Nursing Elites

1. Imagine that two parents both carry the recessive gene for cystic fibrosis. Any homozygous recessive offspring will manifest the disease. What percentage of the offspring is predicted to be carriers but not manifest the disease?

• A. 0%
• B. 25%
• C. 50%
• D. 100%

Correct answer: B

Rationale: When both parents carry the recessive gene for cystic fibrosis (homozygous recessive), there is a 25% chance for each offspring to inherit two recessive alleles and, therefore, manifest the disease. There is also a 50% chance for each offspring to inherit one recessive allele and one dominant allele, making them carriers of the disease but not manifest it. Therefore, 25% of the offspring are predicted to be carriers but not manifest the disease. Choice A (0%) is incorrect because there is a portion of offspring that will be carriers. Choice C (50%) is incorrect as this percentage corresponds to carriers who will not manifest the disease. Choice D (100%) is incorrect as not all offspring will be carriers and not manifest the disease.

2. Which of the following describes how a bacterium reproduces?

• A. Mitosis
• B. Meiosis
• C. Binary fission
• D. Cytokinesis

Correct answer: C

Rationale: Bacteria reproduce through a process called 'binary fission.' During binary fission, a bacterium duplicates its DNA and then divides into two identical daughter cells. This method is the primary way bacteria replicate. Choice A, 'Mitosis,' is incorrect because mitosis is a process specific to eukaryotic cells, where the nucleus divides to produce two identical nuclei. Choice B, 'Meiosis,' is incorrect as meiosis is a specialized type of cell division that produces gametes with half the chromosome number. Choice D, 'Cytokinesis,' is not the correct answer as cytokinesis is the physical process of cell division, which occurs after the genetic material has been divided in mitosis or meiosis.

3. Which structure controls the passage of substances into and out of the cell?

• A. Vacuole
• B. Cell Membrane
• C. Nuclear Membrane
• D. Cytoplasm

Correct answer: B

Rationale: The correct answer is the Cell Membrane. The cell membrane acts as a barrier that controls the passage of substances into and out of the cell. It is selectively permeable, allowing only certain molecules to pass through. Vacuole (Choice A), Nuclear Membrane (Choice C), and Cytoplasm (Choice D) do not primarily regulate the passage of substances in and out of the cell. Vacuoles are responsible for storage, the nuclear membrane surrounds the nucleus providing protection, and the cytoplasm is the fluid where organelles are suspended.

4. 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, involves a series of redox reactions that occur in the mitochondria. The cycle begins with the oxidation of acetyl CoA, which is derived from the breakdown of sugars produced during glycolysis. These sugars are broken down further in the Krebs cycle to produce ATP and reduce electron carriers such as NADH and FADH2. The cycle does not involve proteins produced during glycolysis. Protons are not passed along a gradient to produce ATP directly in the Krebs cycle; rather, they are used in the electron transport chain to generate ATP. The Krebs cycle is not known as the glycolic acid cycle; glycolysis is the metabolic pathway that produces pyruvate from glucose.

5. Why do we perceive chlorophyll as green?

• A. It absorbs yellow and blue light.
• B. It primarily absorbs green light.
• C. It fails to absorb green light.
• D. It primarily absorbs red light.

Correct answer: A

Rationale: Chlorophyll appears green to us because it primarily absorbs yellow and blue light while reflecting green light. The wavelengths of yellow and blue light are absorbed by chlorophyll for photosynthesis, which results in the green color we perceive. Choice B is incorrect because chlorophyll absorbs yellow and blue light, not green light. Choice C is incorrect because chlorophyll does absorb green light, but it also absorbs other wavelengths, primarily yellow and blue. Choice D is incorrect because chlorophyll primarily absorbs yellow and blue light, not red light.

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