B2.5 Proteins- their functions and uses

Question 1

What 4 things do proteins act as?

Answer 1

structural components of tissues such as muscles

hormones

antibodies

catalysts

Question 2

What do catalysts do?

Answer 2

increase the rate of chemical reactions

Question 3

What are enzymes?

Answer 3

biological catalysts

Question 4

Describe the function of general enzymes in the digestive system

Answer 4

Some enzymes work outside body cells. The digestive enzymes are produced by specialised cells in glands and in the lining of the gut. The enzymes then pass out of cells into the gut where they come into contact with food molecules.

THEY CATALYSE THE BREAKDOWN OF LARGE MOLECULES INTO SMALLER MOLECULES

Question 5

Describe the enzyme amylase

Answer 5

produced in salivary gland, pancreas, small intestine

catalyses the breakdown o starch into sugars

in the mouth and small intestine

Question 6

Describe the enzyme protease

Answer 6

produced by the stomach, pancreas, small intestine

catalyse the breakdown of proteins into amino acids

in the stomach and small intestine

Question 7

Describe the enzyme lipase

Answer 7

produced by pancreas, small intestine

catalyse the breakdown of lipids into fatty acids and glycerol

in the small intestine

Question 8

What acid does the stomach produce?

Answer 8

hydrochloric acid

Question 9

Why does the stomach produce hydrochloric acid?

Answer 9

As the enzymes in the stomach work most effectively in acidic conditions

Question 10

Where is bile produced?

Answer 10

in the LIVER

Question 11

Where is bile stored?

Answer 11

in the GALL BLADDER

Question 12

Describe the function of bile in the digestive system

Answer 12

it neutralises the acid that is added to food in the stomach. This provides alkaline conditions in which enzymes in the small intestine work most effectively.

it also emulsifies fat, giving it a larger surface area for lipase to work on

Question 13

Some microorganisms produce enzymes that ….

Answer 13

pass out of cells

Question 14

Describe a use of enzymes in the home

Answer 14

biological detergents may contain protein-digesting and fat digesting enzymes (protease and lipase)

biological detergents are more effective at low temperature than other types of detergents

Question 15

Describe some uses of enzymes in industry

Answer 15

protease are used to pre digest the protein in some baby food

carbohydrases are used to convert starch into sugar syrup

isomerase is used to convert glucose syrup into fructose syrup, which is much sweeter and therefore can be used in smaller quantities in slimming foods

Question 16

What are some advantages of using enzymes in industry?

Answer 16

used to bring about reactions at normal temperatures and pressures that would otherwise require expensive, energy demanding equipment - saves energy and costs

work for a long time so can continually use them

Question 17

What are some disadvantages of using enzymes in industry?

Answer 17

Most enzymes are denatured at high temperatures and many are costly to produce.

some people can develop allergies to the enzymes

Question 18

What happens to enzymes if they become too hot (over 37 degrees) ?

Answer 18

some of the bonds holding the enzyme together break. This destroys the enzymes shape so the substrate can not fit into it anymore. It is said to be denatured.

Question 19

What 2 factors can cause an enzyme to be denatured?

Answer 19

temperature

pH

Question 20

What are protein molecules made up of?

Answer 20

long chains of amino acids. These chains are folded to produce a specific shape that enables other molecules to fit into the protein

Question 21

What is the substance that neutralises stomach acid called?

Answer 21

bile

Question 22

What type of organism are used to produce enzymes that are used in home and industry?

Answer 22

microorganisms

Question 23

Describe the role of the liver and the pancreas in the digestion of fats

Answer 23

• pancreas produces the enzyme lipase
• Lipase catalyses the break down of fats into fatty acids and glycerol in the small intestine
• Liver produces bile
• Bile is an alkali which neutralises the acid, added to food in the stomach, when it enters the small intestine
• Lipase works most effectively in acidic conditions
• Bile also emulsifies fat, giving them a larger surface area to work on

Question 24

In industry, suggest why small amounts of enzymes but a higher temperature is used

Answer 24

smaller amounts of enzymes are cheaper

higher temperatures cause a faster reaction

so takes less time to produce the product

extra heating cost is outweighed by savings on enzyme cost

Question 25

Describe the effect protease will have on baby food

Answer 25

breaks down the food

from protein into amino acids

which makes it softer and runnier