Biomols Flashcards
What is a carbohydrate
Substance containing O, C and H
Monosaccharide examples
- Alpha and beta glucose
- fructose
- galactose
Test for reducing sugars
- Dissolve substance in water
- Add equal amt of Benedict’s solution
- Heat mixture
If substance turns from blue to brick red, reducing sugar present
Test for non reducing sugars
Add dilute hydrochloride acid to break down into monosaccharide monomers
Heat
Add sodium hydrogencarbonate to neutralise
Add Benedict’s and heat
Blue to brick red positive result
How does Benedict’s solution work
Copper (I) sulfate reduced to copper (II) sulfate
Accepts electron from reducing sugar
Blue to brick red colour
Features of starch
Alpha glucose
Storage in plants
Branched or unbranched
Coiled molecule
Compact so good for storage
Branched version has many ends for hydrolysing and quick release of glucose
Larger molecule and insoluble so doesn’t move in and out of cells, doesn’t affect water potential
Features of glycogen
Alpha glucose
Found in animals and bacteria
Highly branched
So can be easily hydrolysed into glucose monomers
Insoluble so doesn’t diffuse across cells
Doesn’t affect water potential
Compact so can be stored in small places
Features of cellulose
Beta glucose
Found in cell walls of plants
Monomers arranged at 180° to each other
Long unbranched chain structure
Held together by many hydrogen bonds
Grouped to form microfibrils and fibres which give plant strength
Test for starch
Add equal amount of iodine
Shake or stir
Orange to blue/ black positive result
Uses of lipids
Waterproofing (waxy cuticles)
Insulation
Protection of more fragile organs (fat concentrated)
Source of energy
Structure of triglycerides
Made up of 1 glycerol and 3 fatty acids
Ester bond
Formed in condensation reaction
Properties of triglycerides
C-H stores a lot of energy which is released as an energy store
Small mass to energy ratio so good storage molecules
Insoluble in water so doesn’t affect water potential of cells
Phospholipid structure
Hydrophilic head (polar)
Hydrophobic tail
Test for lipids
Emulsion test :
Add 5cm3 ethanol to any 2cm3 substance being tested
Shake
Add 5cm3 water
Milky white positive test
Structure of Amino acid
NH3CHRCOOH
Amine group, r group, carboxylate group
What are enzymes
Globular protein which act as biological catalysts
Speed up reactions
Have active site complimentary to substrate
Induced fit model
Enzymes not exact fit to substrate
When substrate near enzyme tertiary structure changes to fit
Fits eighth idea of enzyme being more flexible
Lock and key model
Enzyme exact fit to substrate
Enzyme more rigid structure
Effect of temperature
All enzymes have optimum temperature
As temperature increases, activity increases until hits optimum
After optimum (45°), bonds break and tertiary structure begins to change, so less ES complexes form, so RoR slows
At around 60°, enzyme denatures and is permanently changed
Effect of pH
All enzymes have optimum pH
Further away from pH, less activity occurs and rate of reaction slows
At extreme pHs, enzymes denature and are permenently changed
Competitive inhibitors
Inhibitors complimentary to active site
Block substrate
RoR slows but eventually all substrate still reacts
Non-competitive inhibitors
Complimentary to allosteric site
Changes tertiary structure of enzyme
Substrate can no longer react
Structure of nucleotide
One Penrose sugar (deoxyribose in DNA and ribose in RNA)
One nitrogenous base (Guanine, Cytosine, Thymine and Adenine or Uracil)
One phosphate group
Structure of DNA
nucleotide monomers have phpsphodiester bonds between Penrose sugar of one and phosphate group of next
Complimentary bases from the two strands form H-bonds
Very large molecule
Helical structure protects genetic information and fragile bonds from chemicals
