1. Photosynthesis and Cellular Respiration

2. Outline I. Photosynthesis II. Cellular Respiration A. Introduction
B. Reactions
II. Cellular Respiration

3. Review: What is ATP?

4. Review: What is ATP? Adenosine Triphospate
Adenine + Ribose + 3 Phosphate groups
One of the principle chemical compounds that cells use to STORE and RELEASE energy.

5. Storing Energy ADP (Adenine diphospate)
Only 2 phosphates (hence the “di”)
Key to how living things STORE energy!
(When energy is available, the cell stores it by adding phosphate to make ATP=stored battery ready to power cell).

6. Releasing Energy “Shooting off” 1 phosphate  ENERGY!!
ATP provides energy for a variety of cellular activities!
Ex: active transport across cell membranes, protein synthesis, and muscle contraction

7. ADP ATP
Cells regenerate ATP from ADP as needed by using energy in FOOD, aka …

8. ADP ATP
Cells regenerate ATP from ADP as needed by using energy in FOOD, aka … GLUCOSE!

9. Photosynthesis
Photo = light
Synthesis = putting together

10. Photosynthesis
Converting sun energy into chemical energy usable by cells (glucose)
Autotrophs: self feeders, organisms capable of making their own food
Photoautotrophs: use sun energy e.g. plants photosynthesis-makes glucose from light
Chemoautotrophs: use chemical energy, NOT sunlight
e.g. bacteria that use sulfide or methane

11. Photosynthesis
Photosynthesis takes place in specialized structures inside plant cells called chloroplasts
Light absorbing pigment molecules e.g. chlorophyll

12. Why are leaves green?
Chlorophyll absorbs all of the light waves except green. Because the green is not absorbed, it is reflected, so that is the only color wavelength our eye can pick up.
Accessory pigments – help to fill in this gap
Carotenoids – orange (like carrots)
Xanothphyl – yellow

14. Inside the chloroplast
Thylakoids: Sac-like photosynthetic membranes arranged in stacks.
Organize chlorophyll/other pigments into photosystems (clusters that collect light).

15. What does a plant need to survive?

16. KNOW BOTH OF THESE EQUATIONS.
Overall Reaction
6CO2 + 6H2O + light energy → C6H12O6 + 6O2
Carbon dioxide + water + light  glucose + oxygen
KNOW BOTH OF THESE EQUATIONS.
YOU WILL SEE THEM AGAIN!

17. 2 types of reactions in photosynthesis
Light dependent
Light independent (CALVIN CYCLE)

18. Electron Carriers Overview: Sun excites electrons = gain energy
Need special carrier! (Think red-hot coal!)
Electron acceptor molecules (ex: NADP+)
NADP+ uses hydrogen ions (H+) to trap some of the sunlight in chemical form = converts to NADPH.
Carries e- to other chemical reactions in the cell

19. Light Dependent Reactions
Occur in the thylakoid!
Produce oxygen gas
Converts ADP and NADP+ into energy carriers ATP + NADPH

20. Light Dependent Reactions
Overview:
Pigments in Photosystems absorb light = electrons gain energy
Electrons are passed on to the Electron Transport Chain
Does the chorophyll run out of electrons?

21. Light Dependent Reactions
In Thylakoid:
System that provides new e- to chlorophyll to replace ones lost
Electrons come from water! H2O
Enzymes on inner surface membrane of thylakoid break up each H2O into:
2 e- (replace e- lost to the ETC)
2H+ions (released inside thylakoid membrane)
1 oxygen atom (released into the air!)

22. Light-dependent Reactions
5. H+ ions cant cross membrane directly
ATP synthase!
Allows H+ ions to pass through it!
As it turns, binds ADP and phosphate group ….
Producing ATP!

23. Energy Shuttling
Recall ATP: cellular energy-nucleotide based molecule with 3 phosphate groups bonded to it, when removing the third phosphate group, lots of energy liberated= superb molecule for shuttling energy around within cells.
Other energy shuttles-coenzymes (nucleotide based molecules): move electrons and protons around within the cell
NADP+, NADPH NAD+, NADP FAD, FADH2

24. This light dependent reaction is the source of nearly ALL of the oxygen in Earth’s atmosphere! Thanks photosynthesis!
Start Here 3A!

