lipid and bio membrane Flashcards
Major main class of biomolecule
1 amino acids
2nucleotides
3. Monosaccharides
4. Lipids
Types of lipids
1.fatty acids
2.triglycerols
3.glycerophospholipids
4. Sphingolipids
5. Steroids
6. Other
Amphipathic lipids
Any lipid that has a hydrophilic head and a hydrophobic tails
Hydrophilic head?
Usually a phosphate group (charged)
hydrophobic tail?
Where we see hydeophobic effect?
1.protein folding
2.bilayer
Lipids diffusion within bilayer
1.lateral diffusion
2.rotation
3.flexion
4.transeverse diffusion(flip-flop)
fastest and slowest lipid diffusion
最快：lateral diffusion（最多出现）
最慢：transverse diffusion(最少出现
膜中质量最大的成分
lipids最多 蛋白质其次 碳水最少
Factors determine diffusion rate
1.temperature
2. Length of chains
3.degree of unsturation
4. Cholesterol concentration
Degree of unsaturation and fluidity?
Ability to pack PACK
越不饱和越liudong
cholesterol and fluidity at high temp
at high temp, cholesterol stops lipid movement, make lipid less fluid
cholesterol and fluidity at low temp
at low temp, cholesterol stops lipid packing, make lipid more fluid
Who anchors protein to membrane?
Lipid
大部分穿膜蛋白是什么类型
α-helix
how to identify sphingolipids?
amide bond酰胺
why Bilayers are asymmetrical
Proteins * Lipid head groups * Carbohydrates * NOT cholesterol Enzymes maintain asymmetry(transverse diffusion)
Functions of membrane proteins
- Transporters and channels
- Receptors
- Enzymes
- Anchors
how is facilitated transport different from channels
Channels: open pathway, discriminating based on size and charge
Transporters: specific binding site, conformational changes during transpor
Membrane proteins can diffuse in the bilayer unless restricted true or false
true
what are Glycosphingolipids:
Glycosphingolipids: Head group contains a sugar
Why do transmembrane regions of integral membrane proteins stay within the membrane?
Hydrophobic effect. The transmembrane regions contain hydrophobic side chains that would be exposed to water if they were to leave the membrane.
The hydrocarbon chains of most fatty acids produced by humans:
Contain an even number of carbon atoms
