IB Biology Topic 8 – Metabolism Cell Respiration & Photosynthesis QUESTIONS AND ASWERS 2023.

1. (8.1) What is metabolism?: sum of all chemical reactions in the body 2. (8.1) What are metabolic pathways?: Pathways that consist of chains and cycles of enzyme-catalysed reactions 3. (8.1) What do enzymes do to activation energy?: They lower the activation energy of the chemical reactions that they catalyse 4. (8.1) What are the 2 types of enzyme inhibitors: competitive and noncompetitive 5. (8.1) How can metabolic pathways be controlled?: End-product inhibition 6. (8.1) How does end-product inhibition work in the pathway that converts threonine to isoleucine?: When too much isoleucine is produced, it binds to the allosteric (other) site of the first enzyme that catalyses threonine and hence stops the rest of the metabolic chain 7. (8.1) How do we identify potential new anti-malarial drugs?: Use databases 8. (8.1) What is rate of reaction?: the change in concentration of a reactant or product per unit time 9. (8.1) What happens to rate of reaction when substrate concentration is uninhibited?: The rate of reaction will increase and then begin to plateau when all enzyme active sites are occupied 10. (8.1) What happens to rate of reaction when enzymes are competitively inhibited?: The rate of reaction is decreased yet it can still reach the max rate achieved by uninhibited enzymes if substrate concentration is increased high enough 11. (8.1) What happens to the rate of reaction when enzyme are non-competitively inhibited?: The rate of reaction is decreased and plateaus a lot lower than if it was uninhibited as the enzyme active site is altered. Increasing substrate concentration has no effect 12. (8.1) List the factors that can affect enzyme activity?: pH, Temperature and Substrate concentration 1 / 4 IB Biology Topic 8 - Metabolism, Cell Respiration & Photosynthesis 13. (8.1) Outline competitive enzyme inhibition, using one specific example- : 1. Succinate dehydrogenase catalyses the reaction of succinate into fumarate 2. Malonate (the competitive inhibitor) can bind to the enzyme's active site and prevent this reaction form occuring 14. (8.1) Outline non-competitive enzyme inhibition, using one specific example: 1. Cytochrome oxidase is a carrier molecule and part of the e- transport chain 2. Cyanide binds to this enzyme's allosteric (other) site and alters the shape of the active site. This stops cytochrome oxidase from completing the e- transport chain 15. (8.2) What does cell respiration ultimately involve?: The oxidation and reduction of electron carriers 16. (8.2) What is phos