PHOTOSYNTHESISPHOTOSYNTHESIS

BIOLOGYBIOLOGY

RIVERDELL HIGH SCHOOLRIVERDELL HIGH SCHOOL

Dr. BrandoniDr. Brandoni

SO FAR….SO FAR….Themes that keep arising:Themes that keep arising:

Structure/function:Structure/function:-proteins, -enzymes, cell membrane fluid-mosaic proteins, -enzymes, cell membrane fluid-mosaic model, phospholipid chemistry and polarity…model, phospholipid chemistry and polarity…

Maintaining balance and characteristics of life:Maintaining balance and characteristics of life:

-protein shape and temp/acidity, enzyme -protein shape and temp/acidity, enzyme specificity and homeostasis, osmosis- water specificity and homeostasis, osmosis- water regulation , transport…regulation , transport…

Conservation: of mass, of energyConservation: of mass, of energy

MOST RECENTLY: Structure/function of cell MOST RECENTLY: Structure/function of cell membrane and its role in transport in order to maintain membrane and its role in transport in order to maintain homeostasis.homeostasis.

Which required energy?Which required energy? In pairs: Where do our cells get energy from?In pairs: Where do our cells get energy from?

What is the energy carrying molecule? What is the energy carrying molecule? Where is the energy held in its structure?Where is the energy held in its structure? What do we need to do to get energy? What are “we” called?What do we need to do to get energy? What are “we” called? Where does our energy ultimately come from?Where does our energy ultimately come from?

PLANTS- PHOTOSYNTHESISPLANTS- PHOTOSYNTHESIS

WHERE IS THE KITCHEN OF WHERE IS THE KITCHEN OF THE PLANT?THE PLANT?

CHLOROPLASTSCHLOROPLASTS

IN THIS UNIT WE ARE GOING TO LOOK IN THIS UNIT WE ARE GOING TO LOOK AT THE STRUCTURE/FUNCTION of AT THE STRUCTURE/FUNCTION of CHLOROPLASTS IN GENERATING CHLOROPLASTS IN GENERATING ENERGY AND EXAMINE HOW LIGHT IS ENERGY AND EXAMINE HOW LIGHT IS CONVERTED TO CHEMICAL ENERGYCONVERTED TO CHEMICAL ENERGY

MAIN QUESTIONS: MAIN QUESTIONS: PhotosynthesisPhotosynthesis

A. A. WhatWhat is photosynthesis? is photosynthesis?

B. B. WhereWhere does it take place? does it take place?

C. C. WhenWhen does it take place? does it take place?

D. D. WhatWhat happens during photosynthesis? happens during photosynthesis?

LAW OF CONSERVATION OF LAW OF CONSERVATION OF ENERGY: Carbon CycleENERGY: Carbon Cycle

DO NOW:DO NOW:

1.1. What does the Law of conservation of energy What does the Law of conservation of energy state?state?

2.2. What three things do plants need to stay alive? What three things do plants need to stay alive? What do they make from the raw materials?What do they make from the raw materials?

3.3. What are the equations for photosynthesis and What are the equations for photosynthesis and respiration?respiration?

4.4. THINK: Do plant cells undergo cell THINK: Do plant cells undergo cell respiration?respiration?

What colored light is MOST useful in What colored light is MOST useful in photosynthesis? Least?photosynthesis? Least?

What colored light is MOST What colored light is MOST USEFUL? Which is LEAST?USEFUL? Which is LEAST?

MOST USEFUL…. MOST USEFUL….

RED and BLUERED and BLUE

LEAST USEFULLEAST USEFUL

GREEN!!!GREEN!!!

HOW CAN THIS BE?????HOW CAN THIS BE?????

III. Light and PhotosynthesisIII. Light and PhotosynthesisA. Nature of LightA. Nature of Light

1. light is 1. light is electromagneticelectromagnetic radiationradiation

a.travels in a vacuum at a.travels in a vacuum at 186,000miles/sec186,000miles/sec

b. other examples include microwaves,b. other examples include microwaves,

radio waves, X-rays, gamma raysradio waves, X-rays, gamma rays

c. each type has a different c. each type has a different wavelengthwavelength

and and frequencyfrequency

Nature of LightNature of Light

2. white light is made of different colors2. white light is made of different colors

Red Red OrangeOrange YellowYellow GreenGreen Blue Blue IndigoIndigo VioletViolet--------------------------------------------------------------------------------------------------------------------------------------------

---------------Decreasing wavelength --------------------->---------------Decreasing wavelength --------------------->

---------------Increasing frequency and energy----------->---------------Increasing frequency and energy----------->

3. 3. light that hits an object can be light that hits an object can be absorbedabsorbed, ,

transmittedtransmitted or or reflectedreflected4. color of light reflected is color you see4. color of light reflected is color you see a. all colors reflected - color is white a. all colors reflected - color is white b. all colors absorbed - color is blackb. all colors absorbed - color is black c. all but blue absorbed - color is blue all but blue absorbed - color is blue

The Visible SpectrumThe Visible Spectrum

WHAT DOES LIGHT PROVIDE?WHAT DOES LIGHT PROVIDE?

