Name:Far
zeenSami
Rol
lNo.08
Subj
ect
:Phy
si
ol
ogy
Topi
c:Tr
anspor
tAcr
osst
heCel
lmembr
ane
Submi
t
t
edt
o:Dr
.ToobaZaf
ar
Q1.Di
f
f
er
ent
i
at
ebet
weensi
mpl
eandf
aci
l
i
t
at
eddi
f
f
usi
on.
Si
mpl
eDi
f
f
usi
on
Faci
l
i
t
at
edDi
f
f
usi
on
I
ti
sanunassi
st
edt
y
peof
di
f
f
usi
oni
nwhi
chapar
t
i
cl
e
mov
esf
r
om hi
ghert
ol
ower
concent
r
at
i
on.
I
ti
st
het
r
anspor
tofsubst
ances
acr
ossabi
ol
ogi
cal
membr
ane
t
hr
oughaconcent
r
at
i
ongr
adi
ent
bymeansofcar
r
i
ermol
ecul
e.
Occur
st
hr
ought
hephosphol
i
pi
d Occur
st
hr
ought
r
ansmembr
ane
bi
l
ay
er
.
pr
ot
ei
ns.
Tr
anspor
tsmal
l
,
nonpol
ar
par
t
i
cl
es
Tr
anspor
tl
ar
ge,
pol
arpar
t
i
cl
es.
Occur
sdi
r
ect
l
yt
ot
hecel
l
membr
ane
Occur
st
hr
oughspeci
f
i
c
f
aci
l
i
t
at
ormol
ecul
es
Rat
eofdi
f
f
usi
oni
sdi
r
ect
l
y
Rat
eofdi
f
f
usi
ondependsont
he
pr
opor
t
i
onal
t
ot
heconcent
r
at
i
on
ki
net
i
csofcar
r
i
ermedi
at
ed
gr
adi
entandt
hemembr
ane
t
r
anspor
t
.
per
meabi
l
i
t
yoft
hesol
ut
e
mol
ecul
e
Exampl
es:
Di
f
f
usi
onofgases
Exampl
es:
Count
er
t
r
anspor
tof
acr
osst
her
espi
r
at
or
y
membr
ane,
di
f
f
usi
onof
mol
ecul
esf
r
om bl
oodt
ot
he
chl
or
i
de/
bi
car
bonat
ei
nr
enal
t
ubul
arcel
l
s,
cot
r
anspor
tof
sodi
um wi
t
hsugar
sl
i
kegl
ucose,
cel
l
st
hr
ought
hei
nt
er
st
i
t
i
al
f
l
ui
d. gal
act
ose,
et
c.
……………………………………………………………………………………………
………………………………………………………………………………….
Q2.Di
f
f
er
ent
i
at
ebet
weenpr
i
mar
yandsecondar
yact
i
v
e
t
r
anspor
t
.
Pr
i
mar
yact
i
v
et
r
anspor
t
Secondar
yact
i
v
et
r
anspor
t
I
ti
st
het
r
anspor
tofmol
ecul
es
agai
nstaconcent
r
at
i
ongr
adi
entby
t
heuseofener
gyf
r
om ATP
I
ti
st
het
r
anspor
toft
wodi
f
f
er
ent
mol
ecul
esacr
ossat
r
anspor
t
membr
aneusi
ngener
gyi
not
her
f
or
mst
hanATP
Asi
ngl
emol
ecul
ei
st
r
anspor
t
ed
Twot
y
pesofmol
ecul
esar
e
t
r
anspor
t
edatonce
Usesener
gyf
r
om ATP
Concent
r
at
i
ongr
adi
entoft
hedr
i
v
i
ng
i
onpr
ov
i
dest
heener
gyf
ort
he
t
r
anspor
tofdr
i
v
eni
on/
mol
ecul
e
agai
nsti
t
sconcent
r
at
i
ongr
adi
ent
I
onl
i
kesodi
um,
pot
assi
um &
cal
ci
um ar
et
r
anspor
t
edacr
osst
he
cel
l
membr
ane
I
onsser
v
easdr
i
v
i
ngmol
ecul
es,
Whi
l
ei
onsorot
hermol
ecul
esser
v
e
asdr
i
v
enmol
ecul
es
Tr
ansmembr
anepr
ot
ei
nsar
euni
que Sy
mpor
t
sandant
i
por
t
sar
et
het
wo
t
ot
hei
ont
r
anspor
t
edt
hr
ought
hem
t
y
pesoft
r
ansmembr
anepr
ot
ei
ns
Sodi
umpot
assi
um pump,
cal
ci
um
pumpi
nmuscl
es,
andpr
ot
onpump
i
nst
omachar
eexampl
es
Gl
ucosesodi
um pump,
Na+/
Ca2+
exchanger
,
andsodi
um/
phosphat
e
cot
r
anspor
t
erar
eexampl
es
………………………………………………………………………………….
