1. Basic Concepts and Design
Metabolism
Basic Concepts and Design

2. Metabolism What is metabolism?
all the chemical reactions that take place in cells
series of energy transformations
Why do living organism require energy?
to synthesize large molecules from small ones
to move substances in and out of cells
muscle contraction and cell movement

3. Metabolism What is the difference between phototrophs and chemotrophs?
phototrophs obtain energy from sunlight
chemotrophs obtain energy from breaking chemical bonds
What is the difference between anabolic and catabolic reactions?
catabolic – fuels degraded to release useful energy
anabolic – energy used to synthesize biomolecules

4. Metabolism Why are reactions often coupled in metabolic pathways?
to insure that the overall free energy change is negative
a reaction that requires energy may be paired with one that releases energy

5. Metabolism What is the role of ATP in cells?
donor of free energy in energy requiring reactions
Why is ATP an energy rich molecule?

6. Metabolism
What are the factors that contribute to the large amount of energy released when ATP is hydrolzed?
resonance stabilization
electrostatic repulsion
ease of hydration

7. Metabolism

8. Metabolism What do we mean by phosphoryl transfer potential?
ability to donate a phosphate group
What molecules besides ATP can transfer PO4 groups?

9. Metabolism
How is ATP regenerated in cells?

10. Metabolism
The oxidation of which of these two molecules will produce more ATP and why?

11. Metabolism
How do molecules with high phosphoryl transfer potential couple the oxidation of carbon to the synthesis of ATP?
glyceraldehyde-3-PO4 + NAD+ + HPO4
1,3 biphosphoglycerate + NADH + H+
1,3 biphosphoglycerate + ADP  3-phosphoglyceric acid + ATP

12. Metabolism

13. Metabolism
What is happening at each stage of catabolism?

14. Metabolism
While ATP is an activated carrier of phosphoryl groups, what molecule(s) is (are) activated carrier(s) of electrons during oxidation?
nicotinamine adenine dinucleotide (NAD)
flavin adenine dinucleotide (FAD)

15. Metabolism

16. Metabolism

17. Metabolism
One H is transferred to NAD with 2 electrons and the other H goes into solution as a proton.

18. Metabolism

19. Metabolism

20. Metabolism
What activated carrier for electrons is used in most biosynthetic reactions or the reaction shown above?
NADPH

21. Metabolism Why is coenzyme A an important molecule in metabolism?
carrier of acyl groups

22. Metabolism

23. Metabolism
While metabolism consists of thousands of reactions, each reaction falls into one of six categories.

24. Oxidation-Reduction Reaction

25. Ligation Reaction

26. Isomerization Reaction

27. Group Transfer Reaction

28. Hydrolytic reaction

29. Addition or Removal of Functional Groups

30. Regulation of Metabolism
What are the three basic ways in which metabolic reactions are regulated?
controlling amount of enzyme
influencing rate of transcription
altering catalytic activity
allosterically
covalent modification
controlling accessibility of substrates

31. Regulation of Metabolism
How do hormones influence metabolism?
alteration of enzyme activity
glucagon and glycogen phosphorylase
What other factors influence metabolism?
compartmentalization
energy status of cell

32. Metabolism
What do ATP, NADH, FAD and coenzyme A have in common and what does this indicate about these molecules?
adenosine diphosphate
evolved from early RNA catalysts