Membrane Structure and Function

Page
9

via phagocytosis (TEM)

Plasma

membrane

Vesicle

0.5 µm

Pinocytosis vesicles

forming (arrows) in

a cell lining a small

blood vessel (TEM)

RECEPTOR-MEDIATED ENDOCYTOSIS

Receptor

Coat protein

Coated

vesicle

Coated

pit

Ligand

Coat

protein

Plasma

membrane

A coated pit

and a coated

vesicle formed

during

receptor-

mediated

endocytosis

(TEMs)

0.25 µm

Slide 72

Fig. 7-20a

PHAGOCYTOSIS

CYTOPLASM

EXTRACELLULAR

FLUID

Pseudopodium

“Food” or

other particle

Food

vacuole

Food vacuole

Bacterium

An amoeba engulfing a bacterium

via phagocytosis (TEM)

Pseudopodium

of amoeba

1 µm

Slide 73

In pinocytosis, molecules are taken up when extracellular fluid is “gulped” into tiny vesicles

Animation: Pinocytosis

Slide 74

Fig. 7-20b

PINOCYTOSIS

Plasma

membrane

Vesicle

0.5 µm

Pinocytosis vesicles

forming (arrows) in

a cell lining a small

blood vessel (TEM)

Slide 75

In receptor-mediated endocytosis, binding of ligands to receptors triggers vesicle formation

A ligand is any molecule that binds specifically to a receptor site of another molecule

Animation: Receptor-Mediated Endocytosis

Slide 76

Fig. 7-20c

RECEPTOR-MEDIATED ENDOCYTOSIS

Receptor

Coat protein

Coated

pit

Ligand

Coat

protein

Plasma

membrane

0.25 µm

Coated

vesicle

A coated pit

and a coated

vesicle formed

during

receptor-

mediated

endocytosis

(TEMs)

Slide 77

Fig. 7-UN1

Passive transport:

Facilitated diffusion

Channel

protein

Carrier

protein

Slide 78

Fig. 7-UN2

Active transport:

ATP

Slide 79

Fig. 7-UN3

Environment:

0.01 M sucrose

0.01 M glucose

0.01 M fructose

“Cell”

0.03 M sucrose

0.02 M glucose

Slide 80

Fig. 7-UN4

Slide 81

You should now be able to:

Define the following terms: amphipathic molecules, aquaporins, diffusion