Enzymes Flashcards
Define the term metabolism
The sum of all chemical reactions that take place within an organism
Define the term enzyme
Enzymes are proteins that speed up a reaction without being used up in the reaction
Describe the protein nature and folded structure of enzymes
Proteins are formed by joining a sequence of amino acids togther to form a long polypeptide chains which are then folded into a three dimensional shape. Enzymes are globular shapes.
Describe the role of enzymes in plants and animals, particularly in metabolism
Speed up metabolism which is essential for growth, movement, maintenance of a constant internal state, repair, response to stimuli and reproduction. Metabolism maintains a balanced internal state called homeostasis within an organism.
Name two sources of energy
Solar energy- is energy from the sun
Cellular energy- is the energy stored in the bonds of biomolecules and released by reactions that occur in a cell
Define the term catalyst
A catalyst is a substance that speeds up a reaction without itself being used up in a reaction
Define the term substrate
The substance with which an enzyme reacts
Define the term product
Is the substance the enzyme forms
List the features of Enzymes
- Enzymes are made of protein
- Enzymes work because they have the correct 3d shape to fit the substrate
- Enzyme reactions are reversible, this means they can be anabolic or catabolic
4.Enzymes are named by adding “ase” to the name of their substrate
What are Catabolic Enzymes + name an example
Catabolic enzymes break down a substance into simpler parts. E.g Amylase is an enzyme that converts starch into maltose
What are Anabolic Enzymes + name an example
An Anabolic Enzyme converts simpler molecules into a more complex from. E.g DNA polymerase is an enzyme that forms and repairs DNA
How does temperature affect Enzyme activity
At very low temperature, the cell is solid and enzymes cannot work. Temp increase - molecular moment increases = rate of reaction increases
Above a certain temp enzymes become denatured
What temperature do enzymes work best at in humans and plants
Human enzymes = 37 degrees
Plant enzymes = 20-30 degrees
How does PH affect Enzyme activity
Most enzymes work best between 6-8 PH . Optimum PH = 7. Outside these figures Enzymes become denatured
Define the term denatured enzyme
A denatured enzyme has lost its shape and can no longer function.
Define the term immobilised Enzymes
Enzymes that are attached or fixed to each other or in an inert material
Define the term bioprocessing
Is the use of enzyme controlled reactions to produce a product
Define the term bioreactor
Is a vessel or container in which living things or their products are used to make a product
List some methods of immobilising enzymes
- Attached to eachother
- Attached to insoluble supports
- Enclosed within a membrane or gel
What are the advantages of immobilised enzymes
1.They can be reused
2.Can be recovered easily at the end of the process
3.increased stability- less enzymes needed
4. Cheaper
5. Efficiency of the enzyme is not affected
Give an example of uses of immobilised enzymes
Soft drinks sweetened with fructose. Immobilised enzymes called glucose isomerase is used to convert glucose to the sweeter tasting frucose
Define the term activation energy
Is the minimum quantity of energy required in order to allow a chemical reaction to occur
Define the term active site
Is the part of the enzyme that combines with the substrate
Describe how enzymes work( Induced fit model)
- The substrate combines with the active site of the enzyme.
- The active site is induced or caused to change shape slightly by the substrate.
- The substrate & enzyme form an enzyme-substrate complex. The bonds in the substrate are altered so that the substrate changes into the product.
- The product leaves the active site.
- The active site returns to its original shape and can now accept a new substrate molecule.
Explain the specificity of an enzyme
Each enzyme will react only with one particular substrate
