1. Photosynthesis & Cellular Respiration

2. Characteristics of Life Review
Living things need energy to survive
Organisms get energy through a series of chemical reactions
Chemical Reactions – the forming and breaking of chemical bonds
Reactants Products
Metabolism – all of the chemical reactions occurring in an organism

3. Chemical Reactions for Energy
Photosynthesis – changes the sun’s energy to sugar
Cellular Respiration – changes the energy in sugar into usable energy for organisms (ATP)

4. Ecology Review Primary source of energy is sunlight
Autotrophs/Producers – organisms that use the energy in sunlight to make their own food
Example: Plants (grass, flowers, trees), Moss, Algae

5. Ecology Review cont’d
Heterotrophs/Consumers – Organisms that cannot make their own food and must eat to get energy
Herbivores – eat plants
Carnivores – eat animals
Omnivores – eat plants and animals
Decomposers – breakdown dead plants and animals

6. Chemical Energy and ATP
Energy comes in many forms
Light
Heat
Electricity
Chemical
Living things use chemical compounds to store and release energy
ATP (Adenosine Triphosate) - one of the main chemical compounds that cells use to store and release energy
ATP

7. Chemical Energy and ATP
ATP consists of:
Adenine
Ribose
3 phosphate groups
Adenine
3 Phosphate Groups
Ribose

8. Chemical Energy and ATP
STORING ENERGY
Adenosine diphosphate (ADP) – has two phosphate groups instead of three
When a cell has energy is available, it will store it in a chemical bond by adding third phosphate
ADP + 1 phosphate
ATP

9. ADP ---> ATP

10. Chemical Energy and ATP
RELEASING ENERGY
All of the energy that is stored in that chemical bond between the second and third phosphate is released when that bond is broken.

11. What is ATP? Let’s ask Bill Nye…

12. Photosynthesis – Let’s think…
What things do plants need to grow?
Water (H2O)
Carbon dioxide (CO2)
What do plants need to make?
Sugar/Glucose (C6H12O6)
What do plants give off as waste?
Oxygen (O2)

13. Important Experiments
Van Helmont – Mass does not come from soil
Thought it all came from water
Priestley – Plants give off oxygen
Candle kept burning
Ingenhousz – Light is necessary for plants to produce oxygen

14. Types of Energy Reactions - #1
Photosynthesis – process in which organisms use the energy of sunlight to convert carbon dioxide and water into sugar and oxygen
Happens in plants
Specifically in the chloroplast of plant cells

15. Photosynthesis Equation
REMEMBER:
What it needs = Reactants
What it makes = Products
6CO2 + 6H2O C6H12O6 + 6O2
Carbon dioxide + Water Sugar/Glucose + Oxygen
(Reactants) (Products)
Light
Light

16. How do Plants Capture Light?
Sunlight comes down in the form of light in a mixture of different wavelengths.
We see these different wavelengths as different colors.

17. How do Plants Capture Light?
Plants use pigments – light absorbing molecules
Chlorophyll – the main pigment that plants use to capture light
Found in the the chloroplast of plants

18. Pigments and Light
The color we see is the color wavelength that is reflected from (bounces off of) the object
All other colors are absorbed by the object
When chlorophyll absorbs light, the light’s energy gets absorb also and boosts the energy level of the chlorophyll’s electrons.
Reflected light

19. WHY ARE PLANTS GREEN? They reflect green light!!
Reflected
light
Absorbed
Transmitted
Chloroplast
What color is sunlight? White all colors
What color of light do plants get energy from? Red, orange, yellow, blue, purple, violet
Why? Because it absorbs those colors and therefore their energy
What color of light do plants get the least energy from? Green
Why? Because it does not absorb the light it reflects it.
They reflect green light!!
Remember: THE COLOR OF LIGHT SEEN IS THE COLOR REFLECTED, NOT ABSORBED

20. Light- dependent reactions
Inside a Chloroplast
H2O
CO2
Light
NADP+
ADP + P
Light- dependent reactions
Calvin Cycle
Calvin cycle
What would the plant need the sugar for?
Store it for future use, make cellulose for their cell walls, energy (converted to ATP in cellular respiration), growth
The process of photosynthesis includes the light-dependent reactions as well as the Calvin cycle.
Factors affecting Photosynthesis
amount of water
temperature (too high or too low and the essential enzymes may be damaged)
intensity of light
Chloroplast O2
Sugars
Copyright Pearson Prentice Hall

21. Four things are needed for photosynthesis:
SUNLIGHT
Gives the plant energy
CHLOROPHYLL
The green stuff where the chemical reactions happen
WATER
Travels up from the roots
CARBON DIOXIDE
Enters the leaf through small holes on the underneath

22. Let’s Think Some More… What things do we need to survive?
Sugar/Glucose (C6H12O6)
Oxygen (O2)
What do we give off as waste?
Water (H2O)
Carbon dioxide (CO2)

23. Types of Energy Reactions = #2
Cellular Respiration – process in which organisms breakdown sugar to make ATP
Happens in plants and animals
Specifically in the mitochondria of cells

24. Cellular Respiration Equation
REMEMBER:
What it needs = Reactants
What it makes = Products
C6H12O6 + 6O CO2 + 6H2O +
Sugar/Glucose + Oxygen Carbon dioxide + Water +
(Reactants) (Products)
ATP
ATP

25. Cellular Respiration – Step 1
Glycolysis – the breaking of glucose
Anaerobic – does not require oxygen
Occurs in cytoplasm
Makes 2 ATP

26. Cellular Respiration – Step 2
Krebs Cycle
Aerobic – does require oxygen
Occurs in mitochondria
Makes 2 ATP and lost of high energy electrons

27. Cellular Respiration – Step 3
ATP
Electron Transport Chain
Aerobic – does require oxygen
Occurs in mitochondria
Makes ATP
ATP
ATP
ATP

28. Types of Energy Reactions - #3
If there is no oxygen present, cells go through fermentation instead of cellular respiration to get the ATP they need.
Allows the organism to continue to make ATP as long as the glucose supply lasts.

29. Types of Fermentation
Lactic Acid Fermentation C6H12O6 6CO2 + 6H2O + Lactic Acid +
ATP
Used by animals when they need ATP but are not getting enough oxygen to go through cellular respiration.
Used by some bacteria that live in environments without oxygen – make yogurt, milk, cheese

30. Types of Fermentation Alcoholic Fermentation
C6H12O CO2 + 6H2O + Ethyl Alcohol +
Used by fruit – wine and liquors
Used by yeast – bread and beer (holes in bread/bubbles in beer = CO2!)
Some bacteria
ATP