Regents Biology 2006-2007

Photosynthesis:Life from Light and Air

Regents Biology

Plants are energy producers Like animals, plants need energy to live

unlike animals, plants don’t need to eat food to make that energy

Plants make both FOOD & ENERGY animals are consumers plants are producers

Regents Biology

How do plants make energy & food? Plants use the energy from the sun

to make ATP energy to make sugars

glucose, sucrose, cellulose, starch, & more

sun

ATP

sugars

Regents Biology

H2O

Building plants from sunlight & air Photosynthesis

2 separate processes ENERGY building reactions

collect sun energy use it to make ATP

SUGAR building reactions take the ATP energy collect CO2 from air &

H2O from ground use all to build sugars

ATP

sun

sugars

+CO2

Regents Biology

Using light & air to grow plants Photosynthesis

using sun’s energy to make ATP using CO2 & water to make sugar in chloroplasts allows plants to grow makes a waste product

oxygen (O2)

Regents Biology

What do plants need to grow? The “factory” for making

energy & sugars chloroplast

Fuels sunlight carbon dioxide water

The Helpers enzymes H2O

sugars

ATP

enzymes

CO2

sun

Regents Biology

H2O

Photosynthesis

ENERGYbuilding reactions

SUGARbuilding reactions

ATPADP

CO2

sugar

sun

used immediatelyto synthesize sugars

AP Biology

Chloroplasts double membrane stroma

fluid-filled interior thylakoid sacs grana stacks

Thylakoid membrane contains chlorophyll molecules electron transport chain ATP synthase

Plant structure

outer membrane inner membrane

thylakoidgranum

stroma

AP Biology

Labeling the Chloroplast Outer Membrane = I Intermembrane Space = J Inner Membrane = K Granum Thylakoid = L = GREEN!! Stromal Lamella = M DNA = N Ribosome = O Starch Grain = P Stroma = Q

AP Biology

AP Biology

Lab objectives Separate plant pigments using

chromatography Calculate Rf values for four

different plant pigments Rf value = distance pigment

traveled distance solvent traveled

AP Biology

Pigments of photosynthesis Pigments of photosynthesis Must be present for Pn to occur Embedded in thylakoid membrane Each pigment absorbs light of specific

wavelengths Arranged in a photosystem Collection of pigment molecules embedded in a

protein Examples:

Chlorophyll a: ¾ of chlorophylls in green plants Primary Pn pigment; absorbs blue and red light

Chlorophyll b: absorbs light in blue-green and orange-red spectrum

Carotenoids: absorb light in the blue and blue-green regions of the spectrum (carotenes and xanthophylls)

AP Biology

Pigments of photosynthesis

Chlorophylls & other pigments embedded in thylakoid membrane arranged in a “photosystem”

Collection of pigment molecules embedded in a protein

AP Biology

Photosynthesis

Light reactions light-dependent reactions energy conversion reactions

convert solar energy to chemical energy ATP & NADPH

Calvin cycle light-independent reactions sugar building reactions

uses chemical energy (ATP & NADPH) to reduce CO2 & synthesize C6H12O6

AP Biology

2 Processes of Photosynthesis

1) Light reactions Takes place in the thylakoid

membranes light-dependent reactions Uses water energy conversion reactions

convert solar energy to chemical energy ATP & NADPH

net products: ATP, NADPH, Oxygen Uses photosystems with reaction centers

of 2 chlorophyll-a molecules

AP Biology

Light Reactions of Photosynthesis

Photosystem II

Photosystem I

AP Biology

ETC of Photosynthesis ETC uses light energy to produce

ATP & NADPH go to Calvin cycle

PS II (PS680) absorbs light and gets excited excited electron passes from 2 chlorophyll-

a to “primary electron acceptor” Chlorophyll is now _____________ and

requires an electron enzyme extracts electrons from H2O &

supplies them to chlorophyll splits H2O O combines with another O to form O2

O2 released to atmosphere and we breathe easier!

