B2.5 Proteins - Their Functions and Uses Flashcards
What are proteins made up?
Long chains of small molecules called amino acids
What can proteins act as? (5)
Structural components of tissue, hormones, antibodies and enzymes
What is a catalyst?
A substance which increases the speed of a reaction, without being change or used up in the reaction
What are enzymes an example of?
A biological catalyst
What does an enzyme’s unique shape allow it to do?
Fit onto substances involved in a reaction - this allows the enzyme to work as it helps substances to join together or split apart
What happens to enzymes when the temperature is too high?
The bonds holding the enzyme together break, which destroys it’s unique shape - they are now denatured
What is the optimum temperature for enzymes to work in the human body?
37°C
What happens to enzymes when the pH level they are working in is too high or too low?
The pH interferes with the bonds holding the enzyme together, this changes the shape of the enzyme causing it to denature
What is the optimum pH for enzymes to work in?
The optimum pH is different for different enzyme e.g. for Pepsin in the stomach, it’s optimum pH is 2
How is food broken down in the digestion system? (2)
By mechanical digestion and chemical digestion
What is meant by mechanical digestion?
The breakdown of food through movements like our teeth grinding food down and our stomach churning food
What is meant by chemical digestion?
The breakdown of food where enzymes are present to help
Where do enzymes work?
Outside body cells
Where are enzymes produced?
By specialised cells in glands and in the gut lining
How do enzymes help in the digestion of food?
The help to break big molecules of nutrients into smaller molecules so they can easily be absorbed through the walls of the digestive system
What is amylase?
A digestive enzyme that catalyses the conversion of starch into sugars
Where is amylase made? (3)
In the salivary glands, the pancreas and the small intestine
Where does amylase work? (2)
The mouth and the small intestine
What are proteases?
Digestive enzymes that catalyse the conversion of proteins into amino acids
Where are proteases made? (3)
The stomach, the pancreas, and the small intestine
Where do proteases work? (2)
The stomach and small intestine
What are lipases?
Digestive enzymes that catalyse the conversion of lipids into glycerol and fatty acids
Where are lipases made? (2)
In the pancreas and small intestine
Where do lipases work?
The small intestine
What is the stomach?
An organ in the digestive system which pummels food with its muscular walls
What enzyme does the stomach make?
The protease enzyme, pepsin
What acid does the stomach produce?
Hydrochloric acid
Why does the stomach produce hydrochloric acid? (2)
To kill bacteria and to give the optimum pH level (pH 2) for the enzymes working in the stomach
Where is bile produced?
In the liver
Where is bile stored?
The gall bladder
Where is bile released?
The small intestine
Why is bile released into the small intestine?
Because the enzymes in the small intestine work best in alkaline conditions, but the acid from the stomach makes the small intestine acidic - bile is alkaline and neutralises the HCl making conditions alkaline
What affect does bile have on fat?
Bile emulsifies fat - this breaks the fat into tiny droplets which give a bigger surface area for lipase to work on, making digestion faster
How can enzymes be harvested?
We can grow microorganisms which produce enzymes which pass out of their cells
What’s the difference between biological and non-biological detergents?
Non-bio detergents contain chemicals that break up stains on your clothes, bio detergents contain the same chemical but along with a mixture of enzymes
What enzymes do biological detergents contain? (2) Why?
Proteases and lipases, this makes bio detergents ideal for removing stains like food or blood
How can bio detergents save you money?
Because they work at lower temperatures which saves money as less energy is used
What drawbacks are there to using bio detergents? (3)
They don’t work well at higher temps. because the enzymes denature, they may not work well in very acidic or alkaline tap water, and some of the enzymes can remain on the clothes and can irritate sensitive skin
How are enzymes used in the production of baby food?
The proteins are pre-digested by proteases which makes it easier for the baby to digest
What happens when carbohydrases is added to starch syrup?
Sugar syrup is made which can be used in food products like sweets, jam and sports drinks
How is glucose syrup turned into fructose syrup and why?
It is made by adding isomerase, fructose syrup is sweeter so less can be used, making it ideal for slimming foods
What advantages are there to using enzymes in industry? (4)
They’re specific so catalyse the reaction you want them to, they work in lower temperatures and pressures so they save energy and money, they can be re-used and they are biodegradable so they cause less environmental pollution
What disadvantages are there to using enzymes in industry? (3)
They can easily be denatured by a slight change in conditions so the conditions they work in must be tightly controlled, enzymes can be expensive to produce and contamination of the enzyme with other substances can affect the reaction
