USABO GENETICS COMPREHENSIVE EXAM QUESTIONS WITH
SOLUTIONS 2025 GRADED A+
✔✔heterochromatin vs. euchromatin - ✔✔HeteroChromatin = Highly Condensed
(transcriptionally inactive)
euchromatin = less condensed, transcriptionally active ("truly transcribed")
✔✔RNA polymerase - ✔✔Enzyme similar to DNA polymerase that binds to DNA and
separates the DNA strands during transcription
✔✔Promoter - ✔✔specific region of a gene where RNA polymerase can bind and begin
transcription
✔✔terminator - ✔✔In prokaryotes, a special sequence of nucleotides in DNA that marks
the end of a gene.
✔✔TATA box - ✔✔A DNA sequence in eukaryotic promoters crucial in forming the
transcription initiation complex.
✔✔transcription initiation complex - ✔✔the whole complex of transcription factors and
RNA polymerase II bound to the promoter
✔✔transcription factors - ✔✔Collection of proteins that mediate the binding of RNA
polymerase and the initiation of transcription.
✔✔5' cap - ✔✔The 5' end of a pre-mRNA molecule modified by the addition of a cap of
guanine nucleotide.
✔✔poly-A tail - ✔✔Modified end of the 3' end of an mRNA molecule consisting of the
addition of some 50 to 250 adenine nucleotides.
✔✔Introns - ✔✔Noncoding segments of nucleic acid that lie between coding
sequences.
✔✔Exons - ✔✔Coding segments of eukaryotic DNA.
✔✔UTRs - ✔✔untranslated regions of mRNA
still exist in the 5' to 3' edges of the transcript because the ribosome initiates translation
at the start codon (AUG) and will end at one of the three stop codons
✔✔spliceosome - ✔✔A large complex made up of proteins and RNA molecules that
splices RNA by interacting with the ends of an RNA intron, releasing the intron and
joining the two adjacent exons.
, ✔✔aminoacyl-tRNA synthetase - ✔✔During protein synthesis, an enzyme that attaches
the correct amino acid to a tRNA molecule to form a "charged" aminoacyl-tRNA.
✔✔wobble hypothesis - ✔✔Ability of the tRNAs to recognize more than one codon; the
codons differ in their third nucleotide.
✔✔P site of ribosome - ✔✔holds the tRNA carrying the growing polypeptide chain
✔✔A site of ribosome - ✔✔holds the tRNA that carries the next amino acid to be added
to the chain
✔✔E site of ribosome - ✔✔the exit site, where discharged tRNAs leave the ribosome
✔✔initiation factors - ✔✔A class of proteins that assist ribosomes in binding to a
messenger RNA molecule to begin translation.
✔✔elongation (translation) - ✔✔codon recognition, peptide bond formation,
translocation
✔✔release factor - ✔✔Proteins that can trigger termination of RNA translation when a
ribosome reaches a stop codon.
✔✔signal peptide - ✔✔A stretch of amino acids on a polypeptide that targets the protein
to a specific destination in a eukaryotic cell.
✔✔SRP - ✔✔signal recognition particle, recognizes signal sequence as it emerges from
ribosome, causes a pause in translation, delivers ribosome with mRNA and partial
polypeptide to SRP receptor in ER membrane, composed of an RNA molecule with 6
protein subunits, GTPase
✔✔Polyribosomes are - ✔✔groups of ribosomes "reading" the same mRNA at the same
time
✔✔operator - ✔✔Region of DNA that controls RNA polymerase's access to a set of
genes with related functions.
✔✔operon - ✔✔A unit of genetic function common in bacteria and phages, consisting of
coordinately regulated clusters of genes with related functions.
✔✔repressor - ✔✔A protein that binds to an operator and physically blocks RNA
polymerase from binding to a promoter site
✔✔regulatory gene - ✔✔A gene that codes for a protein, such as a repressor, that
controls the transcription of another gene or group of genes.
