Question

model 2 - the selectively permeable cell membrane
small nonpolar or small polar molecules
phospholipid
small surface protein
membrane - spanning protein
carbohydrate chain
glycoprotein
glycolipid
inside the cell
outside the cell

1. what two major types of biological molecules compose the majority of the cell membrane in model 2?
2. how many different protein molecules are found in model 2?
3. what is the difference between the position of the surface proteins and the membrane - spanning proteins?
4. when a carbohydrate chain is attached to a protein, what is the structure called?
5. when a carbohydrate is attached to a phospholipid, what is the structure called?
6. what types of molecules are shown moving across the membrane?
7. where exactly in the membrane do these molecules pass through?

Explanation:

1. Phospholipids and proteins are the main components of the cell membrane. Phospholipids form the lipid bilayer, and proteins are embedded in or associated with this bilayer.
2. Three types: small surface protein, membrane - spanning protein, and glycoprotein (which is a protein with a carbohydrate chain attached).
3. Surface proteins are on the surface of the membrane (either inner or outer), while membrane - spanning proteins extend across the entire lipid bilayer.
4. Glycoprotein.
5. Glycolipid.
6. Small nonpolar or small polar molecules.
7. Through the phospholipid bilayer (between the phospholipid molecules).

Answer:

1. Phospholipids and proteins.
2. Three.
3. Surface proteins are on the membrane surface; membrane - spanning proteins cross the bilayer.
4. Glycoprotein.
5. Glycolipid.
6. Small nonpolar or small polar molecules.
7. Through the phospholipid bilayer.