Nokea
Cytosine (C) and Thymine (T) are known as:
- A. Purines
- B. Pyrimidines
- C. Both
- D. None of the above
Correct Answer: B
Rationale: Cytosine (C) and Thymine (T) are both pyrimidines. Purines, on the other hand, refer to adenine and guanine. Pyrimidines are characterized by a single-ring structure, while purines have a double-ring structure. Therefore, the correct answer is B: Pyrimidines. Remember, pyrimidines consist of cytosine and thymine, while purines include adenine and guanine.
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Which type of passive transport uses proteins that change shape to move a target molecule through the membrane?
- A. Diffusion
- B. Carrier proteins
- C. Channel proteins
- D. None of the above
Correct Answer: B
Rationale: Carrier proteins are involved in facilitated diffusion, a type of passive transport where molecules move across the cell membrane with the help of specific carrier proteins that change shape to transport the molecules across. Channel proteins, on the other hand, form pores or channels to allow specific molecules to pass through the membrane via passive transport. Diffusion, while a passive transport process, does not involve proteins changing shape to facilitate the movement of molecules.
Lipids are better known as fats, but what are they specifically? (Select one that doesn't apply.)
- A. Fatty acids
- B. Phospholipids
- C. Ketones
- D. Steroids
Correct Answer: C
Rationale: Lipids are a diverse group of molecules that include fatty acids, phospholipids, and steroids. Ketones, while important in metabolism, are not typically classified under lipids. Ketones are produced during the breakdown of fatty acids or amino acids, but they are not themselves lipids. Therefore, option C, Ketones, is the correct answer as it does not specifically fall under the category of lipids.
Which cell organelle can be functionally compared to a door of a house?
- A. Endoplasmic reticulum
- B. Cell membrane
- C. Nucleus
- D. Cytoplasm
Correct Answer: B
Rationale: The cell membrane can be likened to a door of a house because it functions to regulate what enters and exits the cell, maintaining internal balance (homeostasis) and safeguarding the cell's interior. Just as a door controls access to a house, the cell membrane controls the passage of substances into and out of the cell, thereby playing a crucial role in maintaining the cell's integrity and functionality.
Which set is correctly listed from largest to smallest group?
- A. Genus, order, species, phylum.
- B. Phylum, order, genus, species.
- C. Order, phylum, species, genus.
- D. Species, order, phylum, genus.
Correct Answer: B
Rationale:
On what part of a light microscope is the slide placed?
- A. Base.
- B. Arm.
- C. stage
- D. Lens.
Correct Answer: C
Rationale: