Enzymes Flashcards
Why do digestive enzymes break down large food molecules into smaller molecules?
So they can easily be absorbed through the small intestine wall into the bloodstream
What do protease enzymes include?
Pepsin (stomach) trypsin (small intestine)
What does carbohydrase enzymes include?
Amylase (saliva in the mouth) Maltese, sucrase, lactase (small intestine)
Where are lipase enzymes found?
In the small intestine
What is a protein molecule made up of?
Many different amino acids
What does protease break down?
Protein molecules
What is a starch molecule made up of?
Many glucose molecules
What breaks down carbohydrate molecules?
Carbohydrase
What is made up of fatty acids and glycerol molecules?
Fat molecules
What breaks down fat molecules?
Lipase
Each ……………… Group has a chemical test
Food
What can we use food tests for?
To monitor enzyme-controlled reactions
From orangey brown what colour does iodine turn into when it reacts with starch
Blue black
For a strong positive result What colour does blue Benedictics solution turn when it’s boiled with glucose?
Red
For a medium positive result what colour does blue Benedicts solution turn when it’s boiled with glucose?
Yellow orange precipitate
For a weak result what colour does blue Benedicts solution turn when it’s boiled with glucose
Green
For a negative result what colour with blue Benedicts solutions turn when it’s boiled with glucose?
Blue
How do you test if protein is in a food?
Put the chopped up food in a test tube, add potassium hydroxide, shake, add copper surface and if it’s purple in colour there’s protein, if it turn blue there isn’t
What colour does fats go when they are mixed with ethanol and water?
Cloudy white for a positive result
Clear for a negative result
How do you test food for fat?
Place 1cm* of ethanol in a test tube
Add and few drops of oil in the test tube and mix by shaking
Add an equal amount of water in the test tube and shake
What is a substrate?
A substrate is something that an enzyme breaks down
In the lock and key model what does the represent?
The active site
In the lock and key model what does the lock represent?
The enzyme
A key needs to be a …………… ……….. To fit in a specific lock
Specific shape
What are the shapes?
Complementary
What will the key not fit into?
A different lock
What the lock and key model?
It’s analogy for how enzymes work
What are enzymes?
Protein molecules
What do enzymes do?
They are biological catalysts and they speed up reactions in cells
What do they reman?
Unchanged by a reaction and can be re used unless they’re denatured
What fits into the little dip in the enzymes?
The substrate
What is the Optimum temperature for most enzymes?
37*
When does the shape of the active site change?
At higher temperatures
What happens when the shape is the active site changes?
It’s denatured
What happens when an enzyme denatures?
The substrate can no longer fit into the active site, the reaction stops
What is denaturing due to collisions between enzyme and substrate
Heat is irreversible what does heat cause?
What happens when enzymes denature at high temperatures?
The rate of reaction falls rapidly
Apart from at high temperatures what other ways can denaturing happen?
It also happens when the PH far away from the optimum, this change can be reversed
What is the OPTIMUM ph or temperature?
Optimum is the maximum rate of reaction
What is the optimum PH for pepsin (stomach enzyme)?
2
What is the optimum PH for trypsin (intestinal enzyme)?
8
What’s the job of the savlivary amylase!
To break down starch into glucose
What conditions does the salivary amylase work in?
Alkaline conditions
In the stomach what enzyme is denatured due to stomach acid?
Salivary amylase
Why does the pancreas secrete amylase?
So that the digestion of starch can carry on in the small intestine
What acid is there in gage stomachs?
Hydrochloric acid
Why is starch being turned into glucose by amylase essential?
Because glucose is used in the process of respiration which makes energy for the cells
What are enzymes made of?
Proteins
What substances can we describe as being biological catalysts?
Enzymes
What is the job of the enzyme amylase?
Breaks down starch into glucose
What is throb of the enzyme lipase?
Breaks down fats into fatty acids and glycerol
What is the job of the enzyme protease?
Breaks down proteins into amino acids
Name two places in the body you could find amylase
In saliva/mouth and in the small intestine
Where would you find the protease enzyme called pepsin?
In the stomach
Where would you find the protease enzyme called trypsin?
In the small intestine
At what pH does pepsin work best?
PH1-2
At what pH does trypsin work best?
PH8
Where in the body would you find the enzyme lipase?
In the small intestine
Why are enzymes so important?
They make reactions in cells go faster
How would you test for starch?
Add iodine. It should change from image to blue-black
How would you test for protein?
Add sodium hydroxide solution. And fridge blue copper sulphate solution in. It should form a violet precipitate
How would you test for glucose?
Add blue Benedicts solution. And boil for 5 mins. It should turn green then brick red
How would you test for facts?
Add ethanol and shake. It should turn milky (forms an emulsion)
I burn a peanut and use the flame to heat up some water I measure the energy given out. What is the process called?
Calorimetry
In calorimetry, what is the temperature rise of the water equal to?
The heat give out by the burning food
In calorimetry, mass of water X temperature change X 4.2=what?
Energy in food (joules)
In the lock and key model what what do these represent?
Lock= enzyme, key =substrate
Where on an enzyme does the substrate fit?
The active site
Describe the shape of the active site
Specific and complementary to the substrate
What causes enzymes to have a very specific shaped active site?
The particular order of amino acids that make up the protein
What is the optimum temperature for many enzymes?
37 degrees C
Why can amylase not work on proteins?
The active site is not the correct shape
If an enzyme if heated to beyond 40 degrees C, what happens?
The active site is denatured
What do we mean by the optimum pH that an enzyme works at?
The pH that gives the maximum rate of reaction
Why do enzymes work within a very narrow pH range?
Outside of the range, the enzyme is denatured
What happens to the rate of a reaction as you increase the substrate concentration?
It increases until it reaches a maximum rate after which there is no further increase
What is the equation to work out a rate of reaction?
1000 ➗ time taken in seconds
What are digestive enzymes used for?
To break down large food molecules into smaller food molecules
