1. Cellular Respiration
Agriculture Biology

2. Why are photosynthesis and respiration important in agriculture?
Biomass is all plant and animal matter on the Earth's surface. Harvesting biomass such as crops, trees or dung and using it to generate energy such as heat, electricity or motion, is bioenergy.
Farmers try to maintain a 40:1 ratio of photosynthesis to respiration, thus increasing the amount of biomass stored by the plants.
More Biomass= More Energy

3. Why is Respiration Important?
Plants use oxygen in the air (or water) to turn their food (glucose) into energy. This process of using oxygen to release energy from food is called
cellular respiration

4. Interest Grabber What kind of organisms undergo cellular respiration?
All organisms including photosynthetic organisms, undergo cellular respiration as long as oxygen is present

5. Interest Grabber
How are the products of photosynthesis and respiration related?
The products of photosynthesis are the starting materials for respiration

6. Cellular Respiration
C6H12O6 + 6O2 6CO2 + 6H2O + Energy (ATP)

7. Cellular Respiration

8. Photosynthesis vs. Respiration
Food synthesized (made)
Energy from sun stored in glucose
CO2 taken in
Oxygen given off
Produces sugars
Requires light
Occurs only in the presence of chlorophyll
Respiration
Food broken down
Energy in glucose released
CO2 given off
Oxygen taken in
Produces CO2 and H2O
Does not require light
Occurs in all living cells

9. Chemical Pathways Cells don’t “burn” glucose
They gradually release the energy from glucose and other food compounds
The process begins with a pathway called GLYCOLYSIS.
Glycolysis releases only a small amount of energy (net yield of 2 ATP)

10. Glycolysis Process in which one molecule of glucose is broken in half
Occurs in the cytoplasm of the cell
This is an anaerobic process
Produces two molecules of pyruvic acid
A 3 carbon compound

11. Glycolysis At the pathway’s beginning, 2 molecules of ATP are used up
These 2 molecules should be looked at as an “investment”
Gives the cell 2 net ATP molecules

12. Glycolysis This process seems like it doesn’t create very much energy
But…the cells are able to finish the process so fast, that they can create thousands of ATP molecules in just a few milliseconds

13. Interest Grabber
Some of the steps in cellular respiration take place in the membrane inside the cell structure called the mitochondrion, which has a folded inner membrane. What purpose do these folds serve?
To find out the answer to this question, perform this activity.

14. Interest Grabber
Obtain two sheets of paper and a metric ruler. What is the surface area of the paper?
Roll one sheet of paper into a tube lengthwise. What is the surface area of the rolled paper?
Fold the second sheet of paper into a fan. Then, roll the first sheet of paper around the folded paper so it is inside the rolled paper. What has happened to the surface area of the inside of the rolled paper?
What would be the value of increasing the surface area of the membrane inside a mitochondrion?

15. The Krebs Cycle
In the presence of oxygen, pyruvic acid produced in glycolysis passes to the second stage of cellular respiration
The Kreb’s Cycle (also known as the Citric Acid Cycle) occurs in the mitochondria of the cell
Named after Hans Krebs
1937; he discovered the details of what is now known as the Krebs Cycle

16. Krebs Cycle During the Krebs cycle the following occurs
Pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions
NADH, FADH2, CO2 and ATP
A total of 2 ATP are created from this stage

17. Krebs Cycle Every time you exhale, carbon dioxide is released
This carbon dioxide is produced by the Krebs Cycle
The ATP produced is used for cellular activities

18. Electron Transport
Electrons passed around during the Krebs Cycle to the electron transport chain
The electron transport chain uses the high-energy electrons from the Krebs Cycle to convert ADP into ATP
A total of 32 ATP are created in the mitochondria during this stage of resp.

19. Electron Transport Chain

20. Fermentation
If oxygen is not present, glycolysis is followed by a different pathway
The combined process of this pathway and glycolysis is called FERMENTATION
Fermentation releases energy from food molecules in the absence of oxygen

21. Fermentation There are two types of fermentation
Alcoholic Fermentation
Lactic Acid Fermentation

22. Alcoholic Fermentation
Produces carbon dioxide and ethyl alcohol as wastes
This is what is produced when yeast is used to make bread
When the yeast in the dough runs out of air, it begins to ferment and produces bubbles of carbon dioxide to rise the dough
Pyruvic Acid + NADH = Alcohol + CO2 + NAD+

23. Lactic Acid Fermentation
Produces lactic acid and NAD+ as wastes
Produced in your muscles during rapid exercise when the body cannot supply enough oxygen to the tissue
Pyruvic Acid + NADH = Lactic acid and NAD+

24. Quick Energy vs. Long Term Energy
The body provides enough ATP to last about 90 seconds-Quick Energy
Enough time for a runner to finish a meter dash
Fermentation produces lactic acid as a by product
Getting rid of lactic acid requires oxygen
Thus a runner breathes heavily at the end of the race to rid the muscles of lactic acid that built up

25. Quick Energy vs. Long Term Energy
How about when you need energy for a long time?
The body relies on cellular respiration to release energy more slowly
This is why athletes must pace themselves over a long race---why?
To allow oxygen to fuel the process of cellular respiration and make more ATP!!!