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Original post by YWArtist
Reflex arc pathway and why its effective


Stimulus , receptor, co-ordinator, effector, response.

It's effective because it can prevent us from encountering harmful stimuli. Happens via the nervous system where transmission is rapid.



Give the differences between the hormonal and nervous system
Reply 3201
How does the structure of a sensory and motor neurone relate to their function?
No-one answering my questions? Great.....
Original post by JessicaTSR
Not that I could see, although they can reword and combine areas together I suppose :smile: who knows!

Could anybody enlighten me on SCID? Seems to have bypassed my notes..


SCID- Severe Combine Immunodeficiency

From what I know, this disease prevents an enzyme (ADA or adenosine deaminase) to be produced which destroys toxins that normally kills white blood cells. Patients are held in sterile conditions to prevent the transmission of infections.
Reply 3204
Original post by JessicaTSR


Could anybody enlighten me on SCID? Seems to have bypassed my notes..


well hello there,

Severe combined immuno deficiency is caused by a defect in the gene for the enzyme that destroys toxins of white blood cells. It is inherited.

Sufferers do not show cell mediated immune response and do not produce antibodies

These are those people that have to live in bubbles that are sterile (isolation tents) and they inject the enzyme.

You can treat it by isolating the normal gene using restriction enzymes and then inserting it into the T cells of the patient using retro viruses that inject DNA into the cells
Then put the transformed T cells back into the person :colone:
Reply 3205
Original post by James A
Stimulus , receptor, co-ordinator, effector, response.

It's effective because it can prevent us from encountering harmful stimuli. Happens via the nervous system where transmission is rapid.



Give the differences between the hormonal and nervous system


Fs it made me type this twice lol

Remember to include the 3 neurones sensory relay and motor, also that the co-ordinator is the spinal cord. Also that it is effective from birth, involuntary and it has a short neurone pathway and few synapses.

Hormonal
Communication via hormones
Transmission blood stream, slow as It travels to ALL parts of the body not just to specific target organs
Response is slow, widespread and long lasting
Effects may be permanent and irreversible

Nervous system
Communication via nerve impulses
Transmission neurones, rapid as only travels to specific parts of the body
Response is rapid short lived localise
Effects may be temporary and reversible


Chemical mediators...?
Reply 3206
Original post by master y
pg 157 in NT book it talks about the growth factors being made by ALL CELLS located in the plant, but i thought IAA was only produced by the growing tip??? Please help :frown:


They are in all growing regions on the plant :smile:

IAA is a type of growth factor - the only one we need to know about. So if they asked where IAA could be found you would say tip. But if they asked where growth factors could be found you would say growing regions (which i doubt they would ask because meh..)
Can anyone explain q6cii) on June 2010. Why is it a tumour surpressor gene becoming inactivated and not a protooncogene?
Original post by James A
Stimulus , receptor, co-ordinator, effector, response.

It's effective because it can prevent us from encountering harmful stimuli. Happens via the nervous system where transmission is rapid.



Give the differences between the hormonal and nervous system


Hormonal

Effect is long lasting and non-reversible. Hormones are carried in the blood all over the body, but only affect organs with specific receptors.

Nervous system

Effect is reversible and very rapid. Its effects are localised. Transmission carried out by neurones.


Why is the passage of action potentials more rapid in myelinated neurones?
Reply 3209
Original post by Blob2491
Can anyone explain q6cii) on June 2010. Why is it a tumour surpressor gene becoming inactivated and not a protooncogene?


Both tumor suppressor gene has to be mutated in order to express the mutated allele, i think maybe cause it is a recessive. Hence has to be homozygous.
Reply 3210
Original post by JessicaTSR
Not that I could see, although they can reword and combine areas together I suppose :smile: who knows!

Could anybody enlighten me on SCID? Seems to have bypassed my notes..


Scid are known as bubble babies
Basically its a rare inherited disorder in which the sufferer shows no cell mediated immune response, they don't produce there own antibodies,
The normal ADA gene from healthy human is isolated from healthy human tissue using restriction endonuclease, ADA gene is inserted into a retrovirus, retrovirus is then grown with host cells in the lab to increase there number and are then mixed with the patients T-cells, retrovirus injects a copy of the ADA gene into the T-cells, T-cells arte reintroduced into the patients blood and now provide the genetic code needed to make ADA :smile:
Original post by master y
No-one answering my questions? Great.....


What was it?
Hi guys, here is an essay of which, by an examiners standards would easily score full marks.
Original post by master y
No-one answering my questions? Great.....


Brah, what was the question? Im typing on my phone
Reply 3214
Could someone clarify.... Is kinesis and increase in random movements? Does that mean when they are in an unpleasnt environment they move more and rapidly change direction to find a more pleasant environment? thanks
Reply 3215
Original post by YWArtist
Scid are known as bubble babies
Basically its a rare inherited disorder in which the sufferer shows no cell mediated immune response, they don't produce there own antibodies,
The normal ADA gene from healthy human is isolated from healthy human tissue using restriction endonuclease, ADA gene is inserted into a retrovirus, retrovirus is then grown with host cells in the lab to increase there number and are then mixed with the patients T-cells, retrovirus injects a copy of the ADA gene into the T-cells, T-cells arte reintroduced into the patients blood and now provide the genetic code needed to make ADA :smile:


Why is the ADA gene inserted into T cells?
anyone got a 3/4 markscheme answer of

1. what is transcription?

and

2 what is translation?

thanks :biggrin:
Original post by James A
Brah, what was the question? Im typing on my phone



Original post by frogs r everywhere
What was it?


One of them has been answered now... but what would you guys write on energy trasnfers.. especially out of spec stuff? Thanks :smile:
Original post by master y
One of them has been answered now... but what would you guys write on energy trasnfers.. especially out of spec stuff? Thanks :smile:


I haven't revised for energy transfers :tongue:

what could we include for the stuff that is on spec?
Original post by peebs123
Could someone clarify.... Is kinesis and increase in random movements? Does that mean when they are in an unpleasnt environment they move more and rapidly change direction to find a more pleasant environment? thanks


If they are in unpleasant environments, they do not rapidly change direction. They change direction less frequently.

If they are in pleasant environments, they then rapidly change direction which causes the organism to remain in the same place.

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