Translation_Exam3 Flashcards
Each codon contains ____ nucleotides that code for a specific AA
3
Genetic condons for mRNA
A,G,C,U
Adenine, Guanine, cytosine, uracil
____ codons total
64
Genetic code always read
5’-3’
Stop codons are
UAG, UGA and UAA
___ codons code for AA
61
Characteristics of the genetic code
Specificity, Universality, Degeneracy, Nonoverlapping
Codon always codes for a ____
specific amino acid
Multiple codons codr for same
AA
Code read as _____ sequence from start to stop
continuous
1 nucleotide in codon is changed, but still codes for same AA
silent mutation
change in 1 nucleotide codes for a different AA
Missense Mutation
Change in 1 nucleotide codes for stop codon instead
Nonsense Mutation
This may change characteristics of resulting protein
missense mutation
sickle cell anemia is an example of
missense mutation
causes truncated proteins
nonsense mutation
3 base units repeated in tandem may be amplified. Too many repeats are added, so final protein has extra copies of AA.
Trinucleotide repeat expansion
mutations may alter where/how introns are removed from pre-mRNA
splice site mutations
Addition or removal of 1 or 2 bases causes a shift in the reading frame.
frame-shift mutations
With frame-shift mutations, if 3 bases are lost, protein is missing what?
AA
Cystic fibrosis is missing what?
phenylalanine (frame-shift mutation)
Ribosomes contain 3 binding sites for tRNA
A-site
P-site
E-site
A-site =
binds aminoacyl-tRNA
P-site =
contains peptidyl - tRNA
E-site =
contains empty tRNA as it exits ribosome
synthesize proteins for cytosol, nucleus, mitochondria and peroxisomes
free ribosomes