A level Biology: Post your doubts here!

[hassam]

.when making antibodies using hybridomA method.....we test for the cells producing antibody>>>but i dont understand why we r doing this when we have got hybridoma cells since .....alll the cells should be producing antibodies? is it because not all the cells wud have fused to form hybridoma cell??

 

[hassam]

i have difficulty interpreting thie proper ways log scale....whats th

 

[farhan143]

I can't seem to find the answer in the Biology Guide ; the marry jones guide....
if any 1 finds the answer to this question in the guide pls post the page number regarding the topic form the question.......



THANK YOU!!
in advance!!!

 

[farhan143]

another question i am unable to answer!!


please give me the answer to this question
i mean does mRNA have stages after it leaves the nucleus and enters the cytoplasm of a cell????

 

[larina]

example.....u performed a cross and ratio of one trait to other is 3:1......so if total number is 100 then expected number wud be 75 for one trait and 25 for the other one....its just based on the percentage obtained after doing a genetic cross

yeah i know that, but can u explain me how we get the expected number for october/november 2011 paper 53, Q2 b) ii. there's no ratio given here

 

[XPFMember]

yeah i know that, but can u explain me how we get the expected number for october/november 2011 paper 53, Q2 b) ii. there's no ratio given here

assalamoalaikum wr wb!

u have to find the ratio your self

they mentioned iit's for cross 1, and u can notice the parents are heterozygous as we have both phenotypes..when u work out, u'll get the ratio 3:1
total no. of organisms are 40 + 72 = 112
3+1 = 4

therefore without tail = 3/4 x 112 = 84
with tail = 1/4 x 112 = 28

 

[aliya_zad]

.when making antibodies using hybridomA method.....we test for the cells producing antibody>>>but i dont understand why we r doing this when we have got hybridoma cells since .....alll the cells should be producing antibodies? is it because not all the cells wud have fused to form hybridoma cell??

All cells fuse to form the hybridoma cell but in some cases only "certain" hybridoma cells are able to produce the required antibody..
remember the transformed cells in insulin production where they are checked for before being used in fermenters!!so itz something similar!

 

[aliya_zad]

I can't seem to find the answer in the Biology Guide ; the marry jones guide....
if any 1 finds the answer to this question in the guide pls post the page number regarding the topic form the question.......

View attachment 5586

THANK YOU!!
in advance!!!

The questionz asking u why co2 needs to be broken down into the ions rather being transported as co2...
so itz because co2 is transported faster in this way coz there are enzymes involved and they increase rate of reaction..
about 85% of co2 is transported as hco3- ions in the plasma..this makes it easier for co2 to be removed efficiently..
this reactions also maintains the conc of co2 and pH in the blood..

 

[hassam]

can someone explain SYMPATRIC speciation

 

[Amy Bloom]

another question i am unable to answer!!

View attachment 5601
please give me the answer to this question
i mean does mRNA have stages after it leaves the nucleus and enters the cytoplasm of a cell????

Hello. Yes, mRNA undergoes some stages after it leaves the nucleus & enters the cytoplasm.
After the mRNA leaves the nucleus and enters the cytoplasm, a ribosome covers 2 codons of the mRNA.
Two aminoacyltransfer RNA bind to mRNA according to complementary base pairing of the anticodon (found on the aminoacyltransfer RNA) with the codon (found on mRNA).
Two amino acids are synthesised. A peptide bond forms between them. One aminoacyltransfer RNA leaves the ribosome and the latter covers another codon on the mRNA.
Hope my answer has been helpful to you.

 

[farhan143]

Hello. Yes, mRNA undergoes some stages after it leaves the nucleus & enters the cytoplasm.
After the mRNA leaves the nucleus and enters the cytoplasm, a ribosome covers 2 codons of the mRNA.
Two aminoacyltransfer RNA bind to mRNA according to complementary base pairing of the anticodon (found on the aminoacyltransfer RNA) with the codon (found on mRNA).
Two amino acids are synthesised. A peptide bond forms between them. One aminoacyltransfer RNA leaves the ribosome and the latter covers another codon on the mRNA.
Hope my answer has been helpful to you.

may i ask from where did you get this answer...
i mean do u hv any study guides or any othr good reference books?????

bcz i hv only the Biology Revision Guide by Marry Jones

 

[Amy Bloom]

may i ask from where did you get this answer...
i mean do u hv any study guides or any othr good reference books?????

bcz i hv only the Biology Revision Guide by Marry Jones

Well, I've racked my brains & got the answer
I recommend you this book, which I use at school:
And this one: AS/A level Biology by Mary Jones, Richard Fosbery, Jennifer Gregory and Dennis Taylor. Its a black book with a green banner on top.Do you have this one?
Humm... Has my answer helped you?

