Enzymes Flashcards
What constitutes cellular metabolism?
Chemical reactions that take place in cells, maintaining the living state of the cells and organisms
Participating molecules in cellular metabolism are known as what?
Metabolites
What are the two types of reactions in cells?
Anabolic and catabolic
Define endergonic
A reaction requiring an energy input
Define exergonic
A reaction that releases energy
What is an anabolic reaction?
A reaction that consumes energy while synthesising compounds
Energy consumed by the reaction is stored in the chemical bonds
Forms more complex molecules
FORMS BONDS
What is a catabolic reaction?
A chemical reaction that releases energy when chemical bonds are broken
The energy released is used within the cell for other reactions
More simple compounds
BREAKS BONDS
What are enzymes?
Molecules that act as catalysts to speed up biological reactions
Are enzymes consumed doing biological reactions?
No, and they may keep working
The compound on which an enzyme acts is known as a what?
Substrate
What is the structure of an enzyme?
Enzymes are proteins, with an active site where the substrate binds
They are substrate specific
How are enzymes named?
They typically end in -ase, and can be named after their substrate
Eg- an enzyme working on lactose may be lactase
Where does substrate modification occur?
At the active site
What is a high specificity enzyme?
An enzyme that will only bind with a single type of substrate
What is a low specificity enzyme?
An enzyme that will bind with a range of related substrates
When a substrate bonds to an enzyme’s active site, an ___________________ is formed
Enzyme-substrate complex
How do enzymes work?
They charge molecular energy
A substrate requires activation energy to charge. Enzymes reduce the activation energy of a reaction, therefore increasing the rate of reaction (speeding it up)
They can either break down a substrate into two or more products or add two or more substrates together
What is activation energy?
Before a substrate can charge it must overcome an energy barrier. This is known as activation energy
The larger the activation energy the slower the reaction
What is the lock and key model?
Proposes that the the substrate must ‘fit’ into the enzyme’s activation site (it must be compatible) in order to be acted upon
What is the induced fit model?
Two substrate molecules drawn into an active site and the enzyme will change shape to combine the two substrates
The enzyme returns to its normal shape
What is a co-enzyme?
A chemical compound that can take up space in an active site, allowing certain reactions to occur
What is a competitive inhibitor?
A chemical compound that can ‘mimic’ the molecules that fit in an active site.It will stop the enzyme working by preventing substrates binding to the active site
What is a non-competitive inhibitor?
A form on Inhibitor molecule that will bind to other parts of an enzyme (not the active site)
This is known as a allosteric site
The pressen if allosteric compound can change the structure of an enzyme, thus layering the active site and rendering the enzyme inoperable
How are enzymes affected by temperature?
Enzyme activity increases with higher temperatures
Once the temperature gets too high, enzyme denaturation will occur and the enzyme will cease to function
