Photosynthesis Flashcards
What is the natural source of light for plants?
sunlight
Other than natural light what source of light can you use for plants?
artificial light
Where is artificial light used and what is it used for?
Artificial light is often used in greenhouses stimulate growth
What can increasing light do?
Increase growth up to a certain saturation point where no more light can be absorbed and photosynthesis will level off
How many sources of carbon dioxide do plants have?
Plants have 2 sources of carbon dioxide one is external the other is internal
Where do plants get most of their carbon dioxide from?
the atmosphere - this is external
Where do plants get carbon dioxide from internally?
their own cellular respiration
What is sometimes used to stimulate growth in a greenhouse?
Artificial sources of carbon dioxide e.g. burning gas in a greenhouse
Why are artificial sources of carbon dioxide sometimes used?
to stimulate growth e.g. burning gas in a greenhouse
What is an example of an artificial source of carbon dioxide?
burning gas in a greenhouse
How is water absorbed from the soil and what does travel up?
By the roots of plants, the stem
What is water absorbed from the soil used for in plants?
photosynthesis
How many stages of photosynthesis are there are what are they called?
2
Light Stage and Dark Stage
Where does the light stage take place?
In the grana of the chloroplast
What does the light stage involved?
the very fast movement of electrons and is not controlled by enzymes
Is the light stage controlled by enzymes?
no
What is light absorbed by?
A range of pigment clusters found in the chloroplast (almost all colours of light are absorbed but green is normally reflected)
What colours of light are absorbed by pigment clusters?
almost all of them
What colours of light are reflected by pigment clusters?
green
Where is the range of pigment clusters found?
in the chloroplast
What is the light energy transferred to after being absorbed by pigment clusters?
the electron that has been passed to the chlorophyll
Where is the chlorophyll that the electron is passed to?
in the pigment cluster and strategically placed near an electron acceptor
What does the pigment cluster do?
Absorbs as much light energy as possible and passes it to the chlorophyll which passes it to the electron
What is the energised electron passed to after it absorbs as much light energy as possible?
The energised electron is passed to the electron acceptor which can the send it on one of two pathways
How many pathways can the energised electron be sent on?
1 of 2
draw a diagram of the light stage
with pigments in pretty colours
What happens in Electron Flow Pathway 1?
In pathway 1 the electrons pass from the first electron acceptor to a series of other electron acceptors and back again to the chlorophyll.
What happens as the electrons are passed around?
As the electrons are passed around they lose energy
What is energy lost by electrons used for?
To join a phosphate to ADP to form high energy ATP. Water is also formed in this process.
What is formed by energy lost by electrons other than high energy ATP?
Water
Write a formula for cyclic phophorylation
ADP + Energy + P -> ATP + Water
What is phosphorylation?
The addition of phosphate to ADP is called phosphorylation
What is Cyclic Phosphorylation?
The addition of phosphate to ADP while an electron travels in a cycle and returns to its original chlorophyll
What happens first in electron pathway 2?
2 high energy electrons at a time are passed from chlorophyll to the electron acceptor and then along another series of electron acceptors. In this case the electrons do not return to the original chlorophyll. They lose energy as they pass from electron acceptor to electron acceptor and this energy is used to make more ATP.
Do electrons in pathway two return to the original chlorophyll?
no
How many electrons are passed down electron pathway two from the chlorophyll to the electron acceptor at a time?
2 high energy electrons at a time