1. Living Organisms & Energy
Moretz, biology
2017

2. Lecture Outline Importance of energy in living organisms
Photosynthesis
Process of photosynthesis
Purpose of photosynthesis
Respiration
Purpose of respiration
Process of respiration
Fermentation

3. Importance of Energy Living organisms need energy to do everything.
Move
Grow
Reproduce
Photosynthesis & respiration are needed for living organisms to get energy.

4. Photosynthesis vs. Respiration
Photosynthesis- turns energy into sugars
Respiration- turns sugars into energy
Photosynthesis
Energy
Sugars
Respiration

5. How do plants meet their energy needs?
Remember, science is a process…..
…..a brief history lesson is in order

6. The process of understanding photosynthesis
Until almost 350 years ago, plants were thought to feed on soil
Jan Baptista van Helmont
Planted willow tree in pot
Allowed tree to grow for 5 years
Compared weight of tree and soil to original weight
Tree gained 74kg, soil lost 57g

7. The process of understanding photosynthesis
100 yrs later we learned that plants release oxygen into the atmosphere
Joseph Priestly
Candles “damaged” air
Sprigs of mint “restored” air

8. The process of understanding photosynthesis
Finally, ~1800 Jan Ingenhousz determined:
Air was “restored” only in the presence of sunlight
Only by a plant’s green leaves, not by it roots
But, he suggested that the source of the oxygen was CO2

9. What is photosynthesis?
photo = light
synthesis = to put together

10. Process of photosynthesis
Process by which a cell captures energy and uses it to make food.
Photosynthesis is a 2 step process:
Capture energy
Turn energy into food

11. Step 1: Capturing Energy
Plants capture the light energy from the sun.
Chlorophyll absorbs the light energy.
Pigment that is good at absorbing a certain wavelength of light.
Located in the chloroplast.
Organelle located ONLY in plant cells.
The light energy captured by the chlorophyll is needed to turn energy into food.

12. Capturing Energy

13. Capturing Energy

14. Capturing Energy
Chlorophyll

15. Step 2: Turning energy into food
Plant cells use the captured light energy to produce “food.”
Water (H2 O) and carbon dioxide (CO2 ) are needed to make the food.
Roots absorb water from the soil.
Carbon dioxide enters the plant through stomata.
Light energy changes the water & carbon dioxide into glucose and oxygen (O2).

16. Stomata Small openings on the underside of leaves.
Gases enter and exit through these openings.

17. Stomata Small openings on the underside of leaves.
Gases enter and exit through these openings.

18. Glucose “Food” produced during photosynthesis.
Glucose = C6H12O6
“Food” produced during photosynthesis.
Simple carbohydrate (sugar)

19. Process of photosynthesis
6 CO2 + 6H2 O C6H12O6 + 6O2
6 carbon dioxide molecules and 6 water molecules produces 1 glucose molecule and 6 oxygen molecules.
light

20. Photosynthetic Organisms
Carried out by a variety of organisms
simple bacteria, to algae and complex plants.
Photosynthetic organisms = “producer” or “autotroph.”

21. Pd 2

24. Importance of Photosynthesis
Releases oxygen into the atmosphere.
Dead plant matter is a source of fossil fuels.
Most living things obtain energy either directly or indirectly from the sun’s energy captured during photosynthesis.
Pd 1

25. Importance of Photosynthesis
Without photosynthesis, living organisms would not get energy!!!
Energy enters the ecosystem through photosynthesis.
Plants use the sun’s energy to make glucose.
All other organisms consume glucose from the producers as a source of energy.

26. Flow of Energy

27. Flow of Energy

28. Before respiration…
All organisms get energy from the food they eat / make.

29. Before respiration…
Food passes through the digestive system and is broken into smaller pieces.

30. Before respiration…
Smaller food molecules pass from the digestive system to the blood stream.
Small sugar molecules (GLUCOSE) then go to the cells where respiration occurs.

31. Respiration What? Who? Where? Process of getting energy.
Cells break down sugar (glucose) and release the energy.
Who?
ALL living organisms
Where?
Occurs in the cytoplasm and mitochondria of all cells, in BOTH plant and animal cells.

