7.2 Assessment Questions
Why is the cell membrane sometimes referred to as a fluid mosaic? What part of it makes it a fluid and what part of it makes it a mosaic?
It is sometimes referred to as a fluid mosaic because it has many types of molecules which float along the lipids due to the many types of molecules that make up the cell membrane. The liquid part is the lipid bilayer which floats along the lipids due to the many types of molecules that make up the cell. The mosaic are the carbohydrate molecules that act like identification cards that can help individual cells to identify one another.
How do the properties of the lipids explain the structure of a cell membrane?
Lipids give cells membranes a flexible structure which forms a strong barrier between the cell and its surroundings. This tells us that the lipid surrounds the structure which then forms the shape of the cell.
Why do you think it is important that cells are semi-permeable?
Many substances can be able to cross the biological membranes but some can be too large or strongly charged to cross the lipid bilayer. It is important that the cell membrane is selectively permeable because it helps block out some substances and also allows passage to some substances.
