Transcription

Or the making of a molecule named, messenger RNA, aka

mRNA

DNA’s Central Dogma

Do you know what a dogma is? It’s a belief or a truth, so here’s the deal from code to protein:

Replication mRNA proteintranscription translation

Don’t y’all ever wonder where all this stuff comes from to make a you?

Remember chromosomes?

The dark staining patterns on this cartoon version of a chromosome are genes.

Genes are DNA sequences that code for a protein or a trait (something we can see).

All chromosomes have genetic info to make you!

Okay, so here’s TranscriptionThink of DNA (hence chromosomes) as the reference materials of a central library. People can’t check out reference material (like encyclopedias, dictionaries…etc.) because it’s too important that other people need to use it too. If you really need this information, you can make a copy of it for your own use, put the reference material back on the shelf so that others can use it too.Can you imagine if DNA was physically lost? That’s why chromosomes never leave the nucleus.

more transcription

To transcribe is to make a written copy of something. So, transcription is making a copy of a gene sequence on the chromosome because transcription factors say so.

Transcription factors are poorly defined mechanisms by which your body, via chemical messengers, tells itself I need more of something (proteins).

This copy from DNA’s called messenger RNA, abbreviated mRNA.

mRNAIt’s essentially replication except we only copy the useful, 1-side of the DNA ladder (the gene) NOT THE WHOLE CHROMOSOME!

This is called the sense strand. The other side’s the non-sense strand.nonsense

Link. RNA polymerase is responsible for creating mRNA.

Structure of mRNASince RNA polymerase only copies one strand, it looks like half a ladder (duh!).

The red molecule’s the mRNA molecule.

RNA doesn’t have thymine though, it’s replaced by another nucleotide URACIL.

Bye-bye mRNA molecule!So now you have a copy of the useful gene your body needs, now what?

This mRNA molecule goes to the ribosome. Remember the ribosome, site of protein synthesis?

Nucleus (brains of cell, remember?

mRNA leaves nucleus to ribosome in cytoplasm via a nuclear pore

Link review

What information is on mRNA?mRNA carries the message to make a protein one amino acid at a time (monomer to polymer theme).

Three nucleotides on the mRNA code for an amino acid, therefore we call the triplet base a codon.

This example mRNA has 7 amino acids.

Genetic sequence=amino acid sequence

Can you crack the code? Personally try the one on the right first.

Is your brain hurting yet?We’re done