photosynthesis Flashcards
How is diffusion used in photosynthesis
Protons move by facilitated diffusion down electrochemical gradient into the stroma via ATP synthase in thylakoid membrane
Explain what happens in the light dependent reaction
Chlorophyll in photosystem II absorbs light energy which excites electrons to a higher energy level, releasing them from chlorophyll. This is called photoionisation
Some energy from electrons released during photoionisation is conserved in the production of ATP and NADPH
The production of ATP during LDR
Electrons pass down electron transfer chain from PSII to PSI via redox reactions, losing energy at each step.
This energy is used to actively transport protons from stroma into thylakoid
This creates a electrochemical gradient across thylakoid membrane
Protons move by facilitated diffusion down electrochemical gradient into the stroma via ATP synthase which is embedded in thylakoid membrane
Energy from this allows ADP+Pi to form ATP (photophosphorylation) This can also be refereed to as the chemiosmotic theory
Importance of diffusion in photosynthesis
facilitated diffusion for Chemiosmosis is important as the energy from protons moving through ATP synthase allows ATP to be produced. ATP is an immediate source of energy which the plant can use for respiration. Without diffusion protons would remain in the thylakoid and will not be able to give off energy when passing through the ATP synthase to produce ATP. No ATP means less energy is released for the plant. This affects translation as ATP is needed to form peptide bonds between two amino acids to form polypeptide chains. Therfore this has knock on effects on the production of chlorophyll as this is a protein and lack of chlorophyll means less photosnthesis.
