Proteins

Question 1

What are proteins made from?

Answer 1

made from long chains of amino acids

chains are folded to produce a specific shape that enables molecules to fit into the protein

proteins act as:

• structural components of tissues
• hormones
• antibodies
• catalysts

Question 2

What are enzymes?

Answer 2

a biological catalyst

increase the rate of chemical reactions

Question 3

Why are enzymes denatured by heat?

Answer 3

temperature changes their shape

their shape is vital for its function

Question 4

What is the function of digestive enzymes and how are they made?

Answer 4

produced by specialised cells in glands in the lining of the gut

enzymes pass out of the cells into the gut where they come into contact with food molecules

the catalyse the breakdown of large molecules into smaller molecules

Question 5

What is the function of amylase and where is it made?

Answer 5

produced in the salivary glands, the pancreas and small intestine

catalyses the breakdown of starch into sugar in the mouth and small intestine

Question 6

What is the function of protease and where is it made?

Answer 6

produced in the stomach, pancreas and small intestine

catalyse the breakdown of proteins into amino acids in the stomach and small intestine

Question 7

What is the function of lipase and where is it made?

Answer 7

produced by the pancreas and small intestine

catalyse the breakdown of lipids (fats and oils) into fatty acids and glycerol in the small intestine

Question 8

Why does the stomach release hydrochloric acid?

Answer 8

the enzymes work most effectively in the acidic conditions

Question 9

What is the function of bile and where is it produced?

Answer 9

produced in liver, stored in the gall bladder, then released into the small intestine

bile neutralises the acid that was added to the food in the stomach

provides alkaline conditions in which enzymes in the small intestine work best

Question 10

What are the uses of enzymes at home?

Answer 10

biological detergents that contain proteases and lipases to remove fat/protein based stains

more effective at low temperatures

Question 11

What are the uses of enzymes in industry?

Answer 11

proteases are used to pre-digest the protein in baby foods

carbohydrases are used to convert starch into sugar syrup

isomerase is used to convert glucose syrup into fructose syrup, which is sweeter in less quantity, can be used in slimming foods

Question 12

What is the problem with using enzymes as a catalyst in chemical reactions?

Answer 12

costly to produce and are denatured at high temperatures

although they save money by reducing the amount of energy needed for a reaction