8. Photosynthesis

http://www.science.siu.edu/plant-biology/PLB117/JPEGs%20CD/0076.JPG

http://www.youtube.com/watch?v=sQK3Yr4Sc_k

WHAT DO CELLS USE ENERGY FOR ?

ACTIVE TRANSPORT

Na+ - K + PUMPEndocytosisExocytosis

Energy and Life

WHAT DO CELLS USE ENERGY FOR ?

MovementSynthesis of

biomolecules Reproduction

Meiosis: http://www.tokyo-med.ac.jp/genet/anm/Cilia: http://www.sk.lung.ca/content.cfm?edit_realword=hwbreatheReplication: http://www.beyondbooks.com/lif71/4c.aspTranscription:http://www.wappingersschools.org/RCK/staff/teacherhp/johnson/visualvocab/mRNA.gifTranslation:

ATP

ATP

ONE SPECIAL KIND of NUCLEOTIDE is used by cells to store and transport ENERGY

CELLS USE ATP TO STORE and RELEASE ENERGY

ATP = __________________________Adenosine triphosphate

____ PHOSPHATE GROUPS

3

ATP can change into ADP

ADP = __________________________Adenosine diphosphate

____ PHOSPHATE GROUPS

2

ATP → ____ + ____ +

ATP releases energy stored in a high energychemical bond by removing the phosphate and becoming ADP

ADP

ADP + ___ + ________ → ___

The energy to do this comes from____________ like _____________

Cells ________ energy by adding the phosphate back on to ADP to make ATP.

ATP

It’s like recharging the battery !

STORE

FOODS GLUCOSE

_____________ can make their own food usingenergy from sunlight.

Ex: Green plants, a few bacteria

Autotrophs

__________________ get energy by consumingother organisms

Ex: Animals, fungi, most bacteria

Heterotrophs

Photosynthesis

Photosynthesis

• a metabolic pathway that converts light energy into chemical energy.

• is the process by which plants, some bacteria, and some protists use the energy from sunlight to produce sugar.

Photosynthesis

Photosynthesis

Method of converting sun energy into chemical energy usable by cells

Autotrophs: self feeders, organisms capable of making their own food– Photoautotrophs: use sun energy e.g. plants

photosynthesis-makes organic compounds (glucose) from light

– Chemoautotrophs: use chemical energy e.g. bacteria that use sulfide or methane chemosynthesis-makes organic compounds from chemical energy contained in sulfide or methane

Photosynthesis

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

Chloroplasts containing chlorophyll.

Chloroplast

Chloroplast

Chlorophyll

Visible Spectrum

Photosynthetic Pigments

6H2O + 6CO2 C6H12O6 + 6O2

(water) + (carbon dioxide) + (light) (sugar) + (oxygen)

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Leaves and Photosynthesis

How Leaves Work

LIGHT-DEPENDENT REACTIONS

See an animation about the ELECTRON TRANSPORT CHAIN

Pearson Education Inc; Publishing as Pearson Prentice Hall

SEE A MOVIEATP SYNTHASEIN ACTION

http://www.stolaf.edu/people/giannini/flashanimat/metabolism/atpsyn1.sw

http://www.stolaf.edu/people/giannini/flashanimat/metabolism/photosynthesis.swf

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Light Reactions:Noncyclic Electron

Pathway

28

Light Reactions:

Light-dependent Reactions

Overview: light energy is absorbed by chlorophyll molecules-this light energy excites electrons and boosts them to higher energy levels. They are trapped by electron acceptor molecules that are poised at the start of a neighboring transport system. The electrons “fall” to a lower energy state, releasing energy that is harnessed to make ATP

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 cellNADP+, NADPH NAD+, NADP FAD, FADH2

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)

Calvin Cycle (light independent or “dark” reactions)

ATP and NADPH generated in light reactions used to fuel the reactions which take CO2 and break it apart, then reassemble the carbons into glucose.

Called carbon fixation: taking carbon from an inorganic molecule (atmospheric CO2) and making an organic molecule out of it (glucose)

Simplified version of how carbon and energy enter the food chain

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Calvin Cycle Reactions:Overview of C3 Photosynthesis

• A cyclical series of reactions

• Utilizes atmospheric carbon dioxide to produce carbohydrates

• Known as C3 photosynthesis

• Involves three stages:

• Carbon dioxide fixation

• Carbon dioxide reduction

• RuBP Regeneration

CALVIN CYCLE (also called _________________________)

____________ require ____________

Happens in _________ between thylakoidsNADPH donates _______________

ATP donates _________________CO2 donates ______________

to make __________

LIGHT

LIGHT INDEPENDENT

ENERGY

STROMAHydrogen + electrons

Carbon & oxygenGLUCOSE

http://www.estrellamountain.edu/faculty/farabee/biobk/BioBookCHEM2.html

DOES NOT

CO2 Enters the Cycle

Energy Input

5-CarbonMoleculesRegenerated

Sugars and other compounds

6-Carbon SugarProduced

Calvin Cycle

Photosynthesis

includes

of

take place intakes place in uses

to produce to produce

use

Section 8-3

Concept Map

Photosynthesis

includes

of

take place intakes place in uses

to produce to produce

use

Light-dependentreactions

Calvin cycle

Thylakoidmembranes Stroma NADPHATPEnergy from

sunlight

ATP NADPH O2 Chloroplasts High-energysugars

Section 8-3

Concept Map

40

Photosynthesis Overview

Harvesting Chemical Energy

So we see how energy enters food chains (via autotrophs) we can look at how organisms use that energy to fuel their bodies.

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