Lipids Flashcards
Where do Lipids exist?
- Phospholipids in cell membranes
- As lipid droplets in adipose tissue
- As lipoproteins in blood
Are Lipids soluble in water?
No, lipids are insoluble in water (hydrophobic). They are soluble in organic solvents.
Name 6 biological functions of lipids?
- A stored form of energy
- A structural element of membranes
- Enzyme Cofactors
- Hormones
- Vitamins A,D,E,K
- Signalling Molecules
Name 5 Classes of Lipid:
- Fatty Acids
- Phospholipids
- Steroids
- Glycolipid
- Triacylglycerol
What is the makeup and function of Glycolipids?
They contain Carbohydrate and Lipid
They are components of membranes and nerve tissue and a source of antigens that give blood groups.
Define Saturated and unsaturated Fatty Acids:
Saturated FA have no double bonds and so are striaght and have a high melting point
Unsaturdated FA have 1 or more double C=C bonds which produces kinks in the chain and gives them a low melting point.
Explain Linoleate 18:2(9,12)
The FA is Linoleate. its made up of an 18 carbon chain containing two double bonds at carbons 9 and 12. The carbons are counted from the carboxyl group.
Which fatty acids are “good and which are “bad”?
“good” fats are high in polyunsaturated FA such as ovlive oil and veg oil.
“bad” fats are high in saturated fatty acids such as stearic acid in beef.
What are Essential FA?
Essential fatty aids cannot be produced in the human body (beacue the body lacks the enzymes to introduce double bonds beyond carbon 9) so must be gained from eating plants. (e.g. Linoleic and alpha-linoleic acid.
Explain Omega-3 FA:
Omega-3 fatty acids are derived form linolenic acid and are essential FAs wich lower plasma cholesterol to prvent atherosclerosis and lowers TAG to prevent obesity.
Explain Omega-6 FA
Derived from linoleic acid and essential.
What does Essential FA deficiency Cause?
Kidney and liver disorders, skin lesions, growth retardation etc. Also linked to depression and ADHD.
Explain 4 properties of TAG:
Esters of FAs and glycerol
- Neutral uncarged lipids
- Water insoluble (coalesce into lipid drops in adipose tissure)
- Dietary fuel and insulation
What makes up Phospholipids?
Glycerol, a phosphate group and two FA
Explain the term amphitatic:
Charged phosphate group (head) is hydrophilic and the ‘tail’ is hydrophobic, repels water.