Biologcal Molecules: Lipids Flashcards
Properties of lipids?
Non polar
Hydrophobic
Insoluble
What makes up triglycerides? And function?
Glycerol and 3 fatty acids (RCOOH)
- energy store
What are two types of fatty acids?
UNSATURATED - have double bonds (can be MONO (one double bond) or Poly UNSATURATED ( more than 1 double bond)
SATURATED - NO DOUBLE BONDS
What are phospholipids made up of? And function?
2 fatty acids, glycerol and phosphate ion
-PHOSPHATE is polar —> HYDROPHILIC
-FATTY ACID tails are NON POLAR —-> HYDROPHOBIC
- cell membrane component (bc of their amphipathic nature)
How does an ester bond form?
- forms between -OH of glycerol and -COOH group of fatty acid
- by condensation reaction - water molecule is RELEASED
H in glycerol bonds to OH in COOH group to form water
Why are triglycerides good energy stores?
- Hydrocarbon chains are OXIDISED in respiration , causing bonds to break , releasing energy to produce ATP
- triglycerides are HYDROPHOBIC so don’t cause osmotic water uptake so more can be stored
Why are triglycerides good for insulation?
- triglycerides form part of myelin sheath that surrounds nerve fibres —> provides insulation , increasing speed of transmission of impulses
- triglycerides compose part of the adipose tissue layer below skin —> prevent heat loss
How are triglycerides good for buoyancy?
- low density of fat tissue increases ability of animals to float
How do triglycerides provide protection?
- adipose tissue contains stored triglycerides —> protects organs
How is fluidity of cell membrane affected by the type of fatty acid?
Saturated fatty acids- membrane is LESS fluid
Unsaturated fatty acid - membrane is MORE fluid
How does cholesterol’s structure allow them to exist in the bilayer of membrane?
How does it effect the cell membrane ?
Have hydrophobic and hydrophilic regions
- affects FLUIDITY and PERMEABILITY
—> disrupts close packing of phospholipids (increasing flexibility of membrane)
—> acts as a barrier , fitting in spaces between phospholipids- preventing water soluble substances diffusing
What is cholesterol used for?
To produce steroid-based hormones (oestrogen, testosterone and progesterone)
Function of phospholipids?
- control membrane protein orientation - weak hydrophobic interactions between phospholipids/membrane proteins hold proteins in membrane, but allow movement
Forms phospholipid bilayer - presence of hydrophobic fatty acid tails, means a hydrophobic core is created
The core acts as a barrier to water-soluble molecules
hydrophilic phosphate heads form H-bonds with water,so cell membrane can be used to compartmentalise - cells can organise specific roles into organelles
Functions of triglycerides ?
Buoyancy
Energy store/source
Insulation
Protection
Function of fatty acids ?
Form phospholipids - form bilayer
Form membranes
Fatty acids respired to release energy - More triglycerides more energy released
Energy used for cell production / production of named cell component
