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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