Date post: | 06-Jul-2018 |
Category: |
Documents |
Upload: | carol-hathaway |
View: | 218 times |
Download: | 0 times |
of 11
8/17/2019 Cell Biology Test 3
1/11
B[OL265 Exam
3
)
The distinct characteristics
of different
cell tlpes in
a multicellular
organism
result mainly
from
the
diflerential regulation
of the
_.
A) transcription
of
genes
transcribed
by
RNA
polymerase
II.
B) transcriptionofhousekeepinggenes.
C)
proteins
that
dtectly
bind
the
TATA
box of eukaryotic
genes.
D), replication
ofspecific
genes.
The human
genome
encodes
about 21,000
protein-coding
genes.
Approximately
how many
such
genes
does
the typical differentiated
human cell
express at any one
time?
A)
between 5000 and 15,000
B) less
than 2100
C)
between 18,900
and
21,000-at
least
90% of
the
genes
D) 21,0OG-all of them
Which
of the following is not
a
good
example
of
a
housekeeping
protein?
A)
hemoglobin
B)
ATP
synthase
C) DNA
repair enzymes
D)
histones
Which of the following
statements
about differentiated
cells is
true?
A)
Some of
the
proteins
found
in
differentiated
cells
are
found in
all cells
of a multicellular
organism.
B)
Cells
of distinct t)?es
express nonoverlapping
sets
of transcription factors.
C) Once a cell
has
differentiated, it
can
no longer
change its
gene
expression.
D)
Once a cell has differentiated,
it will
no
longer
need
to transcribe
RNA.
Investigators
performed
nuclear
transplant experiments
to determine
whether
DNA
is altered
irreversibly
during
development.
Which
of
the
following
statements about
these
experiments
is
true?
A)
Although nuclear
transplantation
has been successful
in
producing
embryos
in
some mammals
with
the use
of
foster
mothers,
evidence
of DNA
alterations
during
differentiation
has not
been
obtained
for
plants.
B)
Because
the donor nucleus
is
taken
from
an adult
animal, the
chromosomes
from
the nucleus
urust
undergo recombination
with
the
DNA
in
the
egg for successful
development
to occur.
C) The
embryo that develops
from
the nuclear
transplant
experiment
is
genetically
identical
to the
donor
of the nucleus.
D) The meiotic
spindle
of the
egg must interact
with
the chromosomes
of the injected
nuclei
for
successful nuclear
transplantation
to
occur.
J.
4.
5.
Page
I
8/17/2019 Cell Biology Test 3
2/11
Use the
following
to answer
questions
6-9:
You
are
interested in examining
the
Ps/gene.
It is known
that Psf is
normally
produced
when cells
are
exposed
to high levels
of both
calcium
(Ca*)
and magnesium
(Mg'*).
MetA, MetB,
and MetC
are
important for
binding to the
promoter
of the Ps/gene
and are
involved in
regulating
its
transcription.
MetA
binds to
the
"A"
site in the
promoter
region, MetB to
the
"B"
site, and
MetC to the
"C"
site.
You
create
binding-site mutations in
the A, B,
and C sites and observe
what
happens
to transcription of
the
Py'gene.
Your results
are
summarized in Table
Q8-17.
Transcription
in the
presence
of Ca2* andlor
Mgz+
No Ca2*
Binding
sites
present
or Mgz*
with with
with
ca2+
Ca2* Mg'*
and Mg2*
4
u"d
A,
B,
and
C
A only
B only
C only
A and
B only
A and C only
B and C only
For this table:
-
-
no
transcription
of Pst
+
=
low level
of transcription of
Psf,
and
++
=
high levels of transcription
of Psf.
Table
Q8-17
Which of the following
proteins
are
likely
to
act
as
gene
activators?
A)
MetB
only
B) MetC only
C) Both MetA and MetC
D) MetA
only
Which
of
the
following
proteins
are
likely
to act
as gene repressors?
A) MetB
only
B)
Both
MetA and MetC
C)
MetA
only
D)
MetC only
Which
kanscription
factors
are
normally
bound to
the
Ps/promoter
in
the
presence
of Mg2*
only?
A) MetA, MetB,
andMetC
B)
none
C) MetAonly
D) MetA
and
Met B
Which
transcription factors
are normally
bound
to
the
Ps/promoter
in
the
presence
of both Mg2*
and
Ca2*?
A) MetA, MetB,
andMetC
B) MetAandMetC
C)
MetAandMetB
D) MetB
andMetC
.t'
4oI\'
++
6.
