PhotosynthesisPhotosynthesis

ByBy

Dr. HuqDr. Huq

What Is What Is Photosynthesis?Photosynthesis?

PhotosynthesisPhotosynthesis

Photosynthesis Photosynthesis conceptconcept. The . The process by which process by which autotrophs convert autotrophs convert sunlight to a sunlight to a usable form of usable form of energy is energy is photosynthesisphotosynthesis

What is the equation for What is the equation for the chemical reaction of the chemical reaction of

photosynthesis?photosynthesis?

What is the equation for What is the equation for the chemical reaction of the chemical reaction of

photosynthesis?photosynthesis?

Six molecules of carbon dioxide react with six molecules of water to form 1 molecule of

glucose and six molecules of oxygen.

Why is this important to Why is this important to us?us?

We cannot make our own food (glucose, We cannot make our own food (glucose, energy), we must get our food from plants.energy), we must get our food from plants.

Plants are the first step in the food chain.Plants are the first step in the food chain.

Why is this important Why is this important to us?to us?

The oxygen released during The oxygen released during photosynthesis is necessary for all photosynthesis is necessary for all living things.living things.

PhotosynthesisPhotosynthesis

AUTOTROPH. An AUTOTROPH. An organism that organism that produces its own produces its own food from food from inorganic (carbon inorganic (carbon dioxide) dioxide) compounds and compounds and sunlight.sunlight.

What Parts Of The Plants Are What Parts Of The Plants Are Involved In The Process Of Involved In The Process Of

Photosynthesis?Photosynthesis?

ChloroplastChloroplast

Chloroplast--A plastid Chloroplast--A plastid that contains that contains chlorophyll and is the chlorophyll and is the site where site where photosynthesis and photosynthesis and starch formation starch formation occur. occur.

Photosynthetic pigmentsPhotosynthetic pigments Most of the pigments in Most of the pigments in

green plants are bound to green plants are bound to the trimeric light-the trimeric light-harvesting complex II harvesting complex II (LHCII). It is located at (LHCII). It is located at several positions in several positions in photosystem II, but also at photosystem II, but also at other locations. It is very other locations. It is very important for the important for the organization of the organization of the thylakoid membranes in thylakoid membranes in chloroplasts and for the chloroplasts and for the separation of photosystems separation of photosystems I and II. I and II.

Photosynthetic PigmentsPhotosynthetic Pigments

Certain pigments in Certain pigments in autotrophs are autotrophs are essential for essential for photosynthesis. The photosynthesis. The most common and most common and important of these important of these photosynthetic photosynthetic pigments is called pigments is called chlorophyll. chlorophyll.

Photosynthetic PigmentsPhotosynthetic Pigments

Chlorophyll a is the Chlorophyll a is the major pigment. major pigment. However chlorophyll However chlorophyll b & Beta carotene b & Beta carotene are two accessory are two accessory pigments for pigments for photosynthesis.photosynthesis.

What color of light is What color of light is not needed?not needed?

greengreen

What color of light is What color of light is needed?needed?

What Color Of Light Is NeededWhat Color Of Light Is Needed??

chlorophyll which absorbs red and blue chlorophyll which absorbs red and blue light (and appears green) and light (and appears green) and carotenoids which absorb in the blue (and appear which absorb in the blue (and appear

yellow).yellow).

What Organelle Does What Organelle Does This Job?This Job?

Organelles of Organelles of photosynthesisphotosynthesis

Where these Where these reactions take place?reactions take place?

Reactions occur in different areas Reactions occur in different areas of the thylakoid called of the thylakoid called photosystem I & photosystem IIphotosystem I & photosystem II

What are What are photosystems?photosystems?

Inside the Thylakoids, hundreds of Inside the Thylakoids, hundreds of chlorophyll molecules & other chlorophyll molecules & other pigments are organized into units pigments are organized into units called photosystems. These are called photosystems. These are light collecting units of chloroplast.light collecting units of chloroplast.

Besides light and the Besides light and the organelle, what else organelle, what else

is used in this is used in this process?process?

HH22OO And And COCO22

What is Light What is Light reaction?reaction?

