Photosynthesis Flashcards
What is photosynthesis
The process whereby plants make food and oxygen using CO2 and water
What kind of nutrition is photosynthesis
Autotrophic
What is the chemical equation for photosynthesis
6CO2+ 6H2O ——->(light + chlorophyll) C6H12O6 + 6O2
What is light used for in photosynthesis
To make ATP which is to supply energy to make glucose
What are the roles of photosynthesis
Plants use it to make food Animals get their food from plants Produces oxygen which is needed to release energy in respiration Responsible for forming fossil fuels Removes CO2 from the air
What are the two stages in photosynthesis
Light stage and dark stage
What does the light stage depend on
Dependent on energy energy provided by light
What does the dark stage depend on
Does not depend on light
Where does the light stage occur
Grana of the chloroplast
What does the light stage involve
Fast movement of electrons
Is the light stage controlled by enzymes
No
What happens in the light stage
- Light energy hits the leaves and gets trapped in the chlorophyll
- Chlorophyll pigments absorb as much light as it can and passes this energy to a specially placed chlorophyll which in turn passes the energised electrons to the electron acceptor
- The energised electrons leave the chlorophyll and take one of two pathways.
What are the two pathways the energised electrons take after leaving the chlorophyll
Pathway 1
OR
Pathway 2
What happens in pathway 1
- Energised electrons leave the chlorophyll and go through a series of electron acceptors and go back again to the same chlorophyll it left.
- The electrons loose energy and this is used to join ADP and P to form ATP. Water is also formed
What is the chemical formula for pathway one
ADP + energy + P —-> ATP + water
What is the addition of phosphate known as
Phosphorylation
What is the phosphorylation
Source of energy is light
Why is pathway one cyclic
Electrons flow from the chlorophyll to the electrons acceptor and back again
What is pathway one called
Cyclic photophosphlorylation
Why is pathway one call photophosphorylation
Due to the method of making ATP
How does pathway two differ to pathway one
The electrons do not return to the chlorophyll in which it left
What are the stages in pathway two
- Electrons pass through a series of electron acceptors and then onto NADP+ to form NADP- energy isreleased in this process to make more ATP
- The chlorophyll are now short of electrons and they are replaced by the splitting of water.
- Protons are formed from the splitting of water are stored in a pool of protons in the chloroplast.
- These protons are now attracted to NADP- and combine with it to make NADPH this will be used in the dark stage
What are protons attracted to
NADP-
When will NADPH be sued
Dark stage
What is the chemical equation for pathway 2
ADP + energy + P —–> ATP + energy
What is the pathway 2 also know as
No cyclic phosphorylation
What is photolysis
Water split by light to form 2 protons (join in the pool of hydrogen in the chloroplast) 2 electrons ( replace electrons lost in pathway 2) 1/2 O2 (released into atmosphere)
End products of the light stage
ATP energy for the dark stage
NADPH provides proteins and energised electrons for the dark stage
Oxygen made when water is split which is released into the atmosphere
What is th dark stage also known as
Calvin cycle
Where does the dark stage occur
Stroma of the chloroplast
What is the dark stage controlled by
Enzyme which can be effected by ph and temp
What are the stages of the dark stage
- CO2 from the air combines with protons and Evectrons to form glucose
2 H+ and electrons come from the broken down NADPH TO NADP+ - Electrons are added
- Energy required to form glucose comes from the ATP to ADP
What is the reduction reaction
Carbon dioxide reduces to glucose
What are the overall products of the dark stage
NADP+ and ADP and P and glucose
What are the factors needed for photosynthesis
Chlorophyll Temperature Light Water CO2
Why is chlorophyll needed
Absorbs light
Where is chlorophyll found
Chloroplast
What chlorophyll made of
Magnesium
Why is light needed for photosynthesis
Increases rate of photosynthesis to a certain point
Why is water needed for photosynthesis
Absorbs from the soil
What temp does photosynthesis work better
25 as it contains plant enzymes
How can humans increase the rate of photosyntheis
Artificial light
Release CO2 glass and add sodium bicarbonate