7.
8.
9.
Page2
8/17/2019 Cell Biology Test 3
3/11
Use the following
to
answer
questions
l0-13:
You
are
interested
in
the
regulation
of
gene
Q.
Proteins
G, H,
and
J
are
proteins
that
are important
for
regulating
gene
e,
and
bind to
its
promoter
region
in
a
sequence-specific
fashion.
Proteins
G and H
both
bind to site
"A"
but cannot
bind
to site;.A"
ai
the
same
time.
Protein J
binds to site
"B"
on
the
promoter.
The
promoter
region
is
diagrammed
in Figure
Q8-29.
Gt+
m*ftlAaf
gun**
Figure
Q8-29
You
develop
a
cell-free transcriptional
system to study
the effects
of
proteins
G, H,
and
J
on the transcription
of
gene
e.
Using
this
system,
you
can
examine the
effects of
adding these
proteins
to
the
transcriptional
system in
equal amounts
and
measuring
how much
gene
Q
is
produced.
When
you
add these
proteins
to
the system,
you get
the results
shown
in
Table
Q8-29.
e $efifn*nt
r,x*mhef
rBflrrlsttr
pro**ift
*ddsd
I
*nHH*
fi
ll I
laede?
*qf
ffi
?4+*y#
s
Table
Q8-29
Ws
y**
10.
ll.
t2.
Which proteins
are
likely
to
act
as
gene
activators?
A)H
B)J
C) both H
and
J
D)G
Which
proteins
are likely
to
act
as
gene
repressors?
A)J
B)G
C)
both H
and
J
D)H
Your
colleague
looks
at
your
data
above
and
predicts
that
protein
G
will
bind more
strongly
to
the DNA
at
site A,
compared
to
protein
H.
Which
experiment
above is
critical
for
this
prediction?
A)
#6
B) #2
c)
#3
D)
#5
Page
3
8/17/2019 Cell Biology Test 3
4/11
I3.
t4.
Which
proteins
do
you
predict
are
bound
to
the
promoter
in experiment
#8?
A)
onlyG
andH
B)
only J
C)
only
H
and
J
D)
only
G and
J
How are most
eukaryotic
transcription
regulators
able
to affect transcription
when
their
binding
sites
are
far from
the
promoter?
A)
.
by
looping
out the
intervening
DNA
between
their
binding
site and
the
promoter
B)
by
unwinding
the DNA
between
their
binding
site and
the
promoter
C) by attracting
RNA
polymerase
and
modifying
it before
it
can
bind to
the
promoter
D) by
binding to their
binding
site and
sliding
to
the
site of RNA
polymerase
assembly
The
expression
of
the
BRFI
gene
in
mice is
normally
quite
low,
but mutations
in
a
gene
called.BRF2
lead,
to increased
expression
of BRFl.
You
have
a
hunch
that
nucleosomes
are involved
in
the regulation
of
,BRF1
expression and
so
you
investigate
the
position
of
nucleosomes
over
the
TATA
box
ofBRFl in
normal mice
and
in mice
that lack
either
the BRF2
protein
(BRF2)
or
part
of histone
H4
(HHF-)
(histone
H4
is encoded
by the
HHF
gene).
Table
Q8-37
summarizes your
results.
A normal
functional
gene
is
indicated
by a
plus
sign
(+).
Mouse
Nucleosome
positioning
Relative
level
of BRFI
mRNA
BRFZ+
HHF+
specific
pattern
BRF2-
HHF+
randorn
100
BRF?+ HHF-
random
BRF2'HHF-
randgm
100
Table
Q8-37
Which of the
following
conclusions
cannotbe
drawn
from
your
data?
Explain
your
answer.
A)
The
part
of histone
H4 missing
nHHf-
mice is not
required
for
the
formation
of nucleosomes.
B)
The specific pattem
of nucleosome positioning
over
the
BXFI
upstream
region
is required
for BRFI
repression.
C)
BRF2
is requted
for
the repression
of BRFI.
D)
BRF2
is required
for
the
specific
pattern
of nucleosome positions
over
the
BRFI
upstream
region.
Combinatorial
control
of
gene
expression
_.
A) involves groups
of
transcriptional
regulators
working
together
to deiermine
the
expression
of a
gene.
involves
only the
use
ofgene
activators
used
together
to regulate
genes
appropriately.
is
seen
only
when
genes
are
arranged
in
operons.
involves
every
gene
using
a
different
combination
of transcriptional
regulators
for
its
proper
expression.
17.
