Photosynthesis IntroductionBasic Info Photosynthesis Essential for all life

Photosynthesis Introduction/Basic Info

Photosynthesis �Essential for all life on. Autotrophs earth Photosynthesis CO 2 Glucose (only an example) Respiration Consumers

Photosynthesis �So how do we actually see different colors? �The wavelength of the light will determine the color of the light

Photosynthesis �When light waves are absorbed from this region of the visible spectrum it can be used by a plant �Green leaves look green because they have a pigment that does not absorb green light, it reflects it

Photosynthesis

Photosynthesis �The main light absorbing pigment in green plants is chrorophyll—found inside the chloroplasts �Like a mitochondrion, the structure of the chlorophyll is directly related its function (common theme in bio) �Have their on DNA in a ring, ribosomes (70 S), an inner and outer membranes �Only actual green structures in a plant

Photosynthesis starch granule Ribosomes in stroma Stoma lamellae

Photosynthesis �Chlorphyll is a green pigment �Reflects green wavelengths of light, in the middle of the VS, absorbs non-green wavelengths �Blue and regions are absorbed the most �Absorption spectra show which wavelengths are absorbed as a function of O 2 production

Photosynthesis

Photosynthesis �Two stages of photosynthesis: light independent and light dependent �Different sets of reactions used in each stage �Light dependent produces ATP and allows photolysis to occur (O 2 is a waste product) �Light independent allows for carbon fixation

Photosynthesis—Light dependent �Chlorophyll, and other pigments, absorb light from the sun (or other source) �Energy from absorbed wavelengths produces ATP �Light also used to split water into H 2 and O 2 (photolysis) �Released O 2 is source of aerobic respiration; ATP and H 2 used by the plant

Photosynthesis—Light dependent light O 2 water ATP Light dependent reactions electrons Chlorophyll and other photosynthetic pigments • ATP production very similar to that of respiration w/ most energy being acquired via an electron transport chain H+ H 2

Photosynthesis—Light independent �ATP and H 2 generated from light dependent stage used to covert CO 2 and H 2 O into organic compounds (like glucose) 6 CO 2 + 6 H 2 O C 6 H 12 O 6 + 6 O 2 �This carbon fixation…turning inorganic to organic �Fixation requires energy—all comes from sun

Photosynthesis C 6 CO +6 6 H + 6 O 6 H 12 2 O 2 O 2 C 6 H 6 CO 6 O 2 O 12 O 2 6 + 6 H RESPIRATION!!!! �Plants do both…photosynthesis and respiration �Respiration occurs at a slow, steady rate, regardless of light/dark = small yields of ATP. Why? �No muscle, large movement, or other energy requiring processes…less ATP needed vs animals

Photosynthesis-rates �Photosynthesis does not occur at such a steady rate �Greatly affected by intensity of light, temperature, and CO 2 levels �Can be measured directly via CO 2 intake and O 2 production amounts IF adjusted to account for respiration �Biomass (amount of plant/size) is an indirect method of measuring rate of photosynthesis— indirect b/c a lot of other potential factors

Photosynthesis-rates O 2 released + Photosynthesis 0 O 2 taken in -Day 1 Respiration Night 1 Day 2 Night 2

Photosynthesis-rates �Light intensity—varies inversely with the square of the distance (farther away, less intense) Rate of photosynthesis Enzymes at max rate intensity

Photosynthesis-rates �Temperature Rate of photosynthesis Enzymes and other proteins begin to get denatured Temp

Photosynthesis-rates �CO 2 concentration Rate of photosynthesis Plateaus unless light intensity or temp. go up CO 2