photosynthesis year 2 Flashcards
(26 cards)
What is photosynthesis?
The production of organic compounds, such as carbohydrates and lipids, from the inorganic compounds carbon dioxide and water, using light energy.
Photosynthesis equation
6CO2 + 6H20 —light energy, chlorophyll—– C6H12O6 + 6O2
What are the conditions required for photosynthesis?
- carbon dioxide
- water
- light
- chlorophyll
- optimum temp for enzymes
What is ATP made up of?
Adenine (a base)
Ribose (a pentose sugar)
3 phosphate groups
What does ATP do?
provides small packages of energy quickly in a single step reaction.
What enzyme is needed in the hydrolysis of ATP to ADP + P?
ATP hydrolase
What enzyme is needed in the condensation reaction of ADP + P
ATP synthase
Give 4 features of ATP
- releases small packets of energy when its hydrolyses
- hydrolyses quickly in a single step reaction
- re synthesised quickly
- makes other molecules more reactive by transferring one of its phosphate groups
Function of the thylakoid
membranes contain chlorophyll pigments that absorb light, where the light dependent reaction takes place
Function of granum(stack of thylakoids)
More membranes present so rate of photosynthesis is greater
Function of stroma
fluid containing enzymes for the light reactions
Function of the double membrane surrounding the chloroplast
two phospholipid bilayers- one o2 diffuses out of, the other CO2 diffuses into the chloroplast along their conc gradients
What happens in the ribosomes?
enzyme synthesis takes place
What 2 parts can photosynthesis be divided up into?
- ) Light dependent reaction occurs in the thylakoid/ grana of the chloroplast
- ) light independent reaction occurs in the stroma of the chloroplast
Where does light dependent reactions occur?
thylakoid membranes
what term describes- ‘The formation of ATP using energy from light’?
chemiosmosis
What term describes- ‘the emission of an electron from a molecule due to the absorption of light’
photoionization
What is photolysis?
The splitting of water in the presence of light
What are limiting factors of photosynthesis?
light intensity, temp, co2 conc
Explain the trend of light being a limiting factor of photosynthesis
As light intensity (LI) increases, rate of photosynthesis increases as light is the limiting factor;
As LI increases further, rate of photosynthesis stays constant as another factor is now the limiting factor.
Why is light a limiting factor of photosynthesis?
Light excites electrons in chlorophyll, causing photoionisation;
Electrons move through the ETC, releasing energy for the pumping of protons into the thylakoid space;
These diffuse back through ATP synthase, causing photophosphorylation.
Explain the trend of co2 being a limiting factor of photosynthesis
As CO2 increases, rate of photosynthesis increases as CO2 is the limiting factor;
As CO2 increases further, rate of photosynthesis stays constant as another factor is now the limiting factor.
Explain the trend of temperature being a limiting factor of photosynthesis
As temperature increases, rate of photosynthesis increases until the optimum temperature; molecules gain kinetic energy so E-S complexes form more quickly.
Beyond this temperature, rate of photosynthesis decreases, as enzyme denaturation takes place so fewer E-S complexes form.
Why should more CO2 increase growth rate?
More CO2 leads to more GP and more TP thus more glucose;
More glucose means rate of respiration is higher so more ATP for cell division and protein synthesis.
