Nokea
Why is the nucleus important in a cell?
- A. It stores the DNA.
- B. It provides structural support.
- C. It synthesizes proteins.
- D. It produces energy from food.
Correct Answer: A
Rationale: The correct answer is A. The nucleus is crucial in a cell because it stores the DNA, which contains the genetic information necessary for directing the cell's activities and determining its characteristics. The nucleus does not provide structural support, synthesize proteins, or produce energy from food; these functions are carried out by other cell organelles. Therefore, the main role of the nucleus is to safeguard and regulate the genetic material of the cell, ensuring proper cell function and inheritance of traits.
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What is a characteristic of epithelial cells?
- A. Polarized
- B. Neutral
- C. Larger than other cells
- D. None of the above
Correct Answer: A
Rationale: Epithelial cells are polarized, meaning they have distinct apical and basal surfaces with different functions. This polarity is important for their specialized roles in absorption, secretion, and protection. Therefore, the correct answer is A: 'Polarized.' Choices B and C are incorrect as epithelial cells are not neutral and are not necessarily larger than other cells. Choice D is incorrect as epithelial cells do have specific characteristics.
Which genetic descriptor refers to an organism's actual appearance?
- A. Phenotype
- B. Genotype
- C. Homozygote
- D. Karyotype
Correct Answer: A
Rationale: Phenotype refers to the observable characteristics or traits of an organism, including physical appearance, behavior, and physiological properties. It is influenced by the organism's genotype and environmental factors. Genotype, on the other hand, represents the genetic makeup of an organism, while homozygote refers to an individual having two identical alleles for a particular gene. Karyotype, on the other hand, refers to the complete set of chromosomes in an individual.
Anaerobic respiration happens in.............because..............
- A. Animals; they primarily rely on aerobic respiration
- B. Plants; they can perform photosynthesis
- C. Bacteria; they live in environments with low oxygen levels
- D. None of the above
Correct Answer: C
Rationale: Anaerobic respiration occurs in bacteria because they live in environments with low oxygen levels. In the absence of oxygen, these organisms utilize anaerobic respiration to generate energy. Animals and plants primarily rely on aerobic respiration, which requires oxygen to produce energy efficiently. Plants do not lack sunlight; they can perform photosynthesis to derive energy. Animals do require energy but predominantly use aerobic respiration when oxygen is available.
Which method of glucose conversion generates the most usable and efficient form of ATP within the human body?
- A. Lactic acidosis.
- B. Fermentation conversion.
- C. Anaerobic respiration.
- D. Aerobic respiration.
Correct Answer: D
Rationale:
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.