Vocab for ch 17 notes

Ch 17: DNA RNA  Protein

Transcription: direction known as down Stream and reads DNA  RNA

mRNA: Takes DNA code out of nucleus into cytoplasm for translation

Translation: turning mRNA  proteins

Ribosomes: large and small subunits that make proteins

RNA Processing: editing the pre mRNA before it leaves the nucleus, adding tail, rid introns

Primary Transcript: The pre mRNA before processing

Triplet Code: three bases on the RNA that code for one AA…..see page 314

Template DNA Strand: read 3’ 5’ to make RNA 5’3’

Codons: 5’3’ on RNA and non-template DNA strand = 3 nucleotides that code for protein

RNA Polymerase (II Euks): Opens DNA and brings in RNA nucleotides
5-3’ Rule
No need for primer

Promoter: Specific starting gene sequence on DNA

Terminator: Stopping point

Stages of Transcription: Initiation, elongation, termination








Initiation: Getting ready to start transcription
 Transcription Unit: Area between Promoter and Terminator that gets transcribed
 Transcription Factors: Proteins that doc onto promoter and signal RNA Polymerase to bind to DNA in Euks
 Transcription Initiation Complex
Transcription factors
RNA Polymerase II
Promoter

TATA box: Area where transcription factors bind on DNA so RNA Polymerase can doc…lots of T,A’s

Elongation: Making the RNA Strand

Termination: Reaching a stop point and ceasing RNA formation.

Area where Transcription factors fall off 10-35 nucleotides downstream from polyadenylation signal (AAUAAA)….not fully understood in EUKS

RNA Processing:
Pre mRNA Modification

5’ Cap: made during transcription composed of modified G nucleotide with three phosphates

3’ Tail: Poly-A Tail: Made at end of elongation many A nucleotides

RNA Splicing: Cut and paste job in Pre mRNA

Introns: Non-coding regions of pre mRNA that get spliced away

Exons: Coding regions of RNA that stay

Spliceosome: Collection of many snRNPs
snRNPs: (small nuclear ribonucleoproteins) recognize splicing sites composed of proteins and RNA
snRNA the RNA in a snRNP, base pair with RNA in pre mRNA to tag cut areas

Ribozymes: RNA that can function as enzymes. Base pair with self forming enzyme blobs because it is single stranded

Translation: Making a protein from mRNA

Transfer RNA: Brings AA from cytoplasm to ribosomes

Anticodon: base sequence on the tRNA that base pairs with mRNA in ribosome 3’5’

Aminoacyl-tRNA synthetase: stored in the cytoplasm and joins the correct AA to the proper tRNA, then is recycled, 20 different ones

rRNA: The type of RNA found in the structure of a ribosome

P (peptidyl tRNA) Site: Second docking Slot

A (aminoacyl tRNA) Site: First docking Slot

E (Exit) Site: Third docking Slot

APE!


Initiation:
Image 17.17
 Completes a initiation complex
o mRNA
o Initiator tRNA (met)
o Small ribosome
o Large ribosome
o All brought together by initiation complex proteins
o Used GTP as energy
o At completion Met tRNA is in P site and A site is vacant

Elongation:
Image 17.18
 Uses elongation factors to complete until STOP codon reached
 Uses GTP as energy
 Has three steps embedded within it
o Codon recognition
o Peptide bond formation
o Translocation






Termination
Image 17.19
1. Stop Codon in A site
2. Codes for a release factor
3. Causes addition of water to growing AA chain instead of an AA
4. Hydrolyzes polypeptide from P site via exit tunnel in ribosome
5. Everything else dissembles