AP Biology

Light Reactions of Photosynthesis

Photosystem II

Photosystem I

AP Biology

Excited electron passes down ETC to PS I (PS700)

Each time electron is passed, releases a little energy used to pump H+ from stroma into thylakoid

H+ will then diffuse down conc. gradient back into stroma Pass through ATP Synthase allowing phosphorylation of ADP

ATP used in Calvin Cycle

AP Biology

MEANWHILE… PS I (PS700) has also been activated

by light excited electron passes from

chlorophyll to “primary electron acceptor”

need to replace electron in chlorophyll!! Electron comes from ETC of PSII

Excited electron passes to electron carrier molecule down another ETC Reduces NADP+ to make NADPH Sent to Calvin Cycle in the stroma

AP Biology

split H2O

Light Reactions of Photosynthesis

O

ATP

to Calvin CycleH+

H+

H+

H+

H+

H+

H+

H+

H+H+

H+

e e

e e

sunsun

AP Biology

Photosynthesis Lab 2 Photosynthesis Lab 2 ObjectiveObjective Measure the rate of photosynthesis Measure the rate of photosynthesis

using a spectrophotometer.using a spectrophotometer. Cuvette 1 should be used to calibrate Cuvette 1 should be used to calibrate

the machine between each reading. the machine between each reading. Set to 100% transmittance.Set to 100% transmittance.

Cuvette 2 should stay wrapped in foil Cuvette 2 should stay wrapped in foil the whole time unless a reading is the whole time unless a reading is being done.being done.

Remember, DPIP changes from blue to Remember, DPIP changes from blue to clear as photosynthesis occursclear as photosynthesis occurs this will cause a higher % this will cause a higher %

transmittance!transmittance!

AP Biology

AP Biology

From Light Reactions to Calvin Cycle Sugar Building Process

Takes place in the stroma of the chloroplast

Need products of light reactions to drive synthesis reactions ATP NADPH

Uses CO2

stroma

thylakoid

AP Biology

RuBisCo RuBisCo Enzyme which fixes carbon from air

ribulose bisphosphate carboxylase the most important enzyme in the

world! it makes life out of air!

definitely the most abundant enzyme

AP Biology

starch,sucrose,cellulose& more

1C CO2

Calvin Cycle

5CRuBP

3C

RuBisCo

1. Carbon fixation

2. G3P Production

3. Regenerationof RuBP

ribulose bisphosphate

ribulose bisphosphate carboxylase

6 NADP

6 NADPH 6 ADP

6 ATP

3 ADP

3 ATP

usedto make

glucose

3C

3CG3Pglyceraldehyde-3-P

C C C C C

C C C C C

C C C C C

6C

C C C C C C

C C C C C C

C C C C C C

C C C

C C C

C C C

C C C

C C C

C C C

PGAphosphoglycerate

C C C

C C C

C C C

C C C

C C C

C C CC C C

CC

C

5C

AP Biology

AP Biology

AP Biology

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AP Biology

A good scientific title!

AP Biology

Photosynthesis summary Light reactions

produced ____________ produced ____________ consumed ____________ produced ____________ as byproduct

Calvin cycle consumed ____________ produced ____________ regenerated ____________ regenerated ____________

AP Biology

H2O

Energy cycle

Photosynthesis

Cellular Respiration

sun

glucose O2CO2

plants

animals, plants

ATP

CO2 H2O C6H12O6 O2light

energy + ++

CO2 H2OC6H12O6 O2ATP

energy+ ++

AP Biology

Light Reactions

O2

H2O

Energy BuildingReactions

ATP

produces ATP produces NADPH releases O2 as a

waste product

sunlight

H2O ATP O2light

energy ++ + NADPH

NADPH

AP Biology

Calvin Cycle

sugars

CO2

SugarBuilding

Reactions

ADP

builds sugars uses ATP &

NADPH recycles ADP

& NADP back to make

more ATP & NADPHATP

NADPH

NADP

CO2 C6H12O6 ++ + NADPATP + NADPH ADP