ATI TEAS 7
Chemistry
1. Which of the following is a characteristic of a solution with a high viscosity?
- A. It flows easily
- B. It has a low resistance to flow
- C. It has a high resistance to flow
- D. It does not mix with other liquids
Correct answer: c
Rationale: Solutions with high viscosity have a high resistance to flow. The other choices do not accurately describe high viscosity.
2. What is the main function of calcitonin, a hormone produced by the thyroid gland?
- A. Stimulate metabolism and heat production
- B. Increase calcium absorption from the intestines
- C. Enhance bone growth and development
- D. Lower blood calcium levels
Correct answer: D
Rationale: The correct answer is D: 'Lower blood calcium levels.' Calcitonin is a hormone produced by the thyroid gland that helps regulate calcium levels in the blood. It works by inhibiting the breakdown of bone, which in turn lowers the amount of calcium released into the bloodstream. This process helps to decrease blood calcium levels when they are too high. Options A, B, and C are not functions of calcitonin; instead, they are more closely associated with other hormones such as thyroid hormones, vitamin D, and growth hormone, respectively.
3. The measurable electrical activity of the brain is recorded by a:
- A. CAT scan
- B. MRI scan
- C. Electroencephalogram (EEG)
- D. X-ray
Correct answer: C
Rationale: The correct answer is C: "Electroencephalogram (EEG)". An EEG is a non-invasive test that measures the electrical activity of the brain by placing electrodes on the scalp. It is specifically designed to record brain wave patterns, making it a valuable tool in diagnosing conditions such as epilepsy, sleep disorders, and brain injuries. A CAT scan (A) and MRI scan (B) are imaging techniques that show the structure of the brain, while an X-ray (D) is not typically used to measure brain electrical activity.
4. What is the function of ribosomal RNA (rRNA)?
- A. Carries amino acids to the ribosomes
- B. Reads th(a) Carries amino acids to the ribosomes: This is the function of transfer RNA (tRNA), not ribosomal RNA. (b) Reads the genetic code on mRNA: This is the function of the ribosomes as a whole, not just the ribosomal RNA. (d) Controls the rate of protein synthesis: This is a more complex process involving various factors, not solely ribosomal RNA. e genetic code on mRNA
- C. Forms the structural framework of ribosomes
- D. Controls the rate of protein synthesis
Correct answer: C
Rationale: Rationale: Ribosomal RNA (rRNA) plays a crucial role in forming the structural framework of ribosomes, which are the cellular organelles responsible for protein synthesis. Ribosomes consist of both protein and rRNA components, with rRNA providing the structural support necessary for the ribosome to function properly. This structural framework allows the ribosome to interact with messenger RNA (mRNA) and transfer RNA (tRNA) during the process of translation, where the genetic information encoded in mRNA is used to assemble proteins from amino acids. Therefore, the primary function of rRNA is to contribute to the structure and function of ribosomes, rather than directly carrying amino acids, reading the genetic code, or controlling the rate of protein synthesis.
5. The involuntary "fight-or-flight" response is controlled by the:
- A. Sympathetic nervous system
- B. Parasympathetic nervous system
- C. Enteric nervous system
- D. Sensory nervous system
Correct answer: A
Rationale: The correct answer is A: Sympathetic nervous system. The "fight-or-flight" response is an automatic physiological reaction triggered by the sympathetic nervous system in response to a perceived threat or stressor. This system prepares the body for action by increasing heart rate, dilating pupils, and redirecting blood flow to muscles. The parasympathetic nervous system, on the other hand, controls the body's "rest-and-digest" response, promoting relaxation and digestion. The enteric nervous system primarily regulates the gastrointestinal system, while the sensory nervous system is responsible for transmitting sensory information to the brain. Therefore, the sympathetic nervous system is specifically responsible for initiating the fight-or-flight response.
6. Which of the following structures is responsible for preventing the backflow of blood from the left ventricle into the left atrium?
- A. Aortic valve
- B. Pulmonary valve
- C. Tricuspid valve
- D. Mitral valve
Correct answer: D
Rationale: The correct answer is D, the mitral valve. The mitral valve, also known as the bicuspid valve, is located between the left atrium and the left ventricle. Its main function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. The aortic valve (A) is responsible for preventing the backflow of blood from the aorta into the left ventricle, the pulmonary valve (B) prevents backflow from the pulmonary artery into the right ventricle, and the tricuspid valve (C) prevents backflow from the right ventricle into the right atrium. Therefore, the mitral valve is specifically responsible for preventing backflow in the left side of the heart, making it the correct answer in this case.
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