Extra Membranes

Question 1

Describe the structure of a membrane

Answer 1

Hydrophilic phosphate heads, hydrophobic fatty acid tails, glycoproteins, glycolipids, cholesterol, extrinsic and intrinsic proteins

Question 2

Define diffusion

Answer 2

The passive movement of molecules from a high to low concentrartion, down a concentration gradient

Question 3

What affects the rate of diffusion?

Answer 3

Concentration gradient, diffusion distance, surface area, size and nature of diffusing molecule, temperature

Question 4

Define facillitated diffusion.

Answer 4

The passive movement of molecules down a concentration gradient by protein carrier molecules.

Question 5

What are the two types of protein carrier molecules?

Answer 5

Channel (Hydrophilic with protein groups, open and close with need), carrier (transport larger molecules, molecule attach to binding site, protein change shape and releases)

Question 6

What is active transport used for?

Answer 6

Muscle contraction, nerve transmission, reabsorption, mineral uptake

Question 7

Explain the steps to active transport

Answer 7

Molecule joins carrier protein, ATP transfers phosphate to protein, changes shape, molecule released, phosphate returned, protein original shape

Question 8

Define co-transport

Answer 8

Facilitated diffusion that brings molecules into the cell together on the same transport protein

Question 9

How are animal cells different to plant cells in relation to osmosis?

Answer 9

Have no cell wall so water potential = solute potential`12qwasx

Question 10

What are the two types of bulk transport?

Answer 10

Endocytosis and exocytosis

Question 11

Define endocytosis

Answer 11

When materials are engulfed by the membrane, forming a vesicle

Question 12

Define exocytosis

Answer 12

Materials actively transported through the cytoplasm in vesicles, which fuse with the cell membrane.