1. Cellular Respiration
Unit 3 – Lecture 10

2. Cellular Respiration
Cellular Respiration: process used by all living organisms to make energy in the form of ATP.
Equation: C6H12O6 + O2  E + H2O +CO2
for eukaryotic organisms, this takes place in the mitochondria

3. Cellular Respiration – cont’d
Two Kinds:
Aerobic: describes a process that requires oxygen
[Krebs Cycle & ETC]
Anaerobic: describes a process that does not require oxygen
[Glycolysis & Fermentation]

4. Cellular Respiration – cont’d
Aerobic Respiration AND Anaerobic respiration BOTH start with Glycolysis
Glycolysis: breaks down glucose [6-carbons] to form pyruvate [3-carbons]
glyco – refers to glucose [remember glycogen?]
lysis – to break down
takes place in the cytoplasm

5. Glycolysis
ATP used to break glucose [6-C] into two, 3-Carbon molecules

6. Glycolysis – cont’d additional phosphates added to 3-C molecules
makes NADH + H [similar to NADPH except without the phosphate]
NADH = electron carrier
NADH + H goes to the ETC of CR

7. Glycolysis – cont’d
3-C molecule is stripped of extra phosphates by other ADP molecules to form two pyruvate molecules
pyruvate = another 3-C molecule

8. Glycolysis – cont’d TO SUM UP: three products of Glycolysis =
ATP [little bit – 2 molecules!]
NADH +H
Pyruvate

9. Aerobic CR
[begins with Glycolysis anyway, even though that does not require oxygen]
Krebs Cycle: produces CO2 and H2O from the pyruvate & NADH+H [made in glycolysis]
takes place inside of the mitochondrial matrix.
Electron Transport Chain
takes place at inner membrane

10. Krebs Cycle aka Citric Acid Cycle
pyruvate from Glycolysis becomes a 2-carbon compound by releasing CO2

11. Krebs Cycle – cont’d that 2-C compound goes through changes which
produce ATP [from ADP+P]
produce NADH +H (electron carrier) to be used later in ETC of Cellular Respiration
remember – Photo- synthesis has NADPH [both have the ‘P’]; CR has NADH [no P]

12. Krebs Cycle – cont’d that 2-C compound goes through changes which
produce FADH2 (another e- carrier) to be used later in the ETC of Cellular Respiration]
this repeats over and over…

13. Krebs Cycle – cont’d TO SUM UP: products of Krebs = CO2
ATP [little bit – 1 molecule!!]
filled e- carriers
FADH2
NADH +H

14. ETC
e-s from FADH2 and NADH [from Glycolysis & Krebs] move down proteins in membrane
creates NAD+
e-s pass through the ETC, releasing E [like in photo- synthesis]
NAD+
Glycolysis & Krebs

15. ETC – cont’d
this moves H+ ions through ion pumps, forming a gradient of charge & concentration [electrochemical gradient] in the inter- membrane space
NAD+
Glycolysis & Krebs

16. ETC – cont’d
oxygen combines with the e-s & H from the carriers to make water
opposite of ETC in photo- synthesis where we split water with the E… we form it here!
H2O
NAD+
Glycolysis & Krebs

17. ETC – cont’d
H+ ions funnel through the ATP Synthase to make ATP from ADP+P
32-36 molecules!!!
ATP
Synthase
H2O
NAD+
ADP + P
Glycolysis & Krebs

18. ETC – cont’d Processes: ETC Chemiosmosis – ATP Synthesis ATP H2O NAD+
ADP + P
Glycolysis & Krebs
ETC
Chemiosmosis

19. Anaerobic Respiration
[begins with Glycolysis]
Fermentation: recycles the products from glycolysis [pyruvate and NADH+H] if there is no oxygen
no ATP made here
takes place in the cytoplasm of the cell

20. Fermentation can take two forms: lactic acid fermentation
pyruvate from Glycolysis  lactic acid
uses NADH, producing NAD+
NAD+ then goes back to Glycolysis
lactic acid builds up in your tissues
[makes you sore!]

21. Fermentation – cont’d can take two forms: alcoholic fermentation
pyruvate from Glycolysis into ethanol [drinking alcohol]
releases CO2
uses NADH, producing NAD+
NAD+ then goes back to Glycolysis
this is how alcohol is made & bread rises [yeast], and how how yogurt, cheese & sour cream are made [bacteria&fungi]

22. ATP Production If Oxygen Present = Aerobic Respiration [Glycolysis]
Glucose in
2 ATP out

23. ATP Production If Oxygen Present = Aerobic Respiration [Glycolysis]
Krebs Cycle
Oxygen in
CO2 out
1 ATP out

24. ATP Production If Oxygen Present = Aerobic Respiration [Glycolysis]
Krebs Cycle
ETC
Oxygen in
Water out
LOTS of ATP out [32-36]

25. ATP Production – cont’d
If no Oxygen Present = Anaerobic Respiration
[Glycolysis]
Fermentation
If no Oxygen present, only Glycolysis makes ATP.
[questions follow]

26. Where does glycolysis take place?
Where does the Krebs Cycle take place?
Where does the ETC take place?
Where does fermentation take place?
What are the folds in the inner membrane called?
Why is the inner mitochondrial membrane folded into cristae?

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