Question

read each question carefully and decide which is the best answer. fill in the bubble with the letter of the correct answer on your answer sheet.

1. essential nutrients move through a cell membrane by both passive transport and active transport. which of the following correctly describes the transport of materials across a cell membrane?

a active transport requires chemical energy to move nutrients from areas of low concentration to areas of high concentration.
b passive transport requires chemical energy to move nutrients from areas of low concentration to areas of high concentration.
c active transport moves nutrients from areas of high concentration to areas of low concentration without the use of chemical energy.
d passive transport moves nutrients from areas of low concentration to areas of high concentration without the use of chemical energy.

Explanation:

• Active transport: Moves substances against the concentration gradient (from low to high concentration) and requires energy (usually in the form of ATP).
• Passive transport: Moves substances along the concentration gradient (from high to low concentration) and does not require energy.

Let's analyze each option:

• Option A: Active transport requires chemical energy (e.g., ATP) to move nutrients from areas of low concentration to areas of high concentration. This is correct as per the definition of active transport.
• Option B: Passive transport does not require chemical energy. It moves substances along the concentration gradient (high to low). So, this option is incorrect.
• Option C: Active transport requires chemical energy and moves substances against the concentration gradient (low to high). This option is incorrect as it wrongly states that active transport moves from high to low without energy.
• Option D: Passive transport moves substances from high to low concentration without energy. This option is incorrect as it has the direction (low to high) wrong for passive transport.

Answer:

A. Active transport requires chemical energy to move nutrients from areas of low concentration to areas of high concentration.