1. CAPTURING ENERGY Chapter 6
PHOTOSYNTHESIS
CAPTURING ENERGY
Chapter 6

2. ENERGY
Autotrophs – Organisms that make their own food from inorganic substances and energy (ATP).
Use photosynthesis – converting light energy into chemical energy
Store chemical energy as organic compounds (like carbohydrates)
EX: plants, algae, and some bacteria

3. PHOTOSYNTHESIS 6CO2+6H2O+light C6H12O6+6O2
A biochemical pathway that involves a complex series of chemical reactions
The product of this reaction is consumed in the next reaction
Process supports virtually all life on Earth

4. Understanding Photosynthesis
1. Jan Van Helmont (1600’s) – set up an experiment to understand how a small seed grew to a large tree
Concluded that plants need water to grow.
2. Joseph Priestly (1771) – set up an experiment with a candle…he discovered a candle in a jar died out but a candle in a jar with a plant continued burning.
3. Jan Ingenhousz (1779)– found that the plant/candle experiment only worked when the plant was exposed to sunlight
Concluded: light is necessary for plants to produce oxygen

5. The Nature of Light
Visible Spectrum – the separation of white light into different colors (wavelengths)
PIGMENT – a molecule that absorbs certain wavelengths of light and reflects or transmits others

6. Chloroplasts- organelle that contains chlorophyll
Chloroplasts- organelle that contains chlorophyll and other pigments; site of photosynthesis
Contains:
Thylakoids – disk-shaped structures that contain photosynthetic pigments
Grana – Stacks of thylakoids (resemble stacks of pancakes)
Stroma – Solution surrounding the thylakoids
Chlorophyll- light collecting pigment located on the thylakoid disks

7. CHLOROPHYLL and PIGMENTS
The most common and important photosynthetic pigments in plants and algae.
Absorbs violet, blue, and red lights.
Reflect and Transmit Green light – giving plants their GREEN color.
Chlorophyll a – primary photosynthetic pigment
Accessory Pigments – Chlorophyll b and carotenoids

9. LIGHT REACTIONS Initial reactions of photosynthesis
Begins with absorption of light in chloroplasts (in the thylakoids) to create chemical energy (ATP and NADPH)
adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide diphosphate (NADPH2).

10. Light rxn.
Water molecules are split, creating electrons, protons, and oxygen as a byproduct
animation

11. Light rxn. Cont. Reactants: H2O + Sunlight
Products: O2 + ATP + NADPH (energy carrier) + H+
(used later)

12. Chemiosmosis The synthesis of ATP
Occurs when there is a concentration gradient of protons across the thylakoid membrane
ADP  ATP

13. CALVIN CYCLE Second set of reactions in photosynthesis
Is not dependent on light
Occurs in the stroma
(liquid area of the chloroplast) when ATP and NADPH are present
Makes stored energy (in the form of carbs) that the plant can use

14. How is this done?
Carbon fixation: carbon atoms are bonded (“fixed”) into organic compounds
aided by enzymes
Reactants: CO2 + ATP + NADPH + H+
Products: O2 + C6H12O6

15. Animation

18. The rate of photosynthesis varies:
1. light intensity
2. amount of CO2
3. temperature

20. Notebook quiz Write the equation for photosynthesis out in words?
Where in the chloroplast do the light reactions occur?
What are the products of the light reaction?
What are the products of the Calvin Cycle?
What is the primary photosynthetic pigment in plants?

21. ALTERNATIVE PATHWAYS STOMATA – small pores in leaves of plants
C4 Plants – close stomata during hot parts of the day (still able to produce carbohydrates)
EX: corn, sugar cane, crabgrass
CAM Plants – open stomata at night and close them during the day…producing organic compounds at night
EX: cactus, pineapples

22. MAKING ENERGY animation
CELLULAR RESPIRATION
MAKING ENERGY
animation

23. CELLULAR RESPIRATION C6H12O6 + 6O2 6CO2+6H2O+ energy(ATP)
The complex process in which cells make ATP by breaking down organic compounds
Heterotrophs – Organisms that obtain energy from eating autotrophs or other heterotrophs

24. GLYCOLYSIS The beginning of cellular respiration
Glucose is converted into 2 molecules of pyruvic acid
Produces very little ATP and NADH
glucose
pyruvic acid

