What is active transport

Question 1

What is active transport

Answer 1

The uptake of molecules or ions against a concentration gradient using energy from respiration (ATP)

Question 2

How does active transport work

Answer 2

• There are specific carrier proteins in the cell membrane
• Each carrier protein is specific to a single molecule or ion
• However unlike facilitated diffusion, energy is required to move the molecule through the membrane
• Molecule combines with the carrier protein
• ATP transfers a phosphate group to the carrier portein on the inside of the membrane
• The carrier protein changes shape
• Which enable the molecule or ion to transfer through the membrane
• Due to the need for energy, most cells involved tend to have mitochondria and have a high rate of respiration

Question 3

What effects active transport

Answer 3

• Any factor which influences the rate of respiration for example…
• Temperature
• Oxygen concentration
• Poisons e.g. Cyanide

Question 4

Give some examples of active transport

Answer 4

1. Nerve impulse transmission
2. Muscle contraction
3. Absorbtion of amino acids in the gut
4. Absorbtion of mineral salts by plant roots
5. Protein synthesis
6. Excretion of urea in the kidney

Question 5

What is co transport

Answer 5

Then linked, simultaneous transport of two substances accross the same cell membrane in the same direction

Question 6

What is an example of co transport

Answer 6

The absorbtion of amino acids and glucose by cells linining the mammalian ileum