17.1
1.
Draw the nontemplate strand of DNA
for the template shown below.
Compare and contrast its base
sequence with the mRNA molecule.
DNA
A C C A A A C C G A G T
mRNA U G G U U U G G C U C A
17.1
1.
Draw the nontemplate strand of DNA
for the template shown below.
Compare and contrast its base
sequence with the mRNA molecule.
DNA
A C C A A A C C G A G T
T G G T T T G G C T C A
mRNA U G G U U U G G C U C A
17.1
1.
Draw the nontemplate strand of DNA
for the template shown below.
Compare and contrast its base
sequence with the mRNA molecule.
DNA
A C C A A A C C G A G T
T G G T T T G G C T C A
mRNA U G G U U U G G C U C A
17.1
2.
What protein product would you expect
from a poly-G mRNA that is 30
nucleotides long?
5’-GGGGGGGGGGGGGGGGGGGGGGGGGGGGGG-3’
17.1
2.
What protein product would you expect
from a poly-G mRNA that is 30
nucleotides long?
5’-GGGGGGGGGGGGGGGGGGGGGGGGGGGGGG-3’
Gly-Gly-Gly-Gly-Gly-Gly-Gly-Gly-Gly-Gly
17.2
1.
Compare and contrast the functioning
of DNA polymerase and RNA
polymerase.
DNA polymerase
RNA polymerase
DNA polymerase
RNA polymerase
•Assembles chains •Assembles chains
from monomers
from monomers
DNA polymerase
RNA polymerase
•Assembles chains •Assembles chains
from monomers
from monomers
•Complementary
base pairing
•Complementary
base pairing
DNA polymerase
RNA polymerase
•Assembles chains •Assembles chains
from monomers
from monomers
•Complementary
base pairing
•Complementary
base pairing
•Reads 3’→5’
•Reads 3’→5’
•Assembles 5’ →3’ •Assembles 5’ →3’
DNA polymerase
RNA polymerase
•Needs a primer
•Can start from
scratch
DNA polymerase
RNA polymerase
•Needs a primer to •Can start from
start
scratch
•Uses A, T, G & C
•Uses A, U, G & C
•Uses nucleotides
containing
deoxyribose
•Uses nucleotides
containing ribose
17.2
2.
Is the promoter at the upstream or
downstream end of a transcription unit?
17.2
2.
Is the promoter at the upstream or
downstream end of a transcription unit?
Upstream
17.2
3.
In a prokaryote, how does RNA
polymerase “know” where to start
transcribing a gene? In a eukaryote?
17.2
3.
In a prokaryote, how does RNA
polymerase “know” where to start
transcribing a gene? In a eukaryote?
Prokaryote: RNA polymerase
recognizes promoter
Eukaryote: Transcription factors
mediate binding
17.2
4.
How is the primary transcript produced
by a prokaryotic cell different from that
produced by a eukaryotic cell?
17.2
4.
How is the primary transcript produced
by a prokaryotic cell different from that
produced by a eukaryotic cell?
Prokaryote: used immediately as
mRNA
Eukaryote: Must be modified before
being used as mRNA
17.3
1.
How does the alteration of the 5’ and 3’
ends of pre-mRNA affect the mRNA
that exists in the nucleus?
17.3
1.
How does the alteration of the 5’ and 3’
ends of pre-mRNA affect the mRNA
that exists in the nucleus?
•Facilitates transportation
•Prevents degradation
•Facilitates ribosomal attachment
17.3
2.
Describe the role of snRNPs in RNA
splicing.
17.3
2.
Describe the role of snRNPs in RNA
splicing.
•Joins with other proteins to form
spliceosomes.
•Removes introns, splices exons
together.
17.3
3.
How can alternative RNA splicing
generate a greater number of
polypeptide products than there are
genes?
17.3
3.
How can alternative RNA splicing
generate a greater number of
polypeptide products than there are
genes?
THE CAT ATE THE RBAT
17.3
3.
How can alternative RNA splicing
generate a greater number of
polypeptide products than there are
genes?
THE CAT ATE THE RBAT
17.3
3.
