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Molecular Medicine Quiz^2015
Martin Nicklin
1. Which of the following is wrong by a factor of
more than 5-fold? (or select F if all the
estimates are acceptable).
Nucleated human cells (~ 5 ng wet weight)
contain
A.  1 mM (24 µg/ml) magnesium
B.  200 mg/ml (20%) total protein
C.  2 mM (1 mg/ml) adenosine triphosphate
(ATP)
D.  0.1% DNA
E.  75% water
F.  All of these values are roughly correct.
i
2. Which chemical element is present in human
DNA or RNA but is not incorporated into
growing protein chains during translation
(or choose F)?
A. nitrogen (N)
B. oxygen (O)
C. phosphorus (P)
D. chlorine (Cl)
E. sulphur (S)
F. Actually, all of the
above are present.
y
3. Which sugar moiety is the backbone sugar
component present in RNA (or select F)?
A. 
B. 
C. 
D. 
E. 
F. 
ribulose
2-deoxyribose
ribose [ribonucleic acid!]
3-deoxyribulose
2,3-dideoxyribose
none of the above are
present
a
4. Mentally trace a route along the backbone of
a DNA or RNA molecule. Which of the
following sequence of atoms is connected by
bonds in a continuous sequence? (or select
F)?
A. 
B. 
C. 
D. 
E. 
F. 
-O-P-C-O-P-C-H-C-C-O-N-H-C-C-O-N-P-O-C-C-O-P-O-C-C-O-O-P-O-C-C-C-O-P-O-C-C-C-C-O-P-O-C-N-C-C-O-P-O-C-N-CNone of the above is correct
h
5. Where, in this ribonucleoside, is the 2’hydroxyl ? (Hint: it’s the hydroxyl that’s
missing in a deoxynucleoside)
<=D
6
7
5’
A=>
5
2
8
E=>
4
9
4’
3’
1
<=F
<=B
3
1’
2’
<=C
a
6. What is this nucleoside (or choose F)?
A. 
B. 
C. 
D. 
E. 
adenine
guanosine
adenosine
guanidine
TTP
F.  or none of the above
a
7. The diagram shows a two base-pair segment of a DNA
double helix. Which of the following is false (or select
F)?
H
O
–
O
O–
O
†
O
N
N
NH
H
P
O
O
O –
O
O
NH
O
N
O P O–
F. 
O
O
O
A. 
B. 
C. 
D. 
E. 
P
O
O
O
P
O
O
The orange ellipses mark bonds potentially cleaved by DNase I.
The magenta bonds
are hydrogen bonds
The sequence of one strand is 5’-C-A-3’
The pyrimidine bases are marked with yellow circles .
The blue dagger † marks a potential site for CpG methylation. My
mistake!
Actually, all of the above are true.
8. Which of the following is false (or select F)?
A.  Tritium, 3H, is a heavy radioactive isotope of hydrogen that
has been traditionally used to label thymidine to measure
DNA replication activity through incorporation of 3H into DNA.
B.  15N, a rare natural heavy stable isotope of nitrogen. It was
used by Meselson and Stahl to label new strands of DNA, so
that old, entirely new and mixed double strands could be
separated by ultracentrifugation on the basis of their density.
C.  14C is a radioactive isotope of carbon that may be used to
trace the metabolism of any organic compound in which it
has been incorporated.
D.  35S is a synthetic radioactive isotope of sulphur, often used to
metabolically label proteins in cultured cells.
E.  31P is a radioactive isotope of phosphorus that can be used to
trace nucleic acids that are synthesised to contain it.
F. 
Actually, all of the above are true.
32P
and 33P are radioactive
and synthetic and used as
described. 31P is natural and
the only stable isotope.
9. Which of the following is not required for a
polymerase chain reaction reaction involving a
thermophilic DNA polymerase (or select F)?
