Transport Across Cell Membrane

Question 1

Transport across a cell membrane.

Answer 1

The cell membrane is composed of lipid and protein.
The cell membrane is selectively permeable.
Water, carbon dioxide and oxygen can pass through easy.
Larger molecules can’t pass through as easily. E.g. Proteins.

Question 2

Structure of a cell membrane

Answer 2

Double layers of lipid molecules and protein molecules and in the protein molecules there is a protein channel.

Question 3

Passive transport and concentration gradient.

Answer 3

When gasses, liquids or a dissolved substance moves from an area of high concentration to an area of low concentration. Plus no energy is involved this is called passive transport or diffusion. Movement will stop when the gradient has been equiliased.
In living cells diffusion often occurs in the membranes

Question 4

Osmosis

Answer 4

Osmosis is a type of diffusion but for water molecules.
Osmosis is important because fish breath water through their gills which act like a selectively permeable membrane.
It affects plant cells differently because plant cells have a cell wall. So when the cell swells up due to the intake of water they turn turgid a and when they lose the water they become plasmolysed.

Question 5

What is active transport.

Answer 5

Active transport is quick and effective. For moving substances in and out of the cells. Example glucose is moved out of the the gut into the bloodstream this movement requires energy therefore it is called active transport.