Cell Membrane

Question 1

What are all cells surrounded by?

Answer 1

A plasma membrane/cell surface membrane.

Question 2

What is the usual distance of a cell membrane?

Answer 2

7– 8 nm

Question 3

What are the roles of plasma membranes?

Answer 3

They separate the cells components from the outside environment.
It regulates the transport of nutrients in and out of the cell.
It is a receptor site e.g. hormones will bind to the target cells which has the correct receptor site.
Recognition - protein based antigens are built onto the cell membrane enabling them to recognise other cells and triggers the immune response

Question 4

What is the role of internal membranes?

Answer 4

It separates the cells components from the cytoplasm.
It holds some components on some metabolic pathways in place e.g. ribosomes are attached to the membrane of RER.
Chemical reactions take place on membranes e.g. aerobic respiration takes place on the inner mitochondrial with the attached enzyme ATP synthase.