Lecture 1 - Overview of Metabolism Flashcards
What is Metabolism?
Metabolism is composed of many coupled interconnected chemical reactions
> It extracts biologically useful energy from the cells
> Synthesis of the building blocks of the cell
Define catabolic reactions.
Catabolic reactions - Extraction of biologically useful forms of energy
Define Anabolic reactions.
Anabolic reactions - synthesis of complex structures or molecules form simple ones which requires the input of energy from catabolism
What are the 6 classes of enzyme catalysed reaction?
- Oxidation reduction - Electron transfer
- Ligation requiring ATP cleavage - Formation of covalent bonds (uses ATP)
- Isomerization - Rearrangement of atoms to form isomers
- Group transfer - Transfer of functional groups form one molecule to another
- Hydrolytic - Cleavage of bonds by addition of water
- Addition of removal of functional groups - Addition of functional groups to double bonds or their removal to form double bonds
What are the roles of the activated carriers: ATP, NAD/FAD and Acetyl CoA?
“Activated Carriers” have been conserved through evolution
E.g. Adenosine Triphosphate - The release of phosphates causes the release of energy.
E.g. NAD and FAD which are activated carriers of electrons. They can be oxidised to release electrons.
E.g. Acetyl CoA which is an activated carrier of an acetyl unit
How do catalysts affect activated carriers?
In the absence of specific catalysts activated carriers are kinetically stable. This means that enzymes can control the flow of electrons.
In the absence of a catalyst
> NADH and FADH2 - resist oxidation and release of electrons
> ATP and acetyl CoA - are hydrolysed slowly
How is energy extracted from carbon?
Free energy is associated with the oxidation of single carbon compounds. The more oxidised a molecule is the amount of energy released is reduced. Catabolism allows the controlled release of energy thorough electron transport.
