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PHOTOSYNTHESIPHOTOSYNTHESISS
2
PhotosynthesisPhotosynthesis• AnabolicAnabolic (small molecules combined) (small molecules combined)• EndergonicEndergonic (stores energy) (stores energy)• Carbon dioxide (COCarbon dioxide (CO22)) requiring requiring
process that uses process that uses light energy light energy (photons)(photons) and and water (Hwater (H22O)O) to produce to produce organic macromolecules (glucose).organic macromolecules (glucose).
6CO2 + 6H2O C6H12O6 + 6O2
glucoseglucose
SUNphotonsphotons
3
Question:Question:
Where does Where does photosynthesiphotosynthesis take place?s take place?
4
PlantsPlants• Autotrophs Autotrophs – produce their own – produce their own
food food (glucose)(glucose)• Process called Process called photosynthesisphotosynthesis• Mainly occurs in the Mainly occurs in the leaves:leaves:
a.a.stoma - poresstoma - pores
b.b.mesophyll cellsmesophyll cells
StomaMesophyllCell
Chloroplast
5
Stomata (stoma)Stomata (stoma)PoresPores in a plant’s cuticle in a plant’s cuticle
through which through which water vaporwater vapor and and gasesgases (CO(CO22 & O & O22)) are are exchanged between the plant exchanged between the plant and the atmosphere.and the atmosphere.
Guard CellGuard CellCarbon Dioxide (CO2)
Oxygen (O2)
Found on the underside of Found on the underside of leavesleaves
StomStomaa
6
Mesophyll Cell of LeafMesophyll Cell of Leaf
Cell WallNucleusNucleus
Chloroplast
Central Vacuole
Photosynthesis occurs in these Photosynthesis occurs in these cells!cells!
7
ChloroplastChloroplast
OrganelleOrganelle where photosynthesisphotosynthesis takes place.
GranumThylakoid
Stroma
Outer Membrane
Inner Membrane
Thylakoid stacks are connected Thylakoid stacks are connected togethertogether
8
ThylakoidThylakoid
Thylakoid Membrane
Thylakoid SpaceGranum
Grana make up the inner Grana make up the inner membranemembrane
9
Question:Question:
Why are Why are plants plants green?green?
10
Chlorophyll MoleculesChlorophyll Molecules
• Located in the Located in the thylakoid membranesthylakoid membranes• Chlorophyll have Chlorophyll have MgMg++ in the center in the center• Chlorophyll pigments Chlorophyll pigments harvest energy harvest energy
(photons)(photons) by absorbing certain by absorbing certain wavelengths wavelengths (blue-420 nm and red-(blue-420 nm and red-660 nm660 nm are most important) are most important)
• Plants are Plants are greengreen because the because the green green wavelength is reflectedwavelength is reflected, not absorbed, not absorbed.
11
When small molecule combine to make more complex molecules it
is a _____reaction
12
25% 25%25%25%
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34
1. Catabolic2. Anabolic3. Spontaneous4. Combustible
________ reactions store energy
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Endergonic
Exergo
nic
Anabolic
Catabolic
25% 25%25%25%
1. Endergonic2. Exergonic3. Anabolic4. Catabolic
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34
The reactants for photosynthesis are H2O, sun, and ________
14
25% 25%25%25%
1. ATP2. O2
3. CO2
4. C6H12O6
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34 20
What are the products of photosynthesis?
15
25% 25%25%25%1. CO2 + H2O
2. O2 + H2O
3. C6H12O6 + CO2
4. C6H12O6 + O2
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34
In photosynthesis ____energy is converted to ______energy
16
Solar, h
eat
Heat, s
olar
Chemical, l
igh...
Light,
chemica
...
25% 25%25%25%1. Solar, heat2. Heat, solar3. Chemical, light4. Light, chemical
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34 20
Where does photosynthesis take place?
17
Nucle
us
Chloroplasts
Mito
chondria ER
Golgi
20% 20% 20%20%20%
1. Nucleus2. Chloroplasts3. Mitochondria4. ER5. Golgi
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34
Which part of leaves lets gases in and out?
18
Meso
phyll
Gran
a
Stoma
Bundle sheath
25% 25%25%25%1. Mesophyll2. Grana3. Stoma4. Bundle sheath
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34
Why are plants green?
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Absorb
green l..
.
Reflect gre
en ...
