Topic Five exam Flashcards
What are the structures of a chloroplast?
Outer membrane
Intermembrane
Inner membrane
Stroma
Granham
Thylakoids
Lamella
Lumen
What is the thylakoid membrane?
Folded membranes which contain photosynthetic proteins (chlorophyll) and electron carrier proteins are embedded within these membranes which are both involved in LDR.
What is the stroma?
Fluid centre which contains enzymes involved in the LIR.
What are the inner and outer membranes?
Control what can enter and leave the organelle.
Where do the light dependent and light independence stages take place and what is the difference?
They both take place in the chloroplast, however the light dependent reaction occurs in the thylakoid membrane or grana, whereas the light independent reaction occurs in the stroma.
What is the light dependent reaction?
LDR is the first stage of photosynthesis and it requires light. Light energy and water are used to create ATP and reduced NADP which are needed for the light independence stage.
What four stages does the light dependent reaction take place?
- Photolysis.
- Photoionisation of chlorophyll.
- Chemosmosis.
- Production of ATP and reduced NADP.
What is photolysis of water?
Photo = light - lysis = splitting
Light energy is absorbed by chlorophyll and splits water into oxygen H+ and e-.
The H+ is picked up by NADP to form NADPH and is used in the light independent reaction.
The e- passed along a chain of electron carrier proteins.
The oxygen is either used for respiration or diffuses out of the left through the stomata.
What is photoionisation of chlorophyll?
Light energy is absorbed by the chlorophyll and the energy results in electrons becoming excited and raising up energy level to leave chlorophyll.
Therefore, the chlorophyll has been ionised by light.
Some of the energy from the release electrons is used to make ATP and reduced NADP in chemosmosis.
How is ATP produced in chemiosmosis?
The electrons that gained energy and left the chlorophyll move along a series of proteins embedded within the thylakoid membrane.
As the electrons move along the proteins, they release energy and some of the energy from electrons is used to pump the protons across chloroplast membranes.
An electro chemical gradient is created.
The protons pass through the enzyme ATP synthetase which results in the production of ATP.
How do we create NADP in chemosmosis?
The protons combine with the coenzyme NADP to become reduced NADP because the protons move from a high to low concentration gradient this is known as chemiosmosis.
