cell biology test 3

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


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


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


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


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


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


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


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.


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


8/11

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.

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8


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.


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

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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


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

cell biology test 3

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