5.3 Transcription: Code, Initiation, and RNA Synthesis Flashcards
What is transcription?
process of DNA being turned into RNA
Where does transcription occur?
in the nucleus
What are the complimentary pairs in mRNA?
A-U
G-C
What is the triplet code?
every three letters in the mRNA encodes for a word
What is a codon?
three nucleotides that are specific for one amino acid
What does it mean that the genetic code is degenerate?
there can be several codons that encode for the same amino acid
How many of the amino acids are degenerate?
18 of 20
What does it mean that the genetic code is comaless?
there is no delineation or punctuation in the code
Who first established the coding dictionary?
Francis Crick
What are the only amino acids that are encoded by one codon?
methionine
tryptophan
What did Crick postulate about the codon dictionary?
that the first two ribonucleotides were more important than the third
What is the wobble hypothesis?
allows for flexible base pairing rules in the third position of a codon during translation
What is special about the second base in a codon?
often shared between amino acids that share common characteristics
What is the importance of the second base in a codon being shared between like amino acids?
has evolved to ensure that if accidental mutations are transcribed there is less of a chance for a deletorious mutation in the resulting protein
What is the one defined codon?
initiation codon ATG
