1. Membrane Structure & Molecule Transport Part 2
AP Biology
Membrane Structure
& Molecule Transport
Part 2

2. Cell Membrane

3. Cellular Transport 2 Types 1.) Active Transport *Requires Energy
*Goes against concentration gradient
2.) Passive Transport

4. Active Transport Cytoplasmic Na+ bonds to the sodium-potassium pump
EXTRACELLULAR
FLUID
[Na+] high
[K+] low
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
[Na+] low
[K+] high
ATP P
Na+ P
CYTOPLASM
ADP
Cytoplasmic Na+ bonds to
the sodium-potassium pump
Na+ binding stimulates
phosphorylation by ATP.
Phosphorylation causes
the protein to change its
conformation, expelling Na+
to the outside. K+ K+ K+ K+ K+ P P K+
Extracellular K+ binds
to the protein, triggering
release of the phosphate
group.
Loss of the phosphate
restores the protein’s
original conformation.
K+ is released and Na+
sites are receptive again;
the cycle repeats.

5. Proton pumps

6. Proton pumps and co-transport

7. Phagocytosis & Pinocytosis

8. RECEPTOR-MEDIATED ENDOCYTOSIS.
RECEPTOR-MEDIATED ENDOCYTOSIS
Coat protein
Receptor
Coated
vesicle
Coated
pit
Ligand
A coated pit
and a coated
vesicle formed
during
receptor-
mediated
endocytosis
(TEMs).
Coat
protein
Plasma
membrane
0.25 µm

9. Cellular Transport 2 Types 1.) Active Transport *Requires Energy
*Goes against concentration gradient
2.) Passive Transport- No energy needed
*Goes with concentration gradient (required)
*ALWAYS A TYPE OF DIFFUSION

10. Diffusion

11. Fluid Mosaic Model and Phospholipids
Lateral movement
(~107 times per second)
Flip-flop
(~ once per month)
Movement of phospholipids

12. Facilitated Diffusion
EXTRACELLULAR
FLUID
Channel protein
Solute
CYTOPLASM

13. “Grabber” Transport proteins
Carrier protein
Solute

14. Osmosis

15. . Hypotonic solution Isotonic solution Hypertonic solution Animal cell
H2O
H2O
H2O
H2O
Lysed
Normal
Shriveled
Plant
cell
H2O
H2O
H2O
H2O
Turgid (normal)
Flaccid
Plasmolyzed

16. Surface Area of the lungs (alveoli)

17. Digestive Tract Small Intestine averages 23 feet.

18. Villi and Microvilli on the interior of the small intestine
Key
Nutrient
absorption
Vein carrying blood
to hepatic portal
vessel
Microvilli
(brush border)
Blood
capillaries
Epithelial
cells
Muscle layers
Epithelial cells
Large
circular
folds
Lacteal
Villi
Lymph
vessel
Villi
Intestinal wall

19. Excretory Structures

20. Nitrogenous Waste filtering

21. Surface Area vs. Volume