Question 1: Define active transport in the context of cellular processes.

Answer: Active transport is a process by which cells move molecules or ions against their concentration gradient using energy, typically from ATP.

Question 2: Explain why active transport requires energy and how it differs from passive transport.

Answer: Active transport requires energy because it moves substances against their concentration gradient, unlike passive transport which moves substances along the gradient without energy.

Question 3: Describe the role of carrier proteins in active transport.

Answer: Carrier proteins bind to specific molecules and change shape to transport them across the cell membrane using energy.

Question 1: If a cell transports 2.5 x 10^6 sodium ions per second using active transport, and each transport cycle consumes 1 ATP molecule, how many ATP molecules are used in 1 minute? (Show your calculation.)

Answer: 150,000,000 ATP molecules. Calculation: 2.5 x 10^6 ions/sec x 60 sec = 1.5 x 10^8 ions; since 1 ATP per ion, total ATP = 1.5 x 10^8.

Question 2: A cell expends 3.2 x 10^8 Joules of energy to move 8 x 10^7 ions via active transport. Calculate the energy cost per ion in Joules.

Answer: 4 Joules per ion. Calculation: Total energy / total ions = 3.2 x 10^8 J / 8 x 10^7 ions = 4 J/ion.

Question 1: Design a simple experiment to demonstrate active transport in a lab setting, including the variables involved and safety precautions.

Answer: Students could use a dialysis tubing filled with a sugar solution and immerse it in a solution with a different concentration. Variables include sugar concentration inside and outside, temperature, and pH. Safety precautions involve handling solutions carefully to avoid spills and wearing gloves.

Question 2: Explain how active transport is essential for nutrient absorption in the small intestine.

Answer: Active transport allows the small intestine to absorb nutrients like glucose and amino acids against their concentration gradients, ensuring the body gets enough essential nutrients.

Question 3: Identify the main difference between active transport and facilitated diffusion, and give an example of each.

Answer: Active transport moves substances against their concentration gradient using energy, e.g., sodium-potassium pump; facilitated diffusion moves substances along the gradient without energy, e.g., glucose transport via carrier proteins.

Question 4: In a scenario where a cell's sodium-potassium pump becomes non-functional, predict the impact on cell function and explain why.

Answer: The cell would struggle to maintain its sodium and potassium ion gradients, leading to impaired nerve signal transmission, disrupted cell volume regulation, and potentially cell death due to ionic imbalance.