L8 Lipid Structure And Function

Question 1

Why is the cell membrane considered asymmetric

Answer 1

Due to the diff in compostion and orientation of lipids protiens and carbohydrates

Question 2

Name some features of phospholipids

Answer 2

Ionic compunds
Amphipathic(hydrophyllic head and hydrophobic tail)
Can either be phosphoglycrides or sphingophospholipids)

Question 3

What does a phosphoglcyride consist of

Answer 3

Glycerol backbone
Two fatty acids
And a phosphorylated alcohol

Question 4

Give an example for a phosphoglycride

Answer 4

Phosphatidic acid

1,2-diacylglycerol 3-phosphate

Question 5

What are some examples of what the phosphate is esterfied in to in a phosphoglyceride present in the membrane

Answer 5

Ethanolamine,choline,glycerol

Question 6

What is the most abundant phosphoglyceride

Answer 6

Lecithin

Question 7

Whats the phosphorylated alcohol in lecithin

Answer 7

Choline

Question 8

Whats the base of cephalin

Answer 8

Ethanoalmine

Question 9

Whats cephalin imp for

Answer 9

Blood clotting factors

Question 10

What is the structure function relationship of phospholipids

Answer 10

▪️Hydrophobic tail plays major role in maintaining the fluidty of the membrane
▪️They form kinks to inc space between phospholipids inc membrane fluidty
▪️Increased space also allows small mol to pass through quickly and easily
▪️They also form weak non covalent bonds holding the bilayer together

Question 11

How is alzhimer’s associated with problems in the ability of the phospholipid bilayer to preform functions

Answer 11

Plaque forms sticking to the phospholipid bilayer of brain neuorns and blocks communication between brain neurons leading to neuron death

Question 12

What are the 3 types of rotations of phospholipids

Answer 12

Lateral,where phospholipid moves around one leaflet
Rotational,rotates around its acis
Transverse, in a flip flop manner
2 leaflets

Question 13

Imp of cholesterol

Answer 13

Helps with fluidty of cell membrane as they are randomly distrbuted across the bilayer
OH groups aligns with phosphate heads and remaining portion is tucked in to fatty acid portion
Making them less mobile and less soluble for v small water soluble mol to pass through
In cold temp cholestrol inc fluidty as it helps seperate hydrophobic tails so they dont crystalize

Question 14

Whats a caveaolae

Answer 14

Flask invaginations in the plasma memrbane mainly present in fat and muscle cells that can bud from plasma membrane to for a vesicle for endocytosis or can flatten in to the membrane to help cells withstand mechanical stress