Nokea
What is the characteristic of the cell membrane consisting of a bilayer of phospholipids with proteins, cholesterol, and glycoproteins that creates a hydrophobic region between two layers of lipids?
- A. Impermeable
- B. Permeable
- C. Selectively permeable
- D. Selectively impermeable
Correct Answer: C
Rationale: The correct answer is 'C: Selectively permeable.' The cell membrane is selectively permeable because it allows certain molecules to pass through while restricting the passage of others. The hydrophobic region formed by the lipid bilayer makes it selectively permeable by controlling the movement of substances in and out of the cell. This selective permeability is vital for cellular functions, as it regulates the transport of essential molecules and maintains the internal environment required for proper cell operation and overall cellular homeostasis.
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Which of the following cell parts are present in plant cells but not animal cells (there may be more than one answer):
- A. Cell membrane
- B. Cell wall
- C. Ribosome
- D. Chloroplast
Correct Answer: D
Rationale: The correct answer is 'D - Chloroplast' because it is a unique cell part found only in plant cells and is responsible for photosynthesis. Animal cells do not possess chloroplasts. Both plant and animal cells have cell membranes, which are essential for cellular function. The cell wall is a structural component specific to plant cells, providing support and protection. Ribosomes, responsible for protein synthesis, are organelles present in both plant and animal cells.
Where is the apical side of an epithelial cell located?
- A. Is exposed to fluid or air
- B. Is on the top side of the cell
- C. Does not allow any substances to pass through
- D. None of the above
Correct Answer: B
Rationale: The apical side of an epithelial cell refers to the top surface of the cell that is exposed to the external environment, such as fluid or air. This surface is specialized to perform specific functions like absorption, secretion, or protection. The apical side faces the lumen or external environment and is crucial for the cell's interactions with its surroundings. Therefore, the correct answer is that the apical side of an epithelial cell is on the top side of the cell.
What type of cell primarily makes up animals?
- A. Eukaryotic
- B. Simple
- C. Prokaryotic
- D. Bacterial
Correct Answer: A
Rationale: Animals are composed primarily of eukaryotic cells, characterized by a defined nucleus and membrane-bound organelles. Eukaryotic cells are complex and serve as the basis for multicellular organisms such as animals, contrasting with prokaryotic cells that lack a defined nucleus and organelles.
Which characteristic is typically found in prokaryotic cells?
- A. Have a nucleus
- B. Have a capsule
- C. Have membrane-bound organelles
- D. Cannot move on their own
Correct Answer: B
Rationale: Prokaryotic cells are characterized by the absence of a nucleus and membrane-bound organelles. One common feature of prokaryotic cells is the presence of a capsule, which is a protective layer outside the cell wall. This capsule helps protect the cell and can also assist in adherence to surfaces. Therefore, the correct characteristic typically found in prokaryotic cells is that they have a capsule.
Which of the following is a benefit of the intermolecular hydrogen bonding of water? (Select one that doesn't apply.)
- A. Water has a relatively high specific heat capacity.
- B. Water has strong cohesive and adhesive properties.
- C. Polarity of water allows it to act as a versatile solvent.
- D. Water moves from higher to lower concentrations.
Correct Answer: D
Rationale: The process described in option D, 'Water moves from higher to lower concentrations,' is not a direct benefit of intermolecular hydrogen bonding of water. Rather, this movement of water from higher to lower concentrations is attributed to osmosis, a phenomenon driven by differences in solute concentrations across a semi-permeable membrane. The other options, A, B, and C, directly result from water's intermolecular hydrogen bonding. Water's high specific heat capacity (A) is due to the hydrogen bonds, which allow water to absorb and release large amounts of heat with minimal temperature change. The strong cohesive and adhesive properties of water (B) are a result of hydrogen bonding, enabling water to stick to other substances. Lastly, the polarity of water (C) due to hydrogen bonding makes it an effective solvent by interacting with various solutes.