4786915
Description
Mind Map by Bee Brittain, updated more than 1 year ago
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Created by Bee Brittain
over 8 years ago
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1.5 Lipids
- TRIGLYCERIDES
- Three (tri) Fatty
Acids
- Glycerol
(glyceride)
- Each fatty acid forms an ESTER bond with glycerol in a CONDENSATION
REACTION
- Glycerol molecule is same in all moleculets but
there are variations in the fatty acids meaning
there are different properties
- Saturated = NO carbon-carbon double
bonds
- Mono-unsaturated = 1 double
bond
- Polyunsaturated = More than 1 Double
bond
- Saturated = NO carbon-carbon double
bonds
- High ratio of energy-storing Carbon-hydrogen bonds to carbon atoms = excellent source
of energy
- Low mass to energy ratio = good storage
molecules. Beneficial to animals as
reduced mass to carry around
- Large, non-polar and insoluble = doesn't
effect osmosis in cells or water potential
in them
- Triglycerides release water when oxidised, meaning
they're an important source of water for organisms,
especially those living in dry conditions
- Three (tri) Fatty
Acids
- PHOSPHOLIPIDS
- Similar to triglycerides but
one fatty acid replaced with
a PHOSPHATE MOLECULE
- Fatty acid molecules - Hydrophobic 'tail'
- Phosphate Molecules - Hydrophillic 'head'
- Phosphate Molecules - Hydrophillic 'head'
- Polar
- Properties
- Polar so form a bilayer between
intercellular and extra cellular
- Phospholipid structure allows them to form glycolipids by combining
with carbohydrates within the cell-surface membrane. These glycolipids
are important in cell recognition
- Polar so form a bilayer between
intercellular and extra cellular
- Similar to triglycerides but
one fatty acid replaced with
a PHOSPHATE MOLECULE
- Characteristics
- Contain: Carbon, Oxygen and Hydrogen
- Proportion of oxygen to carbon and hydrogen is smaller than in carbohydrates
- Soluble in solvents such as alcohols and acetone
- Insoluble in water
- Contain: Carbon, Oxygen and Hydrogen
- Roles of Lipids
- Source of Energy
- When oxidised, lipids provide over 2x the energy of
carbohydrates
- When oxidised, lipids provide over 2x the energy of
carbohydrates
- Waterproofing
- Lipids are insoluble = good at waterproofing.
- Both plants and insects have
waxy, lipid cuticles that
conserve water. Where as
mammals produce an oily
secretion from the
sebaceous glands in the skin
- Both plants and insects have
waxy, lipid cuticles that
conserve water. Where as
mammals produce an oily
secretion from the
sebaceous glands in the skin
- Lipids are insoluble = good at waterproofing.
- Insulation
- Fats are slow conductors of heat
meaning when stored they help retain
body heat. They also act as electrical
insulators in the myelin sheath around
nerve cells
- Fats are slow conductors of heat
meaning when stored they help retain
body heat. They also act as electrical
insulators in the myelin sheath around
nerve cells
- Protection
- Fat is often stored around delicate organs
- Fat is often stored around delicate organs
- Source of Energy
- Testing For Lipids
- Dry and grease-free testube
- Add sample and ethanol
- Shake tube throughly and dissolve lipid in sample
- Add water, shake gently
- Cloudy white = lipid present and emulsion formed
- As a control, repeat the procedures using after
instead of the sample; the final solution should
be clear
- As a control, repeat the procedures using after
instead of the sample; the final solution should
be clear
- Cloudy white = lipid present and emulsion formed
- Add water, shake gently
- Shake tube throughly and dissolve lipid in sample
- Add sample and ethanol
- Dry and grease-free testube
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