Nokea
Why does cytokinesis occur?
- A. DNA replication occurs
- B. Organelles generate energy
- C. Bacteria are eliminated
- D. Daughter cells can separate
Correct Answer: D
Rationale: Cytokinesis is the process of separating daughter cells at the end of cell division. It ensures that the newly formed cells can function independently. Choice A is incorrect because DNA duplication occurs during the S phase of the cell cycle, not during cytokinesis. Choice B is incorrect as organelles converting energy is not the primary purpose of cytokinesis. Choice C is irrelevant as the elimination of bacteria is not related to cytokinesis.
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Which term means the movement of water across a semi-permeable membrane from a low solute concentration to a high solute concentration?
- A. Active Transport.
- B. Passive Transport.
- C. Osmosis.
- D. Diffusion.
Correct Answer: C
Rationale: The correct answer is C: Osmosis. Osmosis is the movement of water molecules across a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration. This process occurs passively, without the need for energy input.
Rationale:
1. Osmosis specifically refers to the movement of water molecules.
2. It occurs across a semi-permeable membrane.
3. The direction of movement is from low solute concentration to high solute concentration.
4. Osmosis is a passive transport process, as it does not require energy.
Summary:
A: Active Transport involves the movement of molecules against the concentration gradient, requiring energy input.
B: Passive Transport includes processes like diffusion and osmosis but does not involve active energy expenditure.
D: Diffusion is the movement of molecules from high concentration to low concentration, not specific to water movement across a membrane.
Which term means alternate forms of a gene for the same trait?
- A. Phenotypes.
- B. Genotypes
- C. Alleles.
- D. Gametes.
Correct Answer: C
Rationale:
Why do cells need to use exocytosis?
- A. To obtain energy
- B. To defend against invaders
- C. To eliminate waste
- D. To undergo cell division
Correct Answer: C
Rationale: Cells use exocytosis to eliminate waste from the cell. Exocytosis is the process by which cells expel waste materials or products outside the cell. This process helps maintain cellular cleanliness and proper functioning by preventing the accumulation of harmful substances inside the cell, ensuring the cell's health and survival.
Which organelle is responsible for protein synthesis?
- A. Ribosome
- B. Chloroplast
- C. Lysosome
- D. Mitochondria
Correct Answer: A
Rationale: The correct answer is A, Ribosome. Ribosomes are the organelles responsible for protein synthesis in a cell. They are the site where amino acids are assembled into proteins based on the genetic information carried by mRNA. Chloroplasts are responsible for photosynthesis in plant cells, Lysosomes contain enzymes for digestion and waste removal, and Mitochondria are known as the powerhouse of the cell, responsible for generating energy.
What does the mitochondrion produce that causes it to often be called the powerhouse of the cell?
- A. ATP
- B. Enzymes
- C. DNA
- D. Proteins
Correct Answer: A
Rationale: The mitochondrion produces ATP (adenosine triphosphate), which is the primary energy currency of the cell. This energy production is why mitochondria are referred to as the powerhouse of the cell. ATP generated by mitochondria is essential for various cellular processes, such as muscle contraction, cell division, and macromolecule synthesis, making it a crucial organelle for cell function.