Enzymes
- Created by: Anna Corwood
- Created on: 20-04-13 16:23
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- Enzymes
- Biological catalysts
- Speed up reactions by reducing activation energy
- Recyclable- used multiple times
- Types
- Intra cellular- inside cell
- Extra cellular- outside cell
- Specificicitiy
- Catalyse a reaction for only one specific substrate
- Active site
- Inhibition
- Competitive inhibition
- Generally temporary
- Used to control enzyme reations
- Competes for active site
- Inhibitors obstruct active site = reduced rate of reaction
- Non competitive Inhibition
- doesn't compete for active site
- Alters the tertiary structure
- Alters the ionic, hydrophobic/ phillic, disulphide etc. bonds
- permanent change
- Primary structure changes shape
- Reversible/ non- reversible inhibition
- Strength of bonds between the enzyme and inhibitor
- H bond = weak = temporary
- Covalent bonds = strong = permenant
- Strength of bonds between the enzyme and inhibitor
- Metabolic poisins
- Cyanide, Malonate and Arsenic
- Bond to respiratory enzyme = respiration stops = cell dies
- Cyanide, Malonate and Arsenic
- Drugs
- HIV- RNA is injected into cell. Reverse transcriptase converts the RNA into DNA which then reproduces.
- Drug- Inhibitor attaches to the enzyme reverse transcriptase = no viral reproduction
- HIV- RNA is injected into cell. Reverse transcriptase converts the RNA into DNA which then reproduces.
- Cofactors/ coenzymes
- attach to the enzyme and change active site for the better = cellular control of reaction by producing cofactors
- Poison in Anti- freeze. Alcohol is a competitive inhibitor so prevents the Ethylene Glycol from being broken down into oxalic Acid which is highly poisonous
- Penicillin- inhibits the enzyme transpeptidase which catalyses the formation of proteins in bacterial cell walls = weakens cell wall = can't regulate its osmotic pressure = cell bursts and is killed
- attach to the enzyme and change active site for the better = cellular control of reaction by producing cofactors
- Competitive inhibition
- Optimum conditions
- Endothermic animals- self regulate body temp.
- 37 Degrees Celsius
- Limiting factors
- Activity affected by temperature
- Activity affected by pH
- Concentration of enzymes
- Concentration of substrates
- Surface area
- Uses
- Heterotrophs
- Breaking down larger molecules into smaller to extract nutrience
- External digestion
- Enzyme secreted on food which breaks it down into monomers. Organism then absorbs these.
- Internal digestion
- Enzymes mixed in as food passes through the digestive system
- Extra cellular- released from cell onto food within digestive system
- Inter cellular- Found in cytoplasm or attached to cell membrane. These enzymes are active inside the cell.
- Enzymes mixed in as food passes through the digestive system
- Protection
- Defence mechanism- white blood cells (phagocytes) engulf bacteria and then digest them using lysosomal enzymes
- Heterotrophs
- Biological catalysts
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