Lesson 4: Photosynthesis

CO2 + H2O + light → (CH2O) + O2

Chemical Formula of Photosynthesis

Leaves

Photosynthesis primary occurring in the

Photosynthesis

is the process by which green plants manufacture sugars and their precursors.

chloroplasts

This vital function takes place in the, the main organelles involved and requires light and chlorophyll.

carbon dioxide

The process utilizes ________ absorbed from the air via stomata and water transported from the soil (absorbed by the roots) through the xylem.

CHLOROPLAST

usually lens shaped, bounded by a double membrane

CHLOROPLAST

the inner membrane invaginates parallel to the surface and becomes organized into specialized cytoplasmic body.

granum

consisting of a stack of thylakoids called

stroma

embedded proteinaceous matrix called?

Chlorophyll

principal pigment in photosynthesis located in the partition between two adjacent thylakoids

magnesium

the center of porphyrin is occupied by a single___ atom.

PHOTOSYNTHESIS

converts light energy into chemical energy in the form of organic nutrients supplies oxygen to the atmosphere produces food.

Cotton, Sunflower, Spinach, Beans, Rice

Example of C3 Plants

C3

Temperate species can be seen in all photosynthetic plants in what type of pathway

Mesophyll cell

Cells involved in C3

C3

has the leaf anatomy that lacks kranz type anatomy and peripheral reticulum; only one type chloroplast

RuBP

Initial CO2 acceptor of C3

3PGA

First stable product of C3

C3

Has Only one Co2 fixation pathway

Open stomata by day

Stomatal Opening of C3

C4 plants

Tropical or semitropical plants adapted to high light, temperature. and semi

Mesophyll cell and bundle sheath cell

Cells involved in C4

C4

has the leaf anatomy that has kranz type anatomy and peripheral reticulum are essential features

PEP

Initial CO2 acceptor of C4

OAA

First stable product of C4

C4

Has Two Co2 fixation pathway are separated in space

Open stomata by day

Stomatal Opening of C4

Sugarcane, Sorghum, Maiz

Example of C4 Plants

CAM Plants

Xerophytic species, can be seen in semi arid comdition

Both C3 and C4 same as mesophyll cell

type of cells involved in CAM

CAM

has the leaf anatomy that lack kranz type anatomy and peripheral reticulum; only one type of chloroplast

PEP in the dark RuBP in daylight

Initial CO2 acceptor of CAM

OAA in the dark 3PGA in the light

First stable product of CAM

CAM

Has Two Co2 fixation pathway are separated in time

Open stomata by night

Stomatal Opening of CAM

Cacti, Orchids, Succulents

Example of CAM plants

CALVIN BENSON CYCLE/REDUCTIVE PENTOSE PATHWAY

fixation and reduction of one molecule of CO requires three molecules of

ATP and 2 NADPH (coming from light reaction) occurs in the mesophyll cell chloroplast

COacceptor is RUBP

RUBP carboxylase enzyme is needed the first product is 3-PGA

C4 OR HATCH SLACK PATHWAY

occurs in the mesophyll cell

• COzacceptor is PEP, catalyzed by PEP carboxylase enzyme products are 4-carbon organic acids (oxaloacetic acid at the mesophyll

oxaloacetic acid is converted to malate and aspartic acid malic acid is decarboxylated to produce CO the 3-carbon compound goes back the mesophyll cells the COrreleased enters the Calvin cycle for sugar/starch production the 3-carbon compound combined with 1-carbon from the atmosphere to form again into 4-carbon compound

CRASSULACEAN ACID METABOLISM (CAM) PATHWAY

• found in succulent plants (cactus, pineapple)

• during the night, CO-is fixed