PhotosynthesisPhotosynthesis

Energy and LifeEnergy and Life

Nearly every activity in modern Nearly every activity in modern society depends on Energy…think society depends on Energy…think about it.about it. Driving a car!Driving a car! Typing a paper!Typing a paper! Using your IPOD!Using your IPOD! Talking on your cell phone!Talking on your cell phone!

Living things also require Living things also require ENERGYENERGY!!

Where does that Energy come from?Where does that Energy come from?

Autotrophs Autotrophs (AKA: Producers)(AKA: Producers) Use the Use the sunlight sunlight as their as their

ENERGY source.ENERGY source.

HeterotrophsHeterotrophs (AKA: Consumers) (AKA: Consumers) Obtain energy from the plants Obtain energy from the plants

or other organisms that they or other organisms that they consume.consume.

Chemical EnergyChemical Energy

Candles burnCandles burn What does that mean?What does that mean?

Wax molecules store Wax molecules store energy in the bonds energy in the bonds between the hydrogens between the hydrogens and carbonsand carbons

Electrons move Electrons move from higher from higher energy levels to energy levels to lower energy lower energy levels.levels.

Heat and light Heat and light energy are energy are released.released.

Living things use and Living things use and store energy store energy

Plants store energy as sugar or starchPlants store energy as sugar or starch

Animals store energy as glycogen Animals store energy as glycogen (animal starch)(animal starch)

Or as fatOr as fat

ATP: Adenosine TriphosphateATP: Adenosine Triphosphate

AdenineAdenine Ribose:5 carbon sugarRibose:5 carbon sugar 3 phosphate groups3 phosphate groups

Storing EnergyStoring Energy

ADP (adenosine diphosphate) is a ADP (adenosine diphosphate) is a compound that looks like ATP except compound that looks like ATP except it is lacking a __________ group.it is lacking a __________ group.

This one difference is the key to the This one difference is the key to the way in which living things store way in which living things store energy.energy.

Phosphate

Storing Energy (cont.)Storing Energy (cont.)

When a cell has energy available, it When a cell has energy available, it can store small amounts of it by can store small amounts of it by adding a phosphate group to ADP, adding a phosphate group to ADP, producing ATP.producing ATP.

Think of ATP as a fully charged battery Think of ATP as a fully charged battery and ADP as only a partially charged and ADP as only a partially charged battery.battery.

Now that we have Energy stored…how Now that we have Energy stored…how do we release it?....do we release it?....

http://www.biologyinmotion.com/atp/index.html

Releasing EnergyReleasing Energy

Energy that is stored in ATP is Energy that is stored in ATP is released by breaking the chemical released by breaking the chemical bond between the second and third bond between the second and third phosphates.phosphates.

What the energy in ATP can doWhat the energy in ATP can do Active transportActive transport Protein synthesisProtein synthesis Muscle contractionMuscle contraction

What the energy in ATP can What the energy in ATP can dodo

Synthesis of nucleic acidsSynthesis of nucleic acids Move organelles throughout the cellMove organelles throughout the cell Responds to chemical signals of cellResponds to chemical signals of cell Fireflies!Fireflies!

Question?????Question?????

Do you think cells have an abundant Do you think cells have an abundant amount of ATP?amount of ATP? Answer: Most cells have only a small Answer: Most cells have only a small

amount of ATP, enough to last them for amount of ATP, enough to last them for a few seconds of activity.a few seconds of activity.

Why?Why? Answer: ATP is great for transferring Answer: ATP is great for transferring

Energy, not for storing Energy.Energy, not for storing Energy.

ATP Wrap-UPATP Wrap-UP

Long term storage is done by other Long term storage is done by other molecules, such as glucose, molecules, such as glucose, glycogen, starchglycogen, starch

ATP can be regenerated by the cell ATP can be regenerated by the cell over and over againover and over again ADP + Energy + P ADP + Energy + P → ATP→ ATP Required energy comes from food Required energy comes from food

moleculesmolecules

8-2:Overview of Photosynthesis8-2:Overview of Photosynthesis

Van Helmont’s ExperimentVan Helmont’s Experiment Plants gain mass from waterPlants gain mass from water

PriestleyPriestley Plants produce oxygen Plants produce oxygen

Jan IngenhouszJan Ingenhousz Light is necessaryLight is necessary

Photosynthesis converts light Photosynthesis converts light energy into the chemical energy energy into the chemical energy of sugar and other organic of sugar and other organic compounds.compounds.

Light energy drives the reactionsLight energy drives the reactions OO22- byproduct and is released into atmosphere- byproduct and is released into atmosphere

8-2:Overview of Photosynthesis8-2:Overview of Photosynthesis

The Photosynthetic EquationThe Photosynthetic Equation

Light and PigmentsLight and Pigments Pigments: light absorbing moleculesPigments: light absorbing molecules

Chlorophyll absorbs blue-violet and red lightChlorophyll absorbs blue-violet and red light When a pigment absorbs light, it absorbs the When a pigment absorbs light, it absorbs the

energy from that lightenergy from that light Energy excites electronsEnergy excites electrons

8-3: The Reactions of Photosynthesis8-3: The Reactions of Photosynthesis

Where does photosynthesis take place?Where does photosynthesis take place?

