Photosynthesis Flashcards
What is photosynthesis
green plants convert light energy from the sun into chemical energy (glucose)
- produce their own food
where is light energy trapped
chlorophyll
where can you find chlorophyll in a cell
chloroplasts
what is the word equation of photosynthesis
carbon dioxide and water
+ light energy and chlorophyll
=glucose and oxygen
what are the raw materials needed for photosynthesis
carbon dioxide and water
what are the products produced from photosynthesis
glucose and oxygen
what are the two stages of photosynthesis called
light reaction
carbon fixation
Stage one light reactions
light energy is absorbed by chlorophyll
this is then converted into chemical energy
some energy is used to split water into hydrogen and oxygen
oxygen diffuses out of cell
hydrogen passes on to carbon fixation
the rest of the energy is used for ATP which is passed onto stage two
what is the chemical energy in stage one stored as
ATP
it is an energy storing molecule
what is needed from stage one for stage two
hydrogen and ATP
what happens to the oxygen produced in stage one
it diffused out of the cell as a by product
state the process of carbon fixation
carbon dioxide +. hydrogen
(from the air ). (from stage one)
undergo a series of enzyme controlled reactions
energy from the reactions is released by atp from stage one
the final product is glucose
where does stage two occur in a plant cell
chloroplast - stroma
what molecule supply’s the energy required for stage two
ATP
what molecule from the air is used in stage two
carbon dioxide
what special “biological catalysts “ control the reactions in stage two
enzymes
what is the product from carbon fixation
Glucose
what is the bi product from stage one
oxygen
Why is photosynthesis important for animals
start of every food chain
provide a food source
provide oxygen to the atmosphere for us to breathe
What stage does not require energy
carbon fixation
name the three thing glucose can be used for
broken down into chemical energy - respiration
converted into starch - for storage
converted into cellulose - for cell structure
why is glucose used as respiration
to give the cell energy for other processes
why is glucose converted into starch
to allow plants to store starch as it is a larger insoluble molecule
what is the plant cell wall made out of
cellulose
why is glucose converted into cellulose
so they can be woven into complex strong structures
it is the main component in plant cell walls
what is the process of testing a leaf for starch
boil leaf - softens leaf and kills cells
collect a test tube of ethanol
put the leaf in the ethanol and leave to rest - the ethanol will remove green colour
remove an rinse leaf
add iodine
how do green plants store glucose
as starch
what is a limiting factor
anything in short supply that prevents a reaction or process occurring at its maximum rate
what are the limiting factors of photosynthesis
light intensity
carbon dioxide concentration
tempreture
why might the rate of photosynthesis be reduced at very high tempreture
because the enzymes have reached their optimum activity
how does concentration graphs work
as carbon dioxide concentration increase so does the rate of photosynthesis until it becomes steady this is when something else is the issue the same with light intensity
what is the name of the process which plants use to make food
photosynthesis
what is the end product of stage two
glucose
what chemical is used to test for the storage form of glucose
state the colour change
iodine solution
orange to black
