Unit 2 - M/C Flashcards
Based on Chargaff’s rules, which of the following
is TRUE of double stranded DNA molecules?
A. (C+T) = (A+G)
B. (A+T)/(C+G) = 1
C. (A+G)/(U+C) =1
D. C/T = 1
E. A/U = G/C
B. (A+T)/(C+G) = 1
If a DNA molecule contains 27% cytosine bases (C),
then what percentage of thymine bases will it have?
A. 10%
B. 27%
C. 46%
D. 23%
E. 52%
D. 23%
A DNA molecule of 50 base pairs contains 15 cytosine
bases (C). How many thymine bases will it have?
A. 10
B. 15
C. 30
D. 35
E. 60
D. 35
How did Chargaff’s rules contribute to Watson and
Crick’s elucidation of the structure of DNA?
A. The rules suggested an equal concentration
of sugars and phosphates.
B. The rules suggested the amounts of all four
bases were equal.
C. The rules suggested the base-pairing
combinations of adenine with thymine and
guanine with cytosine.
D. The rules suggested that each base
corresponds to an amino acid.
C. The rules suggested the base-pairing
combinations of adenine with thymine and
guanine with cytosine.
Consider two molecules of DNA. They are the same length, and they are both double-stranded. At 75°C, the first one will completely denature; however, at the same
temperature the second one is still double-stranded. What factors might allow for these different melting
temperatures?
A. The first molecule has a higher C+G content than
the second molecule.
B. The second molecule has a higher C+G content
than the first molecule.
C. The first molecule has a secondary structure of B
form, while the second molecule is an A form.
D. The second molecule is methylated more than the
first molecule.
B. The second molecule has a higher C+G content
than the first molecule.
Which of the following DNA strands would
have the LOWEST melting temperature?
A. 10% AT and 90% GC
B. 30% AT and 70% GC
C. 50% AT and 50% GC
D. 70% AT and 30% GC
E. 90% AT and 10% GC
E. 90% AT and 10% GC
You’ve grown an overnight culture of bacteria in media
that is enriched with radioactive nucleotides, so that
both strands of every DNA molecule found in the
bacteria will be radioactive. You harvest the cells and
plan to grow them in new media with nucleotides that
are NOT radioactive, so any DNA synthesized in this
culture will not be radioactive. After the cells grow for
two rounds of replication in the non-radioactive media,
what proportion of DNA molecules will be radioactive?
A. 0
B. 1/8
C. 1/4
D. 1/3
E. 1/2
B. 1/8
GIVEN THE FOLLOWING STATEMENTS:
1) binding to replication origin and
separating the double stranded
DNA to initiate replication.
2) binding to single stranded DNA to
prevent the duplex from
reforming.
3) unwinding the DNA double helix
at the replication fork.
4) sealing nicks in the sugar–
phosphate backbone of newly
synthesized DNA.
5) creating and resealing double
strand breaks to remove coiling.
6) synthesize primers for initiation of
DNA synthesis.
MATCH WITH THE FOLLOWING EVENTS:
A. DNA gyrase
B. DNA ligase
C. Initiator protein
D. DNA primase
E. Single stranded binding protein
F. DNA helicase
Initiator protein: Binding to replication origin and separating the double-stranded DNA to initiate replication.
Single-stranded binding protein: Binding to single-stranded DNA to prevent the duplex from reforming.
DNA helicase: Unwinding the DNA double helix at the replication fork.
DNA ligase: Sealing nicks in the sugar–phosphate backbone of newly synthesized DNA.
DNA gyrase: Creating and resealing double-strand breaks to remove coiling
DNA primase: Synthesize primers for initiation of DNA synthesis.
One of these is NOT required for DNA polymerases
to initiate DNA replication. Which one is it?
a) DNA template
b) RNA primer
c) 3’ to 5’ polymerase activity
d) Initiator proteins
e) Deoxyribonucleotides
d) Initiator proteins
When replicating a chromosome, the synthesis of
DNA is initiated from:
a) RNA template
b) DNA primer
c) 3’ OH
d) Deoxyribonucleotides
e) 5’ phosphate
b) DNA primer
Consider this statement about the synthesis of a molecule. A polymerase enzyme forms phosphodiester bonds using nucleoside triphosphates. Which of the following are described by this statement?
