Biology unit 2 topic 3

Created by: Rachel12341
Created on: 10-05-14 15:10

Proteins

Protein molecules are made of long chains of amino acids. They are folded to produce specific shapes, which depend on its function. Proteins can be: Structural compounds of tissues (e.g muscle), hormones, antibodies or catalysts.

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Enzymes- These are biological catalysts, and are large proteins and the shape of the enzyme is vital for its function.The active site is the shape of area where molecule(s) fit.The substrate can be held in the active site.

Enzymes can:Build large molecules from smaller ones(starch from glucose),change one molecule into another or break down large molecules into smaller ones (proteins-> amino acids)

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Factors affecting enzyme action

Temp- rate of reaction increases until denatures. pH- specific enzymes work best at specific pHs, if too acidic or alkaline, will denature

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Types of enzyme (digestive)

Amylase(a carbohydrase)-produced by salivery glands,pancreas&small intestine,starch->sugars.Protease-produced in stomach,pancreas&small intestine,proteins->amino acids.Lipase-produced by pancreas&small intestine lipids(fats + oils)->fatty acids +glyc

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Speeding up digestion- Protease enzymes in stomach work best in acid conditions, glands in stomach produce HCl.

Amylase & lipase work in small intestine & work best in slightly alkaline conditions so liver produces bile (stored and secreted by gall bladder) which neutralises stomach acid & creates slightly alkaline conditions.

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Making use of enzymes- Biological detergents-contain proteases and lipases that digest food stains–very good at it Work at lower temps than normal washing powders,saves energy+money.if misused can have allergic reactions and

denature at the high temps needed to kill pathogensand materials such as wool will be digested by proteases. Proteases used in baby foods to pre-digest proteins.

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Isomerase used to convert glucose syrup into fructose syrup (much sweeter so less needed, less fattening). Carbohydrases used to convert starch-> sugar syrup for use in foods.

. Industry- enzymes used to bring about reactions at normal temps & pressures so cost of equipment + energy reduced but can be costly to produce.

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Enzymes can:Build large molecules from smaller ones(starch from glucose),change one molecule into another or break down large molecules into smaller ones (proteins-> amino acids)