Photosynthesis Flashcards
Where does photosynthesis occur?
Photosynthesis occurs in the chloroplasts in eukaryotic organisms.
Describe the structure of the chloroplast?
Chloroplasts are surrounded by a double membrane and have internal membranes, called thylakoid membranes, arranged in stacks called grana. In prokaryotes the thylakoid membranes are free in the cytoplasm. The spaces between the grana are called stroma.
Where are enzymes needed for the reactions of photosynthesis found?
They are found inside the chloroplasts- some in the grana membranes and some in the stroma. Chloroplasts contain ribosomes, which are necessary for protein synthesis, in order to create these enzymes.
What is photosynthesis?
Photosynthesis is an essential aspects to living organisms as it transforms sunlight energy into chemical energy, releases free oxygen gas and absorbs carbon dioxide.
Where does the light dependent reaction occur?
In the grana of chloroplasts.
What are the inputs and outputs of light dependent reactions?
Inputs are water and light (NADP and ADP+Pi)
Outputs are oxygen, NADPH and ATP
What happens in the light dependent stage?
The absorbed energy is used to produce ATP and to split water molecules to form H+ ions and the waste product oxygen. The hydrogen ions are carried by a carrier molecule (an acceptor molecule). The ATP and the loaded carrier molecules are used during the next stage.
Where does the light independent stage occur?
Inside the stroma of chloroplasts.
Is the reaction (light independent) dependent on light?
The reaction is not dependent on light but is dependent on the previous stage occurring.
What occurs during light independent reactions?
Carbon atoms are removed from a highly oxidise state (CO2) to a reduced stage (a sugar). Carbon reduction requires a supply of carbon dioxide and hydrogen ions as well as an input of energy H+ ions.
Where do the H+ ions come from?
The loaded carrier molecules
Where does the energy come from?
Comes from the ATP and the loaded carrier molecules from the previous stage
What is the Calvin cycle?
The formation of glucose from carbon dioxide and hydrogen supplied by NADPH occurs in a series of reactions called the Calvin cycle. The breakdown of ATP and NADPH supply the energy needed to drive this to build the glucose.
How does carbon dioxide and water enter the leaf?
The carbon dioxide enters the leaf by diffusion through the stomates in the leaf surface. The water travels from the roots to the leaves through transport tissue called xylem.
