1. Photosynthesis and Cellular Respiration

3. Photosynthesis
Process by which plants and some other organisms use light energy to produce food
Autotrophs- organisms that make their own food
Photosynthesis- uses light
Chemosynthesis- uses chemicals

4. Heterotrophs Can not make their own food
Must eat autotrophs or other heterotrophs for energy or are decomposers

5. Adenosine Triphosphate (ATP)
Both autotrophs and heterotrophs store energy as ATP
                                               

6. ATP W= adenine (a nucleotide) X= ribose (5-carbon sugar)
Y= phosphate (there are 3 phosphate groups)
Z= high energy bond
When the cell needs energy, it breaks a bond between two phosphates
Energy is released and ADP is created

7. History of Plant Nutrition
Priestley In 1700’s discovered that plants could grow in a closed container and support a flame and an animal
Lavoisier discovered that the animals and flame required oxygen, while the plants gave off oxygen
Ingenhousz discovered that plants give off oxygen only in sunlight
By the 1800’s it was known that plants require carbon dioxide, light, water

8. Photosynthesis (Introduction)
Process of capturing energy of sunlight and transforming it into chemical energy
Plants use CO2 and H2O to produce O2 and glucose
Plants produce most of the atmosphere’s oxygen

9. Light Energy Sunlight travels in waves
Wavelength is the distance between the crests (or troughs) of two waves

10. Light Energy (continued)
Sunlight is a mixture of different wavelengths (visible spectrum)
Each wavelength contains different amounts of energy
Pigments are chemicals in plant cells that absorb this energy

11. Photosynthetic Pigments
Chlorophylls-
Chlorophyll a- primary pigment that absorbs light
Chlorophyll b- absorbs light and transfers it to chlorophyll a
Carotenes and Xanthophylls also absorb different wavelengths of light
They are responsible for the autumn colors

12. Chloroplasts
Organelles containing membranes which hold photosynthetic pigments
Membranes are in the shape of flattened sacs called thylakoids
Stacks of thylakoids are grana
Stroma is the area between grana

13. Light Reactions Photosynthesis occurs in many small steps
The light reactions occur in the grana
Light is absorbed by chlorophyll
The light energy excites electrons and they pass through a series of reactions (electron transport chain)
Water is broken down and oxygen is released as a waste product
ATP and NADPH (contain energy) are produced

14. Dark Reactions Occur in the stroma Can occur with or without light
CO2 is used to make glucose- this is carbon fixation
Series of reactions called the Calvin Cycle
The energy needed for this series of reactions comes from the ATP and NADPH made in the light reactions
6 CO2 molecules are needed to make 1 glucose molecule

15. Photosynthesis Equation
6 CO2 + 6 H2O → C6H12O6 + 6O2
light
Carbon + water → glucose + oxygen +
dioxide water
In the presence of light, chlorophyll and enzymes

16. Factors Affecting Photosynthesis
Light Intensity
Water availability
Mineral availability
Temperature- too hot or cold damages enzymes

17. Cellular Respiration Energy- the ability to do work
Living organisms need energy to perform life functions
Living organisms get energy from food
Food is broken down and most of the energy is stored as chemical energy
Some is released as heat energy, which maintains body temperature

18. Cellular Respiration- Overview
The process of breaking down food in the cell and releasing the energy
Takes place in many small steps
Many ATP molecules are formed from 1 molecule of glucose

19. Glycolysis
Occurs as the first step of cellular respiration in ALL cells, even ones that go on to aerobic cellular respiration
Glyco –glucose
Lysis – to break

20. Anaerobic Respiration
Occurs without oxygen
Not as efficient as aerobic (requires oxygen)
Not as many ATP produced

21. Glycolysis- The first step in Cellular Respiration
Takes place in the cytoplasm
2 ATP molecules are needed to start the process
2 phosphate groups attach to a glucose molecule
Glucose then goes through a series of reactions
Glucose becomes PGAL and then pyruvic acid
1 glucose molecule becomes 2 pyruvic acid molecules

22. Glycolysis (continued)
2\2 NADH2 (an electron acceptor) which produce 4 ATP, are produced
2 ATP were used up to start the process, so there is a net gain of 2 ATP

23. Fermentation No more ATP are produced!
The pyruvic acid from glycolysis is converted to another compound

24. Two Types of Fermentation
Alcoholic Fermentation-
Ethyl alcohol and carbon dioxide are produced
Makes alcohol and the carbon dioxide makes bread rise
Occurs in yeast cells and some bacteria

25. Fermentation (continued)
Lactic Acid Fermentation-
Lactic acid is formed
Occurs in human muscle cells

26. Aerobic Respiration Much more efficient than anaerobic
Starts with glycolysis
Pyruvic acid moves from the cytoplasm into the mitochondria
The pyruvic acid is broken down into CO2, NADH2, and a 2 carbon compound called acetyl CoA

27. Krebs Cycle (Citric Acid Cycle)
Is a repeating cycle
Starts with 1 molecule of acetyl CoA
Acetyl CoA moves through a series of reactions, yielding 1 ATP, 3 NADH2, 1 FADH2 , 2 CO2
1 molecule of glucose produces 2 turns of the Krebs Cycle

28. Electron Transport Chain
Last step of aerobic cellular respiration
The energy in FADH2 and NADH2 needs to be converted into ATP
This is done in a series of reactions called the electron transport chain
It occurs in the mitochondria
Oxygen is the final electron acceptor!!
Oxygen combines with 2 H to form water

29. Total ATP Produced Each NADH2 produces 3 ATP Each FADH2 produces 2 ATP
The net amount of ATP produced in aerobic cellular respiration-
Glycolysis- 2 ATP
Krebs ATP
Glycolysis- 2 NADH2 x 2 ATP/ NADH2 =4 ATP
Pyruvic Acid breakdown- 2 NADH2 x 3=6 ATP
Krebs- 6 NADH2 x 3= 18 ATP
2 FADH2 x 2= 4 ATP
36 ATP are produced in aerobic cellular respiration from 1 molecule of glucose!!
Krebs cycle animation

30. Krebs (or citric acid) Cycle

31. Cellular Respiration Equation
C6H12O H2O + 6 O2→ 6 CO2 +
12 H2O + Energy (36 ATP)
Glucose + water + oxygen →
carbon dioxide + water+ 36 ATP
This is a very efficient process!!

32. Respiration of Fats and Proteins
Cells can break down fats and proteins to produce ATP
Fats produce twice as much ATP as glucose
Proteins produce the same number of ATP as glucose, but the breakdown of proteins is not preferred by cells

33. Comparing Aerobic and Anaerobic Respiration
2 ATP produced
NO oxygen needed
Products are- lactic acid, alcohol, CO2, ATP
Aerobic
36 ATP produced
Oxygen IS needed
Products are- CO2, H2O, 36 ATP

34. Comparing Photosynthesis and Cellular Respiration
Where
Chloroplasts
Mitochondria
Reactants
H2O, CO2, light
Glucose, O2, H2O
Products
CO2, H2O, energy (36 ATP)
Function
Energy storage
Energy release
Equation
Know it!!