Active transport

Question 1

Active transport

Answer 1

movement of molecules or ions into or out of cell from a region of lower concentration to a region of higher concentration using ATP and carrier proteins

Question 2

4 ways active transport is different to passive

Answer 2

1. metabolic energy in the form ATP is needed
2. substances are moved against conc gradient
3. carrier proteins are involved
4. process is selevtive

Question 3

Direct active transport process

Answer 3

1. Carrier proteins span plasma membrane and bind to molecule or ion to be transported on one side
2. Molecule or ions binds to receptor sites on carrier protein
3. On inside of cell, ATP binds to portein, causing to to split into ADP and phosphate molecule. Protein molecule changes shape and opens to opposite side of membrane
4. Molecule or ions is released to to other side of membrane
5. Phosphate molecules is released from proteins which causes it to revert to OG shape, ready for process to be repeated
6. Phosphate molecule recombines with ADP to form ATP during respiration

Question 4

Sodium-potassium pump

Answer 4

sodium ions are actively removed from cells whilst potassium ions are actively taken in from surroundings

Question 5

2 ways to increase rate of movement across membranes

Answer 5

1. microvilli- increase surface area for insertion of carrier proteins
2. increase number/density of protein channels and carrier proteins in membrane

Question 6

Co-transport of glucose in ileum

Answer 6

1. sodium ions are actively transported out of epithelial cells by sodium-potassium pump into blood
2. Maintains high conc of sodium ions in lumen of intestine than inside epithelial cells
3. sodium ions diffuse into epithelial cells down conc gradient through co-transport protein in csm. As sodium ions diffuse through, they carrier amino acid molecules or glucose molecules with them(against conc gradient)
4. glucose/ amino acids pass into blood plasms by facilitated diffusion using another type of carrier