Cell Membranes 1

Question 1

What are the four main functions of a cell membrane? (Hint: PRCS)

Answer 1

The Four main functions are:

• Physical isolation: barrier between ICF and ECF
• Regulation of substance exchange
• Communication between cell & environment
• Structural support

Question 2

What are the three main parts that create a cell membrane?

If a cell is highly metabolically active, what composition is it high in?

Answer 2

The Three main parts cell membranes are made of are:
1. Proteins
2. Lipids
3. Carbohydrates

The higher the metabolic activity the more proteins

Question 3

Cell membranes can be made of 3 types of lipids. What are they and what’s the different functions? (Hint: PSC)

Answer 3

The three lipid types and their functions are:

1. Phospholipids - The main lipid of cell membranes
2. Sphingolipids - Lipid that assists in creating lipid rafts (raised platforms)
3. Cholesterol - Lipid that increases viscosity and decreases permeability (Stiffen membrane)

Question 4

True or False? Are lipids Amphipathic?

Answer 4

True. Lipids are amphipathic since they have a polar head region and a hydrophobic tail region

Question 5

What are the two main categories of cell membrane proteins? One main category has can be broken further into two sub-categories. What are they?

What are the main functions of each

Answer 5

Two main categories are:

• Peripheral proteins - loosely attached and used for signaling / cytoskeleton structure
• Integral proteins - receptors, channels, enzymes, intracellular signaling

The subcategories of integral proteins are:

• Transmembrane
• Lipid anchored