Chlorophyll
Cell wall
s
25% 25%25%25%
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34
1. Absorb green light
2. Reflect green light
3. Chlorophyll4. Cell walls
20
Wavelength of Light (nm)Wavelength of Light (nm)
400 500 600 700
Short wave Long wave(more energy) (less energy)
21
Absorption of Light by Absorption of Light by ChlorophyllChlorophyll
wavelengthwavelength
Absorption
violet blue green yellow orange red
Chlorophyll absorbs blue-violet & red Chlorophyll absorbs blue-violet & red light bestlight best
22
Question:Question:
During the fall, During the fall, what causes what causes the leaves to the leaves to
change colors?change colors?
23
Fall ColorsFall Colors• In addition to the chlorophyll In addition to the chlorophyll
pigments, there are pigments, there are other other pigmentspigments present present
• During the fall, the During the fall, the green green chlorophyll pigments are chlorophyll pigments are greatly reducedgreatly reduced revealing the revealing the other pigmentsother pigments
• CarotenoidsCarotenoids are pigments that are pigments that are either are either redred, , orangeorange, or , or yellowyellow
24
Redox ReactionRedox Reaction
The The transfertransfer of one or more of one or more electronselectrons from one reactant from one reactant to anotherto another
Two types:Two types:
1.1. Oxidation is the Oxidation is the lossloss of e of e--
2.2. Reduction is the Reduction is the gaingain of of ee--
25
Oxidation ReactionOxidation Reaction
The The loss of electronsloss of electrons from a from a substance or the substance or the gain of gain of oxygen.oxygen.
glucoseglucose
6CO2 + 6H2O C6H12O6 + 6O2
OxidationOxidation
Carbon Carbon dioxidedioxide WaterWater
OxygenOxygen
26
Reduction ReactionReduction Reaction
The The gain of electronsgain of electrons to a to a substance or the substance or the loss of loss of oxygen.oxygen.
glucoseglucose
6CO2 + 6H2O C6H12O6 + 6O2
ReductionReduction
What types of wavelengths of light have the most energy?
27
Short
Long
Medium le
ngth
Length
doesn’t..
.
25% 25%25%25%
1. Short2. Long 3. Medium length4. Length doesn’t
have an impact on energy
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34 20
What wavelength does chlorophyll absorb best?
28
Gre
en
Yellow
Ora
nge
Blue
25% 25%25%25%1. Green2. Yellow3. Orange 4. Blue
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34
In a redox reaction a substance is ______ if it gains an electron(s)
29
25% 25%25%25%1. Oxidized 2. Reduced3. Photysynthesize
d4. Respired
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34
How do plants store energy?
30
In w
ater
As CO2
In A
TP
In A
DP
25% 25%25%25%
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34
1. In water2. As CO2
3. In ATP4. In ADP
What is added to ADP to make ATP?
31
Oxyg
en
Carbon dioxide
Nitr
ogen
Phosphate
25% 25%25%25%
1. Oxygen2. Carbon dioxide3. Nitrogen4. Phosphate
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34
32
Question:Question:
What do What do cells use cells use
for for energy?energy?
33
Energy for Life on EarthEnergy for Life on Earth
•Sunlight is the ULTIMATE energy for all life on Earth
•Plants store energy in the chemical bonds of sugars
•Chemical energy is released as ATP during cellular respiration
34
Structure of ATPStructure of ATP
• ATP stands for adenosine triphosphate
• It is composed of the 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
35
Removing a Phosphate from Removing a Phosphate from ATPATP
Breaking the LAST PHOSPHATE bond from ATP, will ---– Release ENERGY for cells to use– Form ADP– Produce a FREE PHOSPHATE
GROUP
36
High Energy Phosphate High Energy Phosphate BondBond
37
FREE PHOSPHATE can be re-FREE PHOSPHATE can be re-attached to ADP reforming ATPattached to ADP reforming ATP
Process called Process called PhosphorylationPhosphorylation
38
PhosphorylationPhosphorylation
39
Parts of Parts of PhotosynthesisPhotosynthesis
40
Two Parts of Two Parts of PhotosynthesisPhotosynthesis
Two reactions make up Two reactions make up photosynthesis:photosynthesis:
1.1.Light Reaction or Light Light Reaction or Light Dependent ReactionDependent Reaction - -
Produces energy from solar Produces energy from solar power (photons) in the form power (photons) in the form of ATP and NADPH.of ATP and NADPH.
