Active Transport - 14/11/23

Question 1

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What does Active Transport mean?

Answer 1

The movement of molecules from a low to a higher concentration using ATP energy and carrier proteins

Question 2

How does ATP help active transport? (2)

Answer 2

1) It helps directly move molecules (against their concentration gradient)
2) More molecules to set up a concentration gradient for co-transport

Question 3

What does Co-Transport mean?

Answer 3

The transport of two different substances by a protein

Question 4

Describe the process of Active Transport. (9)

Answer 4

1) The carrier proteins span the plasma membrane of ion/molecule and have a binding site for the molecule/ion to be transported on one side of it
2) The molecule/ion binds to receptor sites on the carrier protein
3) On inside of cell/organelle ATP binds to carrier proteins
4) Causes ATP to split into ADP and Pi
5) The phosphate group remains attached to carrier protein (the protein has been phosphorylated)
6) As a result the protein molecule changes shape and opens up to opposite side of membrane
7) The molecule/ion is released to other side of membrane
8) The phosphate molecule is released from the protein which causes the protein to revert to its original shape, ready for process to be repeated again
9) The phosphate molecule then recombines with ADP to reform ATP during respiration

Question 5

What happens to ATP so energy is released and solutes are transported?

Answer 5

It goes through hydrolysis, and splits ATP into ADP and P (inorganic phosphate)

Question 6

What is mammalian ileum?

Answer 6

The final part of a mammals small intestine

Question 7

Desribe the step of how glucose is absorbed from lumen to ileum to blood by Co-Transport. (5)

Answer 7

1) Na+ ions actively transported out of epithelial cells in ileum, into blood
2) Creates a conc. gradient - high conc. of Na+ in lumen
3) This causes Na+ ions to diffuse from lumen into epithelial cell, down conc. gradient - do this by Co-Transport proteins
4) Co-Transport also carries glucose with sodium, and conc. of glucose inside cell increases
5) Glucose diffuses out of cell into blood down conc. gradient with help from protein channel by facilitated diffusion