8.1 Metabolism (HL) Flashcards
Metabolism
The sum total of all reactions that occur within an organism in order to maintain life
What are metabolic pathways?
When chemical changes result from a series of reactions with each step controlled by a specific enzyme
What are two types of metabolic pathways?
Cycles and chains
How do enzymes help?
They lower the activation energy for reactions they catalyze
Why do metabolic pathways help?
They allow for greater level of regulation as chemical change is controlled by numerous intermediates
Inhibitors
Chemicals that reduce rate of enzymatic activity. They are specific and work at low concentrations
Examples of inhibitors
Many drugs and poisons are inhibitors of enzymes in the nervous system. They block but don’t destroy
Competitive inhibitors
Compete WITH substrate for active site. Action of enzyme is proportionate to its concentration
Do competitive inhibitors resemble substrate structure?
Yes
Can effect of competitive inhibitor be reduced by increasing substrate concentration?
Yes. However it can reach or level close to the maximum rate of reaction if the inhibitor wasn’t there
Non-competitive inhibitors
Bind to allosteric (another site) on enzyme
What happens to active site with non-competitive inhibitors?
The active site gets altered and substrate cannot attach or react
Can effect of non-competitive inhibitor be reduced by increasing substrate concentration?
Not really. Rate of reaction decreases as there are fewer functional active sites for reaction. Max. rate of reaction is also reduced.
End-product inhibition
When the end product of the last enzyme in the chain acts as an inhibitor to an enzyme in the beginning to stop the reaction. It binds to the allosteric site and causes enzyme to change shape
Benefits of end-product inhibition
- Used to regulate metabolic pathways, switching on and off whenever required
- Uses its own products so its efficient
Process of end-product inhibition
- End product is formed in excess
- They inhibit enzymes in the beginning, stopping the metabolic pathway temporarily
- This will continue till all end products are used up
- Allosteric product will get released and metabolic pathway will start again
What can you measure in enzymatic reactions?
- Time taken for substrate to be used up or for product to be made
- Amount of substrate used up or product made over a specific amount of time
What’s on the X axis for plotted enzymatic reactions?
Independent variable
How can you calculate rate of reaction? (s-1)
1/time
How can you calculate amount made over specific amount of time?
Mass or volume/Time
What is one aspect bioinformatics looks at?
How certain compounds bind to target sites
What happens if chemicals bind with parts of a parasite or bacterium?
It can change the infectivity of the pathogen
What is malaria caused by?
A malarial parasite called P. falciparum
How is malaria passed?
It is transmitted from an infected person to another by vectors like mosquitoes
What happens during malaria?
The parasite invades the red blood cells and feeds on the proteins inside
How are databases used in finding cures? Reference malaria
For malaria, genome sequence for a strain called 3D7 was studied extensively. Database was used to screen thousands of chemicals for possible interactions. Chemicals are then tested in labs based on predicted interaction and further studied
How many chemicals have shown promise so far in treating malaria?
35
Why do we need to find new and effective treatments for malaria?
Malarial parasites have become resistant to current antimalarial drugs so it is necessary to find new ones
Who is successful research for malaria and treatments a collaboration between?
Software developers and engineers (for database), statisticians, biochemists and doctors