The
extent
of complementarity
of
a
miRNA
with its
target
mRNA
determines
whether
the
mRNA
will
be
tansported to
the
nucleus.
whether
the
miRNA
synthesizes
a
complementary
strand.
whether
the mRNA
will
be immediately
degraded
or
whether
the rrRNA
will fust
be transported
elsewhere in
the
cell before
degradation.
whether
RISC
is
degraded.
15.
16.
B)
c)
D)
A)
B)
c)
D)
Page
4
8/17/2019 Cell Biology Test 3
5/11
The owners of
a
local bakery ask for
your
help in improving
a
special
yeast
strain they use
to
make
bread.
They would like
you
to help
them
design
experiments using
RNA interference
to
turn off
genes,
to allow
them to
test their hlpothesis that certain
genes
are important for the
good
flavors found in
their bread.
Of
the components
in
the
following list, which
is the most
important to
check
for in
this
yeast
strain
if
you'd
like this
project
to
succeed?
A) the
presence
of
genes
in the
genome
that code
for RISC
proteins
B)
the
presence
of single-standed siRNAs
within
the cell
C)
the
presence
of
foreign
double-stranded
RNA
D)
.
the presence
of
miRNA
genes
in
the genome
You
have
a
circular
plasmid
that
can
be
cut by
the restriction nuclease HindIII,
as
diagrammed in Figure
Qr0-4.
Figure
Q10-4
If
you
were
to
cut
this circular
piece
of DNA with HindIII, which of the answers below
best
predicts
what
you
would
get?
A)
two circular
pieces
of DNA
B)
two semicircular
pieces
of
DNA
C)
t',vo
linqar
pieces
of
DNA
D)
one linearpiece of
DNA
You have a
piece
of circular
DNA that
can
be cut by the
restriction
nucleases
XhoI and SmaI, as indicated
Figure
Q10-5
If
you
were
to cut this circular
piece
of
DNA with
both
XhoI
and SmaI,
how
many fragments of
DNA
would
you
endup with?
A)2
B)4
c)1
D)3
Page
5
8/17/2019 Cell Biology Test 3
6/11
Notl
21.
You
have
a
piece
of
circular
DNA
that
can
be cut
by
the
reshiction
nucleases
EcoR[,
HindIII,
and NotI,
as
indicated
in
Figure
Ql0-6.
EcoRl
Hindlll
Figure
Q10-6
Which of
the following
statements
isfalse?
A)
A
piece
of DNA
that
cannot
be cut
by EcoRI
will
be obtained
by cutting
this
DNA
with
both
NotI
and
HindIII.
B)
Two DNA
fragments
that cannot
be
cut by
HindIII
will
be
obtained
when
this DNA
is
cut
by EcoRI
and
NotI.
C) Two
DNA
fragments
of unequal
size will
be created
when
this DNA
is
cut
by both
HindIII and
EcoN.
D)
One
piece
of
DNA
will
be
obtained
when
this
DNA
is cut
by NotI.
Which
of the following
statements
about
gel-transfer
hybridization (or
Southern
blotting)
isfalse?
A) A
labeled
DNA
probe
binds to
the DNA
by hybridization.
B)
The
DNA
that is
separated
on
a
gel
is
not labeled.
c) In this
technique,
single-stranded
DNA is
separated
by electrophoresis.
D)
This
technique
involves
the
transfer
of DNA
molecules
from
gel
onto
nitrocellulose
paper
or nylon
paper.
DNA ligase
is
an enzyme
used when
making
recombinant
DNA
molecules
in
the lab.
In
what
normal
cellular
process
is
DNA
ligase
involved?
A) transcription
B)
transformation
C) DNA
replication
D)
none,
it is
only found
in
virally
infected
cells
Q10-19
shows
the cleavage
sites
of
several
reskiction
nucleases.
22.
23.
24,
5',
3',
s'
otoocrr
3'
3,rEEEh
s,
5,
ACAT"I,
,,
3'
r[crACA
5'
Figure
Q10-19
You
cut a vector
using
the PciI
restriction
nuclease.
Which
of the
following
restriction
nucleases
will
generate
a
fragment
that
can
be ligated
into
this
cut
vector
with
the
additio;
of
only
ligase
and
ATp?
A)
NspV
B)
HindIII
C)
NcoI
D)
MmeI
t3'
5'ccAlTGG
3'
5'
3'GGTIACC
5'
5',
3',
Page
6
8/17/2019 Cell Biology Test 3
7/11
Figure
Q10-20
depicts
a
strategyby
which
a
DNA
fragment
produced
by cutting
with the
EcoRI
restriction nuclease
can
be
joined
to a
DNA
fragment
produced
by
cutting
DNA
with the HaeIII
restriction nuclease.