…………………………………………………………….
.
Q3.Di
scusst
het
y
pesofsecondar
yact
i
v
et
r
anspor
t
.Gi
v
e
t
woexampl
esofeacht
y
pe.
Ty
pesofSecondar
yact
i
v
et
r
anspor
t
:
A:Ant
i
por
t
:
Ant
i
por
torCount
er
t
r
anspor
tmeanst
hat2di
f
f
er
entmol
ecul
esor
i
onsar
ebei
ngt
r
anspor
t
edatt
hesamet
i
mebutopposi
t
edi
r
ect
i
ons.
Oneoft
hespeci
esi
sal
l
owedt
of
l
owf
r
om hi
ghconcent
r
at
i
ont
oa
l
owerconcent
r
at
i
on(
of
t
enSodi
um)whi
l
et
heot
herspeci
esi
s
t
r
anspor
t
edsi
mul
t
aneousl
yt
ot
heot
hersi
de.
Exampl
es:
Na+Ca2+count
er
t
r
anspor
twher
eNa+bi
ndst
ot
het
r
anspor
tcar
r
i
er
pr
ot
ei
noni
t
sext
er
i
orsi
de,
andCa2+boundt
ot
hesamepr
ot
ei
nont
he
membr
anesi
nt
er
i
orsi
de.Oncebot
har
ebound,
aconf
or
mat
i
onal
changeoccur
swhi
chr
el
easesener
gyandt
hesodi
um i
oni
s
t
r
anspor
t
edt
ot
hei
nt
er
i
orandcal
ci
um t
ot
heext
er
i
or
.Thi
st
r
anspor
t
er
i
ssi
t
uat
edonal
mostal
l
cel
l
membr
anes.
Na+H+count
er
t
r
anspor
t
.Themechani
sm i
st
hesameast
he
pr
ev
i
ousexampl
e.Howev
ert
headv
ant
ageoft
hi
st
r
anspor
t
eri
scl
ear
l
y
seeni
nt
hepr
oxi
mal
t
ubul
esoft
heki
dney
s.Themechani
sm f
or
concent
r
at
i
ngH+i
snotnear
l
yaspower
f
ul
asPr
i
mar
yact
i
v
et
r
anspor
t
,
howev
eri
tcant
r
anspor
text
r
emel
yl
ar
genumber
sandt
husmaki
ngi
t
akeyi
nH+homeost
asi
si
nt
hebody
.
B:Sy
mpor
t
:
Sy
mpor
tor"
Cot
r
anspor
t
"meanst
hatamol
ecul
ei
sal
l
owedt
obe
t
r
anspor
t
edf
r
om hi
ght
ol
owconcent
r
at
i
onr
egi
onwhi
l
emov
i
ng
anot
hermol
ecul
ewi
t
hi
tf
r
om l
owt
ohi
ghconcent
r
at
i
on.I
ti
nf
acti
s
pul
l
i
ngt
heot
hermol
ecul
ewi
t
hi
ti
nt
ot
hecel
l
.
Exampl
es:
Sodi
umGl
ucosecot
r
anspor
tmechani
sm.Oni
t
sext
er
i
orsi
det
he
t
r
anspor
tpr
ot
ei
nhas2bi
ndi
ngsi
t
es,
onef
orsodi
um andonef
or
gl
ucose.Whenbot
hoft
hesebi
ndt
ot
hepr
ot
ei
nt
her
ei
sa
conf
or
mat
i
onal
changeal
l
owi
ngt
heel
ect
r
ochemi
cal
gr
adi
entt
o
pr
ov
i
det
heener
gyneededt
ot
r
anspor
tbot
hoft
hesemol
ecul
esi
nt
o
t
hecel
l
.
