1. Energetics and Metabolism Tutorial
Click on “View” then “Slide show” to view the tutorial.
For some of the slides there are animations so you must be in “slideshow” mode to view them.
Try to answer the thought questions (in the orange boxes) before you move on to the next slide!

2. Metabolism
On the whole, metabolism refers to the managing of material and energy resources within a cell.
A metabolic road map depicting the sum total of the metabolic chemical reactions in cells !
Dots are molecules and lines are chemical reactions.

3. Some types of energy… Kinetic Energy Potential Energy
Heat (thermal energy) energy of molecular motion
Chemical Energy stored in the bonds or molecules
Membrane potential - a voltage gradient across a membrane (like a battery!)
Electrical - movement of charged particles.
Light electromagnetic radiation

4. Energy can be converted from one form to another…
Though questions:
What law of thermodynamics is stated here?
How does this diagram depict this law?
…but it can never be created or destroyed!

5. Life is all about energy and material conversions
Life is all about energy and material conversions! Living organisms are always taking in energy and matter in one form and converting it into another form!

6. Energy to make lots of ATPs
Cellular respiration harvests the chemical energy stored in organic molecules to generate ATP!
C6H12O6 + 6O2
The many steps of cellular respiration!
Organic molecules (food) are like the $100 bills of energy currency!
Energy to make lots of ATPs
ATP is like the “pocket change” of energy currency!
CO2 + H2O
Store small/useful amounts of energy which can be used to provide energy to do work in cell.

7. Many processes that must occur in living organisms are endergonic…they require energy!
List 5 processes that occur at each of the levels below which require energy (they are endergonic).
At the cellular level:
At the organism level:

8. ATP = Cellular Energy!
ATP (adenosine triphosphate) is a molecule that stores small (useable) amounts of energy which can be harnessed to do work in cells.
ATP resembles which kind of organic molecule?

9. How does ATP provide the energy to do work?
This reaction releases 7.3 kcal/mole
DG = -7.3kcal of energy per mole of ATP
The breakdown (hydrolysis) of ATP releases the energy need to “drive” endergonic reactions in the cell.
Thought Questions:
Why do we use the word hydrolysis to describe the reaction above?
Why is the DG of this reaction negative? (How is DG calculated?)
What term do we use to describe energy releasing reactions?

10. Using ATP… Regenerating ATP… + + P DG = -7.3 kcal/mole P

11. Where does the energy come from to regenerate ATP in our cells?
Requires 7.3 kcal of energy per mole of ADP P +
Releases 686 kcal/mole of energy!
Glucose + O CO2 + H2O
From the food we eat!

12. Energy Coupling
The coupling of an energy releasing process with an energy requiring process. The energy released from one provides the energy to drive the other.

13. It’s a lot like a how a hydroelectric dam produces electricity!
Note that the flow of water (kinetic energy) is converted to electrical energy (lighting the bulb)
Equilibrium
Can this system continue to light the bulb indefinitely?
Systems at equilibrium can do NO work!
Thought Question:
What does the 2nd law of thermodynamics say about the efficiency with which the dam above can convert kinetic energy into electrical energy?

14. Thought Question: How could we modify the system below to keep it out of equilibrium?

15. Keep adding starting material
Thought question:
So how do living cells keep the chemical reactions of cellular respiration OUT of equilibrium?
C6H12O6 + O2  CO2 + H2O
End-products are removed from the system!

16. The reaction below is an endergonic reaction which is involved in the production of an essential amino acid (Glutamine).
Thought questions:
What chemical reaction will provide the energy to drive the endergonic synthesis of glutamine?
Here’s how it occurs:
ATP reacts with glutamic acid to produce glutamine phosphate.
DG is -
Glutamine phosphate then reacts with NH3 to produce glutamine
DG is -
Overall energetic summary of each separate reaction!

17. Note the extra energy left over…3.9 kcal
Overall energetic summary of each separate reaction!
Note the extra energy left over…3.9 kcal
Thought question…
What happens to the rest of this energy? What form of energy is it converted into? Hint: think increasing entropy!

