ChloroplastChloroplast

►Organelle where Organelle where photosynthesis takes photosynthesis takes placeplace

►Contain chemical Contain chemical compounds called: compounds called:

ChlorophyllChlorophyll

Leaf StructureLeaf Structure

►Chloroplasts are concentrated in Chloroplasts are concentrated in the mesophyll of the leafthe mesophyll of the leaf

►Tiny pores in the lower epidermis Tiny pores in the lower epidermis (stomata) allows for CO(stomata) allows for CO22 to enter to enter and Oand O22 to exit. to exit.

►Veins carry water and nutrient Veins carry water and nutrient from the plants roots to the leavesfrom the plants roots to the leaves

Chloroplast StructureChloroplast Structure

►Has inner and outer membranesHas inner and outer membranes►Inner membrane encloses a Inner membrane encloses a

thick fluid called thick fluid called STROMASTROMA►Floating in the Floating in the stromastroma are disk- are disk-

shaped sacs called shaped sacs called ThylakoidsThylakoids..(arranged in stacks called (arranged in stacks called GRANAGRANA))

ThylakoidsThylakoids

►The The thylakoidthylakoid is the is the structural unit of structural unit of photosynthesis. Both photosynthesis. Both photosynthetic prokaryotes photosynthetic prokaryotes and eukaryotes have these and eukaryotes have these flattened sacs/vesicles flattened sacs/vesicles

containing containing chlorophyllchlorophyll

The The Light ReactionLight Reaction

►Take place in the Take place in the thylakoidthylakoid membranes, convert light energy membranes, convert light energy to the chemical energy of ATP to the chemical energy of ATP and NADPH. and NADPH.

►The light reactions use the The light reactions use the reactant water from the equation reactant water from the equation and release the product oxygen. and release the product oxygen.

Calvin CycleCalvin Cycle►Like a sugar factory within a Like a sugar factory within a

chloroplastchloroplast. . ►It is called a cycle because the It is called a cycle because the

starting material is regenerated starting material is regenerated each time the process occurs. each time the process occurs.

►The starting material that gets The starting material that gets regenerated is a compound called regenerated is a compound called RuBP, a sugar with five carbons RuBP, a sugar with five carbons

InputsInputs and and OutputsOutputs((ReactantReactant and and ProductsProducts))

►With each turn of the Calvin With each turn of the Calvin cycle, there are chemical cycle, there are chemical inputs inputs andand outputsoutputs. .

►The The inputsinputs are are carbon dioxidecarbon dioxide from the air and the from the air and the ATPATP and and NADPHNADPH produced by the light produced by the light reactions. reactions.

Calvin CycleCalvin Cycle InputsInputs

►The Calvin cycle uses carbon The Calvin cycle uses carbon from the carbon dioxide, from the carbon dioxide, energy from the ATP, and high-energy from the ATP, and high-energy electrons and hydrogen energy electrons and hydrogen ions from the NADPH. ions from the NADPH.

Calvin CycleCalvin Cycle OutputsOutputs

►Is an Is an energy-rich sugar moleculeenergy-rich sugar molecule. . That sugar is not yet glucose, but That sugar is not yet glucose, but a smaller sugar named a smaller sugar named G3PG3P. .

►The plant cell uses G3P as the The plant cell uses G3P as the raw material to make glucose raw material to make glucose and other organic molecules it and other organic molecules it needs. needs.

Summary of PhotosynthesisSummary of Photosynthesis

►Recall that the overall equation for Recall that the overall equation for photosynthesis is: photosynthesis is:

►6 CO6 CO22 + 6 H + 6 H22O CO C66HH1212OO66 + 6 O + 6 O22

The The Calvin cycleCalvin cycle

►Takes place in the Takes place in the stromastroma►Uses ATP and NADPH to Uses ATP and NADPH to

convert carbon dioxide to convert carbon dioxide to sugar sugar

Flow of EnergyFlow of Energy

►By converting light energy to By converting light energy to chemical energy, chemical energy, photosynthesis is the first step photosynthesis is the first step in the flow of energy through in the flow of energy through an ecosystem. an ecosystem.

Some of that chemical energy then passes from producers to consumers.

Even when people eat meat, you can trace its stored energy back to photosynthesis.

Photosynthesis is the ultimate source of all the food you eat and all the oxygen you breathe.

►The nature of lightThe nature of light►The energy produced by the sun The energy produced by the sun

reaches the earth as reaches the earth as electromagnetic radiation. electromagnetic radiation.

►Light and other forms of Light and other forms of electromagnetic radiation are electromagnetic radiation are considered to have both a considered to have both a wave wave naturenature and a and a particle natureparticle nature. .

►Particles or packets of light (its Particles or packets of light (its particle nature) are known as particle nature) are known as photonsphotons - the smallest divisible - the smallest divisible units of light. units of light. The distance moved by a photon The distance moved by a photon during one of it vibrations is during one of it vibrations is referred to as its referred to as its wavelengthwavelength and and is measured in is measured in nanometersnanometers (nm). (nm).

Visible lightVisible light►A very small part of this A very small part of this

spectrum can be seen by the spectrum can be seen by the human eye i.e. between the human eye i.e. between the wavelengths wavelengths 400 and 700400 and 700 nm. nm.

► This part of the electromagnetic This part of the electromagnetic spectrum is called spectrum is called visible lightvisible light.. Almost all life depends Almost all life depends

ultimately on this part of the ultimately on this part of the spectrum for its energy. spectrum for its energy.

Why plants only use visible Why plants only use visible light as a source of energy light as a source of energy

for photosynthesisfor photosynthesis

►Visible light Visible light Each photon of visible light Each photon of visible light contains just enough energy contains just enough energy to excite the electrons of to excite the electrons of molecules without causing molecules without causing damage to the cell. damage to the cell.

Light and photosynthesis Light and photosynthesis

►ChlorophyllChlorophyll absorbs blue-violet and absorbs blue-violet and red-orangered-orange

Reflects green back Reflects green back ►Chlorophyll aChlorophyll a, the most important , the most important

light-absorbing pigment in plants, does light-absorbing pigment in plants, does not absorb light in the green part of not absorb light in the green part of the spectrum.  Light in this range of the spectrum.  Light in this range of wavelengths is wavelengths is reflectedreflected. .

Light and photosynthesisLight and photosynthesis

►Plants do not depend only on Plants do not depend only on chlorophyll achlorophyll a but also have other but also have other pigments pigments ((accessory pigmentsaccessory pigments)) which which absorb light of  different wavelengths. absorb light of  different wavelengths.