Chapter 4: The Structure and Function of the Plasma Membrane Flashcards Preview

Molecular Cell Biology > Chapter 4: The Structure and Function of the Plasma Membrane > Flashcards

Flashcards in Chapter 4: The Structure and Function of the Plasma Membrane Deck (46)
Loading flashcards...
1

What are the functions of the membrane and describe each! (7)

1. compartmentalization - encloses cell boundary and intercellular spaces..each compartment has different contents so specialized activities can occur without interference ..interference = diseases. *Independently regulated.
2. framework for biochemical rxns- ensures components are arranged for effective interaction
-ie. all ETC molecules are embedded in MIT M
3. selectively permeable M - prevents unrestricted exchange of molecules...method of communication (gap junctions in cardiac cells ex)....aquaporins = how water gets into cells.
4. transport- substances can be moved up or down [ ] gradient...up= expenditure of ATP....establishes ion gradients
5. signal transduction - bind ligands to M receptors...changes internal cellular activities (2nd messenger) ex: cyclic AMP= common messenger
6. intercellular interaction - recognition and signalling occurs between cells...ex: immune system!
7. energy transduction - one type of energy is converted into another~>..example photosynthesis.. Light+sugar
L> Sugar --->ATP= cellular respiration

2

Describe the structure of the plasma membrane!

-lipids
-carbohydrates
-ratio of lipid to protein in membrane depends on which membrane , which cell and which organization it is in!
-glycoproteins: carb attached to protein
- glycolipid : carb attached to lipid

3

Mitochondrial membrane concentration?

- high [] of protein to lipid!

4

Neuron membrane concentration?

- high [] of lipid to protein

5

What is between the inner and outer leaflets? Also what the fuck are inner and outer leaflets? (maybe answer in the reverse order)

-inner leaflet is the phospholipids closest to the inside of the cell...outer is closer to the exterior
- between them is a hydrophobic region

6

What are the three membrane lipids?

- phosphoglycerides
- sphingolipids
-cholesterol

7

All lipids that make up a membrane are _____

- amphipathic...have a water loving and hating region!
O - hydrophilic region
| \ - hydrophobic region.....
**they aggregate spontaneously in a membrane

8

Phosphoglycerides:
- ____ and ___ backbone

- phospholipid and glycerol

9

Phosphoglycerides:
- What are the four major phospholipids?

1. choline
2. ethanolamine
3. serine
4. inositool
*phosphatidic acid (base of phospoglyceride)

10

Phosphoglycerides:
- tail composed of?

- saturated FA and Unsaturated FA
*unsaturated = membrane fluid = not as compact...ie why there is a bend in the tail!

--------------------------phosphate
choline |
polar head group ----glycerol backbone |========= fatty chain

11

The polar head group can vary in phosphoglycerides. What are they? (6)

1. Dioleoyl Phosphatidic acid
2. Phosphatidic acid
3. Phosphatidyl-cholne (lecithin) (PC)
4. Phosphatidyl- serine (PS)
5. Phosphatidyl-ethanolamine (cephaline) (PE)
6. Phosphatidyl-inositol (PI)

12

PC?

- mainly found on the outer leaflet
- important in cell signalling
- some viruses can use it to gain entry into the cell

13

PE?

- found in cell M mainly of platelets
-important in blood clotting
- promotes membrane curvature
- inner leaflet of M = where it is found

14

PE and PC?

- neutral phsophoglycerides
- also have EPA ( five double bonds in FA tail) and DHA(6 double bonds in FA tail) aka omega 3's
L> FA that lowers cholesterol

15

PS?

- inner leaflet of PM
- flippase are enzymes that ensure they are on the right leaflet
- sign something is wrong if it is on the outer
L> aka cell is not functioning right
- prevents memory loss

16

PI?

-inner leaflet
- cell signalling and emulation of cellular metabolism and growth

17

Cardiolipin?

- commonly found in the inner mitochondrial membrane

18

PS and PI have what kind of charge?

- negative

19

Sphingolipids:
- ceramide molecules??

- sphingosine (sugar) + FA chain
** sugar containing lipid molecule at the PM surface

20

Sphingolipids are the most or least abundant lipid in PM?

- least

21

Sphingolipids:
- ceramide molecules types?

- Sphingomyelin ( ceramide + phosphorylcholine)
- Glycolipid (ceramide + CHO)
L> cerebroside (simple sugar)
L> ganglioside(cluster of sugars)

22

Sphingolipids
- functions???

- protects PM from harsh exterior ...lipid acts a buffer to low pH of other enzymes
-electrical insulation : insulates axons
-cell recognition : cell service receptor
- binds cell to extracellular matrix ..helps it bind so the cell can grow.

23

-Ceramide function?

- cell signalling
- can be released from PM to act as a signalling molecule for differentiation or proliferation of other cells... Also signal of cell death!

24

Sphingosine functions in?

signal transduction in PM

25

Accumulation of Sphingomyelin leads to?

- Niemann pick disease (lysosomal storage disease)

26

Cerebroside?
L> potential disease associated ?

- Gal + ceramide
- defect in degradation of cerebroside causes organs to malfunction... Gaucher's disease
L> Type 1 and 2
-type can be helped with an enzyme replacement therapy but for type 2 death occurs by age 2.

27

Ganglioside?

- GalNac + Gal + Glu + ceramide
|
SiA
- Tay Sachs Disease
L> fatal...build up of lipid in brain...die by age four...homozygous recessive.....
**GM2

28

Ganglioside:

L> GM1 and GM3?

- GM1
L> acts as cell surface receptor
L> influenze, cholera and bothcelism use to gain entry to the cell.
*cholera attaches to GM1
L> cyclic AMP (cAMP) increases in intracellular level of it which leads to an increase in sodium and water loss in the large intestine.
-GM3:
L> lack of it causes neurological diseases ..blindness...seizures etc

29

Cholesterol:
-__,___ molecules

- flat , rigid

30

Cholesterol:
-interfere with the movement of?

- FA tails...
when present they are not as tightly as packed...making them more fluid
0
|\
| <== cholesterol stiffened region