mm- plant phisiology Flashcards
The Circadian Clock is temperature compensated. What does this mean?
It runs at the same speed regardless of temperature - each process is temperature dependent but it cancels out
rate of synhesis = rate of degredation
Is C4 p/s useful at low temperature
NO! At low temperatures there is little photorespiration, so C4 photosynthesis is too expensive to run as it requires 2 ATP per carbon dioxide assimilate
What pathway of nutrients travels through cell walls without crossing any membranes?
apoplastic or symplastic
Apoplastic pathway all the way up to the cortex. The symplastic pathway goes through the cytoplasm of cells connected by plasmodesmata.
What is the root structure of a Dicot?
Tap root with branching laterals and ephemeral feeder roots. Monocts have a Fibrous root system
What are examples of plants that conduct CAM photosynthesis?
Agave, cacti and vanilla/ rice, wheat and cotton are c3 and Maize, sugarcane are c4
The transcript levels (mRNA) of clock controlled genes changes throughout the day. What type of blot can be used to see this?
NORTH
SOUTH
WEST
northern blots can visualise the levels of mRNA
south is DNA, west is protein
What is the active form of the chromophore Phytochromobilin and where is it located?
trans Pfr and located in the nucleus. The inactive form is Pr located in the cytoplasm. It is changed into the active form by red light and changed back into the inactive form by far-red light.
» initiates germination
> H.jones cheat sheet
What ion is solute-coupled transport linked to in plants?
H+ its Na in animals
POOP
What is the correct order of the Circadian clock mechanism? POOP
“Night - Gene Z is active and produces Z protein
Dawn - When at a certain concentration protein Z activates expression from gene X and Y
Day - X and Y proteins accumulate, affect expression of clock controlled genes and inhibit expression of gene Z”
What adaption do Vessels and tracheids have against cavitation?
Pits! The pits allow water to BYPASS the cavitation. they are areas where secondary wall is missing
The width of vessels actually make them more vulnerable to cavitation but they have less resistance to flow (faster)
When the water potential of the solution > water potential of the cell, what happens?
A no water movement
B water moves into the cells
C water leaves the cell
OPTION B
Solution is hypotonic/less solute/more distilled so water moves into the cell
HIGH TO LOW
What suberin do bundle sheath cells have to minimise carbon dioxide escape?
Suberin in their cell walls. Note that RuBisCO is only found in BS cells so C4 plants need to maximise the concentration of carbon dioxide within them.
What is CAM photosynthesis?
CONSERVES WATER
The temporal separation of initial carbon fixation by PEPC and refixation by RuBisCO
C4 p/s is The spacial separation of initial carbon fixation by PEPC and refixation by RuBisCO
true or false?
rubsico is found in both mesophyll and bundle sheath cells in C4 p/s
FALSE
only in bundle sheath so all sugar porduction here
as a result BS cells are larger
why dont all plants use C4 p/s?
favoured at higher temp only as its p/respiration
> plants that use it foind in tropics / sugarcane, maize
2 ATP needed to regenerate PEP so its expensive
