Question 1: Active transport is a cellular process that moves substances against their concentration gradient. It requires energy, usually in the form of ATP, to enable specific molecules to enter or exit the cell. This process is essential for maintaining cellular function and homeostasis.

Answer: Active transport moves substances against their concentration gradient using energy (ATP), enabling cells to uptake nutrients or remove waste efficiently.

Question 1: Define active transport in the context of cell biology.

Answer: Active transport is the movement of molecules or ions across a cell membrane against their concentration gradient, requiring energy.

Question 2: Describe the role of ATP in active transport.

Answer: ATP provides the energy necessary for carrier proteins to change shape and move substances against their concentration gradient.

Question 3: Which type of molecules are commonly transported via active transport in cells?

Answer: Ions

Question 4: Fill in the blank: Active transport allows cells to accumulate ________ substances even when their concentration outside the cell is higher.

Answer: concentrated

Question 1: Explain how carrier proteins facilitate active transport across the cell membrane.

Answer: Carrier proteins bind specific molecules on one side of the membrane, then change shape using energy from ATP to shuttle the molecules against their concentration gradient to the other side.

Question 2: Identify two examples of substances transported via active transport in human cells.

Answer: Sodium ions and glucose

Question 1: Propose a basic experimental setup to investigate the rate of active transport of sodium ions in a cell membrane. Include the main variables and safety precautions.

Answer: An experiment could involve using a model membrane or live cells with a known sodium concentration. Variables include temperature, ion concentration, and pH. Safety precautions involve wearing gloves and eye protection when handling chemicals and ensuring proper disposal of biological samples.

Question 2: A study reports that in a certain cell type, the rate of active transport of potassium ions increases with temperature up to 37°C, then declines. Explain this observation.

Answer: The increase is due to enhanced enzyme activity at higher temperatures, but beyond 37°C, enzymes denature, reducing efficiency and decreasing transport rate.

Question 3: In a scenario where a cell is exposed to a hypertonic solution, predict how active transport may assist the cell in maintaining homeostasis.

Answer: The cell can actively transport ions or molecules into itself to counteract water loss and maintain internal concentration balance.