How to find the complementary strand of DNA that would form the double helix?


I have an extra credit opportunity I can do, but I’m a bit confused….

The first step is just to find the complementary strand of DNA that would form the double helix… this is the sequence of DNA given…
ATCGGCTATTAA…and so on
Wouldn’t that just be, TAGCCGATAATT??
Also, they next step is to transcribe one strand of the DNA into a strand of transfer RNA… but doesn’t it go to mRNA and then tRNA?
Which one is the transfer RNA and which strand of DNA do I use? The one given or the one I made?
Thank you for all your help!!! I tend to forget everything during Christmas break… oops

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Your first hunch is right. The complementary strand is the opposite strand and it shoul have the complementary neucleotides
So just substitute
As with T
Ts with A
Gs with C
Cs with G

When you use one strand of DNA to make RNA …. you only make an mRNA. This process is called transcription.

So transcription is the process by which the DNA copies its message to mRNA. I would suggest looking this up for transcription
http://en.wikipedia.org/wiki/Transcripti…
It has the following processes
pre initiation
Initiation
Promoter clearance
Elongation
Termination
mRNA processing steps (5’cap addition, splicing and poly A tail addition)
So the DNA message is copied. So if you used that sequence
ATCGGCTATTAA

Then what will the mRNA sequence be?

of course it’s similar to the complementary DNA strand …. right?
instead of Ts you will have uracils this time ….
so it should be UAGCCGAUAAUU
Then this mRNA can be used to synthesize a protein and the process by which this occurs is called translation.

Tranlsation has 3 steps
Initiation
elongation
termination

there are 3 main kinds of RNA
mRNA – carries the message
tRNA – carries the amino acid
rRNA – makes up the ribosomes where the protein synthesis occurs

Protein translation requires ribosome and mRNA which is transcripted from the nucleus (has the DNA code in it) and many other protein factors. In this process mRNA binds to the ribosome and the ribosome reads the nucleotide sequence in the mRNA.
The way it is been read is from 3 nucleotides to 3 nucleotides
Each 3 nucleotides is called a codon. Specific 3 nucleotides will recruit a certain amino acid …. meaning for example the nucleotide sequence “AUG” will recruit only amino acid called methionine.
What these amino acids depending on the codon can be found in this webiste
http://users.rcn.com/jkimball.ma.ultrane…

So for example when the nucelotide sequence AUG is present the specific tRNA that carries the methioinine amino acid will come and bbind to the mRNA and ribosome site. If the next 3 nucleotides present are UCU, the tRNA that has serine amino acid will come and bbind. Then a peptide bond will be formed between methioine and serine. This is done for the rest of the mRNA sequence until a stop codon has been found
Stop codons are UAA. UGA, UAG
These 3 stop codons do not have a specific tRNA with an amino acid. Thus translation will terminate.

So tRNAs don’t get copied by the DNA. they are made in the nucleolus and they are kind of like a clover leaf structure … they just drag amino acids towards the ribosomes and help to synthesize the correct amino acid sequence according to the mRNA sequence.

I can’t think of any other way to explain … I did my best. It’s hard to explain on a webpage no matter what you write … and I don’t know how much you will understand. good luck!

Source(s):

PhD candidate
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