+ ligase
.ffi
-T*
.H,H'
, $_\EtiF-
-+
+ deoxyribo-
nucleotides
-GAATTI
.wffi$#.&_
*'CfTAA.
tr"
;::gip/;:
; i#, ;
+
polymerase
Figure
Q10-20
Note that cutting DNA with EcoRI
produces
a
staggered end,
whereas cutting
DNA
with HaeIII
produces
a blunt end. Why must
polymerase
be added in this reaction?
A)
Without
polymerase,
there will not
be enough
energy
for
the reaction to
proceed.
B) Polymerase
will
add
nucleotides
to
the
end
produced
by the
HaeIII
restriction nuclease.
C) Polymerase will fill in
the staggered
end to create
a
blunt end.
D)
Polymerase is
needed
to
seal
nicks in
the
DNA
backbone.
DNA can
be infoduced into
bacteria by
a
mechanism
called
A)
ligation.
B)
replication.
C) transformation.
D) transcription.
A
plasmid
_.
A) is
a
single-stranded
circular
DNA
molecule
that
can
undergo horizontal
transfer
among
bacteria.
B)
always becomes
part
of
the
bacterial
chromosome
during transformation.
C)
can
confer antibiotic resistance
to a
bacterium.
D)
is
a
tool
designed
in
the lab and never
found in naturally occurring
bacteria.
Which of the following
statements
about DNA
librarie
s
is
true?
A)
Individual
bacteria that have
taken up most
of the library
DNA
are
selected for
during
the
construction
of
a
DNA library.
The library
DNA within the
bacteria
will
only
be replicated
when it hybridizes
to
a
DNA
probe.
By
placing
the
library DNA
into
bacteria,
the
bacteria can
be used to
amplifr
the
desired DNA
fragments
from
the DNA library
Production
of
a
DNA library
involves
the direct insertion
of
short
DNA
fragments
into
bacteria
through transformation.
Which of
the
following
statements
about genomic
DNA
libraries isfalse?
A) The larger
the size
of
the fragments
used
to make
the library,
the
more
difficult it
will be
to find
your gene
ofinterest
once
you
have identified
a
clone that hybridizes
to
your
probe.
B) The
larger
the
genome
of the
organism from
which
a
library
is derived,
the larger
the fragments
inserted into
the vector
will tend to
be.
C)
The
smaller the
gene
you
are
seeking,
the more
likely
it
is that
the
gene
will be found
on a single
clone.
D)
The larger the
size of the fragments
used
to make
the library,
the fewer
colonies
you
will
have
to
examine
to find a
clone that hybridizes
to
your
probe.
B)
c)
D)
PageT
8/17/2019 Cell Biology Test 3
8/11
30.
Why
is
an excess
of
normal
deoxyribonucleoside
triphosphate
molecules
(dNTPs)
needed
during
dideoxy
sequencing?
A)
dNTPs
are
consumed
as
energy
to
fuel the
sequencing
reactions.
B)
When dNTP
levels
are
too
low, there
will be
very
few chain-termination
events.
C)
The dNTPs
can
hybridize
to the
fragment
to
be sequenced
and serve
as
primers for DNA
polymerase.
D)
bN,t
potymerase
uses
the
dNTPs
to synthesize
a DNA
molecule
complementary
to
the
molecule
being
sequenced.
you
create
a
recombinant
DNA
molecule
that
fuses
the coding
sequence
of
green
fluorescent
protein
to
the
regulatory
DNA
sequences
that
control
the
expression
of
your
favorite
genes.
Which
of the
following
pieces of
information
can
you
NOIgain
by examining
the expressiol
of
this
reporter
gene?
A)
the cell
in which
the
protein
encoded
by this
gene
is expressed
B)
when,
during
an
organism's
development,
this
gene
is expressed
C)
the
tissue
where
the
protein
encoded
by
this
gene
is expressed
D)
the specific
location
within
the
cell
of the
protein encoded
by
this
gene
In
the
photosynthetic
archaeat
Halobacterium
halobium,
a
membrane
transport
protein
called
bacteriorhodopsin
captures
"r"rgy
tom
suntigfit
and
uses
it
to
pump
protons
out
ofthe
cell.
The
resulting
proton
gradient
serves
as
an
energy
store
that
can
lulter
be tapped to generate
ATP.
