Nokea
Enzymes are ________ molecules that serve as _______ for certain biological reactions.
- A. Enzymes are irrelevant molecules that serve as suppressors for certain biological reactions.
- B. Enzymes are acidic molecules that serve as catalysts for certain biological reactions.
- C. Enzymes are lipid molecules that serve as catalysts for certain biological reactions.
- D. Enzymes are protein molecules that serve as catalysts for certain biological reactions.
Correct Answer: D
Rationale: Enzymes are protein molecules that serve as catalysts for certain biological reactions. Enzymes are biological molecules that speed up chemical reactions in living organisms by lowering the activation energy required for the reactions to occur. They are typically proteins that have specific shapes and active sites that allow them to interact with specific substrates and facilitate reactions without being consumed themselves. The other choices are incorrect because enzymes are not irrelevant, acidic, or lipid molecules; they are primarily proteins known for their catalytic properties.
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In order to verify if a particular drug is responsible for the recovery of individuals with a disorder, what procedure would be most effective in testing its effectiveness?
- A. Ensure that neither the subjects nor the investigators know which subjects are given the drug and which are given the placebo.
- B. Ensure that the subjects do not know whether they are given the drug or the placebo, but the investigators are aware of who has received the medication.
- C. Ensure that the investigators do not know whether they are administering the drug or the placebo, but the subjects do know which they are receiving.
- D. Ensure that both the investigators and the subjects have full knowledge of which subjects are getting the drug and which are getting a placebo.
Correct Answer: A
Rationale: The most effective procedure in testing whether the drug is responsible for the recovery is to ensure that neither the subjects nor the investigators know which subjects are given the drug and which are given the placebo. This method is known as a double-blind study, which helps eliminate biases and ensures that the results are reliable and not influenced by expectations or beliefs. By keeping both the subjects and investigators unaware of who is receiving the drug or placebo, the study can accurately determine the true impact of the drug on recovery. Choice B is incorrect as it only prevents the subjects from knowing which treatment they are receiving, allowing for potential bias from the investigators. Choice C is also incorrect as it allows for potential bias from the subjects. Choice D is incorrect as full knowledge of treatment allocation can introduce bias and affect the study's validity.
In an oxidation reaction,
- A. an oxidizing agent gains electrons.
- B. an oxidizing agent loses electrons.
- C. a reducing agent gains electrons.
- D. a reducing agent loses electrons.
Correct Answer: B
Rationale: In an oxidation reaction, the substance being oxidized loses electrons, not gains them. An oxidizing agent is responsible for causing oxidation in another substance by accepting electrons, hence it undergoes reduction and loses electrons. Therefore, the correct statement is 'an oxidizing agent loses electrons,' making choice B the correct answer. Choices A, C, and D are incorrect because in an oxidation reaction, the oxidizing agent does not gain electrons, a reducing agent does not gain electrons, and a reducing agent does not lose electrons.
Which of the following terms means close to the trunk of the body?
- A. Superficial
- B. Sagittal
- C. Proximal
- D. Distal
Correct Answer: C
Rationale: The term 'proximal' means situated close to the point of attachment or the center of the body, such as close to the trunk. In anatomical terms, proximal is used to describe locations that are closer to the body's center or point of reference. 'Superficial' refers to something situated near the surface, 'sagittal' refers to a plane that divides the body into left and right portions, and 'distal' refers to a position away from the center or point of reference. Therefore, 'proximal' is the correct term to indicate a position close to the trunk of the body.
How will mildly elevated levels of thyroxine affect the heart rate?
- A. Stop the heart rate
- B. No effect
- C. Decrease the heart rate
- D. Increase the heart rate
Correct Answer: D
Rationale: Mildly elevated levels of thyroxine will increase the heart rate. Thyroxine, a hormone produced by the thyroid gland, regulates metabolism. Elevated thyroxine levels can lead to increased metabolism, resulting in an elevated heart rate. Choice A is incorrect as mildly elevated thyroxine levels do not stop the heart rate. Choice B is incorrect because elevated thyroxine levels do have an effect on heart rate. Choice C is incorrect as elevated thyroxine levels typically lead to an increase rather than a decrease in heart rate.
Which of the following functions is NOT performed by the integumentary system, the skin?
- A. Protect internal tissues from injury
- B. Waterproof the body
- C. Help regulate body temperature
- D. Return fluid to the blood vessels
Correct Answer: D
Rationale: The integumentary system, which includes the skin, performs various functions like protecting internal tissues from injury, waterproofing the body, and helping regulate body temperature. The function of returning fluid to the blood vessels is primarily associated with the lymphatic system, not the integumentary system. The skin contributes to fluid balance by regulating sweating and preventing excessive water loss, but it does not directly return fluid to the blood vessels, making this the correct answer. Choices A, B, and C are functions directly related to the integumentary system and are essential for maintaining the body's overall health and well-being.