Lecture 9: Photosynthesis Flashcards
How many membranes does the chloroplast have?
Three, the outer membrane, inner membrane, and thylakoid membrane.
What features does the chloroplast have which support endosymbiotic theory?
Has its own DNA and ribosomes.
Where do the light reactions take place?
The thylakoid membrane.
Where do the light independent reactions take place?
In the stroma.
Explain the light dependent reaction.
Along the thylakoid membrane are protein complexes that contain chlorophyll. These protein complexes are called photosystems. The chlorophyll is a green pigment which absorbs light in order to excite an electron. This creates a high energy electron. The high energy electrons then travel through the photosynthetic electron transport chain.
The electrons which leave PS1 go to NADPH and the electrons from PS2, proton gradient is formed. Protons travel back through the membrane into the stroma at ATP synthase to make ATP.
In the light dependent reactions water is split and 02 is produced. ATP and NADPH are also produced.
Explain the calvin cycle.
The calvin cycle is a light independent reaction although it needs the products formed in the first step. In this process Carbon Dioxide is turned into Glucose. This cycle can be broken down into three phases.
Carbon Fixation
Carbon Reduction
Carbon Regeneration
In carbon fixation carbon dioxide joins with a five carbon molecule. This forms a 6 carbon molecule which then splits into two three carbon molecules.
In carbon reduction these three carbon molecules, with the use of ATP and NADPH, are converted into two three carbon sugars.
Finally in carbon regeneration some of the G3P molecules, the sugar made above, go onto make glucose. While others are recycled back into the process.
