travel for those wanting to experience the outdoors. Since Anna is interested in hiking and outdoor activities, a guide that focuses on outdoor trails in Northwestern France would be the most suitable choice. Choice A, 'The Top Ten Places to Visit in Brittany,' may not provide detailed information about hiking trails. Choice B, 'Getting to Know Nantes,' focuses on a specific city and may not cover the broader region of Bretagne. Choice D, 'The Complete Guide to Brittany,' although comprehensive, may not emphasize hiking trails and outdoor experiences as much as choice C.

5. Which verb tense is most appropriate to complete this sentence: 'By next week, I _____ the project'?

A. I will be finishing
B. I will have finished
C. I am finishing
D. I would finish

Correct answer: B

Rationale: The correct answer is option B, 'I will have finished'. This choice correctly expresses a future event (finishing the project) that will be completed before another future point in time (next week). The future perfect tense 'will have finished' is used to show an action that will be completed before a specified future time. Choice A, 'I will be finishing', is incorrect as it indicates an ongoing action that will still be in progress by next week, which is not the intended meaning. Choice C, 'I am finishing', is incorrect as it indicates a present action that is ongoing, not a future event. Choice D, 'I would finish', is incorrect as 'would' is used for hypothetical situations or polite requests, which is not suitable in this context of a future project completion.