B2.5 Proteins- their functions and uses Flashcards
What 4 things do proteins act as?
structural components of tissues such as muscles
hormones
antibodies
catalysts
What do catalysts do?
increase the rate of chemical reactions
What are enzymes?
biological catalysts
Describe the function of general enzymes in the digestive system
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
Describe the enzyme amylase
produced in salivary gland, pancreas, small intestine
catalyses the breakdown o starch into sugars
in the mouth and small intestine
Describe the enzyme protease
produced by the stomach, pancreas, small intestine
catalyse the breakdown of proteins into amino acids
in the stomach and small intestine
Describe the enzyme lipase
produced by pancreas, small intestine
catalyse the breakdown of lipids into fatty acids and glycerol
in the small intestine
What acid does the stomach produce?
hydrochloric acid
Why does the stomach produce hydrochloric acid?
As the enzymes in the stomach work most effectively in acidic conditions
Where is bile produced?
in the LIVER
Where is bile stored?
in the GALL BLADDER
Describe the function of bile in the digestive system
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
Some microorganisms produce enzymes that ….
pass out of cells
Describe a use of enzymes in the home
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
Describe some uses of enzymes in industry
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
What are some advantages of using enzymes in industry?
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
What are some disadvantages of using enzymes in industry?
Most enzymes are denatured at high temperatures and many are costly to produce.
some people can develop allergies to the enzymes
What happens to enzymes if they become too hot (over 37 degrees) ?
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.
What 2 factors can cause an enzyme to be denatured?
temperature
pH
What are protein molecules made up of?
long chains of amino acids. These chains are folded to produce a specific shape that enables other molecules to fit into the protein
What is the substance that neutralises stomach acid called?
bile
What type of organism are used to produce enzymes that are used in home and industry?
microorganisms
Describe the role of the liver and the pancreas in the digestion of fats
- 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
In industry, suggest why small amounts of enzymes but a higher temperature is used
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
