Enzymes Flashcards
What is an enzyme
An enzyme is a protein which acts as a biological catalyst
What are enzymes made up of
Enzymes are made up of protein molecules (made up of amino acids folded to produce a specific shape
How many times can an enzyme be used
An enzyme is reusable
What are the factors that affect enzymes
Enzymes are affected by temperature and pH.
What does it mean if it said an enzyme is specific
Each enzyme catalyses one particular reaction
What is a catalyst
A catalyst is a substance which speeds up the rate of reaction but it is not used up or changed itself.
What do enzymes do during digestion
During digestion, enzymes break down large, insoluble food molecules into smaller, soluble ones which can be absorbed through the small intestine wall to enter the bloodstream
State the two types of enzymes
Anabolic enzymes (build up)
Catabolic enzyme (breaks down)
Why do enzymes only catalyse one specific reaciton
Enzymes only catalyse one specific reaction.
This is because, an enzyme’s active site has a specific shape.
Foran enzyme to work (for the reaction to occur), the shape of the enzyme’s active site has to be complimentary to the shape of one particular substrate, so that the substrate can bind to (fit into) the enzymes active site) and an reaction can occur
If the substrate doesn’t match the enzyme’s active site (if they are not complimetnary), then the reaction won’t be catalysed
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For an enzyme to work(for the reaction to occur), the substrate has to fit into (bind to) its active site.
Describe the lock and key theory
1) The shape of the enzyme’s active site is complimentary to the shape of one particular substrate.
2) The two bind together to form an enzyme substrate complex.
3) The reaction between them takes place rapidly (to produce smaller molecules)
4) The products are released from the enzyme’s active site.
The enzyme molecule is unchanged and can be reused.
Where is amylase produced
Salivary glands, pancreas and small intestine
Where is protease produced
Stomach, pancreas and small intestine
Where is lipase produced
Pancreas and small intestine
What is starch broken down into by the amylase enzyme
Sugars e.g. glucose
What is protein broken down into by the protease enzyme
amino acids
What are lipids broken down into by the lipase enzyme
fatty acid and glycerol.
Where can enzymes be found?
Enzymes can be found in animals, plants and micro-organisms
Describe and explain the trend in a temperature/rate of reaction enzyme graph
As the temperature increases, the rate of reaction increases. This is because as the temperature increases, the enzyme and the substrate are moving faster (have more kinetic energy), so there are more collisions per second (more frequent collisions) between the substrate and the active site.
At a certain temperature, the enzyme is working as fast as possible. This is called the optimum temperature.
At this point, there is the maximum frequency of successful collisions between the substrate and the active site
As the temperature increases beyond the optimum, the rate of reaction rapidly decreases to zero (the enzyme has denatured and has stops working)
This is because at high temperatures, the long amino acid chains begin to unravel and as a result the shape of the active site changes. Now the substrate no longer fits perfectly into the active site. The active site is denatured.
The enzyme can no longer catalyse the reaction
The too low/too high or too high temperature would break the bonds in the enzyme and change the shape of the enzyme’s active site.
The enzyme would denature
This would mean the substrate would no longer fits perfectly into the active site.
The enzyme can no longer catalyse the reaction (the enzyme wouldn’t work anymore)
What is the optimum temperature of most human enzymes
37 degrees celcius which is human body temperature
How does pH effect enzymes
The enzyme has an optimum pH where rate of reaction is maximum.
If the pH is made more acidic or more alkaline then the rate of reaction drops to zero.
This is because, a change in pH affects the shape of the active site of an enzyme.
The Shape of the active site of an enzyme comes from forces between the different parts of the protein molecule. These forces hold the folded chains in place. A change in pH can affect these forces, changing the shape of the molecule. As a result, the specific shape of the active site is lost, so the enzyme no longer acts as a catalyst, and becomes denatured.
Describe how temperature affects the enzyme function
Use the graph
Initially, as the temperature increases, the rate of enzyme activity also increases, up to 40 degrees celcius, which is optimum temperature. After 40 degrees celcius, as the temperature increases the rate of enzyme activity decreases
Describe how high temp and very low/high pH affect enzymes
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Explain what effect a very low pH or high pH or a very high temperature would have on the activity of the enzyme
The too low/too high or too high temperature would break the bonds in the enzyme and change the shape of the enzyme’s active site.
The enzyme would denature
This would mean the substrate would no longer fits perfectly into the active site.
The enzyme can no longer catalyse the reaction (the enzyme wouldn’t work anymore)
What do enzymes control
Enzymes control metabolism (the sum of all the reactions in a cell or in the body)
Define active site
The site on an enzyme where the substrate (reactants) bind
