2.9 + 8.3 photosynthesis Flashcards
why is photosynthesis important in food chains?
photosynthesis produces chemical energy which serves as the primary energy source for many living organisms
what component of the chloroplast absorbs light energy?
photosynthetic pigments
what is the role of photosynthetic pigments?
to absorb light energy
is UV light used in photosynthesis?
no!
what kind of light is used in photosynthesis?
visible light
draw the action spectra for photosynthesis
-
draw the absorption spectra for chlorophyll
-
what method can be used to separate photosynthetic pigments?
chromatography
what are the two types of chromatography
paper chromatography and thin layer chromatography
which chromatography gives better results?
thin layer chromatography
what colour of light do leaves absorb best?
violet
what colour of light do leaves not absorb well?
green
how can water with no dissolved carbon dioxide be obtained (for use in photosynthetic experiments)
boiling + cooling water
why is light needed in photosynthesis?
to split water molecules
the splitting of water molecules is called…
photolysis
what are products of photolysis?
it produces electrons, protons and oxygen
what process produces oxygen?
photolysis
how can we measure photosynthetic rate? (know briefly) (4)
- measure the O2 produced
- or CO2 taken in
- increases in biomass
- changes in pH
how can we measure the production of O2?
- count no. of bubbles
- use oxygen probe connected to data logger
how can CO2 concentration be measured?
using a CO2 probe
what factors affect photosynthesis (3)
- temp
- CO2 conc
- light intensity
what are limiting factors?
a factor that directly affects the rate of a process if its quantity is changed
what happens to the plant at high light intensity?
the chlorophyll in da plant might be BLEACHED
why does temperature affect photosynthesis?
the enzymes used in photosynthesis are temperature sensitive!
where does the light dependent reaction occur?
thylakoid membrane
what cycles are there in photosynthesis?
cyclic photophosphorylation and calvin cycle
what process(es) specific to photosynthesis produces ATP?
photophosphorylation
the ‘equivalent’ of photophosphorylation in photosynthesis is __________ phosphorylation in respiration…
oxidative
what is the waste product in photosynthesis?
oxygen
where are chlorophyll molecules located?
in photosystems
in other words, what are photosystems?
light harvesting complexes
which photosystem is the electron first excited?
photosystem II
what causes a photosystem to release an electron?
photoactivation of chlorophyll a by light
at which photosystem does photolysis occur?
II
why is photolysis important in maintaining the ETC?
it provides replacement electrons in the chlorophyll a of PSII to continue the ETC
how is ATP formed? (one word process)
chemiosmosis
in photosynthetic chemiosmosis, protons are pumped from the _______ to the _____________ across the ___________________
stroma to the thylakoid space across the thylakoid membrane
where does the energy for pumping protons come from?
energy released by electrons travelling down ETC
why is the production of H+ from photolysis important?
production of H+ generates a proton gradient which is used to make ATP
ATP is produced by the ________ of H+ ions through __________
movement, ATP synthase
who is the final electron acceptor?
NADP+
what does ATP produced from the light dependent reaction provide?
energy
what does NADPH produced from the light dependent reaction provide?
H+ and e-
the steps of the calvin cycle:
1. carbon fixation
2. ???
3. regeneration of RuBP
reduction
the steps of the calvin cycle:
1. ???
2. ???
3. regeneration of RuBP
carbon fixation, reduction
what are the steps of the calvin cycle?
- carbon fixation
- reduction
- regeneration of RuBP
carbon dioxide is fixed into… (full name)
ribulouse biphosphate; RuBP
what enzyme fixes CO2 into RuBP?
rubisco
RuBP is a ___ (no.) carbon molecule
5
what is the intermediate of fixing RuBP to CO2?
6C intermediate
why is G3P produced as the final product?
6C intermediate is unstable and breaks down into G3P
the 6C intermediate breaks down into…
2 glycerate-3-phosphate; G3P
what is the role of NADPH in the calvin cycle
it reduces G3P
____ (no.) NADPH is used in reducing 1 G3P
1
_____ (no.) ATP is used to phosphorylate 1 G3P
2
what is the function of ATP in the calvin cycle?
- it provides energy for the phosphorylation of G3P to form triose phosphate
- it provides energy for the regeneration of RuBP
how is RuBP regenerated?
some triose phosphates combine using ATP
glucose is produced by triose phosphates _______ the cycle
exiting
2 triose phosphates combine to form
1 glucose molecule
how many times does the calvin cycle occur to produce glucose?
6 times
1 calvin cycle produces
___ NADP
____ ADP
____ triose phosphate
2, 2, 2
how many triose phosphates are used to form glucose?
2
how many triose phosphates are used to regenerate RuBP?
10
what did calvin’s lollipop experiment discover about carbon fixation?
it discovered that G3P was the first product of carbon fixation
how was calvin able to track carbon fixation in his experiment?
using radioactive 14C carbon
heated alcohol was used in the experiment to…
kill the algae and stop photosynthesis
the algae was killed at _____-second- _________
one-second-intervals
what were the methods used to in order to analyse the products from photosynthesis in Calvin’s experiment?
- 2D chromatography
- autoradiography
the film could be _________ to identify the molecules produced and determine the sequence that they were produced
compared
the comparison of the film allowed Calvin to…
identify the molecules produced and the sequence in which they were produced
when does cyclic phosphorylation occur?
in the absence/lack of NADP+
in cyclic phosphorylation, the electron is ________ back to the _______ ETC
recycled, 1st
what is the function of the chloroplast envelope?
separates chloroplast from the rest of the cell
what is the function of the stroma?
it contains enzymes and metabolic products for the calvin cycle
which part of the chloroplast arranges the photosystems and ETCs in a specific order?
thylakoid membrane
what allows the chloroplast to harvest different wavelengths of light?
it has different photosynthetic pigments
what is the structural adaptation of the thylakoid membrane?
- highly folded, with many thylakoids and grana
- incr SAVR for more placement of photosynthetic pigments and proteins eg. ETC and ATP for light dependent rxns
what adaptation of the thylakoid membrane enables it to have a high SAVR?
- highly folded
- has many thylakoids and grana
the thylakoid spaces are _______ (size) so that…
- small
- to facilitate the accumulation of H+ to generate a proton motive force for ATP synthesis
what is a structural adaptation of the thylakoid space?
- narrow
- facilitate accumulation of H+ to generate a proton motive force for ATP synthesis
the thylakoid membrane is impermeable and thus provides…
- compartmentalisation of light-dep and light-indep rxns
- provides optimum conditions for each
how does the structure of the grana enhance photosynthesis?
- stacking of grana optimises light absorption
- and ensures that ATP and NADPH produced are readily available
chloroplasts have ___ ribosomes
70s
what is the function of 70s ribosomes in chloroplasts
synthesise proteins
what parts of the chloroplast are involved in protein synthesis?
DNA and 70s ribosomes
label a electron micrograph of a chloroplast
-
annotate a diagram of a chloroplast
-