Light in photosynthesisLight in photosynthesis provides provides energy that will be stored energy that will be stored in the bonds of a carbon compoundin the bonds of a carbon compound

Bottom Line:Bottom Line:Photosynthesis can be divided into 2 Photosynthesis can be divided into 2

phases:phases: LIGHT REACTIONS: (NEED LIGHTLIGHT REACTIONS: (NEED LIGHT))

Light is converted into chemical energyLight is converted into chemical energy HH220 breaks to H2 + O (release O0 breaks to H2 + O (release O22) ) HH220 is 0 is USEDUSED OO2 2 are are MADE MADE and ENERGY (ATP) !!!! and ENERGY (ATP) !!!!

CALVIN CYCLE (Dark Reactions)CALVIN CYCLE (Dark Reactions):: COCO2, is2, is USEDUSED (and energy used) (and energy used) CC66HH1212OO6 6 is is MADEMADE

PHOTOSYNTHESISPHOTOSYNTHESIS 6CO6CO22 + + 6H6H2200 ------- ------- CC66HH1212OO66 + + 6O6O22

DO AS WE GO QUESTIONSDO AS WE GO QUESTIONS

1. What are the 2 phases of photosynthesis?1. What are the 2 phases of photosynthesis?

2. Where do they occur?2. Where do they occur?

…….to answer this, we need to look at the .to answer this, we need to look at the choloroplasts in detail…choloroplasts in detail…

Structure of the ChloroplastStructure of the Chloroplast

WHERE DO THE LIGHT WHERE DO THE LIGHT PHASE AND CALVIN CYCLE PHASE AND CALVIN CYCLE

TAKE PLACE?TAKE PLACE?

LIGHT: ThylakoidLIGHT: Thylakoid CALVIN CYCLE: StromaCALVIN CYCLE: Stroma

The ChloroplastThe Chloroplast

The Chloroplast and PigmentsThe Chloroplast and Pigments

1. Structure1. Structure

aa. . granagrana: : stacks ofstacks of

thylakoid membranesthylakoid membranes

PIGMENTS:PIGMENTS:

1) 1) chlorophyll a:chlorophyll a: absorbs light in the absorbs light in the

red range and some in the blue rangered range and some in the blue range

2) 2) chlorophyll b:chlorophyll b: absorbs more in the absorbs more in the

blue range and assists chlorophyll ablue range and assists chlorophyll a

DO…as we go QuestionsDO…as we go QuestionsHow does light transfer its energy?How does light transfer its energy? a. Pigments in chloroplast absorb light a. Pigments in chloroplast absorb light 1) light excites electrons 1) light excites electrons Excited electrons transfer energy to high energy compounds Excited electrons transfer energy to high energy compounds

IV. Light Phase - PhotosynthesisIV. Light Phase - PhotosynthesisA. Chloroplast and PigmentsA. Chloroplast and Pigments

3) 3) accessory pigmentsaccessory pigments (carotenoids) (carotenoids)

-yellow, orange, brown pigments that-yellow, orange, brown pigments that

absorb in the green range and absorb in the green range and

sometimes the blue range and pass sometimes the blue range and pass

energy to energy to chlorophyll achlorophyll a

THINK: Where do autumn leaves get their colors?THINK: Where do autumn leaves get their colors?

Light Absorption by Pigments in the ChloroplastLight Absorption by Pigments in the Chloroplast

Light Waves Absorbed and Reflected by the LeafLight Waves Absorbed and Reflected by the Leaf

Light Phase of PhotosynthesisLight Phase of Photosynthesis

VI. Alternate PathwaysVI. Alternate Pathways C. CAM PathwayC. CAM Pathway

1. Carbon dioxide is fixed in a variety 1. Carbon dioxide is fixed in a variety

of compoundsof compounds

2. open 2. open stomatastomata at night and close at night and close

them during the day to conserve them during the day to conserve

water water

3. these plants grow slowly3. these plants grow slowly

4. examples are cactus and pineapple4. examples are cactus and pineapple

Cross Section of a Leaf Cross Section of a Leaf

Stomata Several StomataStomata Several Stomata Open Closed Showing Guard CellsOpen Closed Showing Guard Cells

Light and Dark Phase ComparedLight and Dark Phase Compared

VII. Rate of PhotosynthesisVII. Rate of Photosynthesis

A. Depends onA. Depends on

1. 1. light intensitylight intensity - increases as light - increases as light

intensity increases, then levels offintensity increases, then levels off

2. 2. temperaturetemperature – increases, reaches a – increases, reaches a high point, then decreases as high point, then decreases as temperature increases temperature increases

3. 3. carbon dioxide levelscarbon dioxide levels – increases as – increases as

COCO22 levels increase, then levels off levels increase, then levels off

Light Intensity and Rate of PhotosynthesisLight Intensity and Rate of Photosynthesis

Temperature and Rate of PhotosynthesisTemperature and Rate of Photosynthesis

Temperature and Rate of PhotosynthesisTemperature and Rate of Photosynthesis

COCO22 Concentration and Rate of Photosynthesis Concentration and Rate of Photosynthesis

Three Factors Affecting Rate of PhotosynthesisThree Factors Affecting Rate of Photosynthesis Light Intensity COLight Intensity CO2 2 Concentration TemperatureConcentration Temperature