Nokea
Are all bacteria bad, and do they always cause infections?
- A. TRUE
- B. FALSE
- C. Sometimes
- D. Not sure
Correct Answer: B
Rationale: The misconception that all bacteria are harmful and always cause infections is incorrect. Although some bacteria can lead to diseases, it is essential to note that not all bacteria are harmful. In reality, certain bacteria are beneficial and serve important functions in the body, such as aiding in digestion. Therefore, the correct answer is FALSE.
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Which of the following statements about antibiotics is incorrect?
- A. They can interfere with the bacteria's ability to survive.
- B. They can affect how bacteria multiply.
- C. They can cause more bacteria to grow.
- D. They only work on bacteria.
Correct Answer: C
Rationale: Antibiotics are medications designed to inhibit or kill bacteria. Options A and B are true statements about antibiotics, as they interfere with bacteria's ability to survive and affect their multiplication. However, antibiotics do not cause more bacteria to grow; instead, they aim to decrease bacterial growth by killing or inhibiting them. Therefore, the statement in option C is incorrect, making it the correct answer.
When a child is sick and has a body temperature exceeding 37Å—C, the body 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 scenario illustrates a negative feedback loop. In negative feedback, the body's response opposes the initial change, helping to restore equilibrium. In this case, the body's sweating is a response to reduce the elevated temperature, aiming to return the body to its normal state. This process helps regulate and maintain homeostasis, ensuring the body functions within a narrow range of optimal conditions.
What must any solution injected into tissues be to prevent cells from shrinking or swelling?
- A. Distilled.
- B. Hypertonic.
- C. Hypotonic.
- D. Isotonic.
Correct Answer: D
Rationale: The correct answer is D: Isotonic. An isotonic solution has the same concentration of solutes as the cells in the tissues, preventing them from shrinking or swelling. If a solution is hypertonic (choice B), it has a higher solute concentration and would cause cells to shrink due to water leaving the cells. A hypotonic solution (choice C) has a lower solute concentration and would cause cells to swell as water enters the cells. Distilled water (choice A) lacks solutes and would cause cells to swell. Overall, an isotonic solution maintains cell volume and prevents any osmotic imbalances.
How does the concentration of solutes in a hypertonic solution compare to the cell's?
- A. Same as
- B. Lower than
- C. Higher than
- D. Negative
Correct Answer: C
Rationale: In a hypertonic solution, the concentration of solutes is higher compared to the cell's interior. This causes water to move out of the cell to balance the solute concentrations, resulting in the cell shrinking. Therefore, the correct answer is that the solute concentration is higher in a hypertonic solution than inside the cell.
Why can animal cells use a contractile ring but plant cells cannot?
- A. Plant cells can divide using both methods.
- B. Animal cells divide faster, requiring them to pinch apart.
- C. Plant cells are too rigid to utilize a contractile ring.
- D. Plant cells have a cell wall that hinders the formation of a contractile ring.
Correct Answer: D
Rationale: The correct answer is D because plant cells have a cell wall surrounding them, which provides structural support but makes it challenging for them to form a contractile ring during cell division. The cell wall restricts the flexibility needed for the contractile ring to constrict and separate the cells. In contrast, animal cells do not have a cell wall, allowing them to form a contractile ring composed of actin filaments that constrict during cytokinesis, facilitating cell division.