1. Photosynthesis
Chapter 8

2. What is energy?
the ability to do work

3. Autotrophs and heterotrophs
Plants and some other types of organisms are able to use light energy from the sun to produce food.
- autotroph (producer): organisms such as plants, which use the sun to make their own food through photosynthesis
- heterotroph (consumer): other organisms, such as animals, that cannot use the sun’s energy directly and must eat other organisms for food

4. Autotroph or heterotroph?

5. Autotroph or heterotroph?

6. Chemical Energy and ATP
Energy comes in many forms, including light, heat, and electricity
Energy can also be stored in chemical compounds!

7. Adenosine triphosphate (ATP)
ATP is the chemical compound that living things use to store up energy
made up of:
- adenine (N containing compound)
- ribose (5 C sugar)
- 3 phosphate groups

8. Adenosine diphosphate (ADP)
“Used” ATP
contains:
- adenine (N containing compound)
- ribose (5 C sugar)
- 2 phosphate groups 2

9. ADP vs. ATP
Cells release the energy in ATP by removing a phosphate group and turning it into ADP. Cells can “re-charge” the ADP molecules by reconnecting the phosphate group through respiration.

10. ATP
cells use ATP for active transport and movement

11. ATP and Glucose
Cells must get energy from Carbohydrates to recharge the ATP
a single molecule of glucose (sugar) stores more that 90X the chemical energy of one ATP!

12. 8-2: Photosynthesis, An Overview

13. Photosynthesis vs. chemosynthesis
photosynthesis: plants use the energy of sunlight to convert water and carbon dioxide into oxygen and high energy carbohydrates such as sugars and starches
chemosynthesis: a similar process to photosynthesis, but it uses heat and sulfur compounds instead of sunlight. Found in some bacteria, especially deep in the ocean near volcanic vents.

14. The Photosynthesis Equation
reactants products
MEMORIZE THIS!

15. Light and Pigments
Plants use a pigment called chlorophyll to trap the light. This is what gives them their green color.
pigments: light absorbing molecules found in plants that gather the sun’s energy

16. Light and Pigments Chlorophyll is not the only pigment
Carotenoids: plants also contain red, yellow, and orange pigments that absorb other wavelengths of light. We see these pigments in fall leaves

17. 8-3: The Reactions of Photosynthesis

18. Inside a Chloroplast
photosynthesis takes place inside a chloroplast

19. Inside a Chloroplast
chloroplasts contain thylakoids, a sac-like photosynthetic membrane
thylakoids contain pigments & proteins to capture the energy in sunlight
thylakoids are arranged in stacks called grana (singular: granum)
the gel-like matrix that surrounds the grana is called the stroma

20. Inside a Chloroplast photosynthesis is divided into two stages:
1. light-dependent: reaction that
requires light. It releases Oxygen
into the air.
2. Calvin Cycle: Does not require light. It creates the carbohydrates molecules

21. Light-Dependent Reactions
Part One of Photosynthesis: light dependent reactions use light to produce O2 gas and create a small amount of ATP

22. The Calvin Cycle
Part Two of Photosynthesis is the Calvin Cycle. It does not require light.
Plants use the energy from the ATP made in the light reactions to build sugars that can be stored for a long time
In photosynthesis, 6 CO2 molecules are used to produce 1 6–carbon sugar molecule (C6H12O6)

23. Factors Affecting Photosynthesis
availability of water: too little water will slow or stop photosynthesis
temperature: optimum (most photosynthesis occurs) temperatures between 0C and 35C
intensity of light: more light, more photosynthesis

24. Question 1
Which of the following are autotrophs? a. impalas b. plants c. leopards d. mushrooms

25. Question 2
One of the principal compounds that living things use to store energy is a. DNA b. ATP c. H2O d. CO2

26. Question 3
In addition to light and chlorophyll, photosynthesis requires a. water and oxygen b. water and sugars c. oxygen and carbon dioxide d. water and carbon dioxide

27. Question 4
The leaves of a plant appear green because chlorophyll a. reflects blue light b. absorbs blue light c. does not absorb green light d. absorbs green light

28. Question 5
The products of photosynthesis are a. sugars and oxygen b. sugars and carbon dioxide c. water and carbon dioxide d. hydrogen and oxygen

29. Question 6
Which organelle contains chlorophyll? a. b. c. d.

30. Question 7
The first process in the light-dependent reactions of photosynthesis is a. light absorption b. electron transport c. oxygen production d. ATP formation

31. Question 8
Which substance from the light-dependent reactions of photosynthesis is a source of energy for the Calvin cycle? a. ADP b. ATP c. H2O d. pyruvic acid

32. Question 9
The light-independent reactions of photosynthesis are also known as the a. Calvin cycle b. Priestley cycle c. Ingenhousz cycle d. van Helmont cycle

33. Question 10
Which equation best summarizes the process of photosynthesis? a. b. c. d.