A.  A DNA template
B.  deoxynucleotide triphosphates or their
analogues
C.  water
D.  either magnesium (Mg2+) or manganese
(Mn2+) ions
E.  thermophilic DNA polymerase
F.  All of the above are needed
j
10. What is RNA synthesis using a DNA template
called? (or select F)
A. Transcription
B. Recombination
C. Translation
D. Splicing
E. Plagiarism
F. None of the above.
b
11. Mature mRNA is generated from primary RNA
transcripts through the removal of intron
sequences. What is this process called? (or
select F)
A. Frame shifting
B. Translation
C. Plagiarism
D. Termination
E. Splicing
F. None of the above.
b
12. The segments of RNA that are retained (kept)
after conversion of a pre-mRNA to a mature
mRNA are called
A. 
B. 
C. 
D. 
E. 
Codons
Polymorphisms
Exons
Introns
Splice boundaries
F.  None of the above.
b
13. Which of the following does not happen to
proteins post-translationally within the cell? (or
select F)
A.  A phosphate group may be added to the side-chain
oxygen of glutamine.
B.  Disulphide bonds –S-S- may be created by oxidising
pairs of -SH groups.
C.  Branched polysaccharide chains can be built up on the
side-chain nitrogen of asparagine.
D.  Peptide bonds may be selectively cleaved.
E.  An isopeptide linkage can be formed between the εNH2 group of a lysine and the C-terminal glycine of the
small protein ubiquitin.
F.  Actually, all of the above occur, post-translationally.
c
14. Molecular hybridisation of nucleic acids
means (or select F)?
A.  The specific non-covalent association of two
complementary or partially complementary single-stranded
nucleic acid strands.
B.  Mixing and joining of complementary DNA or RNA from
different species of organism.
C.  The non-covalent association of similar double stranded
nucleic acid molecules.
D.  The covalent joining of two complementary single-stranded
DNA or RNA molecules.
E.  The molecular association of two single-stranded
fragments of DNA or RNA with identical sequences.
F. 
None of the above.
15. Which of the following DNA sequence pairs
are complementary?
5’-AAGTAGTCC and 5’-AAGTAGTCC.
5’-CAGTCCAGG and 5’-GGACCTGAC.
5’-GGGCTAATA and 5’-GGGCATTAT.
5’-GACATACTG and 5’-CAGTATGAC.
5’-TGACAATGC and 5’-GCATTGTCA.
None of the above are complementary.
5’-TGACAATGC
5’-GCATTGTCA
A. 
B. 
C. 
D. 
E. 
F. 
16. Which of the following statements indicate the
direction that DNA or RNA polymerases produce a
new nucleic acid strand (or select F)?
A. 
B. 
C. 
D. 
E. 
F. 
from the 2’ end to the 5’ end.
from the 3’ end to the 5’ end.
from the 5’ end to the 2’ end.
from the 5’ end to the 3’ end.
from the 5’ end to the 5’ end.
All of the above are incorrect.
http://www.visionlearning.com/en/library/Biology/2/DNA-III/180
17. Which pair is odd man out (that is, has not the
same internal relationship as the other pairs)?
Choose F if all have the same relationship.
A. Glucose and glucagon
B. Galactose and polysaccharide
C. Thymidylate and DNA Glucagon [not glycogen] is a peptide
hormone that stimulates (among
other things) breakdown of glycogen
D. Alanine and protein
to glucose. All of the other pairs are
E. Adenylate and mRNA
possible subunits and polymers that
contain them (after condensation
reactions involving the loss of water).
F. All pairs are related in a similar way
b
18. Which chemical element is present in all
nucleic acid but absent from nascent
polypeptides (or choose F)?
A. oxygen (O)
B. phosphorus (P)
C. carbon (C)
D. nitrogen (N)
E. sulphur (S)
F. Actually, all of the
above are present in
both.
19. Which description of the side-chain of an
amino acid residue is incorrect (or select F)?
Description
A. 
B. 
C. 
D. 
E. 
aromatic
bulky, hydrophobic
charged
acidic
sulphur-containing
Amino acid
phenylalanine (Phe, F)
isoleucine (Ile, I)
arginine (Arg, R)
asparagine (Asn, N)
methionine (Met, M)
F.  All of the descriptions are appropriate
20. Which of the following elements is
incorporated into animal proteins during
translation, as part of an amino acid (or select
F)?
