Photosynthesis Flashcards
What’s the similarities of the respiration equation and photosynthesis reaction
The are the reverse of one another
What’s the chemical formula reaction of photosynthesis
6CO2 + 6H2O —> C6H12O6 + 6O2
What’s the word equation for photosynthesis
Carbon dioxide + water —> glucose + oxygen
What type of reaction is photosynthesis
Endothermic reduction reaction
What is a Autotroph and an example
Producer , plants
What is a heterotroph and an example
Consumer , animal( humans )
What’s a saprotroph
Decomposer
What’s the compenSation point
Where photosynthesis and respiration rates are the same
How does low light intensity effect respiration rates
Low light intensity , can’t take up allot of CO2 , not allot of photosynthesis = respiration higher
Why is it important to have lots of different pigments in chloroplasts
To absorb different light wavelengths
Why does chlorophyll give a green. Colour
It absorbs all light wavelengths but reflects green
What pigments can be found in chloroplasts
Chlorophyll A
Chlorophyll B
Xanthophylls
Carotenoids
What’s the light harvesting system and reaction centre are collectively known as ?
The photo system
What are the 2 stages of photosynthesis
Light dependant stage
Light independent stage
In light dependant stage of photosynthesis what are the 2 reactions
Cyclic
Non cyclic
What does the cyclic photo phosphorylation stage include and what does it produce
PSII
ATP , oxygen , hydrogen ions
What does the NON cyclic photo phosphorylation stage include and what does it produce
PSII + PSI
Reduced NADP , ATP, oxygen , hydrogen ions , electrons
What products are produced in the light dependant stage on photosynthesis
Reduced NADP
ATP
Oxygen
Where does the light dependant stage of photosynthesis occur
In the thylakoids
What does the reaction photo phosphorylation do
ATP + Pi = ATP
What does the reaction photolysis do and how
Splits water using sunlight to produce oxygen , hydrogen and electrons which go to the PSII
What is the photosystemn
A funnel shape protein full of photosynthetic pigments
Where is light absorbed by in photosynthesis and what is released
Phptosytems I and II (PSII PSI )
Electrons are realised from the chlorophyll
What do the electrons from photolysis replace
Electrons lost by chlorophyll A
How do you calculate the Rf value
divide the distance travelled by the component by the distance travelled by the solvent( smaller number over larger number )
What’s the process of cyclic photo phosphorylation? (4steps)
Light is absorbed by PSI (P700) thus causes the chlorophyll A molecule to emit a pair of electrons
The energised electrons are picked up by an electron acceptor
The electrons are then passed along the electron transport chain, releasing energy to make ATP from ADP and Pi by chemiosmosis
The electrons are returned to PSI
Cyclic and non cyclic photo phosphorylation is also known as
Light dependant reactions
What’s the difference between cyclic and non cyclic photo phosphorylation
Cyclic involves just PSII
Non cyclic involves PSII and PSI
What is the light independent reaction also known as
Calvin cycle
What does TP stand for in the Calvin cycle
Triose phosphate
What does GP stand for in the Calvin cycle
Glycerate phosphate
How many carbon molecules are GP made up of and how many are produced per cycle
2 3Carbon molecules
How many carbon molecules are TP made up of and how many are produced per cycle
2 3Carbon molecules
How many carbons make up the unstable intermediate in the Calvin cycle
6C
How many carbons make up RuBP in the Calvin cycle
5C
Explain the process of the Calvin cycle in full
CO2 combines with 5C RuBP using the enzyme RuBisCO
This creates a 6C unstable intermediate
The unstable intermediate creates 2 3C GP
Using ATP and NADPH (from the light dependant stage) and 2 GP this creates 2 3C TP
TP is then either used to create carbohydrates or RuBP to start the process again
What 3 factors effect photosynthesis
Light intensity
CO2 concentration
Temperature
How does the light intensity effect photosynthesis
Light is used to create ATP and NADPH which is needed in the light dependent reaction to complete photosynthesis
How does CO2 concentration effect photosynthesis
Carbon is needed to start the Calvin cycle
How does the temperature effect photosynthesis
Effects enzyme controlled reactions ( Rubisca and ATP synthesis)
Why is water not considered a limiting factor in photosynthesis
Although water is required for photosynthesis it is never considered a limiting factor as water can be kept if that stomata closes
What’s the concentration of CO2 in the atmosphere
0.035%
Where does C3 photosynthesis (normal one )occur
Cool
Wet conditions
Average sunlight
Where does C4 photosynthesis occur
High temperatures
Limited water supply
What does CAM photosynthesis do and a plant example
Open stomata at night closed during the day
Cacti
What’s the law of limiting factors
When a prices is influenced by several factors , the rate of which the process proceeds is determined by the FACTOR in SHORTEST SUPPLY
What do farmers use to increase the temperature and CO2 concentration in greenhouses
Paraffin heaters
What’s the optimum temperature for photosynthesis
25 degrees C
At what temperature do enzymes in photosynthesis denature
45 degrees C
Explain water stress (5 steps)
Roots are unable to take up enough water to replace water lost via transpiration
Cells lose water
Plant roots produce abscidic acid , stomata close
Leaves wilt
Rate of photosynthesis gradually reduces
How can you test the rate of photosynthesis?
Place some pond weed in a test tube of sodium hydrogen carbonate.
Place the test tube in a water bath
Let plants acclimatise to temperature
Then count the bubbles per minute 3 times
Then repeat using different colour lights
