Protein synthesis

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Transcription
(genetics) the organic process whereby the DNA sequence in a gene is copied into mRNA, happens in the nucleus, when DNA codes messenger Rna
Translation
Process by which mRNA is decoded and a protein is produced, happens in the cytoplasm, mRNA carries encoded message to RNA, t RNA arrives over the correct amino acid to RNA, where amino acids are correctly put together to create a polypeptide chain, need 2,3,4 chains for a protein, chaperones do the recording of polypeptide chains
Primary
Bond at amino and carboxyl
Secondary
Make hydrogen bonds
Tertiary
Disulfiram bridge, more hydrogen bonding, hydrophobic and hydrophilic
Quaternary
Two polypeptide chains
Genetic code
Nearly universal between all organisms, genes can be expressed with genetic engineering
Prokaryote
A unicellular organism that lacks a nucleus and membrane bound organelles, transcription is one continuous process
Eukaryote
First part occurs in the nucleus, second in the cytoplasm, has a nucleus
pre mRNA
Just before mRNA, has introns, an enzyme slice some splices the parts that do not come for proteins, introns stay inside the nucleus, intervening sequences
Promoter
Where RNA Polymerase attaches to the DNA strand and which signals the starting point of transcription
Transcription factors
Allow RNA polymerase to set down on DNA to begin initiation of transcription
TATA box
Called a promoter, forms the initiation complex in eukaryotes
Transcription steps
Initiation-starts process
Elongation- RNA polymerase transcribes DNA to transcribe
Termination- hits a stop codon
Steps are same in translation
mRNA
Has exons, leaves the nucleus
Exons
Coding segments of eukaryotic DNA.
Introns
Noncoding segments of nucleic acid that lie between coding sequences.
cap and tail
protect the RNA from attack by cellular enzymes and help ribosomes recognize the RNA as mRNA, added to mRNA before it leaves the nucleus
Cap
A sequence of poly-G, added to the 5' end, modified guanine
Tail
A sequence of poly-A, added to the 3' end, 50-250 A
Anticodon
Tells the correct amino acid, carries ribosomes to amino acids
Ribosome Sites
A site: binds free Aminoacyl- tRNA (amino acid)
P Site: binds Peptidyl-tRNA (peptide site)
E Site: Exit site