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a. Inorganic ions
Mg2+ magnesium: component of chlorophyll: photosynthesis – leaves turn yellow without
Fe2+ iron: component of haemoglobin: carries oxygen – anaemia when deficient in diet
Ca2+ calcium: structural component of bones/teeth & cell walls – strength
PO43- phosphate: component of nucleotides (ATP) & phospholipids
b. water
Dipolar: O𝛿- & H𝛿+ – easily form hydrogen bonds – between H & O of different molecules
Lubricant properties due to H-bonding
Cohesion: water molecules attract each other & form H-bonds
- surface tension: allows insects to be supported
Adhesion: attraction of water to different molecules
- allows water to be drawn up xylem vessels
Solvent: transport medium for polar molecules / ions – blood
chemical reactions can occur in solution
dipole attracts (& separates) charged particles of ion / polar molecule = dissolve
- non-polar – don’t readily dissolve: arrange themselves to expose minimal surface to water – lipid micelles
Metabolite
Reactant in Hydrolysis: break bonds by chemical insertion of water molecule
Photosynthesis
Product of Condensation: form bonds – produce molecule of water
Aerobic Respiration
Thermal properties
High specific heat capacity – large amount of energy required to increase temperature
acts as temperature buffer: prevent fluctuations – maintains constant temperature
- enable endotherms to maintain temperature for optimal enzyme activity
- stable environment for aquatic animals in lakes/ponds
High latent heat of vaporisation – large amount of heat energy required to vaporise water
H-bonds attract liquid water molecules to eachother – difficult for molecules to escape as vapour
- used as cooling mechanism – heat energy released when animals’ sweat evaporates
High density – 4˚C
ice = less dense (H-bonds hold molecules further apart than liquid)
floats: insulator – prevents water losing heat & freezing – protect aquatic organisms
Transparent: allows light to travel through – so aquatic plants can photosynthesise
, c. Carbohydrates: C H O – organic
Monosaccharides (CH2O)n
sweet & soluble
Uses
- monomers in complex molecules – ribose: RNA
- glucose: used in respiration & polysaccharides
d. alpha & beta glucose structural isomers: different location of hydroxyl OH group on carbon 1
beaten UP
Disaccharides C12H22O11
2 monosaccharides joined by glycosidic (covalent) bond – O – condensation reaction
sucrose: (non-r) – no free aldehyde/ketone maltose: lactose:
α-glucose–ß-fructose α-glucose–α-glucose α-glucose–ß-galactose
1,2 glycosidic 1,4 glycosidic 1,4 glycosidic
transport in phloem energy source – germinating seeds energy source in milk
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