A. 
B. 
C. 
D. 
E. 
magnesium
iron
calcium
aluminium
selenium [as selenocysteine, at a specific TGA codons]
F. 
None of the above are incorporated during translation
e
21. Transcription factors are components of DNA
binding complexes that regulate transcription
(and some bind directly to DNA). What are
transcription factors generally composed of?
A. 
B. 
C. 
D. 
E. 
protein
DNA
small RNAs
RNA
lipids
F.  All of the above
e
22. Which of the following is not a sequence-specific
DNA location where transcription factors bind and
regulate gene expression in human cells (or select
F)?
A. 
B. 
C. 
D. 
E. 
F. 
A promoter
A kappa-B (κB) element
A TATAA box
A locus control element
An enhancer
All of the above are involved in
transcriptional control
23. Which one of the following enzymes catalyses
precursor-mRNA synthesis in the eukaryotic
nucleus (or select F)?
A. 
B. 
C. 
D. 
E. 
AMV reverse transcriptase
RNA polymerase I
RNA polymerase II
RNA polymerase III
T7 RNA polymerase
F.  None of the above catalyse precursor-mRNA
synthesis
24. Which statement is not true? (or choose F)
What has been called the “universal”
genetic code...
A. indicates how mRNA is translated into
protein.
B. applies to triplets of nucleotides.
C. does not apply to protein synthesis in
mitochondria or chloroplasts.
D. shows redundancy (there being more than
one codon for most amino-acids).
E. always includes the de-coding of “AUG” as
methionine.
F. All of these statements are true.
25. Which of the following sets of codons
would you recognise as the end of the
coding sequence within a genomic DNA
sequence [they are “nonsense” (stop)
codons] in humans and Escherichia coli?
A. UGA, UAA, UAG
B. TAG, TAA, TGA –this is DNA
C. AUG, TGA, TAA
D. ATG, ATC, ATA
E. TCA, TTA, CTA
F. None of the above sets represent the set of
stop codons that might terminate the sense
sequence of a gene.
o
26.
If AAA encodes Lys, AAU encodes Asn,
AUA and AUU encode Ile, UUA encodes Leu
and GAU encodes Asp,
then the translation product, beginning at the initiation
codon of
AAUGAUAUUAAUAAUAAAUUAAAAUAAAAA
MetIleLeuIleIleAsn
would be
A. 
B. 
C. 
D. 
E. 
F. 
Asn-Asp-Ile-Asn-Asn-Lys-Leu-Lys-stop-Lys.
Asn-Asp-Ile-Asn-Asn-Lys-Leu-Lys-Lys.
Met-Ile-Leu-Ile-Ile-Asn-stop-Asn-Lys.
Asn-Asp-Ile-Asn-Asn-Lys-Leu-Lys.
Met-Ile-Leu-Ile-Ile-Asn.
Something other than the above
L
27. Which part or parts of an immunoglobulin G
molecule is/are not involved in antigen specificity?
A. 
B. 
C. 
D. 
E. 
F. 
The Variable regions: VH and VL.
The Fc domain
The Fab domains
The heavy chain
The light chain
All of the above are involved in antigen
specificity
28. In which of the following situations may the
polymerase chain reaction occur?
A.  In ancient DNA
B.  During the replication of HIV.
C.  During a DNA-replication cycle of a thermophilic
bacterium.
D.  In vitro in a thermocycler.
E.  During a replication cycle of mitochondrial DNA.
F.  None of the above.
td
29. Which of the following is not required for all
natural template-directed DNA synthesis in
vivo (or select F)?
A. 
B. 
C. 
D. 
E. 
Reverse transcriptases are
DNA polymerases that can
copy an RNA template to
make DNA.
A DNA template
A DNA polymerase
A primer that hybridises to the template
dTTP
dATP
F.  Actually, all of the above are required.
30. Which of the following is not true of precursor
mRNA processing in human cells (or select F)?
A.  Introns usually represent the greater part of a
primary transcript.
