ATI RN
ATI Anatomy and Physiology Online Practice
1. Is a cell the basic unit of structure and function of an organism?
- A. True
- B. False
- C. Not Sure
- D. None of the above
Correct answer: A
Rationale: The correct answer is A: True. A cell is indeed the basic unit of structure and function of an organism. Cells are the smallest independently functioning unit in the structure of an organism and carry out vital functions necessary for life. Choice B, False, is incorrect because cells are universally recognized as the fundamental unit of life. Choice C, Not Sure, is incorrect as the role of a cell as the basic unit of an organism's structure and function is a well-established scientific fact. Choice D, None of the above, is incorrect as the statement provided in the question is true.
2. Positive feedback mechanisms usually result in
- A. changes returning values away from a set point.
- B. stable conditions around a set point.
- C. unstable conditions.
- D. long-term changes.
Correct answer: C
Rationale: Positive feedback mechanisms usually result in unstable conditions. In a positive feedback loop, the output enhances or amplifies the changes that are occurring, leading to a deviation from the initial set point. Therefore, positive feedback does not bring values back towards the set point (Choice A). Choice B is incorrect because positive feedback does not promote stability around a set point. Choice D is also incorrect as positive feedback mechanisms typically do not lead to long-term changes; instead, they intensify the initial change, causing instability.
3. Macromolecules are built of?
- A. Monomers
- B. Incorrect
- C. Not Applicable
- D. None of the above
Correct answer: A
Rationale: The correct answer is A: Monomers. Macromolecules are built from smaller subunits called monomers. Monomers join together through chemical reactions to form larger molecules known as macromolecules. Option B is incorrect as it does not provide the accurate information regarding the composition of macromolecules. Option C is not applicable as it does not offer a relevant choice. Option D is incorrect because there is a specific answer related to the composition of macromolecules.
4. Signs of aging at the cellular level are
- A. graying hair, waning strength, and wrinkles.
- B. unrepaired DNA and abnormal proteins.
- C. impaired cell division and the ability to break down and recycle worn cell parts.
- D. a fatty liver and clogged blood vessels.
Correct answer: C
Rationale: The correct answer is 'impaired cell division and the ability to break down and recycle worn cell parts.' Aging at the cellular level involves reduced efficiency in cell division and the breakdown/recycling of cellular components, leading to functional decline. Choices A, B, and D are incorrect because they involve external physical manifestations or organ-specific issues rather than cellular-level changes associated with aging.
5. Which of the following cardiac valves prevents blood from returning to the left ventricle of the heart?
- A. pulmonic
- B. mitral
- C. tricuspid
- D. aortic
Correct answer: D
Rationale: The correct answer is the aortic valve. The aortic valve is located between the left ventricle and the aorta, preventing the backflow of blood into the left ventricle once it has been pumped out during systole. Choice A, pulmonic, is incorrect as it is associated with the right side of the heart. Choice B, mitral, is incorrect as it is the valve between the left atrium and ventricle. Choice C, tricuspid, is incorrect as it is located between the right atrium and ventricle.
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