How Succession occurs
Producers begin to eat the plant ...
When larger plants occupy the land, they can block wind
Eventually a final species will begin to inhabit the environment
Species populations stop growing at the carrying capacity
The pioneer species is usually the largest/strongest species, e.g. trees
The pioneer species tends to be very specific
When a climax community is reached it can support an ecosystem
This will let the next primary species develop
When the environment can't support any more life it is known as the climax community
How a single base substitution causes a change in the structure of a polypeptide
This would change the polypeptide like a chain reaction
Haemopoietic stem cell transplantation
This means they can replicate this new normal shaped haemoglobin
This is effective because stem cells take a long time to die
Stem cells have no specific use
This means their immune system will last longer
Gene therapy for sickle cell disease
This method does not require a doner
This will result in the stem cells differentiating into healthy haemoglobin
Child can produce its own stem cells from beta polypeptide gene
The body, once genetically modified stem cells are injected back into the child, will recognise the functional from the faulty, disregarding the faulty
Effects of indole acetic acid IAA on growth of oat seedlings
Plants use IAA to bend
In the roots there would be more growth as roots try to find nutrients
IAA molecules in shoots grow against gravity
Why the shoot tip was removed from the seedling
This allows the end of the shoot to be exposed in order for IAA to be taken up by the plant
The shoot would be able to grow from both ends
Each shoot is different and could grow in different directions
The shoot tips respire aerobically but without them they would have to respire anaerobically
The student removed the shoot tip to remove the opening and closing of stomata to avoid this extraneous variable
The shoot has the best enzyme acceptors that could be needed to collect nutrients and water
The shoot tip contains stem cells
Reason why glucose added
To allow same conditions for growth, for level playing fields
Plants require glucose for photosynthesis
Comparison of effects of IAA on shoot, and results difference if lengths of root were used
The root tip has the greatest concentration of chloroplasts full of chlorophyll
Roots would have grown more as they do not need light for IAA to work as they are constantly in the dark
The shoot could not photosynthesise for long in the dark
Roots require different auxins as they grow downwards rather than up
There would have been more downwards growth from the roots
If the root tip was longer it would have a greater force of gravity acting on it
Roots don't respond to IAA but they do to gravity
If different lengths of root had been used it would suggest that the longest root would grow the least as IAA would have further to travel up the root
If roots are used then ends of roots must be removed
If it differed in length then results wouldn't be fair
This would make them want to grow downwards but they were blocked by the petri dish
As roots are naturally in the dark all the results would increase
The results would be the opposite as roots grow against the projection of light
Evaluation of conclusion
We have no significant different bars
Effect of inorganic phosphate on release of calcium ions within muscle
The calcium ions synthesise ATP
Calcium ions cause myotropism wrapped around actin to move
The calcium ions bind to tropomyosin to move it out of actin so myosin can go in
This means less actinomyosin brides are formed
This causes trypsin to move and expose the binding sites
The only factor affecting the force of muscle contraction was not only the pH difference but also the temperature
Calcium ions also cause the myosin head to be released from tropysomin
A decrease in calcium ions means that depolarisation of the myosin head can occur
There will be a shorter frequency of calcium ions sent to the SAN
Less bone density . . .
Less area for muscles to attach to and less room for them to contract
Why converting pyruvate to lactate allows continued production of ATP
Lactation involves the release of CO2 and causes the release of ATP
This means fewer myoglobin heads will attach and detatch, causing a lower force
The role of glucagon in gluconeogenesis
Glucagon is secreted when bodily glucose levels drop
How increasing cell's sensitivity to insulin will lower the blood glucose concentration
Increasing the sensitivity would mean less glucose is released from the pancreas
The hormone insulin heightens the blood glucose levels over a certain threshold
This will make the cells in the pancreas think there is the right volume of insulin in the body therefore will produce less glucose
This causes more glucose to be broken down in the blood
Insulin will be released more accurately when blood glucose gets high
Liver cells will convert more glucose into glycogen. Then the glycogen can be released into the blood and lower the glucose concentration.
If the cell is sensitive to insulin it will enable insulin to break down blood glucose
Slight changes in glucose will trigger a positive/negative feedback response
This will make the cell break down glucose into glycogen more quickly
Liver cells will allow glucose to be converted into glycerol
How inhibiting adenylate cyclase may help to lower the blood glucose concentration
It may inhibit it after insulin has done its duty
If you inhibit adenylate cyclase the cell membrane cannot bind to receptors inside the cell to activate it
So there will be little or no chains of reactions after this
Adrenaline has a complementary shape to liver cells
This enzyme is used in the reaction to change large polymers into glucose
Inhibiting this enzyme means that insulin would be free to go about its functions as normal
Explanation that the gene for body colour is not on the X chromosome.
There is no imbalance of colour between genders
Calculation of % heterozygotes
p2 hetero dominant 2pq homo q2 hetero recessive
Photoionisation
This causes the H2O to split into 2 electrons
Photons hit chlorophyll in the thylakoids
The higher energy level forces electrons out of the cell
The ray of light causes the electron to gain energy and become more positive
Electrons become ionised
The electrons fall down the energy transport chain
The light energy bleaches the photosynthetic pigments
Light is absorbed by electrons which excites them
This photoionises the electrons
Light excites the chloroplast
This is the process of molecules gaining erections and becoming excited
This causes the hydrogen to break down into oxygen, hydrogen and electrons which are used for the proton pump
This excites the chlorophyll and electrons causing electrons to move out into the intermembrane space
Light is absorbed by chlorophyll from the sun
The electrons gain positive charge and move around the membrane
Electrons gain charge from light
This light energy is passed on to electrons and excites them
This leaves the chlorophyll with a positive charge (election vacancy)
Two e- leave the chloroplast, making it more positive
Light is used to split the ions
Sunlight hits the ions in the plant and excites them
Light is detected by pigments in the chlorophyll
This causes the electron to move out of the chloroplast
The plant absorbs light and turns it into energy to produce photosynthesis
Oxygen passes through the electron transport chain
Water is split by light.
