deck_472623 Flashcards
Welcome to Semester 2 guys! Functions of membranes? (5)
1.Continuous, highly selective, permeability barrier2.Control of enclosed chemical environment3.Communication between cells and their environment4.Recognition e.g. signalling proteins, adhesion proteins, immune surveillance5.Signal generation in response to stimuli e.g. electrical/chemical Castrated Criminals Can’t Really Sex
Name three types of lipid in a membrane?
PhospholipidsGlycolipidsCholesterol
What are the main components of a phospholipid?
Polar head groupAttached to.. PhosphateAttached to..Glycerol backbone Attached to.. Fatty acid chains
What are the main types of polar head groups?
Choline, amines, amino acids, sugars
What are the main types of fatty acid chains?
HydrophobicCan be saturated or unsaturated which contain cis C=C. Introduces a ‘kink’ to the fatty acid tail.
Why is sphingomyelin different to most Phospholipids?
Has no glycerol backbone but is still classed as a phospholipid as it has a phosphate. Contains sphingosine.
What is an ampipathic molecule?
contain both hydrophilic (the “head”) and hydrophobic (the “tail”) regions.
Where are unsaturated fatty acids found? Give an example
In the dietLinolenic acid
What Sphingoyelin found? What is its function?
In myelin sheathes, aids in signal transduction
What is a glycolipid?
lipids with a carbohydrate group attached
Give the structure of a glycolipid
Sugar head group (Cerebroside or Gangioside)Sphingosine backboneNitrogenous baseFatty acid tail
Cerebroside?
monomer head group e.g. galactose
Ganglioside?
oligosaccharide head group
What is cholesterol derived from?
HMG-CoA
What is the enzyme used to convert precursor to cholesterol? What drug inhibits this enzyme?
HMG-CoA reductaseStatins
Give the structure of cholesterol
Polar head –OH which is attracted to exposed C=O in phospholipids’ fatty acid tails Rigid, planar steroid ring Non-polar hydrophobic carbon tail
What two things will an ampipathic molecule form in water?
A micelle or a bi-layer