How can alternative RNA splicing
generate a greater number of
polypeptide products than there are
genes?
THE CAT ATE THE RBAT
17.4
1.
Which two processes ensure that the
correct amino acid is added to a
growing polypeptide chain?
17.4
1.
Which two processes ensure that the
correct amino acid is added to a
growing polypeptide chain?
•Aminoacyl-tRNA synthase
•tRNA codon
17.4
2.
Describe how the formation of
polyribosomes can benefit the cell.
17.4
2.
Describe how the formation of
polyribosomes can benefit the cell.
Multiple copies of a protein in a short
time.
17.4
3.
Describe how a polypeptide to be
secreted is transported to the
endomembrane system.
17.4
3.
Describe how a polypeptide to be
secreted is transported to the
endomembrane system.
•Signal peptide is recognized by SRP.
•SPR brings polypeptide to ER lumen.
17.5
1.
Describe three properties of RNA that
allow it to perform diverse roles in the
cell.
17.5
1.
Describe three properties of RNA that
allow it to perform diverse roles in the
cell.
•Hydrogen bonds with DNA or RNA
•Specific 3-D shape
•Catalize chemical reactions.
17.6
1.
In figure 17.22 (orange book and green
book) number the RNA polymerases in
order of their initiation of transcription.
Then number each mRNA’s ribosomes
in order of their initiation of translation.
17.6
2.
Would the arrangement shown in
Figure 17.22 be found in a eukaryotic
cell? Explain.
17.7
1.
What happens when one nucleotide
pair is lost from the middle of the
coding sequence of a gene?
17.7
1.
What happens when one nucleotide
pair is lost from the middle of the
coding sequence of a gene?
•Frame shift mutation
•Nonfunctional protein
17.7
2.
The template strand of a gene contains
the sequence 3’-TACTTGTCCGATATC5’. Draw a double strand of DNA and
the resulting strand of mRNA, labeling
all 5’ and 3’ ends. Determine the amino
acid sequence. Then show the same
after a mutation changes the template
DNA sequence to 3’TACTTGTCCAATATC-5’. What is the
effect on the amino acid sequence?
17.7
2.
Template strand:
3’-TACTTGTCCGATATC-5’
Draw a double strand of DNA.
17.7
2.
Double strand:
3’-TACTTGTCCGATATC-5’
5’-ATGAACAGGCTATAG-3’
Draw the resulting strand of mRNA,
labeling all 5’ and 3’ ends
17.7
2.
Double strand:
3’-TACTTGTCCGATATC-5’
5’-ATGAACAGGCTATAG-3’
mRNA:
5’-AUGAACAGGCUAUAG-3’
17.7
2.
mRNA:
5’-AUGAACAGGCUAUAG-3’
Determine the amino acid sequence.
17.7
2.
mRNA:
AUG AAC AGG CUA UAG
Determine the amino acid sequence.
17.7
2.
mRNA:
AUG AAC AGG CUA UAG
Polypeptide:
Met-Asn-Arg-Leu
17.7
2.
Then show the same after a mutation
changes the template DNA sequence to
3’-TACTTGTCCAATATC-5’.
17.7
2.
Template strand:
3’-TACTTGTCCAATATC-5’
Draw a double strand of DNA.
17.7
2.
Double strand:
3’-TACTTGTCCAATATC-5’
5’-ATGAACAGGTTATAG-3’
Draw the resulting strand of mRNA,
labeling all 5’ and 3’ ends
17.7
2.
Double strand:
3’-TACTTGTCCAATATC-5’
5’-ATGAACAGGTTATAG-3’
mRNA:
5’-AUGAACAGGUUAUAG-3’
17.7
2.
mRNA:
5’-AUGAACAGGUUAUAG-3’
Determine the amino acid sequence.
17.7
2.
mRNA:
AUG AAC AGG UUA UAG
Determine the amino acid sequence.
17.7
2.
mRNA:
AUG AAC AGG UUA UAG
Polypeptide:
Met-Asn-Arg-Leu
17.7
2.
mRNA:
AUG AAC AGG UUA UAG
Polypeptide:
Met-Asn-Arg-Leu
The resulting polypeptide is the same.
.