This produces H+, electrons and carbon dioxide.
The light energy excites electrons causing a Cl- ion to form
Light hits the chlorophyll which is loaded with electrons
Electrons get energy and jump down the ETC
The electrons are ionised by light
During the LDR, the NADP binds with the Pi which then becomes reduced. The NADP had picked up the light, and the Pi ionised it.
Electrons in the ETC become excited by light energy
Use of pencil line in chromatography
Pencil would not be separated into pigments
The ink is soluable and would travel up the paper as well, where as lead isn't so it won't move
Ink contains some coloured dye which will also evaporate when placed in a tank containing solvent, and will give false positives
Chromatographic separation of photosynthetc pigments
Gently dipping the bottom of the pigment in solvent
This can be done via the use of osmosis on the chromatography paper
The solution is now heated
The solvent will move up the paper separating the pigments depending on their colour
Fill a tube to a shallow point full with solvent
Place paper in solvent so origin is just submerged
Fold the top of the paper over a pencil and balance it over beaker containing solvent
Mark each pigment differently
Put acid in the beaker and attach the paper to the edge of the beaker with a paperclip
The paper would be covered in solvents such as ethanol
Place a solvent on the origin line which will travel up the chromatogram
Advantage of different coloured pigments in leaves
Different pigments in leaves attract insects for pollination
So photosynthesis can take place at different times of the day
Green would show it is chlorophyll whilst other colours would show other uses
So the plant can dissolve different colours of light
Different light waves can be absorbed
Allows for adaptation and camouflage
Able to pick up different waves of light
The green pigment is reflected
So some plants absorb more chlorophyll than others
So bees can distinguish which plants need to be pollinated more easily
This could be a courtship behavious which attracts some species and able to reproduce seccessfully
Could allow for a certain amount of camouflage as a way of protecting itself from being eaten
Able to absorb different wavelengths of light so can still photosynthesise in low light intensity conditions
It maximises the efficiency by which it is converted into glucose
Different concentrations of light can be absorbed
Each pigment requires a different wavelength to be broken down
Different wavelengths of light will pass through them, producing different chromatogram points
Discourages predators as warning colours
More light can be absorbed in different parts of the leaf
A DNA probe
It is similar stranded
How DNA is broken down into smaller fragments
Enzyme restricted endonuclease
Reverse endonuclease
Why DNA is separated into single strands
They will move faster if lighter
How the size of different viral fragments was determined
An electric shock is used to move the DNA fragments to the positive cathode
How to measure population of sundew plants
Mark release recapture
Carry out a statistical test to ensure results are not due to chance
Gather the size of one population and then generalise it to the whole population
Measure the biomass of the small marsh then calculate the biomass of sundew alone
Times each number by the total area
Repeat the process until the mean population size starts to stabilise
Carry out a statistical test (t-test) to ensure these results are not due to chance
Use a generator to get various co-ordinates
Times this figure by the area of the population
You could use a Punnet square over the area
How damage to myelin sheath of neurones can cause muscular paralysis
Impulses travel along the myelin sheath of neurons
The myelin sheath acts as a conductor around the neuron
Neurones require the myelin sheath to protect the auxin which is what connects the myelinated neurone together
The body will not know when to open the Na+ gates
Nerve impulse wouldn't be produced do to damage
This can block the impulse from passing from axon to axon so the neurone doesn't reach the synapse
The myelin sheath aids the transmission of neurons along an axon
Explanation of heart rate irregularities
The autonomic nervous system consists of muscles
If a person is exposed to direct sunlight there may be more epigenetic tags in their DNA.
As muscles are affected the stronger beat of the left side of the heart is reduced
The myelin sheaths send impulses to the heart
Signals to the valves within the heart may be prevented if the myelin sheath is damaged
The contractions may be out of sink
The neurone synapse causes a stimulus and then the receptors are informed
The impulse generated in the SAN travels too quickly, without a delay through non-conducting tissue
The various chambers of the heart need to beat in a specific order
This means impulses are not always getting to the brain
Impulses are sent to the medulla oblong-gata
The SAN transmits impulses to the carotid arteries
The regulation of systole, systole and diastole is interrupted
They may not be able to squeeze the muscles round the atria
The sun will not receive an electrical impulse
The nerve system no longer recognises when it is meant to trigger the heart to beat
Neurones that are inflicted may affect the sinoatrial mode
The impulses are sometimes stopped or at least compromised
How a drug could cause a reduction in the concentration of the protein huntingtin
This causes the protein to die
As a result non-functional amino acids will be produced
Advantages of DNA drug injection over taking a pill
DNA is a protein and it would be digested by protease enzymes
Taking a pill may not always go to the brain
A pill is very time-consuming
Reasons why drug should not be considered a cure
It is caused by a dominant allele which is hereditary so any offspring will still be affected
It could be in someone's genetics from birth
Epigenetics
If an ancestor started getting symptoms then changed their lifestyle, it may have loosened the DNA around the histone allowing it to be copied
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