Nokea
Epithelial cells are:
- A. Polarized
- B. Neutral
- C. Larger than other cells
- D. None of the above
Correct Answer: A
Rationale: Epithelial cells have a distinct top (apical) and bottom (basal) side, demonstrating polarity. This polarity is essential for their specialized functions, such as secretion, absorption, and barrier formation. Choice B, 'Neutral,' is incorrect as epithelial cells exhibit polarity. Choice C, 'Larger than other cells,' is incorrect as epithelial cells come in various sizes and are not specifically larger than other cell types. Choice D, 'None of the above,' is incorrect as epithelial cells are indeed polarized.
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What is the purpose of the mitochondria?
- A. Control the cell
- B. Create energy
- C. Create proteins
- D. Package waste for removal
Correct Answer: B
Rationale: The correct answer is B: Create energy. The primary purpose of the mitochondria is to generate energy for the cell. Mitochondria are known as the 'powerhouses' of the cell because they produce ATP (adenosine triphosphate), which is the energy currency used by cells to carry out various functions and processes. Choice A is incorrect as the mitochondria do not control the cell but rather produce energy. Choice C is incorrect as protein synthesis primarily occurs in the ribosomes. Choice D is incorrect as packaging waste for removal is a function associated with lysosomes, not mitochondria.
What type of tissue is fat?
- A. Connective
- B. Muscle
- C. Nervous
- D. Epithelial
Correct Answer: A
Rationale: Fat is a type of loose connective tissue known as adipose tissue. Adipose tissue primarily functions to store energy and provide cushioning and insulation for organs. While muscle tissue is responsible for movement, nervous tissue transmits nerve impulses, and epithelial tissue covers and protects body surfaces, fat specifically falls under the category of connective tissue.
A child is sick. They have a body temperature that exceeds 37ºC. The body senses this and begins to sweat in order to lower the temperature. What is this an example of?
- A. Positive feedback loop
- B. Negative feedback loop
- C. Both
- D. None of the above
Correct Answer: B
Rationale: This is an example of a negative feedback loop. In a negative feedback loop, the body's response (sweating) works to counteract the initial stimulus of a high body temperature by cooling the body down. The goal is to return the body to homeostasis, maintaining a stable internal environment. Positive feedback loops amplify the initial stimulus rather than counteracting it, which is not the case here. Therefore, choices A and C are incorrect. Choice D is also incorrect as the situation described fits the characteristics of a negative feedback loop.
Which, if any, of the following statements are true?
- A. Water boils at approximately 100°C (212°F) at standard atmospheric pressure
- B. The boiling point is the temperature at which the vapor pressure is higher than the atmospheric pressure around the water
- C. Water boils at a lower temperature in areas of lower pressure
- D. A and C are true
Correct Answer: D
Rationale: Both statements A and C are true. Water indeed boils at approximately 100°C (212°F) at standard atmospheric pressure. However, water boils at a lower temperature in areas of lower pressure due to the decreased atmospheric pressure, which affects the vapor pressure and boiling point of water. Statement B is incorrect because the boiling point is the temperature at which the vapor pressure equals the external pressure (atmospheric pressure in this case), not when it is higher.
Select the option that best shows complementary base pairing in DNA:
- A. A and G
- B. A and C
- C. A and A
- D. A and T
Correct Answer: D
Rationale: The correct answer is D. A purine (A) must pair with a pyrimidine (T) in DNA. This eliminates options A and C as they do not follow the rule of complementary base pairing. Adenine (A) always pairs with thymine (T) due to their specific shape and bonding properties in DNA structure. Choice B is incorrect because adenine does not pair with cytosine in DNA.