1. Cellular Respiration
G 10 Team AISG

2. Why do we eat?

3. To acquire energy (and nutrients) but importantly, energy.

6. How do cells make energy (ATP)?
ATP is the prime energy carrier for autotrophs and heterotrophs
Fermentation and Anaerobic Respiration
Release small amounts of energy
Occurs in cytoplasm of cell
WITHOUT O2
Aerobic Respiration
Releases LARGE amounts of ATP
Occurs in Mitochondrion of cell
USES O2

7. What does ATP look like?

8. Why we need ATP: Types of cell work
ATP is the fuel for cellular work. It fuels all the processes that make use considered “living”

9. Steps of Cellular Respiration:
Glycolysis (Happens in all organisms in cytoplasm)
(Link Reaction-links product of glycolysis to Krebs)
Krebs Cycle (in the matrix of the mitochondria)
Electron Transport Chain (in the inner membrane of mitochondria)
Oxidative Phosphorylation/Chemiosmosis (the processes that result from the ETC)
Oxidative phosphorylation: means oxygen needed (to accept used up electrons) when phosphate is added to ADP to make ATP
Chemiosmosis means “chemical osmosis” so the movement of H+ from high to low concentration (intermembrane space back into matrix)

10. Cellular respiration is an organisms way to extract the chemical PE stored in the bonds in a slow and controlled manner, rather than the large explosive one like we saw with the gummy bear.

11. Substrate level phosphorylation means ATP made without use of an electron transport chain and ATP synthase

12. NADH made
Link Rxn: CO2 given off

13. NADH
Link Rxn: CO2 given off

14. Glycolysis: Glucose Splitting
Glycolysis is a complicated process involving 10 separate chemical reactions but you just need to know ….
It takes 2 ATP to start the process… so we invest 2 ATP at the beginning… and we get out:
4 ATP (for a net gain of 2 ATP)
2 NADH (e- carrier molecule!)
A final product of 2 3-C pyruvate molecules

15. Remember: Glycolysis means “splitting glucose”
A lot of chemical reactions happen to get from Glucose to Pyruvate
Pyruvate is the final product of Glycolysis
Pyruvate is a 3-Carbon Chain (We started with a 6- Carbon chain… known as glucose)

16. Pyruvate in the Link Reaction
Pyruvate must be converted to acetyl CoA in order to enter the Kreb’s cycle
Keys to remember: pyruvate converts to Acetyl CoA, while releasing CO2 and makiing more NADH

17. Krebs Cycle: Check it OUT: It can get really complicated, so we’ll try to keep it simple

19. Summary of Products Summary 2 Turns 3 CO2 for each turn
1 ATP for each turn
4 NADH for each turn
1 FADH2 for each turn
1 Acetyl CoA goes in and we make: 1 ATP, 4 NADH and 1 FADH2 (Yet another e-carrying molecule), from 1 glucose molecule, we have 2 Acetyl CoA so the cycle has to turn twice, resulting in : 2 ATP, 8 NASH and 2 FADH2 for each glucose

20. Electron Transport Chain and Phosphorylation (Fancy word for making ATP): Check it OUT (Looks a LOT like what happens in photosynthesis!)

21. Chemiosmosis couples with the ETC to make ATP
Almost identical to the process in photosynthesis, the ETC is in the inner membrane of the mitochondria, where the electron comes from carriers NADH and FADH who drop of the energetic electron and an H+, the fall of the electron down the ETC, pumps the H+ across the inner membrane from the matrix INTO the intermembrane space where the H+ concentration builds up. H+ will flow down the concentration gradient from high concentration in the intermembrane space to low concentration in the matrix. It can only do this through the ATP syntase enzyme, which as you know by now is the enzyme that converts ADP and P into energetic ATP.
So what happens to the electrons and H+ that are now in the matrix with no place to go….FINALLY we use oxygen. Oxygen to the rescue! O2 is the final electron acceptor and picks up both the electrons and H+ from the matrix and forms WATER!

22. ATP synthase (making ATP)
Same exact process that happen in the chloroplast with the same enzyme and the same H+ concentration gradient…I KNOW so COOL!

23. Overview: Know This

25. Alcohol Fermentation (Anaerobic Respiration)
Humans have used this ability in bacteria and yeasts for thousands of years to make wine, beer and raise bread!

26. Lactic Acid Fermentation
Our bodies can turn to lactic acid fermentation for short periods of time, especially in our muscles when they are oxygen deprived, like during intense exercise. It is the production and build up of lactic acid in your muscles that make you sore the day after.

27. Pyruvate is the KEY Glycolysis WILL HAPPEN
If O2 is present… cellular respiration!
If O2 is NOT present, then fermentation happens (alcohol or lactic acid, it just depends on the organism)
CHALLENGE: Why is it that only very small organisms can exist without oxygen at all?

29. Catabolism of various
food molecules:
Proteins
Carbohydrates
Fats

30. Compare Fermentation, Respiration and Photosynthesis

31. Fermentation Respiration Glycolysis Only Occurs in Cytoplasm 2 ATP
Lactic Acid OR Ethanol
Glycolysis, Krebs Cycle, ETC
Cytoplasm and Mitochondria
ATP
CO2 AND H2O

32. Photosynthesis Respiration ATP formed by chemiosmosis Builds Glucose
Makes some ATP
Reactants:
CO2
H2O
Products:
C6H12O6 O2
ATP formed by chemiosmosis
Breaks down glucose
Aerobic and Anaerobic make ATP
Reactants:
C6H12O6 O2
Products:
CO2
H2O

33. Evolution of Energy Conversion
Anaerobic Respiration
Little ATP with NO O2
Small heterotrophic organisms
Aerobic Respiration
With O2
Lots of ATP
Allowed for more work; thus size increased

34. Evolution of Energy Conversion
Photosynthesis with PSI
Made little ATP/uses Sun’s Energy
no PSII, so no splitting H2O (cyclic electron transport)
No Calvin Cycle-so no sugar
Photosynthesis with PSII
Made ATP with Sun’s Energy
PS II (P680) enough energy to split H2O (release of O2) and non-cyclic electron transport
Calvin Cycle- produced sugars