Which
statement
best
describes
how bacteriorhodopsin
operates?
A)
The absorption
of sunlight
triggers
a contraction
ofthe
b barrel
that
acts as the
protein's
central
channel,
squeezing
a
proton
out
of the
cell.
B)
Th;
absorption
of
sunlight
triggers
a
shift
in
the
conformation
of the
protein's
seven,
membrane
spanning
a
helices,
allowing
a
proton
to
leave the
cell'
C)
The
absorption
of sunlight
triggers
a
restructuring
of
bacteriorhodopsin's
otherwise
unstructured
core
to
forrn the
channel
through
which
a
proton
can
exit the
cell.
D)
The absorption
of
sunlight
triggers
the activation
of an
enzyme
that
generates
ATP.
Insulin
is a small
protein
that
regulates
blood
sugar
level
and
is
given
to
patients
who suffer
from
diabetes.
Many
years
ago,
diabetics
were
given
insulin
that
had
been
purified
from
pig pancreas. Once
recombinant
DNA
techniques
became available,
the
DNA encoding
insulin
could
be
placed into an
expression
vector
and
insulin
could
be
produced
in
bacteria.
Which
of the
followngis
NOT areason
why
purifying insulin
from
bacteria
is
a
better
way
to
produce insulin for
diabetics than
using
insulin
purified
from
a
pig
pancreas.
A) Insulin
made
from a bacterial
culture
and
then
purified will be
free of any
possible
contaminating
viruses
that
pigs
(and
any other
animals)
harbor. Since
pigs
are
more closely
related to
people
than
bacteria
are,
their
viruses
are more
likely
to be
harmful
to
people
than
are
viruses
that
might
infect
bacteria.
B)
Insulin
can
be
easily
produced in large
quantities
from
cells carrying
the
cloned
DNA
sequence.
C)
The
pig
protein
has
slight
amino
acid
differences
compared
to
the
human
protein,
so
human
insulin
produced
by
bacteria
will
work better
in
people.
D)
the
creation
of
transgenic
pigs
that
expressed
insulin was
very expensive
compared
to
the cost of
creating
bacteria
that expressed
insulin.
:,
Which
of
the following
phenomena will be observed
if a
cell's
membrane
is
pierced?
A)
the membrane collapses
B) a tear
is formed
C)
the
membrane
expands
D)
the membrane
reseals
31.
32.
JJ.
34.
Page
8
8/17/2019 Cell Biology Test 3
9/11
38.
39.
The
plasma
membrane
serves
many
functions, many
of which
depend on the
presence
of
specialized
membrane
proteins.
Which of the following roles
of the
plasma
membrane
could
still occur
if
the
bilayer
were lacking
these
proteins?
A) selectivepermeability
B) import/export
of
molecules
C)
intercellularcommunication
D)
cellular movement
Which of the following membrane
lipids does not
contain
a fatty
acid tail?
A)
cholesterol
B)
phosphatidylserine
C)
phosphatidylcholine
D) a
glycolipid
Forrnation
of
a
lipid bilayer
is
energetically favorable. How
does
this arrangement result in higher
entropy
for the system, and thus make
bilayer formation energetically favorable?
A)
Water molecules form
cagelike structures around hydrophobic molecules.
B)
Fatty
acid tails
are
highly saturated
and flexible.
C)
Polar head
groups
form
a
hydrogen-bonding
network
at
the interface
with water.
D)
Hydrogen
bonds fbrm between neighboring
polar
head
groups
in
the
bilayer.
Which of the following
statements is true?
A) In
eukaryotes,
all
membrane-enclosed
organelles
are
surrounded
by one lipid bilayer.,
B) Membrane lipids frequently flip-flop
between
one
monolayer
and
the
other.
C)
Phospholipids
will
spontaneously form
liposomes in nonpolar
solvents.
D) Membrane lipids
difhrse within
the
plane
of the membrane.
A
bacterium is suddenly expelled
from
a
warm human
intestine into
the
cold world
outside. Which
of the
following
adjustments might the
bacterium make
to
maintain
the
same level
of membrane
fluidity?
A)
Decrease
the amount of
glycolipids
in the
membrane.
B) Produce lipids
with hydrocarbon
tails that
are
longer
and have fewer
double bonds.
C)
Produce
lipids with
hydrocarbon tails
that
are
shorter and have more double bonds.
D) Decrease
the amount
of cholesterol
in
the
membrane.
Some
lipases
are
able
to
cleave
the
covalent
bonds between
the
glycerol
backbone and
the attached
fatty
acid.
