Nursing Elites

1. Which cells in the human body lack nuclei?

• A. Nerve cells
• B. Red blood cells
• C. Liver cells
• D. Connective tissue cells

Correct answer: B

Rationale: Red blood cells, also known as erythrocytes, lack nuclei in humans. This absence of a nucleus allows more space for hemoglobin, the protein responsible for carrying oxygen, making red blood cells efficient at their function of oxygen transport in the body. Nerve cells (Choice A), liver cells (Choice C), and connective tissue cells (Choice D) all possess nuclei as they require genetic material for their functions, such as cell signaling, protein synthesis, and structural support.

2. When plants do not receive enough water, their photosynthetic rate drops. This is because:

• A. water is a raw material for the light reactions in photosynthesis
• B. carbon dioxide is not available
• C. water provides the carbon atoms used to make sugar
• D. not enough oxygen is produced to keep fermentation running

Correct answer: A

Rationale: When plants do not receive enough water, their photosynthetic rate drops because water is a raw material required for the light reactions in photosynthesis. In the light reactions, water is split to provide electrons, which are then utilized to produce energy carriers used in converting carbon dioxide into glucose during the Calvin cycle. Therefore, without sufficient water, the light reactions cannot proceed effectively, ultimately leading to a decrease in photosynthetic rate. Choice B is incorrect because carbon dioxide is a separate raw material needed for the Calvin cycle, not the light reactions. Choice C is incorrect as water provides electrons, not carbon atoms, for photosynthesis. Choice D is incorrect because fermentation is not directly related to photosynthesis; oxygen is produced during photosynthesis, not fermentation.

3. Select the cell parts that are present in plant cells but not animal cells (there may be more than one answer):

• A. Cell membrane
• B. Cell wall
• C. Ribosome
• D. Chloroplast

Correct answer: B

Rationale: Plant cells have a cell wall (B) which provides structural support and protection for the cell, a feature that is not present in animal cells. The cell membrane (A) is found in both plant and animal cells. Ribosomes (C) are present in both types of cells and are responsible for protein synthesis. Chloroplasts (D) are unique to plant cells and are responsible for carrying out photosynthesis. Therefore, the correct answers are B and D because the cell wall and chloroplast are specific to plant cells, while the cell membrane and ribosomes are found in both plant and animal cells.

4. What happens during anaphase?

• A. Chromosomes move to opposite ends of the spindle.
• B. Nuclear membrane and nucleoli disintegrate.
• C. Chromatids line up at the center of the spindle.
• D. Nuclear membrane and nucleoli form.

Correct answer: A

Rationale: During anaphase, the sister chromatids, joined at the centromere, separate and move towards opposite ends of the spindle apparatus. This movement ensures that each daughter cell receives an identical set of chromosomes. Choice B is incorrect as the disintegration of the nuclear membrane and nucleoli occurs during prophase. Choice C is incorrect as chromatids align at the center of the spindle during metaphase, not anaphase. Choice D is incorrect as the formation of the nuclear membrane and nucleoli occurs during telophase, not anaphase.

5. How do green plants use nitrates in the nitrogen cycle?

• A. To synthesize proteins
• B. To store food
• C. To decompose ammonia
• D. To break down nitrites

Correct answer: A

Rationale: Green plants use nitrates in the nitrogen cycle to synthesize proteins. Nitrogen is an essential component of amino acids, which are the building blocks of proteins. Plants take up nitrates from the soil through their roots and incorporate nitrogen into their proteins through the process of protein biosynthesis. This helps in their growth, development, and overall health. Choice B, 'To store food,' is incorrect because nitrates are primarily used for protein synthesis, not food storage. Choice C, 'To decompose ammonia,' is incorrect as plants do not decompose ammonia but rather utilize it through nitrification. Choice D, 'To break down nitrites,' is incorrect as plants typically convert nitrites into nitrates through a process called nitrate assimilation for protein synthesis.

Similar Questions