18. In what parts of the cell do the chemical reaction of cellular respiration occur?
The Krebs Cycle and the Electron Transport Chains occur in here!
Glycolysis – occurs in the cell cytosol

19. Where most of the ATP comes from!
Outer membrane
Inner mitochondrial membrane
Matrix
Intermembrane space
Each fold in the inner mitochondrial membrane is called a cristae.

20. Watch the animations on the following slides depicting the Electron Transport Chains, which generate MOST of the ATP during cellular respiration.
As you watch the animations, indicate instances where you observe the coupling of exergonic and endergonic reactions of processes.
To replay the animations, just hit the back arrow 

21. H+ ions ATP Synthase Matrix both a transport protein & an enzyme
Recall that a chemical concentration gradient is a form of stored (or potential) energy. In this case it is a 100 fold difference in the concentration of H+ ions across the inner mitochondrial membrane. This is reflected by the difference in both pH and charge between the matrix and intermembrane space!
ATP Synthase
Matrix
both a transport protein & an enzyme
Low [H+] pH= charge
ATP
H+ ions
ATP
ADP
ADP
High [H+] pH= charge
Intermembrane space

22. Can this cristae do any work (regenerate ATP)?
Nope…notice that the H+ concentration has equilibrated! H+
So…what prevents the concentration of H+ ions from reaching equilibrium across the inner mitochondrial membrane?

23. Maintaining dis-equilibrium!H+
Cytochrome complexes – These are transport proteins that pump H+ ions into the inter- membrane space which maintains the H+ ion gradient.
ATP
ATP
ADP
ADP

24. You may be wondering…
If pumping H+ ions to an area of higher concentration takes energy (endergonic)…where does it come from?
NADH and FADH2 shuttle high energy electrons to the cytochromes.
electrons
NADH & FADH2
Thought questions:
As electrons flow to each cytochrome complex they loose potential energy. This release of energy is used to…?
What is the final acceptor of electrons at the end of the chain?
ATP
H2O  2H+ + O
ATP
ADP
ADP

25. You might be wondering… Where do the high energy electrons of NADH & FADH2 come from?

26. Making NADH & FADH2…
+ 2e- + H+ 
NAD+
NADH
NAD+ picked up 2 electrons and a H+ ion and is therefore reduced into NADH!!
This is a reduction reaction!

27. REDOX! Just remember… LEO says GER!!!! loose electrons oxidation gain
reduction

28. Oxidation and reduction reactions go hand in hand
Oxidation and reduction reactions go hand in hand. When a molecule is oxidized, some other molecule must pick up those highly reactive electrons, and it is therefore reduced!
This cycle of REDOX reactions occurs continuously throughout cellular respiration!
Thought question…
Go back and look at the animation of the electron transport chain (slide #24). Fill in the following sentence….
_________ is finally reduced into _________at the end of the electron transport chain.

29. or another way of asking this….
You may be wondering….
So where does NADH and FADH2 come from?
or another way of asking this….
Where is NAD+ and FAD reduced into NADH and FADH2?

30. Why the Krebs Cycle…of course!
Notice the starting reactant is…
Occurs in the matrix
Why the Krebs Cycle…of course!
Redox!
FADH2
Thought question: Describe what is being oxidized and what is being reduced in each of the REDOX reactions of the Krebs cycle.
Notice some ATP is made in the Krebs cycle

31. So…Where does the pyruvate come from?
Notice the starting reactant is…
So…Where does the pyruvate come from?
Notice…some more NADH is produced!
From Glycolysis of course!!!
Notice – a little more ATP!
Occurs in the cell cytosol

32. So where in the world does the glucose come from?

33. Metabolism
On the whole, metabolism refers to the managing of material and energy resources within a cell.
Thought question:
Find glycolysis and the Krebs cycle in the diagram to the right?
A metabolic road map depicting the sum total of the metabolic chemical reactions in cells !
Dots are molecules and lines are chemical reactions.