Nursing Elites

1. 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.

2. Physical factors such as temperature and pH can alter enzyme activity because they have an effect on the enzyme's ___________.

• A. acidity
• B. shape
• C. chemistry
• D. substrate

Correct answer: B

Rationale: Physical factors such as temperature and pH can alter enzyme activity by affecting the enzyme's shape. Enzymes rely on their specific shapes to function properly and catalyze reactions. Any changes in temperature or pH can disrupt these shapes, causing the enzyme to become denatured and lose its functionality. Therefore, alterations in temperature and pH can impact enzyme activity by directly affecting their shapes. Choices A, C, and D are incorrect because while pH can affect acidity and chemical properties of the enzyme, and temperature can influence the enzyme-substrate interaction, the primary reason for enzyme activity alteration due to temperature and pH is the change in the enzyme's shape.

3. Which of the following is true of optical microscopy?

• A. Utilizes scanning electrons
• B. Utilizes visible light
• C. Utilizes dye for samples
• D. More than one of the above is true

Correct answer: D

Rationale: The correct answer is D, 'More than one of the above is true.' Optical microscopy utilizes visible light (Choice B) and often involves the use of dyes for samples (Choice C). Using dyes helps enhance contrast, making it easier to visualize the structures being observed. Choice A is incorrect as optical microscopy does not utilize scanning electrons, but rather visible light.

4. Which of the following is always true about molecules?

• A. They cannot travel through all cell membranes
• B. They move from low concentration to high concentration without using energy
• C. They move from high concentration to low concentration without using energy
• D. They cannot move

Correct answer: C

Rationale: The statement that molecules move from high concentration to low concentration without using energy is always true due to the natural process of diffusion. This movement occurs to reach equilibrium and does not require any additional energy input directly from the molecule itself. Choice A is incorrect because not all molecules can travel through all cell membranes. Choice B is incorrect as molecules typically move from high concentration to low concentration in a process known as passive transport. Choice D is incorrect as molecules are in constant motion due to factors like temperature and kinetic energy.

5. Which one of the following best describes the function of a cell membrane?

• A. It controls the substances entering and leaving the cell.
• B. It maintains the cell's shape.
• C. It controls the substances entering the cell.
• D. It supports the cell's structures.

Correct answer: A

Rationale: The correct answer is A. The function of a cell membrane is to control the substances entering and leaving the cell. The cell membrane is selectively permeable, allowing it to regulate the movement of ions and molecules in and out of the cell to maintain internal balance and proper function. Choice B is incorrect because while the cell membrane does provide some structural support, its primary function is not to maintain the cell's shape. Choice C is incorrect because the cell membrane controls both the substances entering and leaving the cell, not just those entering. Choice D is incorrect as the primary function of the cell membrane is not to support the cell's structures but to regulate the movement of substances.

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