Enzymes (B2) Flashcards
What are enzymes?
A substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.
Why do enzymes have special shapes?
Enzyme molecules are protein molecules that are folded into very precise shapes.
Changing the order of amino acids would cause it to fold into a different shape – and the substrate molecules would no longer fit into the active site.
Why do enzymes need the right temperature and pH?
As the temperature increases, so does the rate of reaction. But very high temperatures denature enzymes.
The enzyme activity gradually increases with temperature up to around 37ºC, or body temperature.
Name the three digestive enzymes, where they are made and their respective jobs.
Amylase Starch → sugars - Salivary glands, pancreas, small intestine
Protease Proteins → amino acids - Stomach, pancreas, small intestine
Lipase Lipids → fatty acids + glycerol
Where is bile produced and what is its role in digestion?
Bile or gall is a dark green to yellowish brown fluid, produced by the liver of most vertebrates, that aids the digestion of lipids in the small intestine. In humans, bile is produced continuously by the liver (liver bile), and stored and concentrated in the gallbladder (gallbladder bile).
Describe the journey food takes through the digestive system referring to organs, glands and their role
Structure Function:::::::::
Mouth: Where food enters the alimentary canal and digestion begins
Salivary glands: Produce saliva containing amylase
Oesophagus: Muscular tube which moves ingested food to the stomach
Stomach: Muscular organ where digestion continues
Pancreas: Produces digestive enzymes
Liver: Produces bile
Gall bladder Stores bile before releasing it into the duodenum
Small intestine - duodenum Where food is mixed with digestive enzymes and bile
Small intestine - ileum Where digested food is absorbed into the blood and lymph
Large intestine - colon Where water is reabsorbed
Large intestine - rectum Where faeces are stored
Large intestine - anus Where faeces leave the alimentary canal
What are the uses of enzymes?
Enzymes allow certain industrial processes to be carried out at normal temperatures and pressures, thereby reducing the amount of energy and expensive equipment needed. Enzymes are also used in the home, for example, in ‘biological’ detergents. The table shows some common enzyme uses you should be familiar with.
What are the advantages of using enzymes in industry?
Advantages
They are specific so they only catalyse the reaction you want them to
Using lower temperatures and pressures means a lower cost as it saves energy
Enzymes work for a long time so after the initial cost of buying them you can continually use them
They are biodegradable and therefore cause less environmental pollution
What are the disadvantages of using enzymes in industry?
Disadvantages
Some people can develop allergies to the enzymes (e.g. biological washing powders)
Enzymes can be denatured by even a small increase in temperature. They are also susceptible to poisons and changes in pH. This means the conditions they work in must be tightly controlled
Enzymes can be expensive to produce
Contamination of the enzyme with other substances can affect the reaction
