Flashcards in NEW 3 Deck (40):
Amino acid sequence of protein is written...
RNA has a series of...
NONoverlapping three base “words” called codons
Transcription rewrites the DNA ---> RNA, substituting..
U for T
Uracil for Thymine
A + U in RNA**
Each amino acid is...
specified by codon
__ codons are possible
Some amino acids have more than...
one possible codon
Genetic code decides how codons are...
translated into amino acids
Three nucleotides specify ONE...
amino acid in the genetic code
61 codons correspond...
to amino acids
-START of TRANSLATION
-codes for methionine
3 “stop” codons signal...
end of translation
is universal, shared by organisms from simple to complex
RNA molecule is _______ from gene
RNA nucleotides linked by transcription enzyme
nucleotide sequence signal = “start transcribing”
Cap and tail of extra nucleotides are added to ends of the mRNA to...
-help RNA leave nucleus
-protect RNA from damaging enzymes
-help RIBOSOMES bind to mRNA
RNA polymerase CONNECTS to promoter
-amino acids added ONE by ONE
-RNA grows longer
Removes introns and joins exons producing continuos coding sequence
-RNA polymerase reaches base in DNA template called TERMINATOR, signals the END of gene
-polymerase detaches from RNA molecule and gene
picks up _____ _____ and brings them to _______
Translation - can be divided into same...
three phases as transcription:
1 ) initiation
Ribosomes are composed of...
ribosomal rRNAs and protein
Ribosomes have binding sites for...
mRNA and tRNAs
Messenger RNA (mRNA)*
-encodes amino acid sequence
tRNA molecules use special...
TRIPLET of bases called anticodon
first tRNA occupies the p site, which holds growing polypeptide chain
available for next tRNA (transfer RNA)
-ribosome reaches STOP codon
-completed polypeptide is released from the last tRNA
-ribosome goes back into separate subunits
3 types of Mutations
1) base substitution
-complements codons in mRNA
Any change in nucleotide sequence of DNA
1) have NO effect, silent mutation
2) leads to IMPROVED protein that helps enhance survival
3) nonsense mutation
Mutations can involve large chromosomal regions or...
just single nucleotide pair
Mutations caused by...
random errors during DNA replication
Mutagens: cause _______
ex. high energy radiation, chemicals
CHANGES amino acid into stop codon
Insertions & Deletion mutations
-alter reading frame
-produce NONFUNCTIONAL polypeptide
-change in amino acid sequence downstream of mutation
Codons are ____ to each other, NO gaps in between