B.  Exons are removed from pre-mRNA in the
nucleus by splicing during and after
transcription.
exons are not removed!
C.  The 5’ nucleotide cap structure is added to all
transcripts.
D.  The poly-A tail is added when the mRNA is
complete but before the completion of splicing.
E.  Replication-phase histone mRNA transcripts do
not have a poly-A tails.
F.  Actually, all of the statements above are true.
31. Mentally trace a route along the main chain
(the backbone) of a protein following only
the atoms that make the chain. Which of the
following sequence of atoms is connected
(or select F)?
A. 
B. 
C. 
D. 
E. 
F. 
-N-H-C-C-O-N-H-C-C-O-N-C-C-O-H-N-C-C-O-N-C-C-O-N-C-C-O-N-C-C-N-C-C-N-C-N-CNone of the above are
correct
32. Which of the following is false (or select F)?
The activity of transcription at a specific
location in the human genome is regulated
by localised…
A.  methylation of cytosine bases
B.  deamination of cytosine bases
C.  methylation of specific lysine
residues in histones
D.  acetylation of specific lysine
residues in histones
E.  deacetylation of lysine residues in
histones
F.  all of the above are true.
33. For human blood erythrocytes, which of the
following statements is true (or select F)?
A.  X-linked genes in women are present in a single
copy.
B.  The great majority of genes are present in two
copies.
C.  X-linked genes are absent specifically from male
erythrocytes.
D.  There are two copies of the mitochondrial genome.
E.  Women have two copies of all human genes.
F. 
All the statements above are wrong.
Human and all mammalian red cells (erythrocytes) have no nuclei or
mitochondria and thus lack all DNA. This is not true of birds.
f
34. For circulating human leukocytes, which of the
following statements is true? (or select F)
A. 
B. 
C. 
D. 
E. 
All DNA is absent.
Men’s leukocytes have no X chromosomes.
Men’s leukocytes have two copies of each Y-linked gene.
All genes are present in two copies per nucleus.
The Y chromosome in men is present in a single copy
per nucleus.
F. 
All the statements above are wrong.
f
35. Which of the following statements is in
error by at least a factor of ten ? (or select F)?
A.  A single copy of the human genome contains 3100
million base pairs of DNA.
B.  Free-living bacteria have 5,000 protein encoding
genes.
C.  Humans have 300,000 protein-encoding genes.
D.  Each human cardiac myocyte (muscle cell) contains 2
More like
metre of DNA.
20,000. Flies
E.  A single copy of a free-living bacterial genome have 13,000!
contains 8 million base pairs.
F. 
All of the above are fair estimates.
36. Give a best estimate from the numbers below
for the proportion of RNA in a human cell that
is not mRNA.
A. 
B. 
C. 
D. 
E. 
F. 
0.5%
5%
20%
50%
95%
99%
ribosomal RNAs
Total RNA by agarose gel electrophoresis
37. In the organisation of genes in mammals,
which statement is false (or F)?
A.  A transcription promoter usually lies upstream of
or surrounds the transcription start.
B.  The initiation codon must lie in an exon.
C.  An enhancer for a gene can lie inside a
neighbouring gene
D.  The stop codon of a functional coding sequence
can lie in an intron.
E.  The polyadenylation signal lies in the last exon.
F.  All of the above statements are true
38. Which one of the following chemical species
diffuses rapidly through the plasma membrane
without using transporters or channels (or
select F)?
A. 
B. 
C. 
D. 
E. 
F. 
O2
H2O
K+
Cl–
citrate
All of the above require transporters to
cross the plasma membrane.
i
39. A sub-microscopic probe enters a human cell that
is suspended in culture medium. Which type of
cell-associated polymer is the probe likely to
encounter last (or F)?
A. 
B. 
C. 
D. 
E. 
F. 
cholesteryl esters
polypeptide (protein)
nucleic acid
phospholipids
polysaccharide
The molecule cannot encounter any of the above.
40. A sub-microscopic probe escapes from a human
cell that is suspended in culture medium. Which
type of cell-associated polymer is the probe likely
to encounter last (or F)?
