2.4 enzymes Flashcards
What type of protein are enzymes?
Globular proteins
Are enzymes soluble? Why?
- yes
* due to the presence of many hydrophilic side groups
What are enzymes necessary for?
Building up large polymer based components which make cells, which make tissues, which make organs, which make organ systems
How many enzymes are there?
Thousands
What is the difference between each enzyme?
Each one is specific for a specific reaction, as each has a specific active site to fit a specific substrate
What sort of reactions do enzymes catalyse?
Anabolic and catabolic reactions
What are anabolic reactions?
Reactions that build something up
What are catabolic reactions?
Reactions that break something down
What type of reactions are catalysed by enzymes?
Both anabolic and catabolic reactions
In catabolic reactions where is energy released from?
Large organic molecules such as glucose
Where do anabolic reactions get energy from in order to occur?
Catabolic reactions
What are anabolic reactions necessary for?
Building up and growing
Define METABOLISM:
The sum of all the different reactions and reaction pathways happening in all organisms
Why can metabolism happen?
Due to the control and order imposed by enzymes
What part of the enzyme is involved in catalysis?
The active site
What is enzyme shape determined by?
The sequence of amino acids in its structure and the bonds between the atoms in that structure
Why do different types of enzymes have different shapes and functions?
Because the order and type of amino acids in their structure is different
What is enzyme specificity?
Only substrate with the exact shape to fit in the active site will bond to the enzyme and react
What are enzymes?
Biochemical catalysts that speed up reactions without being used up
What do molecules in solution do?
Move and collide randomly
For a reaction to occur what do molecules need to do?
Collide in the right orientation
What is activation energy?
The amount of energy that needs to be supplied to the chemicals/reactants before a reaction will start
How is activation energy often supplied?
As heat
What role do enzymes play with reference to activation energy?
They reduce the activation energy needed to make a reaction happen
• lowering temperature
• speeding up the rate of reaction
What formation lowers activation energy?
The formation of the enzyme substrate complex
Why does the formation of the enzyme substrate complex, lower activation energy, in a reaction where substrate is joining?
- two substrate molecules joining
- attaching to the enzyme holds them close together
- reduces repulsion
- molecules bond more easily
Why does the formation of the enzyme substrate complex, lower activation energy, in a reaction where the enzyme is catalysing a breakdown?
- breakdown reaction
- fitting into the active sites puts strain on the bonds in the substrate
- substrate molecules break up more easily
What does the lock and key model say?
In the same way only the right key will fit into a lock only a specific substrate will fit the active site of the enzyme
How does the lock and key model work?
- substrate enters
- substrate binds to active site
- enzyme substrate complex forms
- products form in enzyme products complex
- products released
- enzyme left unchanged
What does the induced fit hypothesis say?
Recent research suggests the active site of the enzyme changes shape slightly as the substrate enters
How does the induced fit hypothesis work?
- substrate enters
- as substrate hinds active site changes shape slightly
- enzyme substrate complex formed
- enzyme product complex formed
- products released
