1. Ch 7 Cellular respiration

2. What is the equation for photosynthesis?
What do plants need?
What do plants make?
If this is what plants do to make sugar… what do we do once we’ve eaten that sugar?
What do YOU need?
What do YOU make?

3. 7-1: Glycolysis and fermentation
Cellular respiration: complex process by which cells make ATP by breaking down organic compounds
Heterotrophs must do this to obtain energy
Do autotrophs?
Yup!

4. Overview

5. Overview
The products of photosynthesis are the reactants for cellular respiration
The products of cellular respiration are the reactants for photosynthesis

6. Cellular respiration A process with options
Glycolysis always happens first
What happens next depends on Oxygen
Or…
Oxygen present:
Aerobic respiration
Oxygen not present:
Anaerobic respiration

7. Page 132
Copy figure 7-2 in your notebooks. Be sure to include labels

8. Glycolysis 6-C Glucose broken into 2 3-C Pyruvic acid
In the process we invest:
2 ATP
In the process we create:
4 ATP
2 NADH
NADH? Familiar?
Another high energy electron shuttle
This is an ANAEROBIC process (?)
Does not require oxygen

9. What happens next depends on oxygen…
Aerobic respiration
If Oxygen present,
Pyruvic acid broken down to produce more NADH
NADH is used to make ATP
Anaerobic respiration (fermentation)
If oxygen is not present,
Pyruvic acid enters another cycle
Combination of glycolysis and anaerobic fermentation is called fermentation

10. Fermentation When oxygen is not present (anaerobic conditions)
Pyruvic acid converted to other compounds
In cytoplasm
Fermentation: Glycolysis + regeneration of NAD+
Does not produce ATP
Fermentation reproduces NAD+ so ATP can be gained through continual glycolysis
If NAD+ not regenerated  no glycolysis  no ATP

11. Alcoholic fermentation
Pyruvic acid converted to ethanol
yeast
bacteria
Bread
Wine, beer

12. Lactic acid fermentation
Pyruvic acid converted to Lactic acid
Cheeses
Yogurt
Cultivated dairy products
Makes muscles sore after strenuous workout

13. Review Glycolysis Fermentation (oxygen not present)
Glucose  2x pyruvic acid, 2 NADH, & 2 ATP
Fermentation (oxygen not present)
Alcoholic
Pyruvic acid  ethanol + NAD+, & CO2
Lactic acid
Pyruvic acid  lactic acid + NAD+

14. Aerobic respiration
Pathway of cellular respiration that requires oxygen
Produces 20 times more ATP than glycolysis alone
Two major stages (both occur in the mitochondria)
Krebs cycle
Electron transport chain

15. Mitochondria
Pyruvic acid (from glycolysis) diffuses into mitochondrial matrix
Krebs  Mit. Matrix
ETC  Inner membrane

16. Before krebs Pyruvic acid converted to acetyl CoA in matrix
Releases CO2
Creates NADH

17. Krebs cycle Acetyl CoA combines with oxaloacetate to form citric acid
Citric acid is broken down two times
Each time we break off a piece from citric acid, we make:
CO2, NADH, and FADH2 (same function as NADH)

18. So far we have made… A bunch of high energy electron carriers
NADH (glycolysis and krebs)
FADH2 (Krebs)
A little ATP (glycolysis[2] and krebs[2])
CO2 (krebs)
But the whole point of cellular respiration is to make ATP
So… now we turn to the……

19. Electron transport chain
Series of proteins that transfer electrons
Location: inner mitochondrial membrane
H+ and e- removed from NADH and FADH2 in the presence of O2 to make ATP

20. ETC H+ and e- removed from NADH and FADH2
e- moved through chain & lose energy
Energy used to pump H+ from matrix into inner membrane space
Creates concentration gradient of H+ across inner mebrane
Gradient used to make ATP as H+ move through ATP synthase
O2 is final e- acceptor at end of ETC
e- + H+ +O2 = H2O

21. Importance of Oxygen
ATP can only be made as long as e- move through ETC
w/o oxygen, e- transport stops

22. Efficiency of aerobic respiration
Number of ATP produced in Aerobic vs anaerobic respiration:
Aerobic respiration
Fermentation (anaerobic respiration)

23. Efficiency of aerobic respiration
Number of ATP produced in Aerobic vs anaerobic respiration:
Aerobic respiration
38 (glycolysis + krebs + ETC)
Fermentation (anaerobic respiration)
2 (glycolysis only)

24. Summary of cellular respiration
Draw figure 7-14 on page 143
Fill in table below
Reaction
Inputs
Outputs
Location
Gylcolysis
Pyruvic acid  acetyl CoA
Krebs
ETC

25. Anaerobic pathway:
Input
Output
Example organism
Lactic acid fermentation
Alcoholic fermentation