What final
products
do
you
expect
to accumulate
through the action
of
the enzyme
monoacylglycerol
lipase?
A)
free
phosphate
and
glycerol
B)
glycerol
and free fatty
acid
C) sterol and
glycerol
D)
phosphoglycerol
and free
fatty acid
Which of
the
following
phospholipid
precursors is the most
hydrophobic?
A)
glycerol
B)
phosphate
C)
triacylglycerol
D)
diacylglycerol
40.
41.
Page
9
8/17/2019 Cell Biology Test 3
10/11
extracellular
space
43.
44.
42.
Three
phospholipids
X,
Y,
and Z
are
dishibuted in
the
plasma
membrane
as indicated
in Figure
Ql1-14.
For which
of
these
phospholipids
does a
flippase
probably
exist?
Figure
Qf
l-14
A) Y andZ
B) XandY
C) X
only
D) Zonly
New
membrane
phospholipids
are synthesizedby
enzymes
bound to the
membrane.
side
of
the
A) luminal,
Golgi
B) extracellular,plasma
C) cytosolic,mitochondrial
D)
cytosolic,endoplasmicreticulum
Membrane
synthesis in the cell
requires
the
regulation
of
growth
for
both halves
of the
bilayer and
the
selective retention
of certain types
of lipids
on one side
or the other.
Which
group
of en4anes
accomplishes both
of these tasks?
A)
convertases
B)
glycosylases
C)
phospholipases
D) flippases
Membrane
curvature is influenced
by the differential
lipid
composition
of the
two membrane
monolayers.
Which factor
do
you
think
has
the largest impact
on
the curvature
of
biological
membranes?
A)
charge of
the
lipid
head
group
B)
length
of
the
hydrocarbon
tails
C) size of the lipid
head
group
D)
amount
of
cholesterol
46.
In
the
photosynthetic
archaean
Halobacterium halobium,
a
membrane transport
protein called
bacteriorhodopsin
captures
energy from
sunlight
and
uses
it to
pump protons
out
of
the
cell.
The resulting
proton gradient
seryes
as
an energy
store that
can
later
be
tapped to
generate
ATP.
Which
statement
best
describes how bacteriorhodopsin
operates?
A)
The
absorption
of
sunlight
triggers
a
shift in
the conformation
of
the
protein's
seven,
membrane
spanning a
helices,
allowing
a
proton
to
leave the
cell.
B) The absorption
of sunlight
triggers the
activation
of
an
enzyme
that
generates
ATP.
C)
The absorption
of sunlight
triggers
a
contraction
of the
b barrel that
acts as
the
protein's
central
channel,
squeezing a
proton
out
ofthe
cell.
D)
The
absorption of
sunlight triggers
a
restructuring
of bacteriorhodopsin's
otherwise
unstructured
core
to
form
the channel through
which
a
proton
can exit the
cell.
45.
cytosol
Page
l0
8/17/2019 Cell Biology Test 3
11/11
48.
47.
Plasma membranes
are
extremely
thin
and
fragile,
requiring
an
extensive
support network
of fibrous
proteins.
This network is called
the
A)
attachment
complex.
B)
spectrin
C)
cort€x.
D)
cytoskeleton
The lateral movement
of
transmembrane
proteins
can
be
restricted
by several different
mechanisms.
Which mechanism
best describes the
process
by which focal adhesions
are
formed
to
promote
cell
motilitf
A)
proteins
are
tethered
to
the
extracellular matrix
B)
proteins
are
tethered
to the
proteins
on the
surface
of
another
cell
C)
protein
movement
is limited by
the
presence
of a diffusion barrier
D)
proteins
are tethered to the cell cortex
The lateral movement of kansmembrane
proteins
can
be
restricted
by several different
mechanisms.
Which mechanism
best describes
the
process
by which
an
antigen-presenting
cell tiggers
an
adaptive
immune
response?
A)
proteins
are
tethered
to
the
extracellular
matrix
B)
proteins
are
tethered to
the
proteins
on the surface
of
another
cell
C)
protein
movement
is limited
by the
presence
of a diffirsion barrier
D)
proteins
are tethered
to
the
cell cortex
Diversity among
the
oligosaccharide
chains found in the
carbohydrate coating
of the cell
surface
can
be
achieved
in which of
the
following
ways?
A)
varying
the types of linkages
between
sugars
B)
varying the number
of branches in
the chain
C)
varying the types of
sugar
monomers used
D) all
of the above
49.
50.
Page I I