SUNSUN
41
Two Parts of Two Parts of PhotosynthesisPhotosynthesis
2. 2. Calvin Cycle or Light Calvin Cycle or Light Independent Independent ReactionReaction
• Also called Also called Carbon Carbon FixationFixation or or CC33 Fixation Fixation
• Uses energy (Uses energy (ATP and ATP and NADPHNADPH) from light ) from light reaction to make sugar reaction to make sugar (glucose).(glucose).
42
Light Reaction (Electron Light Reaction (Electron Flow)Flow)
• Occurs in the Occurs in the Thylakoid Thylakoid membranesmembranes
• During the During the light reactionlight reaction, , there are there are twotwo possible routes possible routes for electron flow:for electron flow:
A.A. Cyclic Electron FlowCyclic Electron Flow
B.B. Noncyclic Electron FlowNoncyclic Electron Flow
43
Cyclic Electron FlowCyclic Electron Flow• Occurs in the Occurs in the thylakoidthylakoid
membrane.membrane.• Uses Uses Photosystem I onlyPhotosystem I only• P700P700 reaction center- chlorophyll reaction center- chlorophyll
a a • Uses Electron Transport Chain Uses Electron Transport Chain
(ETC)(ETC)• Generates Generates ATP onlyATP only
ADP + ADP + ATP ATP
P
44
Cyclic Electron FlowCyclic Electron Flow
P700
PrimaryElectronAcceptor
e-
e-
e-
e-
ATPATPproducedby ETC
Photosystem I
AccessoryPigments
SUN
Photons
Pigments absorb light energy & excite Pigments absorb light energy & excite e- of Chlorophyll a to produce ATP e- of Chlorophyll a to produce ATP
45
Noncyclic Electron FlowNoncyclic Electron Flow• Occurs in the Occurs in the thylakoidthylakoid membrane membrane• Uses Uses Photosystem II Photosystem II and and
Photosystem IPhotosystem I• P680 P680 reaction center reaction center (PSII)(PSII) - -
chlorophyll achlorophyll a• P700P700 reaction center reaction center (PS I)(PS I) - -
chlorophyll achlorophyll a• Uses Electron Transport Chain Uses Electron Transport Chain
(ETC)(ETC)• Generates Generates OO22, ATP and NADPH, ATP and NADPH
46
Noncyclic Electron FlowNoncyclic Electron Flow
P700
Photosystem IP680
Photosystem II
PrimaryElectronAcceptor
PrimaryElectronAcceptor
ETC
EnzymeReaction
H2O
1/2O1/2O22 + 2H+
ATPATP
NADPHNADPH
Photon
2e-
2e-
2e-
2e-
2e-
SUN
Photon
HH22O is split in PSII & ATP is made, while the energy carrier O is split in PSII & ATP is made, while the energy carrier NADPH is made in PSINADPH is made in PSI
47
Noncyclic Electron FlowNoncyclic Electron Flow
• ADP +ADP + ATPATP• NADPNADP++ + H + H NADPHNADPH• OxygenOxygen comes from the comes from the
splitting of Hsplitting of H22O, not COO, not CO22
HH22O O 1/2 O 1/2 O22 + 2H + 2H++
PP
48
ChemiosmosisChemiosmosis
• Powers Powers ATP synthesisATP synthesis• Takes place across the Takes place across the
thylakoid membranethylakoid membrane• Uses Uses ETCETC and and ATP synthase ATP synthase
(enzyme)(enzyme)• H+H+ move down their move down their
concentration gradient through concentration gradient through channels of ATP synthasechannels of ATP synthase forming forming ATP from ADPATP from ADP
49
ChemiosmosisChemiosmosisH+ H+
ATP Synthase
H+ H+ H+ H+
H+ H+ high Hhigh H++
concentrationconcentration
H+ADP + P ATP
PS II PS IE
TC
low Hlow H++
concentrationconcentration
H+ThylakoidThylakoidSpaceSpace
ThylakoidThylakoid
SUN (Proton Pumping)
50
Calvin CycleCalvin Cycle• Carbon Fixation Carbon Fixation (light independent (light independent
reaction)reaction)• CC33 plants (80% of plants on earth) plants (80% of plants on earth)• Occurs in the Occurs in the stromastroma• Uses Uses ATP and NADPHATP and NADPH from light from light
reaction as energyreaction as energy• Uses Uses COCO22
• To produce To produce glucoseglucose: it takes : it takes 6 6 turns and uses 18 ATP and 12 turns and uses 18 ATP and 12 NADPH. NADPH.
