Photosynthesis Flashcards
theory for Evolution of photosynthesis
Endosymbiosis theory
Endosymbiosis theory
○ Non photosynthetic eukaryotic cell and a free living cyanobacterium join into one and turns into a chloroplast which turns into green algae which turned into plant
what factors does light affect in plants
stomata movement, when leaves r lost, growth
how do plants sense light
photosynthetic pigments and phytochrome, and blue light receptors
what are the particles loight is composed of
photons
UV damages:
what is it blocked by
DNA and proteins
atmosphere
- Shorter wavelength=
high energy and high freq
Electromagnetic radiation
Electromagnetic radiation includes visible light, UV, infared, X-rays
- Created by the sun
lowest and highest energy colors
red and purple
what do bees see
UV light from flowers–> stand out more
where are Both carotenoids and chlorophyll embedded
- Both embedded in thylakoids, in units called photosystems
what tpye of bonds do carotenoids and chlorophyll have
have conjugated double bonds
ringswith these bonds capture photons
fieisfsofse
Carotenoids
○ Accessory pigments to chlorophyll
○ Absorb what chlorophyll cannot
○ Prevent damage to chlorophyll molecules by lugt
○ Eye health in humans
Chlorophyll
○ Essential to photosynthesis
○ In plants, algae, and cyanobacteria
When a photosynthetic pigment absorbs light
electorn become excited, move to higher energy level
When electron returns from higher energy level
Either
1) Fluorescence
2) Heat
3) Resonance entergy transfter (antenna complex)
Resonance entergy transfter
○ Energy transferred to two molecules of chl a in reaction center
1) AMT transferred to two chl A's in PS 2 so great --> that one electron is ejected from each CHL A
2) Electrons ejected get accepted by primary electron acceptor and transported through ETC to PS 1
3) Back in PS 2, Chl a get electrons back from water(split producing O2 and protons), oxygen gets released and protons accumulate in thylakoid space 4) Chl as in PS1 lose elections due to light energy from PS1 antenna pigments. Get back electrons that come from PS2 through ETC, ejected electrons transported to be accepted by NADP to form NADPH
Light reaction products used for
CO2 fixation in calvin cycle
NADPH and ATP
calvin cycle process
1) 5-C acceptor(RuBP) reaction w 1 CO2
2) New C6 mol breaks into 2 3-C mols(PGA)
- RUBISCO: enzyme carries out reaction
- Cycle must run 6 times for glucose (6-C), because RUBISCO needs to fix 6 CO2s
what do photosystems have?
Antenna complex and reaction center
