Question

1. If you took an enzyme from your stomach (ph=2) and placed it inside the intestines (ph=8) would it still have catalytic active? Explain
2. How do molecules unable to diffuse across the bilayer get into/out of the cell?
3. What is the structure of the lipid bilayer? How does the structure allow the membrane to interact with the environment?

Answer 1

1. No the enzymes acting in the stomach acts in acidic environment while there is basic environment in the intestines ,so they will not act.

2. The molecules which are water soluble cannot diffuse the lipid bilayer membrane,so they will diffuse through active transport . It means that energy or ATPs will be used while these molecules gets diffused.

3. The lipid bilayer contains two layers of lipids which are arranged such that the hydrophillic part or head is towards the outside while there is a hydrophobic tail which is towards inside the layer. There is kink in one the chain of the tail which is due to a double bond.

The lipid is mainly phospholipids. It also contains certains proteins and sugar. All these strucutre participate in the fluidity of the membrane whicj means the property of the membrane to allow the molecules flow in or utside of the cells. Thus it interact through the environment.