First Exam Graded Flashcards
Which of the following deoxyoligonucleotides will hybridize with a DNA containing the sequence (5’)AGACTGGTC(3’)?
A) (5’)CTCATTGAG(3’)
B) (5’)GACCAGTCT(3’)
C) (5’)GAGTCAACT(3’)
D) (5’)TCTGACCAG(3’)
E) (5’)TCTGGATCT(3’)
B) (5’)GACCAGTCT(3’)
The phosphodiester bonds that link adjacent nucleotides in both RNA and DNA:
A) always link A with T and G with C.
B) are susceptible to alkaline hydrolysis.
C) are uncharged at neutral pH.
D) form between the planar rings of adjacent bases.
E) join the 3’ hydroxyl of one nucleotide to the 5’ Phosphate of the next.
E) join the 3’ hydroxyl of one nucleotide to the 5’ Phosphate of the next.
Chargaff’s rules state that in typical DNA:
A) A = G.
B) A = C.
C) A = U.
D) A + T = G + C.
E) A + G = T + C.
E) A + G = T + C.
B-form DNA in vivo is a ________-handed helix, _____ Å in diameter, with a rise of ____ Å
per base pair.
A) left; 20; 3.9
B) right; 18; 3.4
C) right; 18; 3.6
D) right; 20; 3.4
E) right; 23; 2.6
D) right; 20; 3.4
- Which of the following are possible base compositions for single-stranded RNA?
%A %G %C %T %U
A) 5 45 45 0 5
B) 25 25 25 0 25
C) 35 10 30 0 25
D) All of the above
E) None of the above
D) All of the above
n living cells, nucleotides and their derivatives can serve as:
A) carriers of metabolic energy.
B) enzyme cofactors.
C) intracellular signals.
D) precursors for nucleic acid synthesis.
E) All of the above.
E) All of the above.
The most precise modern definition of a gene is a segment of genetic material that:
A) codes for one polypeptide.
B) codes for one polypeptide or RNA product.
C) determines one phenotype.
D) determines one trait.
E) codes for one protein
B) codes for one polypeptide or RNA product.
ntrons:
A) are frequently present in prokaryotic genes but are rare in eukaryotic genes.
B) are spliced out before transcription.
C) are translated but not transcribed.
D) can occur many times within a single gene.
E) encode unusual amino acids in proteins
D) can occur many times within a single gene.
The DNA in a bacterial (prokaryotic) chromosome is best described as:
A) a single circular double-helical molecule.
B) a single linear double-helical molecule.
C) a single linear single-stranded molecule.
D) multiple linear double-helical molecules.
E) multiple linear single-stranded molecules
A) a single circular double-helical molecule.
The DNA in a eukaryotic chromosome is best described as:
A) a single circular double-helical molecule.
B) a single linear double-helical molecule.
C) a single linear single-stranded molecule.
D) multiple linear double-helical molecules.
E) multiple linear single-stranded molecules.
B) a single linear double-helical molecule.
Which of the following does not contribute to the octameric histone core?
A) H1
B) H2A
C) H2B
D) H3
E) H4
A) H1
The fundamental repeating unit of organization in a eukaryotic chromosome is the:
A) centrosome.
B) lysosome.
C) microsome.
D) nucleosome.
E) polysome.
D) nucleosome.
When a DNA molecule is described as replicating bidirectionally, that means that it has two:
A) chains.
B) independently replicating segment.
C) origins.
D) replication forks.
E) termination points
D) replication forks.
An Okazaki fragment is a:
A) fragment of DNA resulting from endonuclease action.
B) fragment of RNA that is a subunit of the 30S ribosome.
C) piece of DNA that is synthesized in the 3’ Æ 5’ direction.
D) segment of DNA that is an intermediate in the synthesis of the lagging strand.
E) segment of mRNA synthesized by RNA polymerase.
D) segment of DNA that is an intermediate in the synthesis of the lagging strand.
he fundamental repeating unit of organization in a eukaryotic chromosome is the:
A) centrosome.
B) lysosome.
C) microsome.
D) nucleosome.
E) polysome.
D) nucleosome.
Prokaryotic DNA polymerase III:
A) contains a 5’ -> 3’ proofreading activity to improve the fidelity of replication.
B) does not require a primer molecule to initiate replication.
C) has a b subunit that acts as a circular clamp to improve the processivity of DNA synthesis.
D) synthesizes DNA in the 3’ -> 5’ direction.
E) synthesizes only the leading strand; DNA polymerase I synthesizes the lagging strand.
C) has a b subunit that acts as a circular clamp to improve the processivity of DNA synthesis.
In contrast to bacteria, eukaryotic chromosomes need multiple DNA replication origins
because:
A) eukaryotic chromosomes cannot usually replicate bidirectionally.
B) eukaryotic genomes are not usually circular, like the bacterial chromosome is.
C) the processivity of the eukaryotic DNA polymerase is much less than the bacterial enzyme.
D) their replication rate is much slower, and it would take too long with only a single origin per
chromosome.
E) they have a variety of DNA polymerases for different purposes, and need a corresponding
variety of replication origins.
D) their replication rate is much slower, and it would take too long with only a single origin per
chromosome.
Which of these enzymes is not directly involved in methyl-directed mismatch repair in E.
coli?
A) DNA glycosylase
B) DNA helicase II
C) DNA ligase
D) DNA polymerase III
E) Exonuclease I
A) DNA glycosylase
In homologous genetic recombination, RecA protein is involved in:
A) Strand invasion to form a Holliday intermediates.
B) introduction of negative supercoils into the recombination products.
C) nicking the two duplex DNA molecules to initiate the reaction.
D) pairing a DNA strand from one duplex DNA molecule with sequences in another duplex,
regardless of complementarity.
E) resolution of the Holliday intermediate
A) Strand invasion to form a Holliday intermediates.
Type of bond with role:
(a) phosphodiester
(b) N-glycosidic
(c) phosphate ester
(d) hydrogen
1.___ links base to pentose in nucleotide
2. ___ joins adjacent nucleotides in one strand
3.___ joins complementary nucleotides in two strands
4.___ difference between a nucleoside and a nucleotide
- b
- a
- d
- c
What is the approximate length of a DNA molecule (in the B form) containing 10,000 base pairs?
3.4 Å * 10,000 = 34,000 Å = 3.4 μm.
On the strand synthesized discontinuously, the short
pieces are called (d) ____________ fragments. An RNA primer for each of the fragments is
synthesized by an enzyme called (e) __________,
d: Okazaki
e: primase
DNA replication in E. coli begins at a site in the DNA called the (a) ___________. At the
replication fork the (b) ___________ strand is synthesized continuously while the (c) _________
strand is synthesized discontinuously.
a: origin
b:leading
c:lagging
This RNA primer is removed after the
fragment is synthesized by the enzyme (f) ___________, using its (g) _____________ activity.
The nicks left behind in this process are sealed by the enzyme (h) _____________.
f: DNA polymerase I
g: 5’->3’exonculase
h: DNA ligase
