Cell Membranes

Question 1

Cell Membranes:

Function:

Answer 1

Establish compartments

* Cellular compartments

* Subcellular compartments

Question 2

Plasma membrane-

Answer 2

-the “skin” of the cell

* Physical boundary

*Organ of Contact

* Recognition

*Adhesion

* Communication

* Exchange

*Respiration

Question 3

Cell Membranes:

Composition:

Answer 3

Varies slightly between different organelles and plasma membranes.

• Regardless of location all cell membranes are composed of lipids and proteins and have common general structure

Question 4

Cell Membranes

Composition:

Answer 4

• Lipids- 50% of mass of most membranes
• Proteins- 50%
• Glycoproteins
• Glycolipids

Question 5

Composition

Lipids

Answer 5

• arranged in two closely apposed sheets -Lipid bilayer
• Lipid bilayer- provides the basic structure and serves as a permeability barrier

Question 6

Composition:

Answer 6

* Lipids - 50% of mass of most membranes

* Phospholipids- most abundant membrane lipids

* Phosphatidylcholine- most common phospholipids

* Phosphatidylserine- negatively charged

* phosphatidylethanolamine

* sphingomyelin

* cholesterol

* glycolipids

Question 7

Lipid bilayer

Answer 7

Energetically most favorable arrangement of lipid molecules in an aqueous environment

*Hydrophobic tails- hydrophobic interior

*hydrophilic heads- facing water

Question 8

Lipid Bilayer-

Self-sealing property of bilayer-

Answer 8

driven by hydrophobic nature of tails- spontaneous elimination of free edges—> formation of self-sealing containers defining closed compartments

Question 9

Lipid bilayer-