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A level Biology: Post your doubts here!

anastasia grey113

anastasia grey113

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Deeksha Tamang said:
Can anyone tell me what is Variable number tandem repeats(VNTRs)?
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VNTRs are basically repeated short DNA sequences.
The number of repeats are different for each allele of a gene and these 'variable' number of repeats cause different alleles to form bands on different locations on a genetic finger print.
I think this will help you understand better.
upload_2018-3-24_16-28-56.png
You see for allele A5 there are 5 repeats
while for A4 are 4,
for A3 are 3
and for A2 there are two repeats
so these different numbers of 'CG' repeats cause bands to form at different lengths along the fingerprint
A2 is down below while A5 is at the highest point
 
cool.fireboy24

cool.fireboy24

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kity way said:
Why isnt it A? Why B?
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Umm.. Those hydrophillic R groups are meant to interact with the hydrophillic substances passing through the membrane. Not the inner portion of the membrane.

At least this is what I think so. Cuz remember we have hydrophillic channels in the first place in order to allow ions and polar substances to pass by facilitated diffusion and active transport.
 
Mstudent

Mstudent

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Deeksha Tamang said:
View attachment 63405 can anyone tell me its solution??
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I think Potential ecological effects has to be stated cause, you are testing out both a normal conc. of Bt toxin and a unnaturally high conc. of Bt toxin, so it gives a prediction of what might happen if the Bt toxin conc. suddenly rises too much as an unnaturally high conc. of Bt Toxin will rarely ever occur.

And BTW, all of this is in Laboratory conditions so other researchers reading this can keep it in mind that this may not happen in the natural world, as its only a simulation of what might happen. Hopefully I haven't confused you too much!
 
anastasia grey113

anastasia grey113

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Mstudent said:
People with PKU are homozygous recessive for the PKU allele, so if they are treated for renal cancer, they have a higher chance of survival till reproductive age (thank non treated ones) and they pass on the recessive allele to their offsprings.
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wait so that means the cancer is treatable right?
so if it treats ppl with PKU y can't it treat normal ppl too?
 
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