51
ChloroplastChloroplast
GranumThylakoid
STROMA– where Calvin Cycle occursOuter Membrane
Inner Membrane
52
Calvin Cycle (CCalvin Cycle (C33 fixation) fixation)
6CO2
6C-C-C-C-C-C
6C-C-C 6C-C-C
6C-C-C-C-C
12PGA
RuBP
12G3P
(unstable)
6NADPH 6NADPH
6ATP 6ATP
6ATP
C-C-C-C-C-CGlucose
(6C)(36C)
(36C)
(36C)
(30C)
(30C)
(6C)
6C-C-C 6C-C-C
C3
glucose
53
Calvin CycleCalvin Cycle
Remember: CRemember: C33 = Calvin Cycle = Calvin Cycle
C3
Glucose
54
PhotorespirationPhotorespiration
• Occurs on hot, dry, bright daysOccurs on hot, dry, bright days• Stomates closeStomates close
• Fixation of OFixation of O22 instead of CO instead of CO22
• Produces Produces 2-C molecules 2-C molecules instead of 3-C sugar moleculesinstead of 3-C sugar molecules
• Produces Produces no sugarno sugar molecules molecules or or no ATPno ATP
55
PhotorespirationPhotorespiration
Because of photorespiration, Because of photorespiration, plants have special plants have special adaptations to limit the effect adaptations to limit the effect of photorespiration:of photorespiration:
1.1. CC44 plants plants
2.2. CAM plantsCAM plants
56
CC44 Plants Plants• Hot, moist Hot, moist
environmentsenvironments• 15% of plants 15% of plants
((grasses, corn, grasses, corn, sugarcane)sugarcane)
• Photosynthesis Photosynthesis occurs in 2 placesoccurs in 2 places
• Light reactionLight reaction - - mesophyll cellsmesophyll cells
• Calvin cycleCalvin cycle - - bundle sheath bundle sheath cellscells
57
CC44 Plants Plants
Mesophyll CellMesophyll Cell
CO2
C-C-C
PEP
C-C-C-CMalate-4C sugar
ATP
Bundle Sheath CellBundle Sheath Cell
C-C-C
Pyruvic Acid
C-C-C-C
CO2
C3
Malate
Transported
glucoseVascular Tissue
58
CAM PlantsCAM Plants• Hot, dry environmentsHot, dry environments• 5%5% of plants (cactus and ice of plants (cactus and ice
plants)plants)• Stomates closed during dayStomates closed during day• Stomates open during the nightStomates open during the night• Light reaction - occurs during Light reaction - occurs during
the daythe day• Calvin Cycle - occurs when COCalvin Cycle - occurs when CO22
is presentis present
59
CAM PlantsCAM PlantsNight (Stomates Open) Day (Stomates Closed)
Vacuole
C-C-C-CMalate
C-C-C-CMalate Malate
C-C-C-CCO2
CO2
C3
C-C-CPyruvic acid
ATPC-C-CPEP glucose
60
Question:Question:
Why do CAM Why do CAM plants close plants close
their stomata their stomata during the day?during the day?
Cam plants Cam plants close their close their
stomata in the stomata in the hottest part hottest part of the day to of the day to
conserve conserve waterwater
What is produced in the light reactions?
62
NADP+ &
ATP
NADP+ &
ADP
NADPH &
ATP
NADPH &
ADP
25% 25%25%25%
1. NADP+ & ATP2. NADP+ & ADP3. NADPH & ATP4. NADPH & ADP
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34
What is produced in the calvin cycle?
63
Wate
r
Carbon dioxide
Gluco
se
Sucro
se
25% 25%25%25%
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34
1. Water 2. Carbon dioxide3. Glucose4. Sucrose
Where does the O2 made in photosynthesis come from?
64
CO2 H
2O
The atmosp
here
C6H12O6
25% 25%25%25%1. CO2
2. H2O
3. The atmosphere4. C6H12O6
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34
How do CAM plants limit photorespiration?
65
Stomate
s close
...
Stomate
s close
...
Chloroplast
re...
Makin
g gluco
se
25% 25%25%25%1. Stomates close in
day2. Stomates close at
night3. Chloroplast rests
during day4. Making glucose
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34
In Photorespiration ____ is fixed to make 2 carbon molecules
66
CO2
C6H12O6 O
2 H
2O
25% 25%25%25%
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
1. CO2
2. C6H12O6
3. O2
4. H2O