Chapter 3 Flashcards
(4 cards)
Enzymes
- Biological catalysts that speed up the rate of chemical reactions by bringing two substrates together
- Operates continuously to maintain cellular processes essential for life occur at rates sufficiently fast to maintain the living state
- Proteins that consist of one or more polypeptide chains (monomeric and oligomers)
- Have an active site which is complementary and specific to a substrate, functional group or side chain, or for a bond between particular groups
- Denaturation of enzymes affects H bonds (secondary structure) alters active site and cannot temporarily or permanently function
- Some are inactive proenzymes, and are activated in response to signals
Metabolism
Metabolism- chemical reactions that are taking place in living organisms
Catabolism- cellular reactions that releases useful energy from the breakdown of complex molecules (exergonic)
Anabolism- cellular reactions in which the complex molecules required by cells are synthesised from simpler building blocks, a process that requires an input of energy (endergonic)
Factors affecting enzymes
Temperature (inactivates or denatures, covalent bonds), enzyme concentration, pH (optimum pH), substrate concentration affects enzyme activity
Enzyme inhibitor
a molecule that binds to an enzyme and interferes with it, limiting its activity
Irreversible inhibition- when a molecule covalently bonds to amino acid/s and alters the enzyme structure (poisons)
Reversible inhibition- inactivates enzymes through noncovalent bonds (competitive where the inhibitor has a similar shape of the substrate, and non-competitive where the inhibitor binds to the allosteric site and distorts the 3D shape of the enzyme)
End-product inhibition- where the end product (B) of the metabolic pathway inhibits the production of the first enzyme in the pathway, inhibitor goes away when the concentration of product B increases