32. The Process of Respiration
Glycolysis (fermentation)
Glucose is broken into smaller molecules (pyruvate).
Occurs in the cytoplasm.
Anaerobic - Oxygen is NOT needed.
Four molecules of energy (ATP) is produced.
Two molecules are used in the process.
Net production = 2 molecules of ATP

33. The Process of Respiration
Glycolysis
Glucose is broken into smaller molecules (pyruvate).
Two molecules of energy (ATP) is released.

34. The Process of Respiration
Glycolysis
Glucose is broken into smaller molecules (pyruvate).
Two molecules of energy (ATP) is released.

35. The Process of Respiration
The Kreb’s Cycle
Pyruvate goes into the mitochondria.
Pyruvate molecules is broken into even smaller molecules.
Pyruvate turns into Acetyl-CoA

36. The Process of Respiration
The Kreb’s Cycle
Pyruvate goes into the matrix of the mitochondria.

37. The Process of Respiration
The Kreb’s Cycle
Pyruvate goes into the matrix of the mitochondria.
Pyruvate molecules is broken into even smaller molecules.
Pyruvate turns into Acetyl-CoA
Acetyl-CoA is turned into ATP
CO2 is produced.
Electron carrying molecules are produced (FADH and NADH)
Aerobic - Oxygen is required.
1molecules of energy (ATP) is produced.

38. The Process of Respiration
The Kreb’s Cycle
Pyruvate goes into the mitochondria.
Pyruvate molecules is broken into even smaller molecules.
Pyruvate turns into Acetyl-CoA
Acetyl-CoA is turned into ATP
FADH and NADH are produced.
CO2 is produced.
2 molecules of energy (ATP) is produced.

39. The Process of Respiration
3. Electron Transport Chain
Electrons are passed from one molecule to another.
Given from the NADH and FADH molecules
In the membrane of the mitochondria
Energy produced from electron transfer is stored in ATP
If Oxygen is not present, ETC stops and ATP isn’t produced.

40. The Process of Respiration
Energy produced from electron transfer is stored in ATP
If Oxygen is not present, ETC stops and ATP isn’t produced.

41. The Process of Respiration
3. Electron Transport Chain
Electrons are passed from one molecule to another.
Given from the NADH and FADH molecules
In the membrane of the mitochondria
Produces ATP
Oxygen is the last electron acceptor.
Joins with H+ and produces water.
Aerobic - Oxygen is required.
32 molecules of energy (ATP) is produced.
Energy produced from electron transfer is stored in ATP
If Oxygen is not present, ETC stops and ATP isn’t produced.

42. The Process of Respiration

43. The Process of Respiration
Glucose
In the cytoplasm
Small molecules
In the mitochondria
Energy

44. The Process of Respiration
Water
Oxygen
Carbon dioxide
Smaller molecules
LOTS of Energy

45. Process of respiration
C6H12O6 + 6O CO2 + 6H2 O + ATP
One molecule of glucose and six molecules of oxygen make six molecules of carbon dioxide, six water molecules, and 36 molecules of ATP.

46. ATP = Energy Universal energy storage molecule.
All organisms break down ATP to get energy.
Energy is released when the chemical bonds in ATP are broken.

47. Fermentation What happens if oxygen is not available?
The cell can use Fermentation instead!!
Occurs in the Cytoplasm
Just like glycolysis!!
Anaerobic respiration process

48. Pyruvic Acid + NADH  alcohol + CO2 + NAD+
2 Types of Fermentation
Alcoholic Fermentation
Yeasts use this process to form ethyl alcohol and carbon dioxide as waste products.
This causes bread dough to rise
This is how some alcoholic beverages are made
Pyruvic Acid + NADH  alcohol + CO2 + NAD+

49. Anaerobic respiration
Alcoholic fermentation

50. Lactic Acid Fermentation
Occurs in bacteria (unicellular organisms)
This is how cheese, yogurt, and pickles are made.
Occurs in muscles during rapid exercise
When your body runs out of oxygen your muscle cells must produce some ATP using fermentation and glycolysis
Lactic Acid build-up causes muscle soreness or burning after intense activity.
Pyruvic Acid + NADH  lactic acid + NAD+

51. Anaerobic respiration
Lactic acid fermentation

52. Fermentation Summary Fermentation: 2 Pyruvic Acid  ? or ?
Glycolysis: Glucose  2 Pyruvic Acid

53. Photosynthesis & respiration summary
Glucose is made during photosynthesis.
Glucose is broken down and energy is released during respiration.
All organisms use energy released to do everything.
Photosynthesis
Energy
Sugars
Respiration