25. Light-dependent Reactions
Photosystem: light capturing unit, contains chlorophyll, the light capturing pigment
Electron transport system: sequence of electron carrier molecules that shuttle electrons, energy released to make ATP
Electrons in chlorophyll must be replaced so that cycle may continue-these electrons come from water molecules, Oxygen is liberated from the light reactions
Light reactions yield ATP and NADPH used to fuel the reactions of the Calvin cycle (light independent or dark reactions)

26. Uses: H2O, ADP, and NADP+ Makes: Oxygen, ATP, and NADPH

28. Calvin Cycle (light independent or “dark” reactions)
ATP and NADPH generated in light reactions used to fuel the reactions which take CO2 and H+ to make glucose.
Simplified version of how carbon and energy enter the food chain

30. Harvesting Chemical Energy
Plants and animals both use products of photosynthesis (glucose) for metabolic fuel
Heterotrophs: must take in energy from outside sources, cannot make their own e.g. animals
When we take in glucose (or other carbs), proteins, and fats-these foods don’t come to us the way our cells can use them
So we see how energy enters food chains (via autotrophs) we can look at how organisms use that energy to fuel their bodies.

31. Photosynthesis vs. Cellular Respiration
ENERGY
CO2 and O2
Water
Glucose
Location: Where does it take place?
Light

32. Photosynthesis vs. Cellular Respiration
ENERGY
Energy is stored
CO2 and O2
Water
Glucose
Location: Where does it take place?
Light

33. Photosynthesis vs. Cellular Respiration
ENERGY
Energy is stored
CO2 and O2
Uses CO2; Produces O2
Water
Glucose
Location: Where does it take place?
Light

34. Photosynthesis vs. Cellular Respiration
ENERGY
Energy is stored
CO2 and O2
Uses CO2; Produces O2
Water
Uses water
Glucose
Location: Where does it take place?
Light

35. Photosynthesis vs. Cellular Respiration
ENERGY
Energy is stored
CO2 and O2
Uses CO2; Produces O2
Water
Uses water
Glucose
Produces glucose from energy
Location: Where does it take place?
Light

36. Photosynthesis vs. Cellular Respiration
ENERGY
Energy is stored
CO2 and O2
Uses CO2; Produces O2
Water
Uses water
Glucose
Produces glucose from energy
Location: Where does it take place?
Chloroplasts of green plants, algae, and some microorganisms
Light

37. Photosynthesis vs. Cellular Respiration
ENERGY
Energy is stored
CO2 and O2
Uses CO2; Produces O2
Water
Uses water
Glucose
Produces glucose from energy
Location: Where does it take place?
Chloroplasts of green plants, algae, and some microorganisms
Light
Requires light (light-dependent reaction; Calvin Cycle can occur in light or dark.)

38. Cellular Respiration Overview
Transformation of chemical energy in food into chemical energy cells can use: ATP
These reactions proceed the same way in plants and animals. Process is called cellular respiration
Overall Reaction:
C6H12O6 + 6O2 → 6CO2 + 6H2O

39. Cellular Respiration Overview
Breakdown of glucose begins in the cytoplasm: the liquid matrix inside the cell
At this point life diverges into two forms and two pathways
Anaerobic cellular respiration (aka fermentation)
Aerobic cellular respiration

40. C.R. Reactions Glycolysis
Series of reactions which break the 6-carbon glucose molecule down into two 3-carbon molecules called pyruvate
Process is an ancient one-all organisms from simple bacteria to humans perform it the same way
Yields 2 ATP molecules for every one glucose molecule broken down
Yields 2 NADH per glucose molecule

42. Anaerobic Cellular Respiration
Some organisms thrive in environments with little or no oxygen
Marshes, bogs, gut of animals, sewage treatment ponds
No oxygen used= ‘an’aerobic
Results in no more ATP, final steps in these pathways serve ONLY to regenerate NAD+ so it can return to pick up more electrons and hydrogens in glycolysis.
End products such as ethanol and CO2 (single cell fungi (yeast) in beer/bread) or lactic acid (muscle cells)

