Chapter 7 Flashcards
Autotrophs
sustain themselves w/o consuming organic molecules
Photoautotrophs
use light NRG to build organic molecules
Chemoautotrophs
use chemical NRG to build organic molecules
Heterotrophs
consume other plants or animals or decompose organic material
Chloroplasts
major sites of photosynthesis in green plants. concentrated in the cells of mesophyll
Chlorophyll
important light absorbing pigments in chloroplasts, responsible for green colour of plants and plays central role in converting solar NRG to chemical NRG
Stomata
tiny pores in the leaf that allow CO2 to enter and O to exit
Thylakoids
system of interconnected membranous sacs
Stroma
thick fluid in chloroplasts inner compartment
Photosynthesis is a ____ reaction
redox
Photosynthesis occurs in 2 metabolic stages
- Light reaction
- Calvin cycle
Calvin cycle
cyclic series of reactions that assembles sugar molecule using CO2 and the NRG rich products of the light reactions
Electromagnetic NRG
travels in space as waves, behaves as discrete packets of NRG (photons)
Shorter wavelengths of light =
greater NRG of photon
Photosynthetic pigments absorb NRG of visible light but only..
a small part of the electromagnetic spectrum
Wavelengths now absorbed are..
either reflected of transmitted though the chloroplast
3 chloroplast pigments:
- Chlorophyll a
- Chlorophyll b
- Carotenoids
Chlorophyll a
absorbs mainly blue-violet and red light. reflect green
Chlorophyll b
absorbs mainly blue, organa light. reflects yellow-green
Carotenoids
reflect orange and yellow
Photo-protection
absorb and dissipate excessive light NRG
Pigments in chloroplasts…
absorb photons
Electron take on a _____ NRG state
high (become excited)
Electron is _____ at the higher NRG state
unstable
Chlorophyll and other pigment molecules:
- absorb photons
- transfer the NRG to other pigment molecules
Photosystem
consists of a number if light-harvesting complexes surrounding a reaction-centre complex
Light-haresting complex contains..
various pigment molecules bound to proteins
2 types of photosystems in light reaction:
- photosystem 1
- photosystems 11
Each type of photosystem has a characteristic…
reaction centre
Photosystem 11 (P680)
- functions first
- P680 = pigment absorbs light w/ a wavelength of 680 nm
Photosystem 1
- functions second
- P700 = absorbs light w/ a wavelength of 700 nm
In light reaction light NRG is transformed into..
chem NRG of ATP and NADPH
Between the 2 photosystems, electrons:
- move down an electron transport chain
- provide NRG for the synthesis of ATP
Products if light reactions
- NADPH
- ATP
- Oxygen
Chemiosmosis is the mechanism that..
- involved in oxidative phosphorylation in mitochondria
- generate ATP in chloroplasts
ATP is generated because..
the electron transport chain (ETC) produces a concentrationgradienj of H ion cross membrane
Photophosphylation
using the initial NRG from light, the ETC pumps H into the thylakoid into the stroma through ATP synthase, producing ATP
To produce sugar we need:
- atomopheric CO2
- ATP and NADPH generated by light reactions
Calvin cycle uses CO2, ATP, and NADPH to produce
glyceradehyde-3-phosphate (G3P)
Glycerahyde-3-phosphate
NRG rich 3 carbon sugar
Steps of calvin cycle include:
- carbon fixation
- reduction
- release of G3P
- regeneration of the starting molecules ribulose biphosphate (RuBP)
Calvin cycle occurs in ..
the stroma chloroplasts
Calvin cycle uses.
6 NADPH, 9 ATP per 1 net G3P produced
Greenhouse effect
results from solar NRG warming our planet
Light reactions occur in the ..
thylakoid membranes
Calvin cycle occurs in the …
stroma of the chloroplast
