Photosynthesis Flashcards
What is an autotroph?
An organism that uses light or chemical energy and inorganic molecules to synthesise complex organic molecules
What is a heterotroph?
An organism that invests and digests complex organic molecules to provide them with chemical energy
Define photosynthesis
The process by which light energy is used to form complex organic molecules in chloroplasts
What are photosynthetic pigments?
Molecules that absorb light energy at specific wavelengths (and reflect the others) in the thylakoid membranes
What is a primary pigment?
It is present in the reaction centre of every photosystem
- chlorophyll a: absorbs 450-480nm (blue) and 660-710nm (red) and reflects 480-710 (yellow/green)
What is an accessory pigment?
A pigment that absorbs different wavelength of light to primary pigments and passes the energy to the primary pigments in the reaction centre of a photosystem
What are examples of accessory pigments?
Chlorophyll b - blue/green reflected
Xanthrophyll
Carotene - orange/yellow reflected
What is Photosystem II?
Absorbs wavelengths of 480nm
What is Photosystem I?
Absorbs wavelengths of 700nm
What are light dependent reactions?
A reaction that takes place in the thylakoid membranes
- light energy is converted to chemical energy
What is photophosphorylation?
The formation of ATP in the presence of light energy which occurs in the thylakoid membranes
What is photolysis?
An enzyme catalysed reaction where water molecules are split in PSII using light energy
What are electron carriers?
Molecules that transfer electrons
What are electron acceptors?
Chemicals that accept electrons from other compounds
What are light independent reactions?
Reactions that take place in the stroma and chloroplasts which do not require light energy
-require NADP and ATP from the light dependent stage, where CO2 is also produced
