1. Photosynthesis and Cellular Respiration Biology I K. Beris

2. GPS Standard: SB3a
Students will derive the relationship between single-celled and multi-celled organisms and the increasing complexity of systems.
Explain the cycling of energy through the processes of photosynthesis and respiration.

3. Essential Question:
What is the purpose of photosynthesis in plants and cellular respiration in animals?

4. Autotrophs and Heterotrophs
Where does the energy that living things need come from?
From the food we eat
Originally, the energy in most food comes from the sun.
Plants and some other types of organisms are able to use light energy from the sun to produce food.
Autotrophs make their own food
Heterotrophs obtain energy from the foods they consume
Decomposers obtain food by decomposing other organisms

5. Autotrophs and Heterotrophs, cont.
In order to live, all organisms, including plants, must release the energy in sugars and other compounds.
They get this energy through the stored energy in ATP.
Remember…ATP  ADP  AMP

6. Photosynthesis
Photosynthesis is a series of reactions that uses energy from the sun to convert water and carbon dioxide into sugars and oxygen.
The overall equation for photosynthesis can be shown as
sunlight + 6 CO2 + 6 H2O  C6H12O6 +6 O2
THIS MEANS THAT DURING PHOTOSYNTHESIS:,
SUNLIGHT + 6 CARBON DIOXIDE + 6 WATER MAKES SUGAR + 6 OXYGENS

7. Chlorophyll
Chlorophyll is the principal pigment of plants and other photosynthetic organisms.
It captures light energy in plant cells.
There are two main types
Chlorophyll a (absorbs light in the violet and red regions of the visible spectrum)
Chlorophyll b (absorbs light in the blue and red regions of the visible spectrum)

8. Light Dependent Reactions
The light dependent reactions of photosynthesis use energy from the sunlight to produce ATP, NADPH (electron carrying molecule), and oxygen. These reaction take place in the thylakoid membranes of the chloroplasts.
As the name signifies, these reactions must occur in the light.

9. The Calvin Cycle
The Calvin cycle uses ATP and NADPH to produce high-energy sugars. The Calvin cycle takes place in the stroma of chloroplasts and does not require light.
This is called the Dark reaction.

10. Cellular Respiration 6 O2 + C6H12O6  6 CO2 + 6H2O + ENERGY
Cellular respiration is the process that releases energy by breaking down food molecules in the presence of oxygen.
The equation for cellular respiration is:
6 O2 + C6H12O6  6 CO2 + 6H2O + ENERGY
THIS MEANS THAT
6 OXYGEN + GLUCOSE MAKES 6 CARBON DIOXIDE + 6 WATER + ENERGY
CELLULAR RESPIRATION BASICALLY OCCURS IN THE MITOCHONDRIA OF THE CELL. GLYCOLYSIS, A PRECURSOR OF RESPIRATION, TAKES PLACE IN THE CYTOPLASM OF THE CELL.

11. Comparing Photosynthesis to Respiration
Plants use the products of respiration for their reactants
Animals use the products of photosynthesis for their reactants
For example, in photosynthesis
(reactants) 6CO2 + 6H2O + SUNLIGHT  C6H12O6 + 6 O2 (products)
(reactants) C6H12O6 + 6 O2  6CO2 + 6H2O + ENERGY (ATP) (products)

12. Fermentation
In the absence of oxygen in cellular respiration, fermentation releases energy from food molecules.
During this process, a constant supply of ATP is supplied.
There are two main types of fermentation:
Alcoholic fermentation
Lactic acid fermentation

13. Alcoholic Fermentation
Used by yeasts and other microorganisms to form ethyl alcohol and carbon dioxide as wastes
Used in baking to cause bread dough to rise

14. Lactic Acid Fermentation
Lactic acid is produced in your muscles during rapid exercise when the body cannot supply enough oxygen to the tissues.
Without enough oxygen, the body is not able to produce all of the ATP that is required.
The buildup of lactic acid causes a painful, burning sensation. This is why muscles may feel sore after only a few seconds of intense activity.