a) RNA only
b) DNA only
c) both RNA and DNA
d) neither RNA nor DNA
c) both RNA and DNA
Both strands of a DNA molecule are used simultaneously as a template when which of the following molecules is synthesized?
a) RNA only
b) DNA only
c) both RNA and DNA
d) neither RNA nor DNA
b) DNA only
If the sequence of an RNA molecule is
5ʹ–GGCAUCGACG–3ʹ
what is the sequence of the nontemplate strand of DNA?
a) 5ʹ–GGCATCGACG–3ʹ
b) 3ʹ–GGCATCGACG–5ʹ
c) 5ʹ–CCGTAGCTGC–3ʹ
d) 3ʹ–CCGTAGCTGC–5ʹ
e) 3ʹ–CGTCGATGCG–5ʹ
a) 5ʹ–GGCATCGACG–3ʹ
If the sequence of an RNA molecule is
5ʹ–GGCAUCGACG–3ʹ
what is the sequence of the template strand of DNA?
a) 5ʹ–GGCATCGACG–3ʹ
b) 3ʹ–GGCATCGACG–5ʹ
c) 5ʹ–CCGTAGCTGC–3ʹ
d) 3ʹ–CCGTAGCTGC–5ʹ
e) 3ʹ–CGTCGATGCC–5ʹ
d) 3ʹ–CCGTAGCTGC–5ʹ
You are sequencing an RNA molecule. Which
of the following sequences would be the
template strand for this RNA molecule:
5ʹ–UUCAUCGACG–3ʹ
a) 3ʹ–AAGUAGCUGC–5ʹ
b) 5ʹ–TTCATCGACG–3ʹ
c) 5ʹ–AAGTAGCTGC–3ʹ
d) 3ʹ–AAGTAGCTGC–5ʹ
e) 3ʹ–TTCATCGACG–5ʹ
d) 3ʹ–AAGTAGCTGC–5ʹ
Which of the following statements about RNA
polymerase is NOT true?
A. RNA polymerase has many subunits.
B. During transcription of a gene, RNA
polymerase reads only one of two strands of
DNA.
C. RNA polymerase reads a template strand of
DNA 3ʹ to 5ʹ.
D.RNA polymerase adds ribonucleotides to the 3ʹ
end of a growing RNA molecule.
E. RNA polymerase binds to an enhancer
sequence to initiate transcription
C. RNA polymerase reads a template strand of
DNA 3ʹ to 5ʹ.
Modification is necessary for efficient initiation of _____________ , __________ of mRNA from ________ and protects mRNA from _______________, and enhances ______ _______.
Modification is necessary for efficient initiation of translation, export of mRNA from nucleus, and protects mRNA from degradation, and enhances translation efficiency.
The spliceosome is large ___________ complex,
which contains five _______ molecules and
functions in the _________ of the cell.
a) Protein; rRNAs; nucleus.
b) Protein; snRNAs; cytoplasm.
c) Ribonucleoprotein; snRNAs; cytoplasm.
d) Ribonucleoprotein; snRNAs; nucleus.
e) Ribonucleoprotein; rRNAs; nucleus.
d) Ribonucleoprotein; snRNAs; nucleus.
During pre-mRNA splicing, the branch point is
recognized and bound by which spliceosome
subunit?
a) U1 snRNP
b) U2 snRNP
c) U2, U5 and U6 snRNPs
d) U1 and U2 snRNPs
e) U2 and U6 snRNPs
b) U2 snRNP
What is the CORRECT order for the process of pre-
mRNA processing by the spliceosome?
- Attachment of the U1 snRNP to the 5’ splice site
- Transcription of the DNA template into the pre-
mRNA molecule - Release of lariat structure
- Splicing together of exons
- Transesterification reaction at the branch point
adenine
a) 1, 2, 3, 4, 5
b) 4, 1, 3, 5, 2
c) 2, 1, 5, 3, 4
d) 3, 5, 1, 2, 4
e) 5, 3, 4, 1, 2
b) 4, 1, 3, 5, 2
Which end of the polypeptide chain emerges from the
Ribosome first? amino (N) or carboxyl (C)
The amino (N)-terminal end of the polypeptide chain emerges from the ribosome first during translation.
Synonymous codons always match with the same tRNA . T/F
False
Synonymous codons always code for the same amino acid. T/F
True
The anticodon region helps aminoacyl-tRNA synthetase match the tRNA to the correct amino acid. T/F
True