1.1 Biological Molecules Flashcards
Magnesium
Constituent of chlorophyll used for photosynthesis
Iron
Constituent of haemoglobin which transports oxygen in rbc
Phosphate
Makes nucleotides - ATP, DNA and RNA
Constituent of phospholipids found in cell membranes
Calcium
Hardens bones and teeth
Component of plant cell walls
What is a polar molecule?
Water bc the oxygen has a slight negative charge that is attracted to the slight positive charge on the hydrogen
Water has high specific heat capacity
Water requires a lot of energy to heat up 1kg of water by 1 degree
Water has high latent heat of vapourosation
A lot of energy is required to turn a liquid into a vapour
Cohesion
Attraction between water molecules which allows it to move up xylem
Density
Water has a maximum density at 4 degrees meaning ice floats on water bc it is less dense
Solvent
The positive and negative charges attracted other ions and polar molecules such as glucose
High surface tension
Cohesion between water molecules supports organisms such as pond skaters allowing them to walk on water
Monosaccharides
Sweet and soluble
General formula (Ch2O)n
Triose
Important in metabolism
Intermediates in respiration and photosynthesis
Pentose
Constituents of nucleotides - deoxyribose in DNA or ribose in RNA
Hexose
Glucose is a source of energy in respiration
C - H and c-c bonds are broken to release energy which is transferred to make ATP
Isomers
Have the same chemical formula and same number of atoms but a different arrangement of atoms
Eg - alpha and beta glucose
Disaccharides
Two monosaccharides joined together by a glycosidic bond and the elimination of water which is a condensation reaction
Glucose + glucose =
Glucose + fructose =
Glucose + galactose =
- Maltose - in germinating seeds
- Sucrose - product of photosynthesis
- Lactose - mammalian milk
Benedict’s reagent
Used to test for reducing sugars
Heat 80 degrees or above
Reduce copper II sulphate to copper I sulphate
Colour change is blue to brick red precipitate
Sucrose
Non reducing sugar so benediticts test won’t work and will remain blue
Must be hydrolysed first to form glucose and fructose which donate an electron to reduce copper II sulphate to copper I sulphate to form the brick red precipitate
Lipids
Non polar compounds so insoluble in water but dissolve in organic solvents
Triglycerides
Three fatty acids and a glycerol molecule that join together by a condensation reaction where three molecules of water are removed and ester bonds form between the glycerol and fatty acids
