1. Cell Energy: Photosynthesis & Respiration

2. Autotroph or Heterotroph? Why?
How does it make its own food?
PHOTOSYNTHESIS

3. Overview of Photosynthesis and Respiration
Photosynthesis –Use sunlight to make carbon compounds (food)
Cellular Respiration – Turns the food into ATP (energy)
Autotrophs Photosynthesis and Cellular Respiration Why both? Because autotrophs have to make their food first and then break it down.
Heterotrophs
Cellular Respiration

4. How Does a Plant Make It’s Own Food?
Plants use carbon dioxide (CO2), water (H2O), and sun’s energy to make food.
This is called “photosynthesis”
The food gives plants energy
Animals get the energy stored in plants when they eat them.

5. What “Food” do Plants Make?
The “food” plants make is a sugar called glucose (C6H12O6).
Glucose and oxygen (O2) are made during photosynthesis.

6. The Stages of Photosynthesis
1. Energy is captured from sunlight on the chloroplast. 2. Light energy is converted to chemical energy through the electron transport chain. 3. The chemical energy in ATP and NADPH powers the formation of organic compounds (food) using carbon dioxide.

7. Stage One “Light Reactions”
Leaves contain light-absorbing substances called pigments located in the chloroplast.
Chlorophyll is the primary pigment used.
Why is it green?
It absorbs mostly blue and red light and reflects green and yellow.
Pigments are stored in thylakoids.

8. Stage One: Light Reactions
What Happens? Light strikes a thylakoid in a chloroplast, energy is transferred to the electrons in the chlorophyll. The electrons jump to a higher energy level and are said to be “excited”.

9. Stage Two: Electron Transport Chain
The series of molecules through which excited electrons are passed along a thylakoid membrane are called Electron Transport Chains.
What Happens:
3. The electron moves down the chain and makes NADPH which carries the electron to the next stage.
The excited electrons cause hydrogen to come into the thylakoid.
2. This sets up a concentration
gradient of Hydrogen that provides the energy to make ATP.

10. Stage 3: Calvin Cycle
ATP, NADPH and carbon dioxide are used to make carbon compounds (food)
What Happens?
Calvin Cycle- a series of enzyme-assisted chemical reactions that produces a three-carbon sugar (food).

11. What affects photosynthesis?
Light Intensity
Temperature
Carbon Dioxide Concentration
Water Availability

12. REVIEW
What are the three stages of photosynthesis and what do they do?
1. Light reactions
Captures sunlight
2. Electron Transport Chain
Makes ATP (stored energy) and NADPH (electron carrier)
3. Calvin Cycle
Uses CO2 , ATP and NADPH to make carbon compounds (food)

13. Photosynthesis and Cellular Respiration
Which processes do plants cells perform?
Both
Why?
Make food, then make energy
Which processes do animal cells perform?
Just cellular respiration.

14. How Do Organisms Get Energy From Food?
Animals cannot make their own food like plants can.
But, BOTH plants and animals must break down (digest) food in order to get energy from it (so they can live, grow, & develop)
Where does this happen?
In the Mitochondria

15. Aerobic Cellular Respiration
Aerobic vs. Anaerobic
Metabolic processes that require oxygen are called Aerobic.
Metabolic process that DO NOT require oxygen are called Anaerobic.
Most eukaryotes (ex. Plants and animals) get their energy through aerobic cellular respiration.
Aerobic Cellular Respiration
oxygen (O2) to break down food
Cellular respiration releases more energy from food than Fermentation.
Fermentation
does not use oxygen
Produces lactic acid and alcohol

16. Process of Cellular Respiration
Food (glucose) is broken down into CO2 and H2O and energy is released
C6H12O6 + 6 O2  6 CO2 + 6 H2O + energy (ATP)
This energy can be used for:
Keeping a constant body temperature
Storage (ATP) - to be used later for things like growth

17. Stages of Cellular Respiration
1. Glycolysis 2. Krebbs Cycle and Electron Transport Chain Or 2. Fermentation

18. Glycolysis
The primary fuel for cellular respiration comes form glucose (from food)
Enzymes break down glucose into 2 pyruvates (3 –carbon molecule)
Result- 2 NADH molecules and 2 ATP molecules produced.

19. Krebs Cycle (with oxygen)
When oxygen is present, pyruvate enters the mitochondrion and is converted to NADH and acetyl-CoA
Acetyl-CoA goes through the Krebs cycle in enzyme assisted reactions produces NADH and FADH2
Energy is stored in the form of electrons in NADH and FADH2

20. Electron Transport Chain (with oxygen)
Electrons donated by NADH and FADH2 pass through the electron transport chain.
Electrons cause Hydrogen ions to accumulate on the outside of the membrane.
Hydrogen ions diffusing back in create ATP (stored energy)

21. What Do You Notice?

22. Check It Out!
Did you notice that cellular respiration is just the opposite of photosynthesis?
Cellular Respiration

23. The Relationship Between Photosynthesis and Cellular respiration

24. Fermentation
Happens when cells cannot get the oxygen they need for aerobic cellular respiration
Fermentation is a way to get energy when NO oxygen is available
Lactic Acid Fermentation
In short, fast races you might get a burning feeling in you leg muscles because of a build up of lactic acid (made during fermentation)
Alcoholic Fermentation
Alcoholic fermentation by yeast, a fungus, is used in the preparation of wine and beer.

25. Aerobic Respiration vs. Fermentation
Aerobic Respiration produces 38 ATP
Anaerobic/Fermentation produces 2 ATP

26. Review Create a concept map with the following words:
Cellular respiration, glycolysis, with oxygen, without oxygen, krebs cycle, electron transport chain, fermentation, lactic acid fermentation, alcoholic fermentation