PhotosystemII uses sunlight to split PhotosystemII uses sunlight to split water into water into HH++,, energized electronsenergized electrons and and OO22. Most of the . Most of the OxygenOxygen diffuses out into the air. The diffuses out into the air. The electronselectrons enter the electron enter the electron transport chaintransport chain

Electron transport Electron transport SystemsSystems

ATP = Adenosin triphosphateATP = Adenosin triphosphate

ADPADP ATP ATP

NADPH = Nicotinamide Adenine Dinucleotide NADPH = Nicotinamide Adenine Dinucleotide phosphatephosphate

NADP NADPHNADP NADPH

Then what Happens in Then what Happens in Light Reaction?Light Reaction?

Electron transport:Electron transport: Energized Energized electrons are shuttled from electrons are shuttled from Photosystem II by carrier Photosystem II by carrier molecules. The carrier molecules molecules. The carrier molecules use the electron’s energy to use the electron’s energy to actively transport actively transport HH++ from the from the stroma into the thylakoid spacestroma into the thylakoid space

What is next in Light What is next in Light Reaction ?Reaction ?

Photosystem IPhotosystem I. Using sun’s energy . Using sun’s energy the the

energy- depleted electrons are energy- depleted electrons are reenergized in Photosystem I. The reenergized in Photosystem I. The energized electrons are used to energized electrons are used to produce produce NADPHNADPH, (, (Nicotinamide Adenine Nicotinamide Adenine Dinucleotide phosphate)Dinucleotide phosphate) a molecule that a molecule that will later be used to make glucose.will later be used to make glucose.

What next in light What next in light Reaction ?Reaction ?

ATP synthesis: The high HATP synthesis: The high H++ concentration in the thylakoid concentration in the thylakoid space creates a concentration space creates a concentration gradient. Hgradient. H+ + difuses back into the difuses back into the stroma through an enzyme, ATP stroma through an enzyme, ATP synthase. The energy released by synthase. The energy released by the flow of Hthe flow of H+ + converts ADP to ATPconverts ADP to ATP

What is Dark What is Dark reaction?reaction?

The The Calvin cycleCalvin cycle follows light-dependent follows light-dependent reaction. It takes place in the stroma. It uses reaction. It takes place in the stroma. It uses NADPH NADPH ,,ATP (ATP (Adenosin triphosphate)Adenosin triphosphate) and and HH++.. It needs It needs COCO22 to make sugar. 6 molecules of to make sugar. 6 molecules of COCO22 is used to make one molecule of Sugar. is used to make one molecule of Sugar. However one molecule of However one molecule of COCO22 is processed at a is processed at a timetime

What is Step 1 of Dark What is Step 1 of Dark Reaction?Reaction?

Carbon FixationCarbon Fixation: For each glucose : For each glucose molecule , molecule , 66 molecules of molecules of COCO22 reacts reacts with6 molecules of five carbon sugar with6 molecules of five carbon sugar RuBP (Ribulose 1,5 phosphate).RuBP (Ribulose 1,5 phosphate). The The result is 12 molecules of result is 12 molecules of 33 carbon carbon PGA(3-Phosphoglyceric Acid)PGA(3-Phosphoglyceric Acid). Only . Only one one COCO22 goes through the Calvin goes through the Calvin cycle at a time.cycle at a time.

What happens in Step 2?What happens in Step 2?

Production of G3P: Production of G3P: Each molecule Each molecule of PGA is converted to of PGA is converted to G3PG3P, using , using energy from energy from ATPATP and hydrogen and hydrogen from from NADPHNADPH. Two . Two G3PG3P molecules molecules can be combined to form glucose can be combined to form glucose in other cellular process.in other cellular process.

And in Step 3 of Calvin And in Step 3 of Calvin Cycle?Cycle?

Restoring RuBP:Restoring RuBP: The other ten G3P The other ten G3P molecules are recycled back to molecules are recycled back to RuBPRuBP. This requires energy from 6 . This requires energy from 6 ATPATP. . RuBP RuBP is used in the next turn is used in the next turn of the Calvin cycle.of the Calvin cycle.

What are the What are the products of this products of this

process?process?

What is the Chemical What is the Chemical reaction?reaction?

Chemical reactionChemical reaction6CO6CO22 + 6H + 6H22O light enegry & O light enegry & chlorophyll Cchlorophyll C66HH1212OO6 6 + O+ O22

Name of the scientist:Name of the scientist:

Melvin CalvinMelvin Calvin