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3’ T A C C A G C C G G T A A T A G G G A C C A T T 5’ DNA TEMPLATE
5’ A U G G U C G G C C A U U A U C C C U G G U A A 3’ mRNA
METH VAL
GLY HIST TYR PRO
TRP
____
____ ___
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3’ U A C C A G C C G G U A A U A G G G A C C A U U 5’ ANTI – CODON Sequence
Does the DNA Sequence (Million Dollar Blueprint) look like the Anti-codonSequence? Remember, this is how the ribosome “knew” the Amino Acid wasCorrect.
PROTEIN
RNA plays multiple roles in the cell: Type of RNA Functions
Messenger RNA (mRNA)
Carries information specifying amino acid sequences of proteins from DNA to ribosomes
Transfer RNA (tRNA)
Serves as adapter molecule in protein synthesis; translates mRNA codons into amino acids
Ribosomal RNA (rRNA)
Plays catalytic (ribozyme) roles and structural roles in ribosomes
Type of RNA Functions
Primary transcript
Serves as a precursor to mRNA, rRNA, or tRNA, before being processed by splicing or cleavage
Small nuclear RNA (snRNA)
Plays structural and catalytic roles in spliceosomes
SRP RNA Is a component of the the signal-recognition particle (SRP)
Type of RNA Functions
Small nucleolar RNA (snoRNA)
Aids in processing pre-rRNA transcripts for ribosome subunit formation in the nucleolus
Small interfering RNA (siRNA) and microRNA (miRNA)
Are involved in regulation of gene expression
Histone Proteins and Supercoiling
DNA double helix
Histonetails
His-tones
Linker DNA(“string”)
Nucleosome(“bead”)
10 nm
2 nm
Histone H1
Nucleosomes (10-nm fiber)
DNA Control stages in Protein Synthesis
Signal
NUCLEUS
DNA
RNA
Chromatin
Gene availablefor transcription
Gene
Exon
Intro
Transcription
Primary transcript
RNA processing
Cap
Tail
mRNA in nucleus
Transport to cytoplasm
CYTOPLASM
mRNA in cytoplasm
Translation
Degradationof mRNA
Polypeptide
CleavageChemical modificationTransport to cellular
destination
Degradation of protein
Active protein
Degraded protein
.
Histonetails
Amino acidsavailablefor chemicalmodification
DNAdouble helix
Histone tails protrude outward from a nucleosome
Acetylation of histone tails promotes loose chromatinstructure that permits transcription
Unacetylated histones Acetylated histones
Enhancers
Distal controlelement Activators
Enhancer
DNA
DNA-bendingprotein
TATAbox
PromoterGene
Generaltranscriptionfactors
Group ofmediator proteins
RNApolymerase II
RNApolymerase II
RNA synthesisTranscriptionInitiation complex
Notice the different nucleotide control
sequences(red vs, pink)
Controlelements
Enhancer Promoter
Albumingene
Crystallingene
Availableactivators
Availableactivators
Albumingene notexpressed
Albumingeneexpressed
Liver cell Lens cell
Crystallin genenot expressed Crystallin gene
expressed
Liver cellnucleus
Lens cellnucleus
miRNA &siRNA
Dicer
Hydrogenbond
Proteincomplex
miRNATarget mRNA
Degradation of mRNA
OR
Blockage of translation