The Medical College - Page 54
203.
If 100 somatic cells of higher animals are
allowed
to divide once in
2H
2O (water containing
only
deuterium), _____ of the cells will have
only
DNA containing deuterium.
A.
none
C.
one half
B.
one fourth
D.
all
204.
Ultimately, sythesis of protein
requires:
A.
DNA.
C.
protein.
B.
RNA.
D.
all of the above.
DIRECTIONS: Read each passage carefully, study
each
table, chart, or formula, then answer the
question follow-
ing it. Eliminate those choices that you think
to be incor-
rect and mark the letter of your choice on the
answer
sheet.
Maloney sarcoma tumors were implanted in
Brown
Norway (BN), Lewis (Le), and Lewis-Brown
Norway
(LBN) rats. Studies were then done to determine
the
types and amounts of host serum antibodies
produced
against the protein components of the virus
contained in
the tumor cells. The following data are from
one such
experiment.
ANTIPROTEIN 30 ACTIVITY IN SERA
OF TUMOR BEARING BN, Le, and LBN
RATS
Mg Equivalent Anti-p30 Antibody
AgB
Day 25
Day 31
Host
Phenotype
Post Implant
Post Implant
BN
3/3
3.5 ± 0.8
5.3 ± 1.7
LBN
1/3
2.4 ± 0.4
4.5 ± 1.4
Le
1/1
0.4 ± 0.1
0.4 ± 0.2
205.
The following statements are related to the
infor-
mation presented. Select the statement
supported
by the information given.
A.
Brown Norway rats produced more
anti-p30
antibody at both 25 and 31 days than
the
other two hosts.
B.
On the basis of this information,
Brown
Norway rats are more resistant to
cancer
than either LBN or Le rats.
C.
All three hosts produced more anti-p30
anti-
body at 31 days than they did at 25
days.
D.
An AgB phenotype containing threes
seems
to be related to lower anti-p30
production
The graphs represent experimental results
obtained
when the pituitary gland was removed (A), the
ovaries
were removed (B), and lesions were placed in
the hypo-
thalamus (C), that part of the brain most
closely related
to the pituitary gland. The hormones LH and
prolactin
were measured in blood by
radioimmunoassay.
206.
It can be concluded from these results
that:
A.
prolactin is produced by the
ovaries.
B.
LH release stimulates prolactin
release.
C.
ovarian hormones inhibit LH release, but
not
prolactin release.
D.
presence of the ovaries inhibits removal
of
LH from the blood.
The urophysis of teleosts secretes a
neurohormone
directly into the blood circulatory system.
This secretory
apparatus is believed functional in
osmoregulation in
fishes from marine and freshwater habitats.
Fifteen blue-
back herring (Pseudoharengus aestivalis) were
main-
tained in a marine aquarium at temperatures
of
40°–45°C. The fish were subjected
to increasing salt
concentration to a final concentration equal to
twice that
of seawater. At each concentration four of
twelve uro-
physes were dissected and extracted, and
electrophoresis
on polyacrylamide gels were performed. Two
specific
bands of protein were identified as being
specific to the
urophysis. The amount of protein was determined
by
microdensitometry. The results are shown in the
graph.
207.
The experiment indicates that:
A.
the protein material was unaltered in
the
urophysis of fish subjected to varying
con-
centrations of seawater.
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