Biological membranes are composed of phospholipid molecules, cholesterol, and proteins. They have a fluid mosaic structure with phospholipid bilayers and embedded proteins that allows for selective transport. Membranes demonstrate lateral and transverse asymmetry, with unique compositions in each layer and set of proteins. Cholesterol regulates fluidity. Passive transport relies on diffusion and requires small, polar molecules, while active transport uses membrane proteins and ATP to move ions and large molecules against gradients.

1. Build and features of biological membranes.
1. Mark and sign these elements in the illustration:
(glycolipides, surface proteins, transmembrane proteins, glycoproteins,
molecule of cholesterol, phospholipid molecule)
2. Name functions of biological membranes.
...........................................................................................................................................
...........................................................................................................................................
3. Write which properties of biological membranes the following descriptions relate to:
The feature is demonstrated by the fact that each layer has a unique lipid composition
and its own set of embedded proteins. ..................................................................... .
It is due to the constant movement of phospholipids. In animal cells is
regulated by cholesterol ........................................................................................... .
Only small polar molecules can pass through the membrane but small polar
molecules penetrate to a limited degree. Transport of ions and large polar molecules
without the charge requires the participation of the relevant membrane
proteins.................................................................................................................. .
4. Construct the table comparing modes of transport(passive, active) through the
membrane, consider in it direction of transport, the presence of protein carriers, the
proportion of energy (ATP) in transport and an example of transmitted substances.
5. Identify and label illustrated modes of transport through the cell membrane.