Plasma Membrane

Question 1

What are the several functions of the cell membrane?

Answer 1

1. Regulates which molecules enter and leave the cell.
2. Separates internal chemical reactions from the external environment.
3. Allows cell to excrete wastes and interact with their environment.

Question 2

What is the plasma membrane and the membranes of cel organelles primarily made of?

Answer 2

a double layer of phospholipids called the lipid bilayer

Question 3

What type of head does a phospholipid have?

Answer 3

a phosphate head that is polar and hydrophilic

Question 4

What type of tail does a phospholipid have?

Answer 4

a fatty acid tail that is nonpolar and hydrophobic

Question 5

How are phospholipids arranged?

Answer 5

They are lined up so that their heads point outward toward the water and their tails point inward, away from the water.

Question 6

What are the cholesterol molecules in membranes of eukaryotic cells used for?

Answer 6

they stabilize the membrane and help prevent freezing

Question 7

Where are proteins of the lipid bilayer located?

Answer 7

some proteins sit on the surface while others extend through the membrane and help move specific molecules into or out of the cell

Question 8

How is the cell membrane like a fluid mosaic?

Answer 8

1. It is flexible and is constantly changing.

2. It is a mosaic because it has many proteins embedded within it