Question

a scientist observes a cell shrinking when placed in a particular solution. this indicates that the solution is:

• hypertonic to the cell.
• isotonic with the cell.
• hypotonic to the cell.
• hypertonic to the cell.

diffusion in the root hairs of a plant is used to absorb mineral ions from the soil, where the concentration of these ions is lower than inside the root hair cell. this process requires energy. this is an example of:

• active transport.
• facilitated diffusion.
• osmosis.
• simple diffusion.

which of the following best describes the primary role of the cell membrane in both active and passive transport?

• to produce energy for the cell.
• to synthesize proteins needed for transport.
• to store genetic information related to transport mechanisms.
• to control which substances enter and exit the cell.

which of the following scenarios describes movement of molecules from an area of low concentration to an area of high concentration across a cell membrane?

• water moving into a cell placed in a hypotonic solution.
• glucose entering a cell via facilitated diffusion when its concentration is higher outside.
• sodium - potassium pump moving potassium into a cell.
• oxygen moving from the lungs into the blood.

passive transport across the cell membrane requires:

• energy in the form of atp.
• the assistance of carrier proteins only.
• the movement of substances down their concentration gradient.
• the movement of substances against their concentration gradient.

Explanation:

1. Question 1: A scientist observes a cell shrinking when placed in a particular solution. This indicates that the solution is:

• Brief Explanation: When a cell shrinks in a solution, it means water is moving out of the cell. This occurs in a hypertonic solution where the solute concentration outside the cell is higher than inside.
• Answer: Hypertonic to the cell.

1. Question 2: Daffs in the root hairs of a plant need to absorb mineral ions from the soil, where the concentration of these ions is lower than inside the root hair cells. This process requires energy and is called:

• Brief Explanation: Active transport is the movement of substances against their concentration gradient, which requires energy. Since the ions are moving from an area of lower concentration (soil) to an area of higher concentration (root - hair cells), it is active transport.
• Answer: Active transport.

1. Question 3: Which of the following best describes the primary role of the cell membrane in both active and passive transport?

• Brief Explanation: The cell membrane regulates which substances enter and exit the cell in both active and passive transport. It acts as a selective barrier.
• Answer: To control which substances enter and exit the cell.

1. Question 4: Which of the following scenarios describes movement of molecules from an area of low concentration to an area of high concentration across a cell membrane?

• Brief Explanation: Active transport is the movement of molecules against their concentration gradient (from low to high concentration).
• Answer: Using energy in the form of ATP to move a molecule across a membrane.

1. Question 5: Passive transport across the cell membrane requires:

• Brief Explanation: Passive transport occurs along the concentration gradient and does not require energy. It is the movement of substances down their concentration gradient.
• Answer: The movement of substances down their concentration gradient.

Format used: Answer - Explanation Format

Answer:

1. Question 1: A scientist observes a cell shrinking when placed in a particular solution. This indicates that the solution is:

• Brief Explanation: When a cell shrinks in a solution, it means water is moving out of the cell. This occurs in a hypertonic solution where the solute concentration outside the cell is higher than inside.
• Answer: Hypertonic to the cell.

1. Question 2: Daffs in the root hairs of a plant need to absorb mineral ions from the soil, where the concentration of these ions is lower than inside the root hair cells. This process requires energy and is called:

• Brief Explanation: Active transport is the movement of substances against their concentration gradient, which requires energy. Since the ions are moving from an area of lower concentration (soil) to an area of higher concentration (root - hair cells), it is active transport.
• Answer: Active transport.

1. Question 3: Which of the following best describes the primary role of the cell membrane in both active and passive transport?

• Brief Explanation: The cell membrane regulates which substances enter and exit the cell in both active and passive transport. It acts as a selective barrier.
• Answer: To control which substances enter and exit the cell.

1. Question 4: Which of the following scenarios describes movement of molecules from an area of low concentration to an area of high concentration across a cell membrane?

• Brief Explanation: Active transport is the movement of molecules against their concentration gradient (from low to high concentration).
• Answer: Using energy in the form of ATP to move a molecule across a membrane.

1. Question 5: Passive transport across the cell membrane requires:

• Brief Explanation: Passive transport occurs along the concentration gradient and does not require energy. It is the movement of substances down their concentration gradient.
• Answer: The movement of substances down their concentration gradient.

Format used: Answer - Explanation Format