Why heat stress leads to a decrease in the light-independent reaction
The LDR produces the fuel for the LIR
Increased temperature denatures the enzymes that break down ATP into ADP and Pi in the chemiosmotic theory
Less CO2 will be formed
The light doesn't convert to energy
Too much heat leads to too many electrons being excited
Why a decrease in the activity of the enzyme rubisco would limit the rate of photosynthesis
Rubisco is used to bind 2 3-C compounds back together
How alterations to tumour suppressor genes can lead to the development of tumours
If there's uncontrollable cell division of mutated DNA then it'll cause the development of tumours
If there is a mutation in the amino acid that codes for a protein ...
mRNA formed may not be translated correctly
A mutated gene may be dividing uncontrollably
How you would determine the mean percentage cover for beach grass on a sand dune
Count how many metres of beach grass there was and add them together
Divide the total area of the sand dunes to 10m x 10m quadrats
At each quadrat measure the % cover by using the 1m x 1m divisions
Use a statistical test after calculating the mean
I would use a random quadrat
Succession explained
Beach grass is growing, possibly a pioneer spishy
Conditions are initially harsh and inhospital
The population dies due to lack of biotic and abiotic factors
Beach grass is the initial successor
Trees were successful successors of Beach Grass
How the drug furosemide causes an increase in the volume of urine produced
This allows water to be fully absorbed
Sodium and chloride ions are solvents which would decrease the water potential
How dopamine stimulates the production of nerve impulses in postsynaptic neurones
This acts as a domino to activate the next action potential
Dopamine travels down the axon
How GABA inhibits postsynaptic neurones
This means that when a real synapse is occurring it has to be larger than usual
GABA prevents a chemiosmotic gradient from forming which means that the vesicles crossing the synaptic cleft do not fuse with the postsynaptic neurone
Chloride ions depolarise the membrane so neurotransmitters cannot bind to post synaptic receptors
It inhibits postsynaptic neurones by using charged chloride ions as a bridge, which acts as an insulator and therefore inhibits it
Due to the chloride ions being negatively charged, they would try to move to a more positive side
Chloride ions would prevent an influx of sodium ions from entering
Cl- ions cause Na+ ions to diffuse out
So the post synaptic neurone needs to do more to allow the impulse across the synapse
Entry of chloride ions is negative in itself
This prevents the chemical impulse from changing into an electrical impulse
This stops the synapse from taking place
This means that the impulse is no longer attracted to the next synapse because that is also negatively charged
Why people with red-green colour blindness are unable to distinguish between red and green, and also between other colours
Rod cells are all connected to one bipolar cell
Cone cells are unable to absorb pigment
The rod cells are not able to see a lot of visual
Red-green colour blindness blurs the colours together
Red and green are opposite colours and people struggle to distinguish between them
How iPS cells could correct red-green colour blindness
Pluripotent stem cells are able to develop into any human cell.
Therefore they could be developed into rod cells that allow for photosynthetic pigments
to be coded for that allow for red-green sight
Reasons why iPS cells could have advantages over the use of gene therapy to correct red-green colour blindness
In gene therapy the offspring of the patient cannot choose whether they have the treatment or not, which is an ethical problem
Cone cell would have working photosynthetic pigment
Cells could multiply by mitosis when dying
The IPS cell is a steam cell
Gene therapy could be a waist of money
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