1. Cellular Respiration Objectives
1. Define Cellular Respiration
2. Identify the two major steps of cellular respiration
3. Compare lactic acid fermentation with alcoholic fermentation
4. Summarize the steps of aerobic respiration

2. Cellular Respiration
First and foremost: IT IS NOT THE SAME AS BREATHING!!!
ALL living things must undergo cellular respiration in order to use their food (even plants)
This is a complicated process that breaks the chemical bonds of carbohydrates to release the energy

3. It can be broken down into 2 basic steps:
1. Glycolysis
2. Respiration (2 types)
Aerobic respiration (with Oxygen) or
Anaerobic (without Oxygen) respiration

4. 1. Glycolysis
Glycolysis is the breakdown of carbohydrates made in photosynthesis
This happens in the cytoplasm of our cells
The 6 Carbon sugar made in photosynthesis is broken into two 3 carbon molecules called Pyruvic acid

5. In the process, 2 ATP molecules are produced
-The pyruvic acid moves onto the next step
-But first, the cell must determine whether or not Oxygen is present

6. Chemiosmosis 4 ATP ADP Pyruvic Glycolysis Acid formed 2 carbohydrates
from
photosynthesis
Pyruvic
Acid formed
Glycolysis

7. A choice must be made…
If Oxygen IS present then the cell performs Aerobic Respiration
If Oxygen IS NOT present, then the cell performs Anaerobic Respiration

8. Anaerobic Respiration
When there is NO Oxygen available, a cell still needs energy so it must take a different route to make it
Anaerobic respiration is called fermentation
It has two directions to choose from:
1. Lactic Acid Fermentation
2. Alcohol Fermentation

9. Lactic Acid Fermentation
In Lactic acid fermentation, Pyruvic acid is converted into lactic acid
This occurs naturally in some foods like milk
When it is controlled we can use it to produce sour cream, yogurt, cheese & buttermilk
Lactic acid is also produced in our bodies during time of strenuous exercise

10. You experience soreness, fatigue & sometimes muscle cramping
The liver converts it back to pyruvic acid, which is then taken back to the cells

11. Sour cream, yogurt & buttermilk Liver converts Back to Pyruvic acid
Pyruvic acid formed
Sour cream, yogurt & buttermilk
Liver converts
Back to
Pyruvic acid
Anaerobic
Pathway
Pyruvic acid is
Converted to
Lactic acid
Lactic Acid
fermentation

12. Alcoholic Fermentation
In this form of respiration, pyruvic acid is converted to ethyl alcohol
Single celled fungal organisms called yeast perform alcoholic fermentation
Beer, & the baking industry & Alcohol fuels are produced this way

13. Liver converts back to pyruvic acid
Ethyl Alcohol
Fermentation
Pyruvic acid
Is converted to
Ethyl alcohol
CO2 waste
Beer, wine
Fuels, baking