I. Objectives for section 7-2: The Plasma Membrane

A. State the function of the cell membrane

B. Explain how proteins, carbohydrates, and

cholesterol play a role in the plasma membrane

Section 2

II. Plasma Membrane is a thin, flexible boundary between the cell and its environment

Cellular Structure and Function

A. Allows nutrients into and wastes to leave the cell

Section 2

B. Selective Permeability: controlsmovement of substances into and out of cell

Cellular Structure and Function

C. Controls amount ofsubstances entering and leaving

the cell

Section 2

D. Composed of phospholipid bilayer

Cellular Structure and Function

1. Composed of a glycerol backbone, two fatty acid chains, and a phosphate group

Section 2

2. Polar (partially charged) head and 2 nonpolar (no charge) tails

Phospholipid bilayer

Section 2

Phospholipid molecule

Lipid bilayer

Lipid bilayer makes up the cell membrane

E. Overall picture

F. Fluid Mosaic Model

Cellular Structure and Function

1. Bilayer allows other molecules to “float” in membrane

Section 2

Transport protein

2. Nonpolar tails on inside do not allow water-soluble substances to pass through easily

a. Allows cell to separate inside environment from the outside

b. Proteins are held in membrane in a similar fashion

Section 2

A. Proteins act as a support structure

Cellular Structure and Function

III. Other components of plasma membrane

Section 2

1. Receptor proteins transmit signals inside the cell

a. “intercellular communication”

Section 2

2. Transport proteins: aid movement of substances into and out of cells

Section 2

3. Marker proteins: attached to a carbohydrate on cell’s surface and advertise cell type

a. Will recognize foreign invaders including transplanted organs!!

Section 2

Cellular Structure and Function

B. Cholesterol prevents fatty acid tails from sticking together

Section 2

C. Carbohydrates identify chemical signals

Cellular Structure and FunctionSection 2

Cellular Structure and FunctionSection 2

1. A2. B3. C4. D

Cellular Structure and Function

A. identifiers

B. receptors

C. supporters

D. transporters

1. Which term describes the function of proteins

found on the outer surface of the plasma membrane?

Section 2 Formative Questions

Chapter

1. A2. B3. C4. D

Cellular Structure and Function

Section 2 Formative Questions

A. phospholipids

B. proteins

C. carbohydrates

D. cholesterol molecules

2. Which component of the plasma membrane contributes to the fluidity of the plasma membrane?

Chapter

1. A2. B3. C4. D

Cellular Structure and Function

Section 2 Formative Questions

3. What is the function of carbohydrates that stick out from the outer surface of the

plasma membrane?A. They give the cell shape and enable it to

move.B. They give the plasma membrane fluidity.C. They help the cell identify chemical signals.D. They hold the cell in place.

Chapter

1. A2. B3. C4. D

Cellular Structure and Function

Standardized Test Practice

A. membrane proteinsB. transport proteinsC. the nonpolar tails in the middle of the

plasma membrane

D. the polar heads facing the inside and outside of the cell

4. What part of the plasma membrane makes it

difficult for water-soluble substances to move freely into and out of the cell?

Chapter

1. A2. B3. C4. D

Cellular Structure and Function

A. identifiers

B. receptors

C. supporters

D. transporters

1. Which term describes the function of proteins

found on the outer surface of the plasma membrane?

Section 2 Formative Questions

Chapter

1. A2. B3. C4. D

Cellular Structure and Function

Section 2 Formative Questions

A. phospholipids

B. proteins

C. carbohydrates

D. cholesterol molecules

2. Which component of the plasma membrane contributes to the fluidity of the plasma membrane?

Chapter

1. A2. B3. C4. D

Cellular Structure and Function

Section 2 Formative Questions

3. What is the function of carbohydrates that stick out from the outer surface of the

plasma membrane?A. They give the cell shape and enable it to

move.B. They give the plasma membrane fluidity.C. They help the cell identify chemical signals.D. They hold the cell in place.

Chapter

1. A2. B3. C4. D

Cellular Structure and Function

Standardized Test Practice

A. membrane proteinsB. transport proteinsC. the nonpolar tails in the middle of the

plasma membrane

D. the polar heads facing the inside and outside of the cell

4. What part of the plasma membrane makes it

difficult for water-soluble substances to move freely into and out of the cell?

Chapter