Parts of the chloroplastsParts of the chloroplasts

ThylakoidsThylakoids-Proteins in the thylakoid -Proteins in the thylakoid membrane organize chlorophyll and other membrane organize chlorophyll and other pigments into clusters known as pigments into clusters known as photosystems.photosystems.

PhotosystemsPhotosystems--light collecting unitslight collecting units Reactions of photosystems in 2 parts:Reactions of photosystems in 2 parts:

Light-dependent reactionsLight-dependent reactions (take place in (take place in thylakoid membrane)thylakoid membrane)

Light-independent reactionsLight-independent reactions (take place (take place in the stroma)in the stroma)

Parts of the chloroplastsParts of the chloroplasts

Light-Dependent ReactionsLight-Dependent Reactions

The light-dependent reactions produce oxygen The light-dependent reactions produce oxygen gas and convert ADP and NADP+ into ATP gas and convert ADP and NADP+ into ATP and NADPH.and NADPH.

NADP+ is an electron carrier molecule, which NADP+ is an electron carrier molecule, which holds two electrons and a Hydrogen Ion which holds two electrons and a Hydrogen Ion which then traps energy and turns it into NADPH then traps energy and turns it into NADPH which is used to help build glucosewhich is used to help build glucose

Occur in the thylakoidOccur in the thylakoid

Calvin Cycle (light-independent)Calvin Cycle (light-independent)

The Calvin Cycle uses The Calvin Cycle uses ATP and NADPHATP and NADPH from from the light-dependent reactions to produce high-the light-dependent reactions to produce high-energy sugars.energy sugars.

It takes carbon dioxide from the atmosphere It takes carbon dioxide from the atmosphere and converts it into high-energy sugars that and converts it into high-energy sugars that can be used to meet the plant’s energy needs can be used to meet the plant’s energy needs and to build more complex molecules.and to build more complex molecules.

What does all of that mean?What does all of that mean?

The two sets of photosynthetic reactions work The two sets of photosynthetic reactions work together…together… The light-dependent reactions trap the energy of The light-dependent reactions trap the energy of

sunlight in chemical formsunlight in chemical form The light-independent (Calvin cycle) uses that The light-independent (Calvin cycle) uses that

chemical energy to produce stable, high-energy chemical energy to produce stable, high-energy sugars from carbon dioxide and water.sugars from carbon dioxide and water.

Light ReactionsLight Reactions

O2

H2O

Energy BuildingReactions

ATP

produces ATP produces NADPH releases O2 as a

waste product

sunlight

H2O ATP O2light

energy ++ + NADPH

NADPH

Calvin CycleCalvin 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

H2O

Energy cycleEnergy cycle

Photosynthesis

Cellular Respiration

sun

glucose O2CO2

plants

animals, plants

ATP

CO2 H2O C6H12O6 O2light

energy + ++

CO2 H2OC6H12O6 O2ATP

energy+ ++

Factors Affecting PhotosynthesisFactors Affecting Photosynthesis Shortage of waterShortage of water can slow down or stop can slow down or stop

photosynthesisphotosynthesis Plants have adaptations to reduce water loss: waxy Plants have adaptations to reduce water loss: waxy

coating on plants in dry areas.coating on plants in dry areas. TemperatureTemperature

Plants have enzymes that work best from 32-95 Plants have enzymes that work best from 32-95 degrees F. Temperatures above or below can degrees F. Temperatures above or below can damage these enzymes which can slow down or damage these enzymes which can slow down or stop photosynthesis.stop photosynthesis.

Intensity of lightIntensity of light Increasing light intensity increases the rate of Increasing light intensity increases the rate of

photosynthesis. (It will reach a max level)photosynthesis. (It will reach a max level)

Factors Affecting PhotosynthesisFactors Affecting Photosynthesis

Chromatography LabChromatography Lab Purpose: To discover all the pigments in both spinach leaves Purpose: To discover all the pigments in both spinach leaves

and M&M dyes. (Test at least three M&M colors) Also Test, and M&M dyes. (Test at least three M&M colors) Also Test, coffee filter chromatography vs. actual chromatography papercoffee filter chromatography vs. actual chromatography paper

Procedure: 1. Grind down spinach leaves with a mortar and Procedure: 1. Grind down spinach leaves with a mortar and pestle. (Melt M&M’s in your hand).pestle. (Melt M&M’s in your hand).

2. Pour about ¼ inch of alcohol into your beaker. Draw a small 2. Pour about ¼ inch of alcohol into your beaker. Draw a small line on the bottom of your Filter paper, above the alcohol level.line on the bottom of your Filter paper, above the alcohol level.

3. Place a dot of the dye in the middle of your line, then place 3. Place a dot of the dye in the middle of your line, then place paper wrapped around pencil into beaker so bottom is touching paper wrapped around pencil into beaker so bottom is touching the alcohol.the alcohol.

4. Place a line wherever pigment colors show. Measure this 4. Place a line wherever pigment colors show. Measure this distance, as well as the distance the alcohol traveled up the distance, as well as the distance the alcohol traveled up the paper.paper.

5. Measure the Rf, retardation factor for each pigment. Rf = 5. Measure the Rf, retardation factor for each pigment. Rf = distance pigment traveled from baseline/ distance alcohol distance pigment traveled from baseline/ distance alcohol traveled.traveled.