B2- Enzymes Flashcards Preview

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Flashcards in B2- Enzymes Deck (16):

Define an enzyme.

Proteins acting as biological catalysts.


What is the lock and key theory?

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The enzyme has an active site, into which only the substrate fits because only the correct substrate is the correct shape to fit into the active site.


Enzymes can...

-Build large molecules from smaller ones.

-Change one molecule into another one.

-Break down large molecules into smaller ones.


What does amylase do, where is it found and what is the optimum pH?

Breaks down starch➡️sugars.

-Salivary gland.


-Small Intestine.

pH7 or just below.


What does protease do, where is it found and what is the optimum pH?

Breaks down proteins➡️amino acids.



-Small Intestine.

pH2- hydrochloric acid.


What does lipase do, where is it found and what is the optimum pH?

Breaks down lipids➡️fatty acids + glycerol.


-Small Intestine.



What does bile do?

Bile neutralises the hydrochloric acid when it's in the small intestine and emulsifies fats.


What factors affect enzymes and how?

-pH ➡️ some work best in acidic pH, some in alkali and some neutral.

-Temperature ➡️ at higher temperatures the molecules move around quicker and so collide more often and with more energy. If temperature gets too high the active site changes shape and the enzyme becomes denatured.


What do biological detergents contain and why are they used?

Proteases and lipases➡️amino acids and fatty acids + glycerol

Breaks down substances in stains into smaller, water-soluble substances.

They work at lower temperatures than ordinary washing powders, so they save energy and money.


Why is isomerase used in slimming foods?

Isomerase converts glucose into fructose, which is sweeter than glucose so less is needed in foods. The foods, therefore, are less fattening.


What do baby foods contain and why are they used?

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Protease ➡️amino acids.

Used to pre-digest proteins during manufacture of baby foods.


Why is carbohydrase used in foods?

Carbohydrase converts starch syrup into sugar syrup.

Starch syrup is cheap whilst sugar syrup is more valuable. Sugar syrups can be used in foods and drinks e.g: sports drinks.


What are the advantages and disadvantages of industrial enzymes?

A- Enzymes in washing detergents are very efficient.

A- Biological washing powders can be used at lower temperatures ➡️ saves money.

A- Some enzymes can be used in medicine to diagnose, control or even cure disease.

D- Misuse of washing powders may result in allergic reactions.

D- Industrial enzymes are expensive to produce.

D- Enzymes denature at the high temperatures needed to kill pathogens in washing.

D- Some fabrics such as wool will be digested by proteases.


Proteins are...

Proteins are made of long chains of amino acids.


Baby food manufacturers use 0.5% trypsin at 35°C. Suggest why the manufacturers make most profit with these conditions. (4 marks).

0.5% trypsin is cheap (1). 35°C will make the reaction happen faster (1). This means there is less time to make the product (1). Extra heating outweighs savings on enzyme costs (1).


It is better to give ions to the plants in a solution without soil.



-Can supply optimum amount of nutrients.

-Can supply optimum pH.