1.3-lipids, 1.7- water , 1.8 - inorganic ions

How do triglycerides form?

• condensation reaction

• 1 glycerol molecule

• 3 fatty acids

• Ester bonds

• 

Contrast saturated and unsaturated fatty acids

Saturated:

• only single bonds

• Straight chain, many contact points

• Higher melting point, solid at room temp

• Animal fats

Unsaturated

• contains C=C bonds

• Bent molecules, have less contact points

• Lower melting point, liquid at room temp

• Found in plant oils

Relate the structure of triglycerides to their function

• high energy:mass ratio - high calorific value from oxidation (energy storage)

• Insoluble chain - no effect on the water potentials of cells

• Slow conductor of heat - thermal insulation

• Less dense than water - buoyancy of aquatic animals

Describe the structure and function of phospholipids

• amphipathic molecule

  • Glycerol backbone attached to 2 fatty acids and one hydrophilic phosphate heads

• Forms a phosphate bilayer in water - component of membranes

• tails can splay outwards - waterproofing

Compare phospholipids and triglycerides

• both have a glycerol backbone

• Both may be attached to a mixture of types of fatty acids

• Both contain C, H and O

• Both formed in condensation reactions

State 4 biologically important properties of water

• Solvent for chemical reactions in the body

• High specific heat capacity

• High latent heat if vapourisation

• Cohesion between molecules

Explain why water is significant to living organisms

• A solvent for polar molecules during metabolic reactions

• Enables organisms to avoid fluctuations in temperature

• Cohesion-tension of water molecules in the transpiration stream

What are inorganic ions and where are they found in the body?

• ions that don’t contain carbon atoms

• Found in the cytoplasm and extracellular fluid

• May be in high or low concentrations

Explain the role of hydrogen ions in the body

• High concentrations of H+ = low pH

• H+ ions interact with Hydorgen bonds and ionic bonds in tertiary structure of proteins which can cause them to denature

Explain the role of phosphate ions in the body

Used in:

• DNA

• ATP

• NADP

• cAMP