Cell Bio - Cell Membrane and Cell Wall

Question 1

What is the CELL WALL made out of in plant cells?

Answer 1

Cellulose (a structural carbohydrate) - glucose molecules joined together. It is freely permeable

Question 2

What is the Cell Membrane made out of?

Answer 2

Phospholipids and Proteins

Question 3

What is a phospholipid made up of and what type of layer do they form?

Answer 3

• Glycerol molecule, two fatty acids and a phosphate group.
• They form a bilayer - two layers of lipid molecules.

Question 4

Why are cell membranes selectivley permeable?

Answer 4

Because of its structure. Its made up of a phospholipid bilayer (hydrophobic tails facing inside), that stops large molecules from easily diffusing through it.

Question 5

Name and describe 3 jobs proteins in the cell membrane have

Answer 5

1. Some form channels in the membrane allowing small molecules to move through passively.
2. Some are partially embedded in the phospholipid bilayer or rest on its surface. They work as chemical receptors or enzymes for reactions.
3. Others act as carrier proteins for the active transport of materials across the membrane

Question 6

Describe 3 conditions that can disrupt the structure of the cell membrane

Answer 6

• High Temperature - denatures proteins
• Ethanol - dissolves the phospholipids (fat)
• Osmotic imbalance