SOLUTIONS 2025 GRADED A+
✔✔heterochromatin vs. euchromatin - ✔✔HeteroChromatin = Highly Condensed
(transcriptionally inactive)
euchromatin = less condensed, transcriptionally active ("truly transcribed")
✔✔RNA polymerase - ✔✔Enzyme similar to DNA polymerase that binds to DNA and
separates the DNA strands during transcription
✔✔Promoter - ✔✔specific region of a gene where RNA polymerase can bind and begin
transcription
✔✔terminator - ✔✔In prokaryotes, a special sequence of nucleotides in DNA that marks
the end of a gene.
✔✔TATA box - ✔✔A DNA sequence in eukaryotic promoters crucial in forming the
transcription initiation complex.
✔✔transcription initiation complex - ✔✔the whole complex of transcription factors and
RNA polymerase II bound to the promoter
✔✔transcription factors - ✔✔Collection of proteins that mediate the binding of RNA
polymerase and the initiation of transcription.
✔✔5' cap - ✔✔The 5' end of a pre-mRNA molecule modified by the addition of a cap of
guanine nucleotide.
✔✔poly-A tail - ✔✔Modified end of the 3' end of an mRNA molecule consisting of the
addition of some 50 to 250 adenine nucleotides.
✔✔Introns - ✔✔Noncoding segments of nucleic acid that lie between coding
sequences.
✔✔Exons - ✔✔Coding segments of eukaryotic DNA.
✔✔UTRs - ✔✔untranslated regions of mRNA
still exist in the 5' to 3' edges of the transcript because the ribosome initiates translation
at the start codon (AUG) and will end at one of the three stop codons
✔✔spliceosome - ✔✔A large complex made up of proteins and RNA molecules that
splices RNA by interacting with the ends of an RNA intron, releasing the intron and
joining the two adjacent exons.
, ✔✔aminoacyl-tRNA synthetase - ✔✔During protein synthesis, an enzyme that attaches
the correct amino acid to a tRNA molecule to form a "charged" aminoacyl-tRNA.
✔✔wobble hypothesis - ✔✔Ability of the tRNAs to recognize more than one codon; the
codons differ in their third nucleotide.
✔✔P site of ribosome - ✔✔holds the tRNA carrying the growing polypeptide chain
✔✔A site of ribosome - ✔✔holds the tRNA that carries the next amino acid to be added
to the chain
✔✔E site of ribosome - ✔✔the exit site, where discharged tRNAs leave the ribosome
✔✔initiation factors - ✔✔A class of proteins that assist ribosomes in binding to a
messenger RNA molecule to begin translation.
✔✔elongation (translation) - ✔✔codon recognition, peptide bond formation,
translocation
✔✔release factor - ✔✔Proteins that can trigger termination of RNA translation when a
ribosome reaches a stop codon.
✔✔signal peptide - ✔✔A stretch of amino acids on a polypeptide that targets the protein
to a specific destination in a eukaryotic cell.
✔✔SRP - ✔✔signal recognition particle, recognizes signal sequence as it emerges from
ribosome, causes a pause in translation, delivers ribosome with mRNA and partial
polypeptide to SRP receptor in ER membrane, composed of an RNA molecule with 6
protein subunits, GTPase
✔✔Polyribosomes are - ✔✔groups of ribosomes "reading" the same mRNA at the same
time
✔✔operator - ✔✔Region of DNA that controls RNA polymerase's access to a set of
genes with related functions.
✔✔operon - ✔✔A unit of genetic function common in bacteria and phages, consisting of
coordinately regulated clusters of genes with related functions.
✔✔repressor - ✔✔A protein that binds to an operator and physically blocks RNA
polymerase from binding to a promoter site
✔✔regulatory gene - ✔✔A gene that codes for a protein, such as a repressor, that
controls the transcription of another gene or group of genes.
