1- lipids Flashcards
1
Q
triglycerides are
A
lipids made of one molecule of glycerol and 3 fatty acids joined by ester bonds formed in condensation reactions
2
Q
triglycerides diagram
A
3
Q
saturated lipids
A
- found in animal fats
- only contain carbon-carbon single bonds
4
Q
unsaturated lipids
A
- found in plants
- contains carbon-carbon double bonds
- kinked and don’t pack together well
- weaker intermolecular forces
- melt at lower temperatures than saturated fats
5
Q
function of lipids
A
- energy storage
- waterproofing
- insulation
6
Q
functions of lipids- energy storage
A
- more energy per gram than carbs or proteins due to their large number of C-H bonds
- insolubility in water lets them act as energy reserves without disrupting osmotic balance
7
Q
functions of lipids- waterproofing
A
- lipids are hydrophobic so repel water which makes them ideal for waterproofing
- in plants, the waxy cuticle prevents excessive water loss
- in animals, lipids in the skin and feathers provide waterproofing
8
Q
functions of lipids- insulation
A
- lipids in adipose tissue form an insulating layer, preventing heat loss
- in nerve cells, a lipid-based myelin sheath speeds up never impulse transmission
- lipids in cell membranes provide insulation between different cellular environments
9
Q
molecular structure of phospholipids
A
- one of the fatty acid tails of a triglyceride is substituted by a phosphate group
- the phosphate heads are hydrophilic and fatty acid tails are hydrophobic
10
Q
formation of phospholipid bilayer
A
- phospholipids form a lipid bilayer in cell membranes
- the hydrophilic heads point outwards
- the hydrophobic tails face inwards, creating a barrier to most substances
11
Q
functions of phospholipids
A
- main component of cell membrane
- acts as a barrier to water- soluble molecules due to their hydrophobic tails
- contributes to membrane fluidity (
more saturated tails = less fluid membrane)