A. 
B. 
C. 
D. 
E. 
F. 
cholesteryl esters
polypeptide (protein)
polysaccharide
nucleic acid
phospholipids
The molecule cannot encounter any of the above.
41. Which of the following statements about the
endoplasmic reticulum (ER) is false (or select F)?
A.  Smooth ER is so named because in electron
microscopy it contains no ribosomes.
B.  The smooth and rough ER are extensively
connected.
C.  Rough ER is the site of the synthesis of secreted
and trans-membrane proteins.
D.  Membrane-bound vesicles leave the ER to carry
proteins into the Golgi apparatus.
E.  Signalase clips off signal peptides from secreted
proteins in the lumen of the ER.
F.  Actually, all of the above statements are true.
Smooth and rough ER are actually entirely
separate. Smooth ER has metabolic and lipid
synthesis functions
42. Which answer does not correctly identify a
function that is performed by the following
organelles in human cells (or select F)?
A.  The Golgi body is the major site of protein glycosylation.
B.  Desmosomes are points of anchorage for cell membranes
to the extracellular matrix
C.  Mitochondria release cytochrome c into the cytoplasm to
trigger cell death.
D.  Chloroplasts harvest light energy to reduce NADP+ for
photosynthesis. [humans? pjhotosynthesis?]
E.  Nucleoli are the sites for ribosomal RNA synthesis.
F.  All of the above are true in humans.
43. Which of the following membrane-bound
organelles are not included in the
continuous sorting of proteins in lipid
vesicles within the cell (or select F)?
A. 
B. 
C. 
D. 
E. 
endosomes
mitochondria
rough endoplasmic reticulum
Golgi apparatus
lysosomes
F.  All of the above are linked by vesicular
membrane transport.
s
43. Which of the following membrane-bound
organelles are not included in the
continuous sorting of proteins in lipid
vesicles within the cell (or select F)?
A. 
B. 
C. 
D. 
E. 
endosomes
mitochondria
rough endoplasmic reticulum
Golgi apparatus
lysosomes
F.  All of the above are linked by vesicular
membrane transport.
44. Which is false? (or indicate F if all other
answers are true)
A. 0 Integral membrane transporter proteins carry molecules
through generally impermeable cellular membranes.
B. 27Translation factors are involved directly in mRNA
synthesis.
C. 0 Growth factors signal cells to grow and divide.
D. 1 Cell surface receptors bind to extracellular molecules.
E. 0 Apoptosis is programmed cell death.
F. 7 All of the above are actually true.
45. Which of the following statements about
the mitochondrion is not true? (or select F)
A. 5 Carbon from carbohydrate metabolism is transported
inward as pyruvate.
B. 5 Mitochondria contain the products of ~1500 protein
coding genes.
C. 10The human mitochondrial genome encodes only thirteen
proteins.
D. 1 In mammalian cells, it is only in the mitochondria that
ATP generation is directly coupled to oxygen
consumption.
E. 9 Fatty acid synthesis occurs in the lumen of the
mitochondrion. [happens in the cytoplasm/SER]
F. 5 All of the above are true.
s
46. Synapses are found between which of the
following cells types?(or select F).
A. 1 B cells and neurones.
B. 0 Dendritic cells and epithelial cells.
C. 6 Cortical neurones and dendritic cells.
26Skeletal muscle cells and motor neurones.
D. 
E. 1 Neutrophils and natural killer cells.
F. 1 None of the above cell types are associated
through synapses.
t
47. The commonest type of cell surface receptor for
small molecules (and therapeutic drugs) is the
seven transmembrane domain “serpentine” class
of receptor proteins. Which protein molecules
interact directly with their cytoplasmic domains
and transduce signals from them?
A. 
B. 
C. 
D. 
JAK-like protein kinases.
Protein tyrosine phosphatases (PTP).
Ras-like “small” GTP-ases.
Membrane associated cytoplasmic protein
tyrosine kinases.
E.  3-subunit “large” GTP-ases.
F.  None of the above.
t
END OF QUIZ