Plasma Membranes 2.4

Question 1

What are the components of the cell membrane and how do they function?

Answer 1

Phospholipids form a bilayer.

Question 2

Describe the orientation of the components for the structure of the phospholipid.

Answer 2

Phospholipid phosphate head- polar and hydrophilic

Phospholipid fatty acid tail- nonpolar and hydrophobic

Question 3

How does the phospholipid bilayer maintain the internal environment of a cell?

Answer 3

Only certain types of molecules can pass through the membrane (nonpolar small) or whatever passes through selective proteins.

Question 4

What are 6 functions of membrane proteins?

Answer 4

Transport
Cell-cell recognition
Enzymatic activity
Signal Transduction
Intercellular joining
Attach cytoskeleton

Question 5

What are the two types of proteins and how does the polarity of the membrane protein affect its orientation in the membrane?

Answer 5

If it is polar, then it is hydrophilic, so it is on the outside of the membrane (peripheral). If it is has polar ends and nonpolar middle, it spans the membrane(integral).

Question 6

How does the membrane protein maintain the internal environment of a cell?

Answer 6

They only let certain monomers into the cell.

Question 7

Define the fluid mosaic model.

Answer 7

Cell membranes are structured as a mosaic of protein molecules on a phospholipid bilayer. The bilayer is held together by unstable hydrophobic bonds, so lipids can get through.

Question 8

What is the function of steroids in the plasma membrane?

Answer 8

They regulate bilayer fluidity. (make sure phospholipids can move amongst themselves)

Question 9

What is the function of glycoproteins and glycolipids in the plasma membrane?

Answer 9

Glycoprotein-membrane protein w attached carbohydrates
Glycolipid- lipid with carbohydrates attached
Useful in cell to cell recognition and stabilize membrane