 

[farhan143]

Well, I've racked my brains & got the answer
I recommend you this book, which I use at school:
And this one: AS/A level Biology by Mary Jones, Richard Fosbery, Jennifer Gregory and Dennis Taylor. Its a black book with a green banner on top.Do you have this one?
Humm... Has my answer helped you?

think my liked answered your question!
yes i have the text bt i find it confusing!!

 

[Amy Bloom]

think my liked answered your question!
yes i have the text bt i find it confusing!!

Okay! ^^
I use another one but i don't know if it will b available in your country.
Biological science by D. Taylor, N.P.O Green, G.W stout and Soper. The third edition.

 

[farhan143]

Okay! ^^
I use another one but i don't know if it will b available in your country.
Biological science by D. Taylor, N.P.O Green, G.W stout and Soper. The third edition.

can u post a cover page of that book
and which country ru 4rm??

 

[Amy Bloom]

Unfortunately my scanner is not working.
As far as i can tell you its a big fat red book with no photos/illustrations on its cover page with white font. The book is endorsed by cambridge university press.
Well i'm from Mauritius.

 

[farhan143]

i have another doubt and these doubts are from 2011 may/june paper 21



i posted the image so that it wud b easier 4 the person willing to answer it can c it !!

 

[rz123]

i have another doubt and these doubts are from 2011 may/june paper 21

View attachment 5756

i posted the image so that it wud b easier 4 the person willing to answer it can c it !!

the vaccination is not given in the first few months after the baby hatches because his B and T Lymphocytes haven't yet matured so not being able to carry out a effective immune response, secondly in the first few months the baby carries the antibodies passed on by the mother via placenta. so he is temporarily immune for this period of time. immune system is in the process of developing...

c) u just need to explain the data given above. comment on it like you can see that at 90% of children being immunised the death rate is very less and ahead of it's very low as well. before 90% u can see a great variation in the mortality rate of under 5 years children. at 95 % the death rate is less then 50 deaths per 1000 children. so this supports the recommendation of WHO to immunise children in different districts up to 90 % or more.

 

[farhan143]

the vaccination is not given in the first few months after the baby hatches because his B and T Lymphocytes haven't yet matured so not being able to carry out a effective immune response, secondly in the first few months the baby carries the antibodies passed on by the mother via placenta. so he is temporarily immune for this period of time. immune system is in the process of developing...

c) u just need to explain the data given above. comment on it like you can see that at 90% of children being immunised the death rate is very less and ahead of it's very low as well. before 90% u can see a great variation in the mortality rate of under 5 years children. at 95 % the death rate is less then 50 deaths per 1000 children. so this supports the recommendation of WHO to immunise children in different districts up to 90 % or more.

thank you!!!!
very much!!
people over here are kind and willing to help

i too love the subject biology, but am not very good at tweaking the information i study
i mean i can only write what i study....

for example the mRNA question i posted i have the notes about the topic under which it comes but i donno how to answer using the ,,, i mean the info is scattered ....

do you have any ideas on how to customize the notes which i study and make it applicable for exam??????

 

[rz123]

thank you!!!!
very much!!
people over here are kind and willing to help

i too love the subject biology, but am not very good at tweaking the information i study
i mean i can only write what i study....

for example the mRNA question i posted i have the notes about the topic under which it comes but i donno how to answer using the ,,, i mean the info is scattered ....

do you have any ideas on how to customize the notes which i study and make it applicable for exam??????

welcome, yeah dre r many helping people, dats the beauty of this forum . i also enjoy bio but sometimes it is a PAIN. anyway u should do 5 year past ppr practice, whichever concept u lack u should go back to ur notes books etc, i think dats the way to cement ur concepts and memorize stuff effectively. u should see the marking schemes as well. and keep posting questions.

this might help : http://www.biologymad.com/
http://www.mrothery.co.uk/