transport across cell membranes

Question 1

describe the structure of the cell surface membrane.

Answer 1

fluid mosaic phospholipid bilayer with extrinsic and intrinsic proteins embedded.

Question 2

describe the function of the cell-surface membrane.

Answer 2

isolates cytoplasm from extracellular environment.

selectively permeable to regulate transport of substances.

involved in cell recognition.

Question 3

explain the role of cholesterol in the cell-surface membrane.

Answer 3

present in some membranes and restrict the lateral movement of other molecules in the membrane.

makes the membrane less fluid at high temperatures.

prevents water and dissolved ions leaking out of the cell.

Question 4

explain the role of glycoproteins in the cell surface membrane.

Answer 4

cell recognition and binding cells together.

Question 5

explain the role of glycolipids in the cell surface membrane.

Answer 5

cell recognition.

Question 6

what is an intrinsic protein?

Answer 6

span from one side of the bilayer to the other.

e.g. protein channels and carrier proteins.

Question 7

what is an extrinsic protein?

Answer 7

occur in the surface of the bilayer.

e.g. receptors.