Which of the following occurs in prokaryotes but not in eukaryotes?
Answers:
post-transcriptional splicing concurrent
transcription and translation translation in the absence of
a ribosome gene regulation

2

A particular triplet of bases in the coding sequence of DNA is AAA.
The anticodon on the tRNA that binds the mRNA codon is _____.
Answers:
TTT UUA UUU AAA

4

What does it mean when we say the genetic code is redundant?
Answers:
A single codon can specify the addition of more than one amino
acid. The genetic code is different for different domains of
organisms. The genetic code is universal (the same for all
organisms). More than one codon can specify the addition of
the same amino acid.

4

An original section of DNA has the base sequence AGCGTTACCGT. A
mutation in this DNA strand results in the base sequence AGGCGTTACCGT.
This change represents _____.
Answers:
a missense mutation a point mutation a
silent mutation frameshift mutation

4

A nonsense mutation in a gene _____.
Answers:
changes an amino acid in the encoded protein has no
effect on the amino acid sequence of the encoded protein
introduces a premature stop codon into the mRNA alters
the reading frame of the mRNA

3

Which of the following best describes the significance of the TATA
box in eukaryotic promoters?
Answers:
It is the recognition site for a specific transcription
factor. It sets the reading frame of the mRNA. It is
the recognition site for ribosomal binding. Its
significance has not yet been determined.

1

Of the following, which is the most current description of a gene?
Answers:
a unit of heredity that causes formation of a phenotypic
characteristic a DNA subunit that codes for a single complete
protein a DNA sequence that is expressed to form a functional
product: either RNA or polypeptide a discrete unit of
hereditary information that consists of a sequence of amino
acids

3

Accuracy in the translation of mRNA into the primary structure of a
polypeptide depends on specificity in the _____.
Answers:
binding of ribosomes to mRNA binding of the anticodon
to small subunit of the ribosome attachment of amino acids
to rRNAs binding of the anticodon to the codon and the
attachment of amino acids to tRNAs

4

How does termination of translation take place?
Answers:
The end of the mRNA molecule is reached. A stop codon
is reached. The 5' cap is reached. The poly-A tail
is reached.

2

Put the following events of elongation in prokaryotic translation in
chronological order.
1) 1,2,3,4,5
2) 2,1,4,3,5
3) 5,4,3,2,1
4) 1,2,3,5,4

4

A particular triplet of bases in the template strand of DNA is 5' AGT
3'. The corresponding codon for the mRNA transcribed is _____.
'Answers:
3' UCA 5' 3' UGA 5' 5' TCA 3' 3'
ACU 5'

1

Codons are part of the molecular structure of _____.
Answers:
a protein mRNA tRNA rRNA

2

How might a single base substitution in the sequence of a gene affect
the amino acid sequence of a protein encoded by the gene, and why?
Answers:
Only a single amino acid could change, because the reading
frame is unaffected. The amino acid sequence would be
substantially altered, because the reading frame would change with a
single base substitution. All amino acids following the
substitution would be affected, because the reading frame would be
shifted. It is not possible for a single base substitution to
affect protein structure, because each codon is three bases
long.

1

Once researchers identified DNA as the unit of inheritance, they
asked how information was transferred from the DNA in the nucleus to
the site of protein synthesis in the cytoplasm. What is the mechanism
of information transfer in eukarotes?
Answers:
DNA from a single gene is replicated and transferred to the
cytoplasm, where it serves as a template for protein synthesis.
Messenger RNA is transcribed from a single gene and transfers
information from the DNA in the nucleus to the cytoplasm, where
protein synthesis takes place. Proteins transfer
information from the nucleus to the ribosome, where protein
synthesis takes place. Transfer RNA takes information from
DNA directly to a ribosome, where protein synthesis takes
place.

2

Translation requires _____.
Answers:
mRNA, tRNA, DNA, and rRNA mRNA, DNA, and rRNA
mRNA, tRNA, and rRNA mRNA, tRNA, and DNA

3

Which one of the following, if missing, would usually prevent
translation from starting?
Answers:
exon 5' cap AUG codon poly-A
tail

3

According to the central dogma, what molecule should go in the
blank?DNA ? _____ ? Proteins
Answers:
mtDNA rRNA mRNA tRNA

3