BI 121 Exam 2 Questions with 100% Correct
Answers
Translation
Synthesis of a polypeptide chain corresponding to the coding sequence present in a molecule
of messenger RNA
Messenger RNA (mRNA)
The RNA molecule that combines with a ribosome to direct protein synthesis; it carries the
genetic "message" from the DNA to the ribosome.
Ribosomes
Complex structures of RNA and protein that bind with mRNA and are the site of translation;
have a large and small subunit
A (Aminoacyl) Site
One of three sites in a ribosome occupied by a tRNA in translation. All charged tRNAs (with
the exception of the initiator tRNA) first enter the A site in translation.
P (Peptidyl) Site
One of three binding sites for tRNA that carries the polypeptide chain on the large subunit of
a ribosome.
E (Exit) Site
One of the three binding sites for tRNA that allows the tRNA to exit the ribosome
Codon
,A group of three adjacent molecules in RNA that specifies an amino acid in a protein or that
terminates polypeptide synthesis
Reading Frames
Following a start codon, a consecutive sequence of codon for amino acids
Anticodon
The sequence of three nucleotides in tRNA that base pairs with the corresponding codon in
an mRNA
Aminoacyl tRNA synthetase
An enzyme that attaches a specific amino acid to a specific tRNA molecule.
Genetic Code
The correspondence between codons and amino acids, in which 20 amino acids are specified
by 64 codons.
Initiation Codon
Codon at which translation begins; AUG in the eukaryotes
Three Stages of Translation
Initiation, elongation, and termination
Initiation
The stage of translation in which methionine (met) is established as the first amino acid in a
new polypeptide chain.
Elongation
, The process in protein translation in which successive amino acids are added one by one to
the growing polypeptide chain.
Termination
The time at which the addition of amino acids stops and the completed polypeptide chain is
released from the ribosome.
Elongation Factors
Proteins involved in the elongation phase of translation, assisting ribosomes in the synthesis
of the growing peptide chain.
Initiation Factors
A class of proteins that assist ribosomes in binding to a messenger RNA molecule to begin
translation.
Release Factor
The protein that binds to the stop codon during termination of translation
Polycistronic mRNA
A single molecule of messenger RNA that is formed by the transcription of a group of
functionally related genes located next to one another along bacterial DNA.
Operon
A group of functionally related genes located in tandem along the DNA and transcribed as a
single unit from one promoter; the region of DNA consisting of the promoter, the operator,
and the coding sequence for the structural genes.
Definition of Translation
Answers
Translation
Synthesis of a polypeptide chain corresponding to the coding sequence present in a molecule
of messenger RNA
Messenger RNA (mRNA)
The RNA molecule that combines with a ribosome to direct protein synthesis; it carries the
genetic "message" from the DNA to the ribosome.
Ribosomes
Complex structures of RNA and protein that bind with mRNA and are the site of translation;
have a large and small subunit
A (Aminoacyl) Site
One of three sites in a ribosome occupied by a tRNA in translation. All charged tRNAs (with
the exception of the initiator tRNA) first enter the A site in translation.
P (Peptidyl) Site
One of three binding sites for tRNA that carries the polypeptide chain on the large subunit of
a ribosome.
E (Exit) Site
One of the three binding sites for tRNA that allows the tRNA to exit the ribosome
Codon
,A group of three adjacent molecules in RNA that specifies an amino acid in a protein or that
terminates polypeptide synthesis
Reading Frames
Following a start codon, a consecutive sequence of codon for amino acids
Anticodon
The sequence of three nucleotides in tRNA that base pairs with the corresponding codon in
an mRNA
Aminoacyl tRNA synthetase
An enzyme that attaches a specific amino acid to a specific tRNA molecule.
Genetic Code
The correspondence between codons and amino acids, in which 20 amino acids are specified
by 64 codons.
Initiation Codon
Codon at which translation begins; AUG in the eukaryotes
Three Stages of Translation
Initiation, elongation, and termination
Initiation
The stage of translation in which methionine (met) is established as the first amino acid in a
new polypeptide chain.
Elongation
, The process in protein translation in which successive amino acids are added one by one to
the growing polypeptide chain.
Termination
The time at which the addition of amino acids stops and the completed polypeptide chain is
released from the ribosome.
Elongation Factors
Proteins involved in the elongation phase of translation, assisting ribosomes in the synthesis
of the growing peptide chain.
Initiation Factors
A class of proteins that assist ribosomes in binding to a messenger RNA molecule to begin
translation.
Release Factor
The protein that binds to the stop codon during termination of translation
Polycistronic mRNA
A single molecule of messenger RNA that is formed by the transcription of a group of
functionally related genes located next to one another along bacterial DNA.
Operon
A group of functionally related genes located in tandem along the DNA and transcribed as a
single unit from one promoter; the region of DNA consisting of the promoter, the operator,
and the coding sequence for the structural genes.
Definition of Translation
