Plants - Photosynthesis Flashcards
Photosynthesis
the process that converts solar energy into chemical energy within chloroplasts
Autotrophs
“self-feeders” that sustain themselves without eating anything derived from other organisms
Photoautotrophs
use the energy of sunlight to make organic molecules (almost all plants)
Photosynthesis also occurs in
algae, certain other protists, and some prokaryotes
Photosynthesis reverses the direction of
electron flow compared to respiration
Photosynthesis is a redox process in which
H2O is oxidized and CO2 is reduced
Photosynthesis is an ……… process; the energy boost is provided by ……..
endergonic / light
What organelle performs photosynthesis?
Chloroplasts
A chloroplast has an envelope of two membranes surrounding a dense fluid called the
stroma
Thylakoids
connected sacs in the chloroplast that compose a third membrane system
Thylakoids
connected sacs in the chloroplast that compose a third membrane system
Chlorophyll
pigment that gives leaves green color, in the thylakoid membranes
Photosynthesis consists of the ……. …….. and ……. …….
light reactions / Calvin cycle
The light reactions (in the thylakoids)
- Reduce the electron acceptor NADP+ to NADPH
- Generate ATP from ADP by photophosphorylation
The Calvin cycle makes sugar from ….., using the …… and …… generated during the light reactions
CO2 / ATP / NADPH
The Calvin cycle begins with ….. ……., incorporating CO2 into organic molecules
carbon fixation
Chloroplasts split H2O into hydrogen and oxygen, incorporating the
electrons of hydrogen into sugar molecules and releasing O2 as a by-product
Light reactions
- Are carried out by molecules in the thylakoid membranes
- Convert light energy to thechemical energy of ATP and NADPH
- Split H2O and release O2 to the atmosphere
Calvin cycle reactions
- Take place in the stroma
- Use ATP and NADPH to convertCO2 to the sugar G3P
- Return ADP, inorganic phosphate,and NADP+ to the light reactions
Spectrophotometer
measures a pigment’s ability to absorb various wavelengths
Absorption spectrum
a graph plotting a pigment’s light absorption versus wavelength
Chlorophyll a
the key light-capturing pigment that participates directly in light reactions
Chlorophyll b
an accessory pigment
The absorption spectrum of chlorophyll a indicates that ………. and …….. light will work best for photosynthesis, while ……. is the least effective
violet-blue / red / green