Enzymes Flashcards
True or false? Enzymes act as biological catalysts to speed up useful chemical reactions in the body.
True.
What is the definition of a catalyst?
A catalyst is a substance which increases the speed of a reaction, without being changed or used up in the reaction
Fill the gaps. Enzymes are all _____ and all _____ are made up of chains of _____ _____.
proteins, proteins, amino acids
Give three purposes of proteins other than enzymes.
Act as structural components of tissues (e.g. muscles), hormones and antibodies.
Explain the process of enzymes catalysing reactions.
Why won’t enzymes work if the temperature is too hot?
If it gets too hot, some of the bonds holding the enzyme together break which destroys the enzyme’s special shape and it will no longer work. It is known as being ‘denatured’ when this happens.
What temperature do enzymes in the human body work best at?
37°C, body temperature
Why can pH affect enzymes?
If it is too high or too low, the pH interferes with the bonds holding the enzyme together. This changes the shape and denatures the enzyme and prevents it from working.
True or false? pH 7 is the optimum pH for all enzymes.
False. It is often pH 7 that enzymes work best at however not all of them need this neutral pH. An example is pepsin which is an enzyme used to break down proteins in the stomach which works best at pH 2 meaning that it is suited to the conditions there.
What do enzymes in digestion do? Give examples.
The digestive enzymes break down the big molecules in to the smaller ones. Starch, proteins and fats are big mollecules that can’t pass through the walls of the digestive system and so need to be broken down in to smaller ones like sugars, amino acids, glycerol and fatty acids.
What does amylase do? Where is it made?
What does protease do? Where is it made?
What does lipase do? Where is it made?
Where is bile produced, stored and released into?
- Produced in the liver
- Stored in the gall bladder
- Released into the small intestine
What is the job of bile and why is it needed?
The hydrochloric acid in the stomach makes the pH too acidic for enzymes in the small intestine to work properly because these enzymes work best in alkaline conditions. Bile is alkaline and so neutralises the acid and makes the conditions alkaline.
It also emulsifies fats. It breaks the fats in to tiny droplets which gives a larger surface area for the lipase enzyme to work on and so results in digestion being faster.
What happens at the salivary glands?
Amylase is produced and is found in the saliva.
What happens in the liver?
Bile is produced.
What happens in the gall bladder?
Bile is stored before it is released.
What happens in the stomach?
The stomach pummels the food with its muscular walls and it produces the protease enzyme, pepsin. It also produces hydrochloric acid to kill bacteria and to give the right pH for the protease enzyme to work.
What happens in the pancreas?
Protease, lipase and amylase enzymes are produced and released in to the small intestine.
What happens in the large intestine?
Excess water is absorbed from the food.
What happens in the small intestine?
Protease, amylase and lipase enzymes to complete digestion. The digested food is also absorbed out of the digestive system in to the blood.
Why are enzymes used in biological detergents?
They are mainly made up of protein-digesting enzymes (protease) and fat-digesting enzymes (lipase). This means that because the enzymes break down animal and plant matter, they’re ideal for removing stains like food or blood.
Explain how enzymes can be used to change foods. Three examples.
- The proteins in some baby foods are ‘pre-digested’ using protease so that they are easier for babies to digest
- Carbohydrase enzymes can be used to turn starch syrup into sugar syrup
- Glucose syrup can be turned in to fructose syrup using an isomerase enzyme. Fructose is sweeter so you need less of it making it ideal for slimming foods.
