Translation Flashcards
in translation, a sequence of ___ is translated into a sequence of __
nucleotides; amino acids
the genetic code gives the relation between __ and __
sequence of bases in DNA and of amino acids in proteins
T/F the genetic code is nearly universal
true
the genetic code is read from the _ to __ end of the mRNA
5’-3’
an amino acid is coded by a group of 3 bases called a __
codon
T/F there is only one codon for each amino acid
false
what is protein synthesis?
formation of peptide bonds between amino acids in a specific sequence
what are ribosomes made of?
rRNA and protein
a ribosome can be called a ___
ribonucleoprotein
what part of a ribosome catalyzes the peptide bond formation?
rRNA
function of small ribosomal subunit
binds mRNA
function of large ribosomal subunit
binds tRNA and amino acids
ribosomes are typically identified by their Svedberg coefficient (s) which is __
rate at which particle moves during centrifugation
what three factors influence the Svedber coefficient?
particle mass, density and shape
rRNA molecules are ___ stranded
single
how do rRNA molecules achieve their complex secondary /teriary structures to be able to function?
base pair
a ribosome has 3 slots for tRNA which are ___
A site, P site, E site
amino acids are delivered to the ribosome by__molecules
tRNA
tRNA serves as the adapter molecule between the ___ and its specific ___
codon; amino acid
tRNAs are usually between ___ and ___ nucleotides long
70-90
all tRNA molecules include what two things?
a CCA amino acid attachment site at the 3’ end
an anticodon
what is an anticodon?
3 nucleotides that are complementary to the codon on mRNA
the proper amino acid is also called the __
cognate amino acid
what dictates the proper amino acid?
anticodon loop base pairing with the codon
tRNAs are covalently labeled with their cognate amino acids by enzymes called___
aminoacyl-tRNA-synthetases
charged tRNA is called
aminoacyl tRNA
what are the 2 steps in aminoacyl tRNA synthetase activity?
- activation of the amino acid
2. transfer of the aminoacyl group to the tRNA
how is an amino acid activated?
adenylation
what is used to adenylate the amino acid?
ATP
how is the amino acid transferred to the tRNA?
ester linkage
t/f aminoacyl tRNA syntheses are highly specific for a given amino acid
treue
what are the 3 steps of translation?
- initiation
- elongation of polypeptide
- termination
what 3 things happen in the initiation of translation?
assembly of ribosome, binding of mRNA and binding of first Aa-tRNA
what 2 things happen in the enlogation of polypeptide of translation?
translocation and peptide bond formation
what happens in the termination of translation?
recognition of the end of the coding region in mRNA
what is the start codon and what amino acid does it code for?
AUG; methionine
catalysis of peptide bond formation occurs in the ___ site of ribosomes
P (peptide)
peptide bond formation is catalyzed by which ribosomal subunit?
the large one
what are the 3 stop codons?
UAA, UGA, UAG
T/F there is a tRNA with an anticodon for the stop codons
false
what is the role of a release factor protein?
will bind to the A site and release the polypeptide chain
