1. Photosynthesis, Cellular Respiration, and Fermentation
Cellular Processes
A unit to review 3 main processes cells undertake that deal with energy creation:
Photosynthesis, Cellular Respiration, and Fermentation

2. Candles release energy as HEAT & LIGHT
Energy Takes Many Forms such as light, heat, electrical, chemical, mechanical, etc.
Energy can be changed from one form to another
Energy can be stored in chemical bonds & then released later
Candles release energy as HEAT & LIGHT

3. PHOTOSYNTHESIS
The process of converting sunlight into FOOD that can be used by the plant cell. This process DOES NOT create energy for the plant.

4. It Begins with Sunlight!

5. Energy for Life on Earth
Sunlight is the ULTIMATE energy source for all life on Earth
Plants store energy in the chemical bonds of sugars
Chemical energy is released as ATP during cellular respiration

6. Photoautotrophs Absorb Light Energy

7. Autotrophs Autotrophs include organisms that make their own food
Some use the sun’s energy directly
Euglena

8. Autotrophs
Plants, and some other organisms that contain chlorophyll, are able to use light energy from the sun to produce food.

9. Heterotrophs Heterotrophs can NOT directly use the sun’s energy
Heterotrophs are organisms that must consume (eat) other organisms for food

10. Plants Autotrophs – produce their own food (glucose)
Process called photosynthesis
Mainly occurs in the leaves:
a. stoma - pores
b. mesophyll cells
Mesophyll
Cell
Chloroplast
Stoma

11. Stomata (stoma)
Pores in a plant’s cuticle through which water vapor and gases (CO2 & O2) are exchanged between the plant and the atmosphere.
Oxygen
(O2)
Guard Cell
Carbon Dioxide
(CO2)

12. Chlorophyll Molecules
Located in the thylakoid membranes
Chlorophyll pigments harvest energy (photons) by absorbing certain wavelengths (blue-420 nm and red-660 nm are most important)
Plants are green because the green wavelength is reflected, not absorbed.

13. Inside A Chloroplast

14. Absorption of Light by Chlorophyll
Chlorophyll absorbs blue-violet & red light best
violet blue green yellow orange red
Absorption
wavelength

15. Fall Colors
In addition to the chlorophyll pigments, there are other pigments present
During the fall, the green chlorophyll pigments are greatly reduced revealing the other pigments
Carotenoids are pigments that are either red, orange, or yellow

16. Photosynthesis Anabolic (small molecules combined)
Endergonic (stores energy)
Carbon dioxide (CO2) requiring process that uses light energy (photons) and water (H2O) to produce organic macromolecules (glucose).
6CO H2O  C6H12O O2 + ATP
glucose
SUN
photons

17. The Photosynthesis Equation

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

19. Two Parts of Photosynthesis
Two reactions make up photosynthesis:
Light Reaction or Light Dependent Reaction
Produces energy from solar power (photons) in the form of ATP and NADPH.
Calvin Cycle or Light Independent Reaction
Also called Carbon Fixation or C3 Fixation
Uses energy (ATP and NADPH) from light reaction to make sugar (glucose).

20. Photosynthesis Overview

21. Light Dependent Reaction
Reactants:
H2O
Light Energy
Products:
ATP
NADPH

22. The Calvin Cycle Uses ATP and NADPH from light reaction as energy
Uses CO2
To produce
glucose

23. C3 Plants Temperate environement
85% of all plants (evergreens, grain plants, deciduous trees)
Stomates open during day and closed at night
Leaves with larger air spaces

24. C4 Plants Hot, moist environments
3% of plants (weeds [crabgrass], corn, sugarcane)
Stomates open
during day and
closed at night
Thinner leaves with less air space

25. CAM Plants Hot, dry environments 8% of plants (cactus and ice plants)
Stomates closed during day and open during the night
Thick fleshy leaves

26. Structure of ATP ATP stands for adenosine triphosphate
Composed of a nitrogen base (adenine), the pentose (5C) sugar (ribose), and three phosphate groups.
The last phosphate group is bonded with a HIGH ENERGY chemical bond
This bond can be broken to release ENERGY for cells to use
High Energy Phosphate Bond

27. Removing a Phosphate from ATP
Breaking the last phosphate bond from ATP will:
Release ENERGY for cells to use
Form ADP
Produce a free phosphate group
Energy

28. Releasing Energy From ATP
ATP is constantly being used and remade by cells
ATP provides all of the energy for cell activities
The high energy phosphate bonds can be broken to release energy
The reforming the ATP molecule is called phosphorylation (joining free phosphate and ADP together)

29. Releasing Energy From ATP
Adding A Phosphate Group To ADP stores Energy in ATP
Removing A Phosphate Group From ATP Releases Energy & forms ADP
Lose
Gain

30. More on ATP Cells have enough ATP to last for a few seconds
ATP must constantly be made
ATP transfers energy very well
ATP is
NOT good
at energy
storage

31. Cells Using Biochemical Energy
Cells Use ATP For:
Active transport
Movement
Photosynthesis
Protein Synthesis
Cellular respiration
All other cellular reactions

32. Glucose
Glucose is a monosaccharide
C6H12O6
One molecule of glucose stores 90 times more chemical energy than one molecule of ATP

33. Cell Respiration
The process of using glucose (sugar) and O2 (oxygen) to create energy (ATP) for all cells.

34. When is ATP Made in the Body?
During a process called Cellular Respiration that takes place in both plants & animals
Cellular Respiration breaks down the glucose molecules to release energy.

35. Equation for Cellular Respiration
C6H12O O2
yields
6CO2 + 6H ATP’s

36. Cellular Respiration Requires oxygen
Metabolic Pathway that breaks down carbohydrates
Breakdown of one glucose results in 36 to 38 ATP molecules
Glucose is oxidized and O2 is reduced, therefore is an oxidation-reduction reaction.
Process is Exergonic as High-energy Glucose is broken into CO2 and H2O
Process is also Catabolic because larger Glucose breaks into smaller molecules

37. Where Does Cellular Respiration Take Place?
It actually takes place in two parts of the cell:
Glycolysis occurs in the cytoplasm
Krebs Cycle & ETC take place in the mitochondria

38. Stages of Cellular Respiration
Glycolysis
Occurs in cytoplasm, anaerobic and aerobic, uses two ATP and produces 4, splits glucose into two pyruvate molecules
The Krebs Cycle
Occurs in matrix (mitochondria), aerobic, occurs twice (creates 1 ATP each cycle), releases CO2 and two ATP molecules

39. Stages of Cellular Respiration
Electron Transport Chain
Occurs in the inner membrane (mitochondria), aerobic, creates 34 ATP molecules and releases H2O
The end result of Cellular Respiration is 38 ATP molecules.

40. Fermentation
The process of creating energy in the absence of O2.

41. Fermentation Occurs when O2 NOT present (anaerobic)
Called Lactic Acid fermentation in muscle cells (makes muscles tired)
Called Alcoholic fermentation in yeast (produces ethanol)
Nets only 2 ATP

42. Fermentation
Alcoholic
Fermentation
Lactic Acid
Fermentation