Nokea
Which antioxidant is identified as a healing vitamin?
- A. A
- B. D.
- C. K
- D. E
Correct Answer: D
Rationale:
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Why can animal cells use a contractile ring but plant cells cannot?
- A. Plant cells can use both methods to divide.
- 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: Plant cells have a rigid cell wall surrounding their cell membrane, which prevents the formation of a contractile ring during cell division. The contractile ring is a structure composed of actin filaments responsible for pinching the cell in two during cytokinesis. Since plant cells cannot form a contractile ring due to the presence of the cell wall, they rely on other methods such as cell plate formation to complete cell division.
How many different types of nucleotides are there in DNA?
- A. one
- B. two
- C. four
- D. eight
Correct Answer: C
Rationale: The correct answer is C: four. DNA is composed of four different types of nucleotides: adenine (A), thymine (T), cytosine (C), and guanine (G). These nucleotides pair specifically (A with T and C with G) to form the double-stranded DNA structure.
Which of the following DNA strands would complement the segment: ACTTGCA?
- A. TGAACGT
- B. GACCATG
- C. ACTTGCA
- D. None of the above
Correct Answer: A
Rationale: In DNA, adenine pairs with thymine (A-T) and cytosine pairs with guanine (C-G). To find the complementary strand, you need to match each base with its complementary base. The segment ACTTGCA consists of bases A, C, T, T, G, C, A, which would pair with T, G, A, A, C, G, T, respectively. Therefore, the complementary strand would be TGAACGT. Thus, option A (TGAACGT) is the correct choice as it follows the base-pairing rules in DNA.
A scientist needs 12 mL of a solution. They have a bottle with 0.12L in it. Do they have enough?
- A. Yes, they have exactly what they need
- B. Yes, they have more than what they need
- C. No, they do not have enough
- D. None of the above
Correct Answer: B
Rationale: To accurately compare the quantities, it is important to convert both to the same unit. As 1L is equal to 1000 mL, the bottle contains 120 mL (0.12L x 1000 mL/L). Since the scientist only needs 12 mL, it is evident that they have more than enough solution in the bottle, making choice B the correct answer.
Many control, both positive and negative, maintain body processes. What is this phenomenon called?
- A. Homeostasis.
- B. Endothermy.
- C. Metabolism.
- D. Respiration.
Correct Answer: A
Rationale: Correct Answer: A: Homeostasis.
Rationale:
1. Homeostasis refers to the ability of the body to maintain internal stability despite external changes.
2. It involves various control mechanisms to keep key physiological parameters within a narrow range.
3. Positive and negative feedback loops regulate processes to achieve homeostasis.
4. Choices B, C, and D do not specifically relate to the concept of maintaining internal stability like homeostasis does.