Photosynthesis Flashcards
Autotrophs
“self-feeders” - use photosynthesis
Heterotrophs
“different-feeders” - non-photosynthetic organisms
Equation of Photosynthesis
carbon dioxide + water + light energy -> sugar(usually glucose) + oxygen
What type of reaction is photosynthesis?
Redox Reaction
What is the byproduct of photosynthesis?
oxygen
What is reduced in photosynthesis?
CO2 is reduced to sugar
What is oxidized in photosynthesis?
Oxygen!
Thylakoid
flattened sac-like structures inside the chloroplast
Grana
Groups of thylakoids
Lumen
Space inside the thylakoids
Stroma
Fluid-filled space between the thylakoids and the inner membrane
Pigments
molecules that absorb only certain wavelengths of light
Why are pigments coloured?
We see the reflected wavelengths that are not absorbed.
What is the most common pigment?
Chlorophyll
What are pigments organized into?
Complexes
Where does photosynthesis occur in prokaryotes?
The entire cell - they don’t have chloroplasts
What is the liquid matrix in chloroplasts called?
Stroma
Do longer or shorter wavelengths have more energy?
Shorter wavelengths
What type of light do chlorophylls absorb?
Red and blue
What type of light do cholorphylls reflect?
Green
What type of light do carotenoids absorb?
Blue and green
What type of light do carotenoids reflect?
Yellow, orange or red
Action Spectrum
Wavelengths that drive the light-capturing reactions
Absorption spectrum
This measures how the wavelength of photons influences the amount of light absorbed by a pigment
What is the difference between chlorophyll a and b?
a has CH3 and b has CHO. a is more common that be.
What are the parts of a chlorophyll pigment molecule?
Isoprenoid tail, and “head” (ring structure w/ Mg in centre
What is the role of accessory pigments?
They absorb light and pass energy on to chlorophyll. Ex. carotenoids
What does ultraviolet light do to pigments?
May eject electrons from pigment and create a free radical
Fluorescence
When the electron energy produces light
What percentage of chloroplast excited electrons produce fluorescence?
2%
Overview of Light Reaction
A series of molecules are reduced by passing along this electron, ending with NADP, which picks up the electron to become NADPH.
Antenna Complex/Reaction Centre
chlorophyll molecules and accessory pigments organized by an array of proteins