Nokea
Which of the following statements is false regarding cell structures?
- A. Animal cells use lysosomes to break down old cells
- B. Animal cells use chloroplasts to gain energy
- C. Plant cells have a cell wall to maintain structure
- D. All of the above are true
Correct Answer: B
Rationale: The statement in option B is false because animal cells do not use chloroplasts to gain energy. Chloroplasts are found in plant cells and are responsible for photosynthesis, a process where plants convert light energy into chemical energy. Animal cells rely on mitochondria to produce energy through cellular respiration. Options A and C are true statements as lysosomes are responsible for breaking down old cells in animal cells, and plant cells have a cell wall to provide structural support.
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Why is DNA crucial for the metabolic activities of the cell?
- A. It initiates cellular mitosis.
- B. It provides cell wall stability.
- C. It increases glucose absorption.
- D. It controls the synthesis of enzymes.
Correct Answer: D
Rationale: DNA is crucial for the metabolic activities of the cell because it contains the genetic information necessary to regulate the synthesis of enzymes. Enzymes are essential for catalyzing biochemical reactions involved in metabolic processes within the cell. DNA controls the production of enzymes, which are vital for driving various metabolic pathways. Therefore, the correct answer is D, as DNA's role in controlling enzyme synthesis is fundamental for the cell's metabolic activities.
When a child is sick and has a body temperature exceeding 37Å—C, the body begins to sweat in order to lower the temperature. What is this an example of?
- A. Positive feedback loop
- B. Negative feedback loop
- C. Both
- D. None of the above
Correct Answer: B
Rationale: This scenario illustrates a negative feedback loop. In negative feedback, the body's response opposes the initial change, helping to restore equilibrium. In this case, the body's sweating is a response to reduce the elevated temperature, aiming to return the body to its normal state. This process helps regulate and maintain homeostasis, ensuring the body functions within a narrow range of optimal conditions.
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.
Animals are composed primarily of what type of cell?
- A. Simple.
- B. Prokaryotic.
- C. Bacterial.
- D. Eukaryotic.
Correct Answer: D
Rationale:
What is the purpose of cellular respiration?
- A. Produce enzymes.
- B. Produce oxygen molecules.
- C. Enable fermentation.
- D. Obtain energy in the form of ATP.
Correct Answer: D
Rationale: