photosynthesis the “rodney dangerfield” process of biology
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PhotosynthesisPhotosynthesis
The “Rodney Dangerfield” The “Rodney Dangerfield” process of Biologyprocess of Biology
The Process that Feeds the BiosphereThe Process that Feeds the Biosphere
Q: Where does photosynthesis Q: Where does photosynthesis occur?occur?
Photosynthetic Photosynthetic ORGANISMS ORGANISMS include…..include…..
……plants, algae, protists, plants, algae, protists, cyanobacteriacyanobacteria
Where does photosynthesis occur?Where does photosynthesis occur?
(Assume plants)(Assume plants)The The ORGANORGAN of of photosynthesis photosynthesis is….is….
Leaf: ORGAN of photosynthesisLeaf: ORGAN of photosynthesis
Leaf: ORGAN of photosynthesisLeaf: ORGAN of photosynthesis
Let’s take a closer look at a Let’s take a closer look at a chlorenchyma (mesophyll) cell…chlorenchyma (mesophyll) cell…
Introducing the Introducing the OrganelleOrganelle of of PhotosynthesisPhotosynthesis
The ChloroplastThe Chloroplast
Remember this?Remember this?
HumanHuman OrganismOrganism RedbudRedbud
OrganOrgan
TissueTissue
CellCell
OrganelleOrganelle
MoleculeMolecule
Possible Answers:Possible Answers:
HumanHuman OrganismOrganism RedbudRedbud
BrainBrain OrganOrgan
NervousNervous TissueTissue
NeuronNeuron CellCell
NucleusNucleus OrganelleOrganelle
DNADNA MoleculeMolecule
Levels of OrganizationLevels of Organization
HumanHuman OrganismOrganism RedbudRedbud
BrainBrain OrganOrgan LeafLeaf
NervousNervous TissueTissue ChlorenchymaChlorenchyma
NeuronNeuron CellCell ChlorenchymaChlorenchyma
NucleusNucleus OrganelleOrganelle ChloroplastChloroplast
DNADNA MoleculeMolecule ChlorophyllChlorophyll
Equations of PhotosynthesisEquations of Photosynthesis
Complete:
6 CO2 + 12 H2O + Light energy C6H12O6 + 6 O2 + 6 H2 O
Net:6 CO2 + 6 H2O + Light energy C6H12O6 + 6 O2
Photosynthesis & Cellular Photosynthesis & Cellular RespirationRespiration
PhotosynthesisPhotosynthesis::6 CO2 + 6 H2O + Light energy C6H12O6 + 6 O2
Remember:First Law of Thermodynamics
Redox Reactions
Cellular Respiration:
C6H12O6 + 6O2 6CO2 + 6H2O + ATP Energy
Purpose of Photosynthesis?Purpose of Photosynthesis?
Parts of PhotosynthesisParts of Photosynthesis
Photosynthesis consists of two Photosynthesis consists of two processes:processes:
1.1. The Light reactionsThe Light reactions
2.2. The Calvin cycleThe Calvin cycle
Parts of PhotosynthesisParts of Photosynthesis
1.1. The Light reactionsThe Light reactions
Purpose: To trap photons of light energy Purpose: To trap photons of light energy and temporarily store in in molecules of and temporarily store in in molecules of ATP and NADPHATP and NADPH
Location: surface of the Thylakoid disksLocation: surface of the Thylakoid disks
Note Thyllakoid Disk:Note Thyllakoid Disk:
Parts of PhotosynthesisParts of Photosynthesis
2. The Calvin cycle (aka) dark reactions:2. The Calvin cycle (aka) dark reactions:
Purpose: To remove the trapped energy Purpose: To remove the trapped energy from temporary storage, combine from temporary storage, combine with carbon dioxide, to make sugar!with carbon dioxide, to make sugar!
Location: Stroma of chloroplastLocation: Stroma of chloroplast
Note stroma:Note stroma:
Chlorophyll:Chlorophyll: Key molecule Key molecule (pigment) of photosynthesis(pigment) of photosynthesis
The above image is from http://www.nyu.edu:80/pages/mathmol/library/photo.
Key VocabularyKey Vocabulary
Pigment -Pigment - Photosystem –Photosystem – photonphoton
Nature of LightNature of Light
Steps of Light ReactionsSteps of Light Reactions
See handout (& remember purpose)See handout (& remember purpose) Note: “reaction center”Note: “reaction center”
What happens when chlorophyll What happens when chlorophyll absorbs light?absorbs light?
Light Reactions!Light Reactions!
Understanding checkUnderstanding check(Light Reactions)(Light Reactions)
Where is energy of photons of light?Where is energy of photons of light?
Why do plants need water (during Why do plants need water (during photosynthesis)?photosynthesis)?
How has oxygen been produced?How has oxygen been produced?
Has carbon dioxide been used?Has carbon dioxide been used?
Calvin CycleCalvin Cycle
Understanding CheckUnderstanding Check(Calvin Cycle)(Calvin Cycle)
Which products of the light reactions Which products of the light reactions are necessary to drive the Calvin are necessary to drive the Calvin cycle?cycle?
What is the most abundant protein What is the most abundant protein on Earth? What does it do?on Earth? What does it do?(Aside: What is the most abundant carbohydrate (Aside: What is the most abundant carbohydrate on Earth?)on Earth?)
Understanding CheckUnderstanding Check(General)(General)
Do plants use oxygen? Why or why Do plants use oxygen? Why or why not?not?
Do plants produce both oxygen & Do plants produce both oxygen & carbon dioxide?carbon dioxide?
Big picture #1:Big picture #1:
Indicate “light” or “Calvin” for each Indicate “light” or “Calvin” for each reactant and product:reactant and product:
CO2 + H2O + Light E C6H12O6 + O2 (dark) (light) (light) (dark) (light)
Big picture #2:Big picture #2:
Indicate how each enters or leaves the Indicate how each enters or leaves the plant: plant:
CO2 + H2O + Light E C6H12O6 + O2
Big Picture #3:Big Picture #3:
Importance of PhotosynthesisImportance of Photosynthesis(3 ways to view photosynthesis……..)(3 ways to view photosynthesis……..)
1) 1) Traps energyTraps energy for plant and for entire for plant and for entire ecosystemecosystem(Remember: Plants are (Remember: Plants are autotrophs/producersautotrophs/producers
2) 2) C-fixationC-fixation for plant and for entire for plant and for entire ecosystemecosystem(Remember: Plants are (Remember: Plants are autotrophs/producers)autotrophs/producers)
Big Picture #3Big Picture #3
Importance of PhotosynthesisImportance of Photosynthesis
3) Produces 3) Produces oxygenoxygen for entire planet! for entire planet!
Note: This is an accident!Note: This is an accident!in purple bacteria:CO2 + H2S + Light E C6H12O6 + S
Question: What organisms USE oxygen?Question: What organisms USE oxygen?
For what purpose?For what purpose?
Evolutionary PerspectiveEvolutionary Perspective
Earth formed about 4.5 byaEarth formed about 4.5 bya
Original atmosphere was anaerobic (no Original atmosphere was anaerobic (no oxygen)oxygen)
Cyanobacteria (first photosynthesizers) Cyanobacteria (first photosynthesizers) released oxygenreleased oxygen
Build-up of oxygen allowed eukaryotes Build-up of oxygen allowed eukaryotes and multi-cellular organisms to flourish!and multi-cellular organisms to flourish!
Evolutionary Perspective (cont)Evolutionary Perspective (cont)
Oxygen build-up in atmosphere also Oxygen build-up in atmosphere also allowed for the formation of OZONE!allowed for the formation of OZONE!
3 03 022 2 0 2 03 3
Why is ozone important?Why is ozone important?
Big Picture #4Big Picture #4
Can you list SIX similarities and SIX Can you list SIX similarities and SIX differences/opposites between differences/opposites between cellular respiration and cellular respiration and photosynthesis?photosynthesis?
Big Picture #4 (cont) Big Picture #4 (cont)
Similarities between mitochondria & Similarities between mitochondria & chloroplast:chloroplast:
Both have internal and external Both have internal and external membranemembrane
Both believed to have originated Both believed to have originated from once free-living bacteria cellsfrom once free-living bacteria cells(Endosymbiotic Theory)(Endosymbiotic Theory)
Both use chemiosmosis to generate Both use chemiosmosis to generate ATPATP
Chloroplasts and MitochondriaChloroplasts and Mitochondria• Generate ATP by the same basic Generate ATP by the same basic
mechanism: mechanism: ChemiosmosisChemiosmosis• Compare/Contrast:Compare/Contrast:
2. Movement of H+ (between what 2. Movement of H+ (between what spaces, what direction?)spaces, what direction?)