1. Cellular Energy ( )
Cellular Energy

2. 8.1 Energy:
The ability to do work

3. Autotrophs Organisms that make their own food Use sun directly
Chemoautotrophs: use inorganic substances instead of sunlight
Photoautotrophs: use the sun for photosynthesis

4. Heterotrophs
Organisms that need to ingest food to obtain energy

5. Metabolism :all of the chemical reactions within a cell
Catabolic pathway: releases energy by breaking larger molecules down
Example: cellular respiration
Anabolic pathway: use energy release from catabolic pathway to build larger molecules
Example: Photosynthesis

6. 8.2 Photosynthesis
series of reactions that use carbon dioxide to form carbohydrates
Examples of carbohydrates: glucose, sucrose
Light energy is turned in chemical energy
Who undergoes photosynthesis?
Autotrophs!

7. Overview of photosynthesis and respiration
SUN
RADIANT ENERGY
CELL
ACTIVITIES
PHOTOSYNTHESIS
RESPIRATION
GLUCOSE
ATP(ENERGY)

8. 2 phases of Photosynthesis:
Light – dependent reactions: converts light energy into chemical energy
Light – independent reactions: ATP from dependent reactions fuel these reactions to produce glucose (sugar)

9. The Photosynthesis Equation
6CO2 + 6H2O + light energy --> C6H O2
(reactants) (products)
CO2 = carbon dioxide
H2O = water
O2 = oxygen
C6H1206 = glucose (sugar)

11. It Begins with Sunlight!

12. A. Light-Dependent Reactions
Require sunlight
Sunlight strikes chloroplasts, and the light energy is captured
Thylakoids: flattened sac-like membranes arranged in stacks (called grana)
Stroma: fluid-filled space outside of grana (this is where the 2nd phase occurs!)

13. Light-Dependent Reactions (cont’d)
Pigments: molecules that absorb specific-colored light
Chlorophyll a and Chlorophyll B: absorb violet/blue and reflect green
Carotenoids: absorb blue/green and reflect yellow/orange/red (think of carrots!)

14. Light-Dependent Reactions (cont’d)
What happens to the chlorophyll when leaves change colors?
Chlorophyll begins to break down; therefore cannot absorb all other colors, so only the red/orange/yellow is reflected

15. What is produced in the light reactions?
Products of the light reactions (light dependent reactions) go on to the Calvin Cycle
NADPH, ATP, and oxygen as byproducts

16. What’s necessary for the light reactions?
NADP, ADP, water, and sunlight.

17. Light-Dependent Reactions (cont’d)
Thylakoid membrane is the key to the electron transport chain (ETC)
ETC: series of electrons embedded in the thylakoid membrane
-acts as a bucket brigade (electrons lose their energy little by little)
Chemiosmosis: Water is broken down to produce ATP in conjunction with electron transport
:process by which ATP is produced by the flow of electrons down a concentration gradient

18. The Light-Independent Reactions
Now that the Light reactions (Light-dependent) reactions are complete…these products go to (or feed) the next phase…
The Light-Independent Reactions
(or Dark Reactions)

19. Light-Independent Reactions
Aka Calvin Cycle
Does not need light
Takes place in stroma of chloroplasts
Named after Melvin Calvin

20. If there is not enough water or carbon dioxide or sunlight to undergo photosynthesis, what happens?
C4 Pathway: helps maintain photosynthesis while minimizing water loss
Examples: corn, sugarcane
CAM pathway: occurs in water-conserving plants from deserts, salt marshes, etc.
Examples: pineapple, orchids, cactus (cacti)

21. What’s Necessary for the Dark Reactions?
The dark reactions cannot take place without the ATP and NADPH that was produced during the light reactions. Recall that ATP and NADPH are energy carriers.
Carbon dioxide from the environment is also necessary for the dark reactions.

22. What’s produced by the dark reactions?
Glucose (a 6 carbon sugar) and other energy storing organic compounds are made.
NADP+ and ADP are produced to be reused by the light reactions.

23. Concept Map Photosynthesis Light dependent reactions Light independent
includes
Light
dependent
reactions
Light
independent
reactions
occurs in
uses
uses
occur in
Light
Energy
Thylakoid
membranes
Stroma
ATP
NADPH
to produce of
to produce
ATP
NADPH O2
Chloroplasts
Glucose

24. BIG Factors Affecting the Rate of Photosynthesis
Amount of available water
Temperature
Amount of available light energy