Transport Across Membranes

Question 1

What are phospholipids

Answer 1

A type of lipid composed of fatty acids phosphate and glycerol. These form part of all cell membranes and play a key role in cell function.

Question 2

The cell membrane has two layers. What are the two man components of each layer?

Answer 2

Phospholipids and proteins

Question 3

What can pass directly through the phospholipids In the cell membrane

Answer 3

Some small molecules such as water, oxygen and carbon dioxide

Question 4

What do larger molecules require to move across the cell membrane

Answer 4

Larger molecules such as glucose require a specific transport protein to facilitate their movement across the cell membrane

Question 5

What molecules are the call membrane said to be impermeable to?

Answer 5

Very large molecules such as proteins are too big to move through the cell membrane which is said to be impermeable to them.

Question 6

What determines which substances the call membrane is permeable to?

Answer 6

The type of transport proteins present in the cell membrane

Question 7

What is diffusion?

Answer 7

Diffusion is the net movement of molecules from an area where they are at higher concentration to areas where they are at a lower concentration. This is die to the random movement of the molecules.

Question 8

What is the concentration gradient?

Answer 8

The difference in the concentration of a substance between two areas