44. Aerobic Cellular Respiration
Oxygen required=aerobic
2 more sets of reactions which occur in a specialized structure within the cell called the mitochondria
1. Kreb’s Cycle
2. Electron Transport Chain

45. Kreb’s Cycle Completes the breakdown of glucose
Takes the pyruvate (3-carbons) and breaks it down, the carbon and oxygen atoms end up in CO2 and H2O
Hydrogens and electrons are stripped and loaded onto NAD+ and FAD to produce NADH and FADH2
Production of only 2 more ATP but loads up the coenzymes with H+ and electrons which move to the 3rd stage

47. Electron Transport Chain
Electron carriers loaded with electrons and protons from the Kreb’s cycle move to this chain-like a series of steps (staircase).
As electrons drop down stairs, energy released to form a total of ATP
Oxygen waits at bottom of staircase, picks up electrons and protons and in doing so becomes water

49. Energy Tally 34-36 ATP for aerobic vs. 2 ATP for anaerobic
Glycolysis ATP
Kreb’s ATP
Electron Transport ATP
36-38 ATP
Anaerobic organisms can’t be too energetic but are important for global recycling of carbon

52. Photosynthesis vs. Cellular Respiration
Comparing/Contrasting worksheet!

53. Photosynthesis vs. Cellular Respiration
ENERGY
Energy is stored
Energy is released
CO2 & O2
Uses CO2; Produces O2
Water
Uses water
Glucose
Produces glucose from energy
Location: Where does it take place?
Chloroplasts of green plants, algae, and some microorganisms
Light
Requires light (light-dependent reaction; Calvin Cycle can occur in light or dark.)

54. Photosynthesis vs. Cellular Respiration
ENERGY
Energy is stored
Energy is released
CO2 & O2
Uses CO2; Produces O2
Uses O2; Produces CO2
Water
Uses water
Glucose
Produces glucose from energy
Location: Where does it take place?
Chloroplasts of green plants, algae, and some microorganisms
Light
Requires light (light-dependent reaction; Calvin Cycle can occur in light or dark.)

55. Photosynthesis vs. Cellular Respiration
ENERGY
Energy is stored
Energy is released
CO2 & O2
Uses CO2; Produces O2
Uses O2; Produces CO2
Water
Uses water
Produces Water
Glucose
Produces glucose from energy
Location: Where does it take place?
Chloroplasts of green plants, algae, and some microorganisms
Light
Requires light (light-dependent reaction; Calvin Cycle can occur in light or dark.)

56. Photosynthesis vs. Cellular Respiration
ENERGY
Energy is stored
Energy is released
CO2 & O2
Uses CO2; Produces O2
Uses O2; Produces CO2
Water
Uses water
Produces Water
Glucose
Produces glucose from energy
Burns glucose from energy
Location: Where does it take place?
Chloroplasts of green plants, algae, and some microorganisms
Light
Requires light (light-dependent reaction; Calvin Cycle can occur in light or dark.)

57. Photosynthesis vs. Cellular Respiration
ENERGY
Energy is stored
Energy is released
CO2 & O2
Uses CO2; Produces O2
Uses O2; Produces CO2
Water
Uses water
Produces Water
Glucose
Produces glucose from energy
Burns glucose from energy
Location: Where does it take place?
Chloroplasts of green plants, algae, and some microorganisms
Glycolysis: Cytoplasm of eukaryotic, prokaryotic cells Aerobic respiration: mitochondria of ALL eukaryotes
Light
Requires light (light-dependent reaction; Calvin Cycle can occur in light or dark.)

58. Photosynthesis vs. Cellular Respiration
ENERGY
Energy is stored
Energy is released
CO2 & O2
Uses CO2; Produces O2
Uses O2; Produces CO2
Water
Uses water
Produces Water
Glucose
Produces glucose from energy
Burns glucose from energy
Location: Where does it take place?
Chloroplasts of green plants, algae, and some microorganisms
Glycolysis: Cytoplasm of eukaryotic, prokaryotic cells Aerobic respiration: mitochondria of ALL eukaryotes
Light
Requires light (light-dependent reaction; Calvin Cycle can occur in light or dark.)
Occurs in dark and light