Transcription and Translation - GCSE Biology

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sabihah_m
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Hi, I am having trouble understanding how transcription and translation work. There are very many steps and it can get complicated. Does anyone have a simple way of explaining it or have a link to something that could help me? I have already looked at BBC Bitesize, my CGP guide and a video on youtube but I don't quite seem to get it. I am doing GCSE Biology OCR Gateway Separate Sciences. Any help would be much appreciated. Thanks.
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willow239
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Transcription (occurs in the nucleus):
You start with a gene (a double-stranded molecule). The base sequence of the gene is copied into a template molecule (a single-stranded molecule). This template molecule is complementary to the base sequence (meaning the bases of the template are opposite to the bases on the gene e.g. - if the gene base sequence is AGT CGA, then the template molecule will be UCA GCU --- the template strand uses U instead of T). The template molecule is called Messenger RNA or mRNA. The mRNA moves out of the nucleus and into the cytoplasm.

Translation (occurs on a ribosome in the cytoplasm):
The mRNA molecule attaches to a ribosome in the cytoplasm. Carrier molecules, called Transfer RNA or tRNA, bring amino acids to the ribosome. Each of these amino acids is called a triplet. The ribosome reads the triplets of bases on the mRNA and joins them together with the complementary amino acids. The protein chain is now complete.

I hope this helped! (Feel free to message me if you don't understand)
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sabihah_m
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Hi, thanks for the reply your help is much appreciated! I think I understand translation but transcription is a little complicated. What does the mRNA do? Also do you have any ways for me to remember this as I have a very bad memory. Thanks.
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willow239
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Hi,
The mRNA is used as a template strand to create a new protein using the code of the original base sequence of DNA. So in transcription, there is a double stranded DNA molecule. The molecule unravels so the strands are separate. One of the strands is going to be copied. An mRNA molecule forms that is complementary to one of the strands. This will then act as a template strand, where it will undergo translation at the ribosome.

Maybe it will help if you think of it in a different way:
Say you were asked to translate a word in another language. First, you will be asked to transcribe it - this means you are copying it from one place to another (eg from a textbook to your notebook) (TRANSCRIPTION). You would then translate the word into English, using a dictionary (TRANSLATION).
The DNA strand is the original word in the textbook; the mRNA is the word in the notebook (it has been copied from the original); the ribosome is the dictionary that is used to translate the copied word; and the protein formed is the translated English word.
(I know this is a weird explanation but it might help you to visualise it in a different way!)

To help you remember, I would suggest drawing an annotated diagram in poster form on an A4 sheet of paper. This way you can visualise it as well as explain it.

I hope this has made it more clear and I haven't confused you with the weird comparison!
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sabihah_m
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Not at all! The comparison is great! Thanks so much for helping I really appreciate it. Yes I will copy the steps and a diagram into my notes to help me.
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willow239
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No problem, I'm glad I could help!
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