DNA to RNA - Transcription and Translation Notes

Chap 12.3 Notes: DNA to RNA - Transcription and Translation Notes

The nucleus and DNA controls cell activities by controlling the production of proteins:

* DNA is the “blueprint” for a protein.

* RNA is a copy of the “blueprint” that travels out

of the nucleus to the ribosome where, the protein is built.

* The protein then carries out its job and is expressed as a trait. Ex) eye color

· In DNA, the sequence of Nbases along one of the strands of nucleotides is a “code” for protein production.

· The code is composed of sequences of three nitrogen bases called Codon that code for a specific amino acids.

· There are 64 different codons. See Codon Charts.

· DNA cannot travel out of the nucleus to the ribosome. Instead, another form of nucleic acid is required – RNA – ribonucleic acid.

1) 5-C sugar – ribose

2) Phosphate

3) N – bases – Adenine, cytosine, guanine, and a new one – URACIL. There is no thymine in RNA.

1) mRNA – messenger – copy of “blueprint” of how to build protein.

2) tRNA – transfer – carries amino acids to the ribosome - 20 different

types.

3) rRNA – ribosomal – makes up the ribosome.

· To make RNA the cell carries out transcription .

Ex) DNA: ATT GAC CCT GAT GAC CAA

RNA: UAA CUG GGA CUA CUG GUU

· RNA is then sent to the ribosome and “translated” into a protein.

Once the RNA has reached the ribosome , building of the protein begins. This is called translation .

· First – the ribosome reads the mRNA one codon at a time.

· Second – the tRNA matches its anticodon to a complimentary codon of mRNA.

· The amino acid is dropped off and joined by peptide bonds to build a protein.