Sodi
umAmi
noaci
dcot
r
anspor
toccur
si
nt
hesamemannerasf
or
gl
ucose,
exceptt
hatusesadi
f
f
er
entsetoft
r
anspor
tpr
ot
ei
ns,
howev
eri
t
smechani
sm i
st
hesame.
…………………………………………………………….
……………………………………….
.
Q4.Def
i
ner
est
i
ngmembr
anepot
ent
i
al
.
Ans:
I
ti
sanel
ect
r
i
cal
pot
ent
i
al
di
f
f
er
encewhi
chexi
st
sacr
osst
he
membr
anesofv
i
r
t
ual
l
yal
l
cel
l
soft
hebodyi
nt
her
est
i
ngst
at
ei
.
e
wheni
ti
snotbei
ngst
i
mul
at
e.I
ti
snegat
i
v
ei
nsi
dewi
t
hr
espectt
o
posi
t
i
v
eout
si
det
hecel
l
membr
ane.I
ti
snotequal
i
nal
l
cel
l
s.
…………………………………………………….
.
……………………
……………………………………………….
Q5.Di
scusst
hef
act
or
sr
esponsi
bl
ef
ormai
nt
enanceof
RMP.
Ans:
A:
Theconcent
r
at
i
onofi
onsont
hei
nsi
deandout
si
deoft
hecel
l
B:
Theper
meabi
l
i
t
yoft
hecel
l
membr
anet
ot
hosei
ons(
i
.
e.
,
i
on
conduct
ance)t
hr
oughspeci
f
i
ci
onchannel
s
C:
Byt
heact
i
v
i
t
yofel
ect
r
ogeni
cpumps(
e.
g.
,
Na+/
K+ATPase
…………………………………………………………
…………………………………………….
.
Q6.Namet
heequat
i
onuset
ocal
cul
at
et
hedi
f
f
usi
onofa
si
ngl
ei
onacr
osst
hecel
lmembr
ane.
Ans:NERSTequat
i
oni
susedt
ocal
cul
at
et
hedi
f
f
usi
onof
asi
ngl
ei
onacr
osst
hecel
l
membr
ane.
……………………………………………………….
………………………………….
Q7.Namet
heequat
i
onuset
ocal
cul
at
et
hedi
f
f
usi
onof
mor
et
hanonei
onacr
osst
hecel
lmembr
ane.
Ans:GOLDMANHODKI
NGKATZequat
i
oni
suset
o
cal
cul
at
et
hedi
f
f
usi
onofmor
et
hanonei
onacr
osst
he
cel
l
membr
ane.
………………………………………………
…………………………….
.
Q8.Cal
cul
at
et
hedi
f
f
usi
onpot
ent
i
alofsodi
um usi
ng
Ner
nstequat
i
on.
Ans:
Ner
nstpot
ent
i
alf
orsodi
um:
Ner
nstpot
ent
i
al
(
mv
)=61l
og(
Concent
r
at
i
oni
nsi
de÷Concent
r
at
i
on
out
si
de)
Ner
nstpot
ent
i
al
(
mv
)=61l
og(
14÷142)
Ther
at
i
oi
s0.
1&t
hel
ogof0.
1i
s1.
1X61mv
=+
61mv
……………………………………………………………………….
.
……………………………………………….
Q9.Cal
cul
at
et
hedi
f
f
usi
onpot
ent
i
alofpot
assi
um usi
ng
Ner
nstequat
i
on.
Ans:
Ner
stPot
ent
i
alf
orPot
t
asi
um:
Ner
stpot
ent
i
al
(
mv
)=61l
og(
Concent
r
at
i
oni
nsi
de÷
Concent
r
at
i
onout
si
de)
Ner
stPot
ent
i
al
(
mv
)=61l
og(
41÷4)
=61(
1.
54)
=94m v
Q10.Howmuchpot
ent
i
ali
scont
r
i
but
edbyNaKpumpi
n
RMP?
Ans:Thecombi
nedpot
ent
i
al
ofpot
assi
um andsodi
um i
s
cal
cul
at
edbyGOLDMANHODGKI
NKATZi
s86mv