1. What is Cellular Respiration?
Once the energy that was in sunlight is changed into chemical energy by photosynthesis, an organism has to transform the chemical energy, glucose, into a a form that can be used by the organism.
This process is cellular respiration.

2. Cellular Respiration
Cells break down simple food molecules and release energy.
The process by which cells use oxygen to produce energy from food (glucose).

3. Respiration is in many respects
Energy flow & Chemical Cycling in the Biosphere
Sunlight
energy
Ecosystem
Photosynthesis
(in chloroplasts)
Respiration is in many respects
the reverse
of Photosynthesis
Glucose
Carbon dioxide
Oxygen
Water
Photosynthesis
Build up
Cellular respiration
(in mitochondria)
Respiration
Break down
for cellular work
Figure 6.3
Heat energy

4. Cellular Respiration Respiration IS NOT Ventilation =breathing
Lungs
Muscle
cells
Cellular
respiration

5. EQUATION FOR RESPIRATION
CARBON DIOXIDE
ATP
GLUCOSE
C6H12O6 +
6O2
6CO2 +
6H2O +
ENERGY
OXYGEN
WATER

6. Two Stages of Respiration
1st stage – takes place in cytoplasm
Glucose broken down into smaller molecules
No O2 is involved
Not much energy

7. Two Stages of Respiration
Takes place in mitochondria
Small glucose molecules made even smaller
Requires O2
Great amount energy
Powerhouse

8. Stages of Respiration Glucose O2 Mitochondria Cytoplasm Sm. Mole. H2O
Energy
Sm. Mole.
Energy
CO2 O2
Mitochondria
Cytoplasm

9. Comparing Photosynthesis and Respiration
The equations for Photo and Resp. are OPPOSITE!
Form a cycle that keeps the levels of CO2 and O2 fairly constant

10. Energy flow and Chemical Cycling in the Biosphere
Sunlight
energy
Ecosystem
Photosynthesis
(in chloroplasts)
Carbon dioxide
Oxygen
Glucose
Respiration
in many respects is the reverse of
Photosynthesis
Water
Respiration (in mitochondria)
Cellular respiration
(in mitochondria)
for cellular work
Heat energy
Figure 6.3

11. Fermentation Some cells obtain energy without using O2
Fermentation provides energy for cells without O2
Energy from each sugar molecule is much lower than Respiration

12. Fermentation in Microorganisms
Various types of microorganisms perform fermentation
Yeast cells carry out a slightly different type of fermentation pathway
This pathway produces CO2 and ethanol
Glucose  ATP + CO2 (g) + EtOH

13. Alcoholic Fermentation
Occurs in yeast and some other single celled organisms.
Alcohol is a product that is made when these organisms break down sugar
Important to brewers and bakers.

14. Lactic Acid Fermentation
Takes place in the body
Muscle cells use up O2 faster than it can be replaced
Cells lack O2 – fermentation occurs

15. A Harvest of Light: Photosynthesis
Life on Earth is solar powered