Topic 8: Metabolism, Cell Respiration and Photosynthesis
8.1 Metabolism
Methabolic Pathways
Definition: a chain or cycle of reactions that are catalysed by enzymes
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Definition: a chain or cycle of reactions that are catalysed by enzymes
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reactions happen mostly at small steps
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Cycle pathways - the end product is used to start the pathway, such as in Krebs Cycle
add krebs cycle and glycolysis
Enzymes and activation energy
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Activation Energy: min. of energy required for a reaction to take place
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is used to break or weaken the bonds in the substrates
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binding of enzymes ⇾ lower the the activation energy
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Activation Energy ⇾ + rate of reaction
Types of enzyme inhibitors
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Definition: enzyme inhibitors bind to enzymes and reduce their activity
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Competitive:
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competes for the same site - is similar to the substrate
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interferes with the active site ⇾ enzyme can not bind
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does not modify the active site
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+ substrate = - effect of the inhibitor
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Non-Competitive:
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binds to a different location than the active site
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changes the shape of the enzyme ⇾ enzyme can't bind
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+ substrate ⇾ does not change the impact of the inhibitor
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add graph
End-product inhibition
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form of non-competitive inhibition: the end product binds to the allosteric site - inhibits products to be produced
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allosteric interactions ⇾ happens away from the active site ⇾ on the allosteric site
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excess of end product = stops the pathway
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Example: amino acid threonine is transformed in isoleucine
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high concentration of isoleucine ⇾ makes isoleucine bind to the allosteric site of the first enzyme, threonine deaminase
Bioinformatics and new antimalarial drugs
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research of metabolic pathways is facilitated through chemogenomics
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chemogenomics: a range of target sites and chemicals that work on those target sites are identified for each organism
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those informations create a database used to help find cure for diseases
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Example: new anti-malarial drugs
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increasing drug resistance of the pathogen
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need to develop new drugs ⇾ identification of those
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Calculating rate of reactions
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measure rate of disappearance of substrate
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measure rate of appearance of product
add graph