Freshman Biology Photosynthesis Lecture

1. Photosynthesis
Harnessing the power of
LIGHT to CREATE food!

2. By the end of this unit, you will be
able to…
 Explain why plants are green.
 Identify where photosynthesis takes place.
 Identify the structures of a chloroplast.
 Write the chemical equation of
photosynthesis.
 Explain how glucose is made.
 Compare and contrast the light dependent
and independent reactions

3. Essential Question:
 What is the process of photosynthesis and
where does it take place?
Objective:
I can identify where photosynthesis takes place,
write the chemical equation for photosynthesis,
and explain why plants are green.

4. Let’s start this off with some
MUSIC!
https://www.youtube.com/watch?v=8u_hwwztRqI

5. Photosynthesis- LIGHT
 White light from the sun is a blend of many
different wavelengths (colors) of light.
 An object is a certain color because it
RELFECTS a certain portion of the light and
absorbs the rest.

6. • A leaf is green because it reflects green light.

7. Photosynthesis- Producers
 Producers are organisms that make their own energy.
They do not eat.
 Producers are autotrophs, meaning they make their
own food.
 Photosynthesis is a process that producers use to
store light energy as chemical energy (usually in the
form of sugars)

8. Chemical Equations
 Chemical equations have reactants (things that
chemically react) and products (that which is
produced)
Reactants ---------------> Products
 CAREFUL!
Products are always on the end of the arrow
Products <------------------- Reactants

9. Pancake Recipe
1 cup flour + 1 cup milk + 2 TBSP baking powder + 1 egg + 1 TSP salt
(REACTANTS)
(heat)
-----------------------> 12 Pancakes
(PRODUCTS)

10. Photosynthesis Equation
light energy
6 CO2 + 6 H2O ------------> C6H12O6 + 6 O2
How to read that:
Carbon dioxide + water + light YIELDS Glucose + oxygen
Reactants Products
absorbed by chlorophyll

12. Where?
 Photosynthesis occurs in the Chloroplast
 Stroma- fluid part of chloroplast (like cytoplasm)
 Grana- stack of thylakoids, contains chlorophyll
 Thylakoids- looks like stack of coins
Draw that! ----->

13. Here’s another picture of a
chloroplast

14. And another…

15. Here’s what they look like, for
real

16. What absorbs the light?
 Chlorophyll- green pigment in plants that
absorbs the energy from sun and converts it
to chemical energy
 Carotenoids- Yellow, orange & red pigments
that absorb light energy and pass onto
chlorophyll

17. Quiz Yo Self!!
 Using the white boards, write your answer to
the following questions.
 USE YOUR NOTES!!

18. What is the light absorbing green
pigment in chloroplasts called?
A. Carotenoids
B. Green
C. Chlorophyll
D. Water

19. What is the light absorbing green
pigment in chloroplasts called?
A. Carotenoids
B. Green
C. Chlorophyll
D. Water

20. Light energy is converted to
chemical energy through the
process of….
A. Glycolysis
B. Photosynthesis
C. Cellular Respiration
D. Fermentation

21. Light energy is converted to
chemical energy through the
process of….
A. Glycolysis
B. Photosynthesis
C. Cellular Respiration
D. Fermentation

22. Plants appear green
because…..
A. They absorb green wavelengths of light
B. They reflect green wavelengths of light
C. They absorb blue and yellow wavelengths, which
makes green
D. It’s an optical illusion and we’re all seeing
different colors.

23. Plants appear green
because…..
A. They absorb green wavelengths of light
B. They reflect green wavelengths of light
C. They absorb blue and yellow wavelengths, which
makes green
D. It’s an optical illusion and we’re all seeing
different colors.

24. Which of the following is an
example of an autotroph?
A. Dog
B. Cat
C. Elephant
D. Tree

25. Which of the following is an
example of an autotroph?
A. Dog
B. Cat
C. Elephant
D. Tree

26. The TWO parts of a chemical
equation are…
A. Reactants and Products
B. Oxygen and Carbon dioxide
C. Mitochondria and chloroplasts
D. Peanut butter and jelly

27. A. Reactants and Products
B. Oxygen and Carbon dioxide
C. Mitochondria and chloroplasts
D. Peanut butter and jelly
The TWO parts of a chemical
equation are…

28. Write out the CORRECT
chemical equation for
photosynthesis

29. Check Yo Self…
6 CO2 + 6 H2O ------------> C6H12O6 + 6 O2

30. In which organelle does
photosynthesis take place?
A. Mitochondria
B. Golgi body
C. Nucleus
D. Chloroplast

31. In which organelle does
photosynthesis take place?
A. Mitochondria
B. Golgi body
C. Nucleus
D. Chloroplast

32. Label the chloroplast!
 Word Bank
 Stroma
 Grana
 Thylakoid
 Cell membrane

33. Label the chloroplast!
Stroma
Grana
Thylakoid
Cell Membrane

34. Now you can….
 Identify where photosynthesis takes place
 Write the chemical equation for
photosynthesis
 Explain why plants are green!
Pat yourself on the back!

35. Essential Question
 What is the difference between the Light
Reaction and Calvin Cycle during
photosynthesis?
Objective:
I can explain how glucose is made.

36. Let’s Review!
 Using the notecards at your table, rearrange
them into the correct chemical equation for
photosynthesis.

37. Does it look like this?
6 CO2 + 6 H2O ------------> C6H12O6 + 6 O2

38. 2 Cycles
There are two cycles that work together
to create glucose (C6H12O6)
 Light Reactions (require light)
 Calvin Cycle (doesn’t require light or dark)
 Photolysis- when a chemical (like water) is
broken down by photons

39. Light Reaction- Needs Light
Occurs in the grana of
chloroplasts
Adds a phosphate to
ADP to become ATP
Splits water (H2O) to
release O2 (oxygen) and
H+ (hydrogen)
Sends H+ over to
Calvin Cycle
That’s what
we
breathe!!

40. Remember Diffusion?
 After the Light
Reaction, oxygen
(O2) diffuses out of
the cell that we
then breathe!
That pore is called a
stomata

41. Calvin Cycle- Doesn’t need light!
 Occurs in the stroma of chloroplasts
 Takes in CO2 (Carbon Dioxide)
 Uses the ATP (energy) and H+ from Light
Reaction
 Synthesizes (makes) GLUCOSE (C6H12O6)
 This can happen day or night