25. GLYCOLYSIS PRODUCTION
Glycolysis USES 2 ATP molecules to start the pathway
Glycolysis MAKES 4 ATP molecules at the end of glycolysis
Therefore, glycolysis produces:
Net total of 2 ATP
NADH
2 molecules of Pyruvic Acid

26. With Oxygen…glycolysis is followed by AEROBIC RESPIRATION to produce more ATP
Examples of aerobic exercise: long distance activities
Without Oxygen…glycolysis is followed by FERMENTATION (anaerobic respiration) producing no ATP
Examples of anaerobic exercise: sprinting

27. FERMENTATION Without Oxygen…Glycolysis goes to Anaerobic Respiration
Does not produce ATP
Recycles NAD+ from NADPH to keep glycolysis going
2 most common fermentation pathways:
LACTIC ACID FERMENTATION
ETHYL ALCOHOL FERMENTATION

28. LACTIC ACID FERMENTATION
Converts pyruvic acid into lactic acid
Helps produce some foods
ex) yogurts and cheeses
Also occurs in your muscle cells during very strenuous exercise
ex) sprinting
As lactic acid accumulates…it reduces the ability of the muscle cells to contract…resulting in fatigue, pain, and cramping

29. ALCOHOLIC FERMENTATION
Used by some plant cells and unicellular organisms
Converts pyruvic acid into ethyl alcohol
Used in the wine and beer industries and in the making of breads

30. Electron Transport Chain
AEROBIC RESPIRATION
Occurs when Oxygen is present in the cell
Pyruvic acid is converted to CO2 and water
Produces large amounts of ATP
Takes place in the mitochondria
2 major stages:
The Kreb’s Cycle
Electron Transport Chain

31. THE PRODUCTION OF ATP

32. THE KREB’S CYCLE
Occurs in the mitochondrial MATRIX (space inside the inner membrane of the mitochondria)
Biochemical pathway that breaks down acetyl CoA, and produces CO2, hydrogen atoms, and ATP
1 Glucose molecule gives 2 cycles of the Kreb’s cycle and produces:
6 NADH
2 FADH2
2 ATP
4 CO2

33. ELECTRON TRANSPORT CHAIN
Second stage of aerobic respiration…occurs along the many folds (cristae) of the mitochondria
4 NADH from Glycolysis produce a total of ATP
6 NADH from Kreb’s produce a total of 18 ATP
2 FADH2 from Kreb’s produce a total of 4 ATP
Electron Transport Chain Produces a TOTAL of 34 ATP

34. THE ENTIRE PROCESS CAN PRODUCE A TOTAL OF 38 ATP
CELLULAR RESPIRATION
THE ENTIRE PROCESS CAN PRODUCE A TOTAL OF 38 ATP

36. Why do leaves change color in the fall?
How do annuals and perennials survive winter?
Why do deciduous trees loose their leaves and evergreens do not loose their needles?
Why do the leaves fall from the trees in autumn?
How and why do the leaves separate from the tree?
What is anthocyanin?
Name other pigments that appear in leaves after the chlorophyll disappears.
Where is the best place to see the color change? Why?

37. Photosynthesis Comic Directions
Create a minimum 6 slide comic strip summarizing the process of photosynthesis .Be sure to include the reactants and products of the light and dark reactions.

38. Cellular Respiration Poster!
Design a poster summarizing all important parts of the stages of aerobic and anaerobic cellular respiration.
Show how all of the processes are related
Be creative
Be prepared to show your poster to the rest of the class and explain its contents

39. Notebook Quiz Distinguish between autotrophs and heterotrophs.
What are the (3) products of glycolysis?
After glycolysis, what determines the next step?
What type of fermentation occurs in animal cells?
What are the 2 steps of aerobic respiration?
How many ATP are produced in cellular respiration?

40. Notebook Quiz What is the primary photosynthetic pigment in plants?
In photosynthesis, where do the light reactions occur? Where does the Calvin Cycle occur?
What is the chemical energy produced in photosynthesis?
What molecule made in photosynthesis is “burned” in cellular respiration?
Distinguish between autotrophs and heterotrophs.
What are the 3 products of glycolysis?
After glycolysis, what determines the next step?