Nursing Elites

1. Which color of light is least effective at driving photosynthesis?

• A. Violet
• B. Green
• C. Orange
• D. Red

Correct answer: B

Rationale: Green light is the least effective at driving photosynthesis because chlorophyll, the primary pigment responsible for absorbing light in plants, does not absorb green light well. Instead, chlorophyll absorbs more effectively in the blue and red regions of the light spectrum. Therefore, green light is relatively less efficient in promoting photosynthesis compared to violet, orange, and red light. Violet light, although at the shorter wavelength end of the spectrum, can still drive photosynthesis better than green light. Orange and red light are more efficiently absorbed by chlorophyll, making them more effective in driving the process of photosynthesis.

2. Which of the following is true of heterozygous traits?

• A. They are haploid
• B. They are denoted AA
• C. They are denoted aa
• D. They are denoted Aa

Correct answer: D

Rationale: Heterozygous traits are denoted by having two different alleles for a particular gene, represented as Aa. This means that they are not haploid (A), not denoted AA (B), and not denoted aa (C). Therefore, the correct answer is D, as heterozygous traits are represented as Aa.

3. The cell membrane consists of a bilayer of phospholipids with proteins, cholesterol, and glycoproteins. What does this bilayer create?

• A. Impermeable
• B. Permeable
• C. Selectively permeable
• D. Selectively impermeable

Correct answer: C

Rationale: The correct answer is 'Selectively permeable.' The cell membrane's bilayer structure allows it to be selectively permeable, meaning it can control the passage of substances. This property enables the membrane to regulate the entry and exit of specific molecules, ions, and other substances. Choice A, 'Impermeable,' is incorrect as the cell membrane is not completely impermeable and does allow certain substances to pass through. Choice B, 'Permeable,' is also incorrect as it does not address the selective nature of the membrane. Choice D, 'Selectively impermeable,' is a contradictory term and does not accurately describe the cell membrane's function.

4. 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.

5. Which of the following cell types has no nucleus?

• A. platelet
• B. red blood cell
• C. white blood cell
• D. phagocyte

Correct answer: B

Rationale: The correct answer is B, red blood cell. In humans, red blood cells do not have a nucleus. This unique feature allows them to have more space to carry oxygen efficiently. Platelets (choice A), white blood cells (choice C), and phagocytes (choice D) all have nuclei. Platelets are cell fragments, while white blood cells and phagocytes are types of immune cells that contain a nucleus for DNA and cellular functions.

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