1. An Introduction to MetaBOlism
Chap 8 pg

2. Many reactions in our bodies are “coupled” together!

3. Metabolism & Metabolic Pathways

4. All of the chemical reactions that occur in a cell
MetabolIsm:
“Change”
All of the chemical reactions that occur in a cell
Metabolism is driven by cellular respiration
Converts energy from sugars to do work!

5. METABOLIC PATHWAYS E1 E2 E3 E4 A B C D E
A series of steps, catalyzed by enzymes that create a new product
Most reactions in a cell are “coupled” ( linked) NOT random
Every rxn in a cell requires its specific enzyme!
Can you think of 3 enzymes you know?
E1 E E E4
A B C D E

8. Catabolic Pathways “Downhill” Reactions…release energy
Breakdown complex molecules into simpler molecules
Ex: Hydrolysis Reactions
Ex: Cellular Respiration

9. Anabolic Pathways “Uphill” Reactions…consume energy
Build complex molecules from simpler molecules
Ex: Dehydration Synthesis Reactions
Ex: Protein Synthesis from Amino Acids

10. You try… Catabolic or Anabolic
`1) 2) 3)

11. Energy released from the catabolic reaction can be used to drive the anabolic reaction.
this transfer is called
energy coupling

12. Energy Energy: the capacity to do work
Kinetic Energy: energy of motion
Potential Energy: stored energy
Bond Energy or Chemical energy: the potential energy available for release in a chemical reaction (stored/found in ATP)

13. Organic compounds store energy in their arrangements of atoms.
Cells harvest chemical energy stored in molecules and use this to generate ATP.
Organic compounds store energy in their arrangements of atoms.
The goal is to break these bonds and release energy our cells can use.

14. Laws of energy Transformation (Thermodynamics)
1) Energy cannot be created or destroyed
Only transferred and transformed!
2) Changes in energy increases entropy
Entropy: the measure of disorder or randomness

15. Free Energy: energy available to do work
Represented by G
therefore the change in free energy = G
Final energy-Initial energy
If G is NEGATIVE the reaction is Exergonic (energy has been released in products...ex=out)
If G is POSITIVE the reaction is Endergonic (energy has been consumed in reactants...end=in)

16. What type of reactions cause these squid to glow
What type of reactions cause these squid to glow?!? Describe the change in free energy!

17. How would the following scenario be similar or different?

18. Atp, cellular work & coupling RxnS
Sec 8.3 pg 149

19. A cell does 3 main kinds of work:
I) Chemical work
carrying out endergonic rxns (like building polymers)
II) Transport work
pumping substances across membranes (against concentration gradients)
III) Mechanical work
Beating of cilia, contraction of muscle cells etc

20. Energy Coupling:
The use of an exergonic process to drive an endergonic one!

21. The structure of (ATP) Nitrogenous base: adenine Sugar: ribose
3 phosphate groups

22. The 3 Phosphate groups are each neg. charged
Creates a mutual repulsion & instability
 chemical equivalent of a compressed spring

23. The hydrolysis of ATP
ATP + H20  ADP + Pi + energy

24. The hydrolysis of ATP Exergonic rxn  releases energy
Energy is used to drive many cellular processes !
Example of chemical work:
Making the amino acid glutamine from glutamic acid and ammonia (see fig 8.9)

25. The hydrolysis of ATP Example of Transport work:
Ex) ATP hydrolysis drives protein pumps in the cell membrane  changes the shape & binding affinity
Example of Mechanical work:
ATP attaches to motor proteins, hydrolysis helps create movement along cytoskeletal track
can move vesicles & organelles!

26. Regeneration of ATP

27. Big Idea:
Free energy becomes available for metabolism by the conversion of ATP  ADP, which is coupled to many steps in metabolic pathways!

29. Assignment: Concept Check 8.2 Qs 1-3 pg 149

30. Relevant Links
KHAN Academy- enzymes/atp-reaction-coupling/v/reaction-coupling-to-create-glucose-6-phosphate
Bozeman-