2b Flashcards
What is a catalyst?
A catalyst is a substance which increases the speed of a reaction without being changed or used up in the reaction
Why do enzymes have special shapes?
So they can catalyse reactions
What is needed for an enzyme to work?
The substance involved in the reaction has to fit its shape for the reaction to be catalysed
At what temperature, in the human body, do enzymes work best?
37 degrees
What happens if an enzyme gets too hot?
Bonds holding the enzyme together are broken, so the special shape is destroyed. The enzyme is denatured
What pH do enzymes USUALLY work best at?
pH 7
What pH do protease enzymes work best at?
pH 2
Why does the stomach produce hydrochloric acid?
To kill bacteria and give the right pH for the protease enzyme to work
What do digestive enzymes do?
Break down big molecules into small one so they can pass through the walls of the digestive system
What enzyme converts starch into sugars?
Amylase
Where is amylase made?
- The salivary glands
- The pancreas
- The small intestine
What converts proteins into amino acids?
Protease
What is protease called in the stomach?
Pepsin
Where is protease made?
- The stomach
- The pancreas
- The small intestine
What converts lipids into glycerol and fatty acids?
Lipase
Where is lipase made?
- The pancreas
2. The small intestine
What does amylase convert?
Starch into sugars
What does protease convert?
Proteins into amino acids
What does lipase convert?
Lipids into glycerol and fatty acids?
Where is bile produced?
The liver
Where is bile stored?
The gall bladder
Where is bile released?
The small intestine
What does bile do?
Neutralises the stomach acid and emulsifies fat
Why does bile neutralise the stomach acid?
The hydrochloric acid produced in the stomach makes the pH too acidic for enzymes in the small intestine to work
How does bile neutralise stomach acid?
It’s alkaline so makes conditions alkaline
How does bile emulsify fat?
It breaks fat into tiny droplets
Why does bile emulsify fat?
To give a bigger surface area of fat for lipase to work on to speed up digestion
What is the function of the salivary glands?
They produce saliva which contains amylase
What does the stomach do?
- Pummels the food with the muscular walls
- Produces pepsin
- Produces hydrochloric acid
What is the function of the liver?
It produces bile
What is the function of the gall bladder?
It stores bile
What does the pancreas do?
Produces protease, amylase and lipase. It RELEASES these into the small intestine
What does the large intestine do?
It absorbs excess water from food to form faeces
What does the small intestine do?
- Produces protease, lipase and amylase to complete digestion
- Absorbs digested food into the blood
What are enzymes used for?
- Biological detergents
- Change foods
- Industry
How are enzymes useful in biological detergents and washing powders?
They work at low temperatures so are cost and energy efficient
What enzymes are involved in biological detergents and washing powders?
Proteases and lipases, they digest proteins and fat so remove stains like food and blood
How are enzymes used in baby food?
Proteins are pre-digested by proteases which makes it easier for babies to digest food
How are enzymes used in foods?
Glucose syrup can be turned into fructose syrup using isomerase enzyme
What is an advantage of fructose syrup?
It is sweeter so less is needed, which is good for slimming food as it is less calories
How are enzymes useful in industry?
They speed up reactions without the need for high temperatures and pressures
What are the advantages of using enzymes in industry?
- They are specific so only catalyse the reaction if you want them to
- 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 so cause less pollution
What are the disadvantages of using enzymes in industry?
- Some people can develop allergies to the enzymes
- Enzymes can be denatured by a small increase in temperature or an increase/decrease in pH so conditions need to be controlled
- Enzymes can be expensive to produce
- Contamination of the enzyme with other substances can affect the reaction
