RNA• Ribonucleic acid• Single-stranded• sugar phosphate backbone• Nucleotides:

• C=G A=U• mRNA: messenger• rRNA: ribosomal• tRNA: transfer

Gene expression

1. TRANSCRIPTION- a segment of the DNA is transcribed into mRNA- mRNA is matured- mRNA leaves the nucleus for a ribosome

2. TRANSLATION- ribosome reads the mRNA- matching tRNA’s insert amino acids in the correct order

RNAtranscription translation

CENTRAL DOGMA

DNA

= Protein synthesis

PROTEINS

promoter region

“start”

“stop”

terminator region

transcription

RNA polymerase

inside the nucleus

A G U U C A G C A U G

T C A A G T C G T A C DNA

mRNA

transcription

EXONS: coding regions; code for amino acids INTRONS: non-coding regions;

useless DNA; “spam”

RNA MATURATION: introns must be removed from the mRNA before it is allowed to leave the nucleus

transcription

TRANSCRIPTION

1. A segment of the DNA is unzipped from its double helix by RNA polymerase

promoter region

“start”

“stop”

RNA Polymerase

2. As RNA Polymerase unzips the double helix, it reads the DNA and makes a complimentary strand called mRNA

DNA = templatemRNA = copy

3. RNA Maturation:only coding regions (exons) are kept; non-coding regions (introns) are removed