1. Photosynthesis and Cellular Respiration

2. Let’s Review
Matter is transferred among organisms in an ecosystem when organisms eat, or are eaten by others for food. 
How do organisms obtain energy from food?
All organisms, including plants, require food for survival

3. Cell Energy (Photosynthesis and Respiration)
Energy for living things comes from food. Originally, the energy in food comes from the sun.

4. Review
Energy can change from one form to another in living things. Animals get energy from oxidizing their food, releasing some of its energy as heat. Almost all food energy comes originally from sunlight.

5. Review Continued
Chemical energy is transferred from one organism in an ecosystem to another as the organisms interact with each other for food.

6. Review
The atoms that make up the organisms in an ecosystem are cycled repeatedly between the living and nonliving parts of the ecosystem. 

7. Review
As in all material systems, the total amount of matter remains constant, even though its form and location change.

8. Two ways to get food “troph” = food Autotrophs Heterotrophs
Auto = self
Autotrophs make their own food
Heterotrophs
Hetero = different
Heterotrophs get their food from something else (they have to eat it)

9. Two ways to get food
Autotrophs
Plants
Heterotrophs
Animals

10. Photosynthesis

11. Photosynthesis
Converts the sun’s energy into chemical energy stored in sugar
Takes place in specialized structures inside plant cells called chloroplasts
Chlorophyll is the pigment that absorbs sunlight.

12. Photosynthesis Reaction
6CO2 + 6 H2O + light
energy → C6H12O6 + 6O2
The food plants make is called glucose (sugar)

13. Photosynthesis 2 different reactions Light Reactions Calvin Cycle
Capture light energy for photosynthesis
Calvin Cycle
Produces glucose sugar

16. Cellular Respiration
Cells
Breathing

17. Cellular Respiration
Cellular respiration is a process in which cells use oxygen to release energy stored in sugars.
Carbon dioxide is a waste product of cellular respiration. CO2 must then be removed from the cells.

18. Cellular Respiration
cellular respiration is the process by which stored chemical energy in substances is broken down and converted into energy that can be used by the cell.
cellular respiration takes place in the cell, specifically in the mitochondria of eukaryotic cells.

19. Cellular Respiration Happens in both plant and animal cells
Overall Reaction:
C6H12O6 + 6O2 → 6CO2 + 6H2O

20. Cellular Respiration Overview
Depends on whether or not there is oxygen
Aero = oxygen
Aerobic Respiration – makes energy
Anaerobic Respiration – Fermentation (makes alcohol)

21. Step 1: Glycolysis The energy that cells make and use is called ATP
Adenosine triphosphate
Glycolysis makes 2 molecules of ATP (energy)
Glycolysis happens in the cytoplasm of the cell

22. Step 2: Check for Oxygen
If oxygen is present, the cell can make more ATP
If no oxygen is present, the cell has to recycle the pieces from glycolysis and makes alcohol.

24. Step 3 with oxygen: Cellular Respiration
Oxygen required=aerobic
2 more sets of reactions which occur the cell’s mitochondria
1. Kreb’s Cycle – makes 2 ATP
Also called the Citric Acid Cycle
2. Electron Transport Chain – makes ATP

25. Kreb’s Cycle (Citric Acid Cycle)

26. Step 3 without oxygen: Fermentation
The cell must recycle the materials from glycolysis.
This recycling process is called fermentation.
The product of fermentation is alcohol.

28. Energy Tally 36 ATP for aerobic vs. 2 ATP for anaerobic
Glycolysis ATP
Kreb’s ATP
Electron Transport 32 ATP
36 ATP
Anaerobic organisms can’t be too energetic but are important for global recycling of carbon

31. Cells carry on the many functions needed to sustain life
Cells carry on the many functions needed to sustain life. They grow and divide (mitosis or meiosis), thereby producing more cells.
This requires that they take in nutrients, which they use to provide energy for the work that cells do and to make the materials that a cell or an organism needs.

32. Cells Continued
The way in which all cells function is similar in all living organisms. Within cells many of the basic functions of organisms, such as releasing energy from food and getting rid of waste, are carried out by different cell elements.

33. Mitosis: the state of the cell cycle during which the cell’s nucleus divides into two new cells
Meiosis: a type of cell division that results in four cells each with half the number of chromosomes