Nokea
Which of the following is true of the Krebs cycle?
- A. It is a redox reaction involving proteins produced during glycolysis
- B. It is a redox reaction involving sugars produced during glycolysis
- C. Protons are passed along a gradient to produce ATP
- D. It is also known as the glycolic acid cycle
Correct Answer: B
Rationale: The Krebs cycle, also known as the citric acid cycle, is a series of chemical reactions that generate energy through the oxidation of acetyl-CoA derived from sugars produced during glycolysis. It is not primarily a reaction involving proteins or protons being passed along gradients to produce ATP. The cycle is distinct from the glycolic acid cycle, which is a separate metabolic pathway. Therefore, the correct answer is B.
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Epithelial cells are:
- 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 structural and functional differences between their apical and basolateral surfaces. This polarity allows them to perform specialized functions efficiently. The statement that epithelial cells are larger than other cells is incorrect as cell size can vary across different cell types, and being larger is not a defining characteristic of epithelial cells.
How are viruses categorized?
- A. Size and shape
- B. Presence or absence of an outer envelope
- C. All of these are ways in which a virus is categorized
- D. Type of nucleic acid
Correct Answer: C
Rationale: Viruses are categorized based on several criteria, including size and shape, presence or absence of an outer envelope, and type of nucleic acid (DNA or RNA). Therefore, the most comprehensive answer is that all these factors are used for categorization.
What process do sex cells undergo to reproduce?
- A. Meiosis
- B. Cytokinesis
- C. Fission
- D. Mitosis
Correct Answer: A
Rationale: Sex cells, also known as gametes, undergo the process of meiosis to reproduce. Meiosis is a specialized type of cell division that reduces the chromosome number by half, resulting in the formation of four genetically diverse haploid cells from a diploid cell. This reduction is essential for sexual reproduction to ensure genetic diversity in the offspring.
Which of the following statements is false?
- 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 correct statement is B. Animal cells do not use chloroplasts to gain energy; instead, they rely on mitochondria for energy production through cellular respiration. Lysosomes in animal cells are responsible for breaking down old cells and cellular waste. Plant cells have a cell wall to provide structural support and protection. Therefore, option B is false, as animal cells do not utilize chloroplasts for energy.
The aerodynamic nature of a bird's wing is an example of what central theme in biology?
- A. Heredity.
- B. Ontogeny.
- C. Organisms and their environment.
- D. Structure and function.
Correct Answer: D
Rationale: