• Water Molecules

• a bond between the positive pole of one water molecule and the negative pole of another 

• Cohesion- Water molecules stick to each other (Hydrogen Bonds)  USE-  (Strong pulling force/ tops of trees/transport medium in xylem of plants) 
• Solvent Properties- substance disslovation (polarity)- Sodium ions (inorganic particles with positive or negative charges), glucose(organic substance with polar molecules), enzymes 
• Heat capacity- lottsa energy needed to raise temp (hydro bonds)USE-medium for metablic reactions. USE- blood can carry heat from warm to cooler parts of body (blood used as transport for heat)  
• Boiling point- (100c) from water to gas all H bonds need to be broken. USE-medium for metabolic reactions
• Cooling effect of evap- Evaporation possible below boiling point/ H bonds broken for this to happen/ need heat which is taken from water which cools water down. USE- coolant

Elements in living organisms

• Most common Carbon, Hydrogen, Oxygen, Nitrogen  (Others include Sulphur ( Protein Syn (2/20)Calcium (messenger) Phosphorus (Phosphate grouo in ATP and DNA molecules) IRon electron transport in aerobic cell respiration) Soduim (pumped into cytoplasm to raise solute concentration and cause water to enter by osmosis)

Organic and inorganic compounds

• Org- contain carbon/ some carbon compounds are inorg though (simple CC- CarbDIox, Carbonates, H Carbonates)
• Compounds with no Carbon are inorganic
• Three types of org comp in liv org/ Carbs, Lipids, Proteins

Macro Molecules (Subunits)

Compounds are made up of molecules (Large ones called macro molecules

Built by subunits such as these:

Ribose, Glucose, fatty acids, AA's

• Two molecules joined to form a larger molecule (Water also formed) IE- Two AA's can be joined to form a dipeptide -results in peptide linkage
• a polypeptide can be formed by linking more AA's to either end of DP
• CR's can be used similarly with Carbs or Lips (Carbs basic unit- Monosacchs- 2M= D/ M+D= P)
• Fatty acids can be linked to glycerol by CD  to produce lipids called glycerides (three equals a triglyceride)

• Large molecules (Polypeptides, Polysaccharides, Triglycerides) can be broken down
• Water used
• reverse of CR

PP + H2O --> dipeptides or AA's

PS + H2O --> dissacharides or monosaccharides

Glycerides + H2O --> fatty acids and glycerol

Examples of Carbs

• MonoS- Glucose, Galactose, Fructose/ USE(A)- glucose/blood/transport/for energy/ USE(P)- fruit is sweet tasting (Fructose) -Animals eat it --> seeds are dispersed which are in the fruit
• DiS- Maltose, Lactose, Sucrose/ USE(A)- Lactose sugar in milk/ energy for young mammals/ USE(P)- Sucrose carried by phloem  to transport energy to cells in plant
• PolyS- Starch, Glycogen, Cellulose/ USE(P)- energy in liver and muscles short term(Glycogen) USE(P) Cellose/ strong cell wall fibre

Functions of Lipids

• Energy storage- Fat  in humans oil in Plants 
• heat insulation- a layer of fat under skin reduces heat loss  
• help animals to float (less dense than water)

• Carbs (Shortterm) Lipids (Longterm) 
• Lipids contain more enrgy per gram so store of lipids is lighter than stores of carbs that contain same amount of energy
• lipids are insoluble in water so they cause no problem with osmosis 
• Carbs easily digested (easily accessed)
• Carbs are soluble in water so are easier to transport to and from the store)