1. Photosynthesis and Cellular Respiration
Chapter 5

2. 5.1 Energy and Living Things
Remember: Metabolism is either the energy used to build molecules or the release of energy by breaking down molecules

3. Photosynthesis Turn light energy into chemical energy
Autotrophs – make their own food
Most are photosynthetic
Some are chemosynthetic (get energy from inorganic compounds)

4. Cellular Respiration Get energy from food
Heterotrophs – must ingest energy
Produces ATP

5. Transfer of Energy to ATP
Energy from food released gradually in a series of enzyme-assisted chemical reactions
Product of 1 reaction becomes the reactant in the next reaction
Some energy is released as heat
Most energy is stored in ATP which can deliver it where it is needed

6. How ATP Works (Yes, again)
ATP = Adenosine Triphosphate
3 negative phosphates repel each other
Energy released when bonds break
Produces ADP = adenosine diphosphate

7. Can be reversed back into ATP
If a 2nd phosphate is broken off = irreversible
Water is used in breaking
H2O + ATP = ADP + P + ENERGY

8. Photosynthesis Stages of Photosynthesis
First 2 are called Light Dependent Reactions
Stage 1: Energy is captured from sunlight
Stage 2: Light energy is changed to chemical energy
Chemical energy stored temporarily in ATP and a carrier molecule called NADPH
Stage 3 is called Light Independent or Dark Reactions
Energy in ATP and NADPH powers the formation of organic compounds using CO2

9. Where does all of this take place?
In the chloroplasts of plant cells and algae and in the cell membrane of certain prokaryotes
6CO2 + 6H2O light> C6H12O6 + 6O2
Carbon dioxide and water make sugars and oxygen with the help of light energy
Some sugars form starch and are stored in stems and roots
These can be broken down later to make ATP
Sugars break down and make proteins, nucleic acids, and others

10. Stage 1 Absorption of Light Energy (Light Dependent)
Light is a form of radiation
Pigments are light absorbing substances
But they only absorb certain wavelengths
Chlorophyll is the primary pigment
Absorbs mostly blue and red
Reflects green and yellow which is why we see them as these colors

11. A few different kinds Chlorophyll a Chlorophyll b Carotenoids
Yellow and orange reflecting pigments
Absorb different wavelengths than chlorophyll

12. 5.3 Cellular Respiration
You eat food and the chemical energy is transferred to ATP
This is called Cellular Respiration
This is much more efficient with Oxygen and this is called Aerobic
When no Oxygen it is called Anaerobic

13. Cellular Respirations Formula
C6H12O6 + 6O2 enzymes> 6CO2 + 6H2O + energy (ATP)
How does it compare to the equation for Photosynthesis?

14. Respiration in the Absence of Oxygen
38 ATPs can be made if there is Oxygen
Only 2 ATPs when oxygen is absent
When no oxygen is present we have fermentation

15. Lactic Acid Fermentation
During strenuous exercise when oxygen has run out, a chemical (pyruvate) in muscles is converted to lactate
If this is not removed quickly it can build up in muscles and cause soreness

16. Alcoholic Fermentation
In other organisms the pyruvate is instead turned into ethanol
Used by yeast and fungi to make wine, beer, and bread