Enzymes Flashcards
What are enzymes?
They are biological catalysts. These biological catalysis increase the rate of a chemical reaction without being permanently changed themselves.
What is an advantage of enzymes in the body?
They enable cellular reactions to take place at lower temperatures
What group of chemicals do enzymes belong to?
Proteins
Describe how DNA controls the production of a specific enzyme
• DNA codes for a specific sequence of amino acids
•the order of amino acids determines how the enzyme folds and its structure.
• the shape of the enzyme determines its function.
What is the chemical that an enzyme works on called?
Substrate
What is the active site of an enzyme?
The region of an enzyme to which a substrate molecule binds and the reaction takes place.
Why are enzymes described as having a ‘high specificity’ for their substrate?
Only substrates with a specific, complementary shape can fit into an enzymes active site.
What must happen between an enzyme and its substrate for a reaction to occur?
Enzyme and substrate must collide
Describe the ‘lock and key’ model
- Substrates collides with the active site of an enzyme.
- Substrate binds, enzyme-substrate complex forms.
- Substrate converted to products.
- Products released from the active site which is now free to bind to another substance.
What factors affect the rate of an enzyme-controlled reaction?
•Temperature
•pH
Explain how increasing temperature initially affects the rate of an enzyme-controlled reaction
•as temperature increases molecules have more KE.
•movement of molecules increases.
•probability of a successful collision increases.
•more enzyme- substrate complexes form.
•rate of reaction increases.
Explain how increasing temperature above the optimum affects the rate of an enzyme- controlled reaction
•temperature increases above the optimum.
•increase vibrations break bonds in enzymes structure.
•active site changes shape, enzyme is denatured.
•no more enzyme-substrate complexes can form.
•rate of reaction decreases.
