CB1E/F/G Enzymes Flashcards
What is an enzyme
A biological catalyst that controls reactions in the body
How can you make a reaction happen more quickly
By raising the temperature
What do enzymes do in the body
They enable cellular reactions to take place at lower temperatures
What is the substrate
The molecule changed in the reaction
What is the active site of an enzyme
The region of an enzyme which a substrate molecule binds onto and catalyses
Why are enzymes described as having ‘high specificity’ for their substrate
Because only enzymes with a specific complementary shape can fit into an enzymes active site
Describe the ‘lock and key’ model
Substrate collides with enzymes active sight
Enzyme binds
Substrate converted to products
Products released from the active sight are now free to bind to another substrate
What three factors affect the rate of an enzyme reaction
Temperature
pH
Substrate concentration
How does increasing temperature affect the rate of an enzyme reaction
Temp increases so molecules have more KE
Movement of molecules increase
Collision increases
Enzyme substrate complexes form
Rate of reaction increases
Explain how increasing the temperature above the optimum affects the rate of an enzyme controlled reaction
Temperature increases above the optimum
Increased vibrations break bonds in enzyme’s structure
Active sight changes shape, enzyme is denatured
No more enzyme-substrate complexes can form
Rate of reaction decreases
Graph to show effect of increasing temperature on the rate of an enzyme-catalysed reaction
Explain how pH affects the rate of an enzyme
Enzymes have an optimum pH
pH shifts from the optimum
Bonds in the enzyme’s structure are altered
Active sight changes shape, enzyme is denatured
Rate of reaction decreases
Draw a graph to show the effect of increasing pH on rate of enzyme catalysed reaction
Explain how the substrate-concentration affects the rate of an enzyme reaction
Substrate concentration increases
Number of substrate molecules in the same volume increases
Probability of a successful collision increases
More enzyme-substrate complexes form
Rate of reaction increases
Once all active sites become full, the rate of reaction plateaus
Draw a graph to show the effect of increasing substrate concentration on the rate of an enzyme-catalysed reaction
Why must large organic molecules be broken down into smaller, simpler molecules in the body
Large molecules are broken down into smaller molecules for absorption into the bloodstream
Give an example of the breakdown of large molecules in plants
Starch is broken down by enzymes into simple sugars which are respired to release energy
What types of molecules are proteins and carbohydrates
Polymers
What are the monomers of carbohydrates
Simple sugars
Which group of enzymes catalyses the breakdown of carbohydrates
Carbohydrases
Which type of carbohydrate catalyses the breakdown of starch
Amylase
What are the monomers of proteins
Amino Acids
Which type of enzyme catalyses the breakdown of proteins
Proteases
What is the function of lipases
Enzymes which catalyse the breakdown of lipids into fatty acids and glycerol
Why are small molecules synthesised into larger organic molecules in the body
Large molecules are used for storage or are used to build structures
Which enzyme catalyses the formation of glycogen from glucose
Glycogen synthase
