17 - Photosynthesis Flashcards
What are the 4 photopigments found in the group of chlorophyll?
- Chlorophyll A 2. Chlorophyll B 3. Carotenoids 4. Xanthoypll
Which of the 3 photopigments found in the group of chlorophyll is the main one?
Chlorophyll A
What colour are Chlorophyll A, Chlorophyll B and Carotene respectively?
Green, blue and orange
What is a photosystem?
Clusters of photopigments and proteins that capture light energy
Where are photosystems found?
In the thylakoid membrane
What is found at the centre of a photosystem?
The reaction centre
What are organisms which photosynthesise classed as?
Autotrophs
What is an advantage of the highly folded structure of thylakoid membranes?
Provides a large surface area for the absorption of photons
Apart from the photopigments from the chlorophyll group can you name one other?
Xanthophyll or Carotenoids
Where in a photosystem is chlorophyll a located?
The reaction centre
What is the role of the antennae complex?
To absorb different wavelengths of light in order to transfer this energy to the reaction centre
What are the two stages of photosynthesis?
Light-dependent and light-independent
Summarise what goes on in the light-dependent stage of photosynthesis?
Energy from sunlight is absorbed and used to form ATP, and hydrogen from water is used to reduce coenzyme NADP to NADPH
Summarise what goes on in the light-independent stage of photosynthesis?
Hydrogen from NADPH and CO2 are used to build organic molecules such as glucose, with ATP supplying the required energy.
Which of the two photosystems absorbs light at lower wavelengths?
Photosystem II
At around what wavelength does PSII absorb light?
680nm
At around what wavelength does PSI absorb light?
700nm
Which of the two photosystems reacts first?
PSII
What are the two possible types of photophosphorylation?
Cyclic and non-cyclic
Briefly explain what happens in cyclic photophosphorylation?
Instead of the electrons from PSI being used to reduce NADP, they can be returned to PSI to form ATP without the input of electrons from PSII
What is not produced during cyclic photophosphorylation?
NADPH
What is photolysis?
Where water molecules are broken down using energy supplied by photons
What is the oxygen-evolving complex?
An enzyme which catalyses photolysis of water
Where is the oxygen-evolving complex found?
PSII