Cell Membrane Structure

Question 1

Name the functions of Cell Surface Membrane

Answer 1

• Recognition of other Cells
• Site of biochemical reactions
• Allowing a cell to change shape
• Allowing selected molecules to move in and out of cell
• Keeping all cellular components inside the cell

Question 2

What is a Cell Surface Membrane?

Answer 2

The outer layer that surrounds all cells, separating the cytoplasm from the external environment.

Question 3

What is the Fluid Mosaic Model?

Answer 3

The arrangement of proteins, carbohydrates, and lipids within the bilayer that reflects the diverse array of molecules embedded in the fluid bilayer.

Question 4

What are the two faces in Cell Membranes?

Answer 4

E-Face: Looking up at the outer layer of membrane

P-Face: Looking down inner layer of membrane

Question 5

What are the components of Cell Surface Membrane?

Answer 5

Phospholipids
Proteins
Extrinsic Proteins
Glycoproteins
Intrinsic/Integral Proteins
Cholesterol

Question 6

What are Phospholipids?

Answer 6

Polar molecules with:
Hydrophilic Head: Attract water
Hydrophobic Tail: Repel Water

Question 7

What happens when Phospholipids are in water?

Answer 7

They either form a micelle (Circular) or a bilayer.
Hydrophilic heads face water and tails point away

Question 8

Describe Proteins in the Cell Membrane

Answer 8

Arranged more randomly and consist of Extrinsic and Intrinsic proteins.

Extrinsic: Partially embedded. Provide mechanical support to membrane. Act as cell receptors in conjunction with Glycolipids

Intrinsic: Span whole bilayer. Some are carrier proteins transporting water-soluble material across membrane. Some are enzymes.

Question 9

Describe Glycoproteins in Cell Membrane

Answer 9

They have branching carbohydrate chain attached. Acts as a recognition site for chemicals (e.g Hormones)

Question 10

Name the functions of Proteins in the Membrane

Answer 10

• Act as receptor sites
• Helps cells adhere
• Form recognition sites by identifying cells
• Act as carriers for water soluble molecules
• Provide structural support
• Allow Active Transport

Question 11

Describe Cholesterol in Cell Membrane

Answer 11

Type of lipid that control membrane fluidity. More cholesterol means less fluid. This means membrane is less permeable. Keeps membranes stable at normal body temperature. Without it, cells would burst open.