0.
Ke Conc Concep epts ts 10.1 10.1 Phot Photos osyn ynth thes esis is conv conver erts ts ligh ligh ener energy gy to th chem chemic ical al ener energy gy of food food .2
he ligh ligh acti action on nv rt ol th chem chemic ical al ener energy gy of an
er
10.4 10.4
vi to conv conver er
le es to suga suga
lter lterna nati tive ve ve ev lv
nd
echa echani nism sm of carb carbon on fixa fixati tion on in ho ri li ates ates
to
Framework PHOTOSYNTHESIS rl-li-gl-lt-e-n-er-g~~~1 into
in whic whic
in whic whic
reduce + t
to form form to genera generate te
apte apte
evie evie
verte verte int chem chemica ica energ energ stored stored in organ organic ic molec molecule ules. s. Orga Organi nism sm obta obtain in th orga organi ni olec olecul ules es they they requ require ire fo erot erotro roph phic ic nutr nutrit itio io utot utotro roph ph "fee "fee them themse selv lves es in th th ke th ir ic le le from from inor inorga gani ni ra mate materi rial als. s. Plan Plants ts alga algae, e, so othe othe protist protists, s, an some some prokar prokaryo yotes tes are photo photoau autot totrop rophs hs tr ts anim animal al ec po ic litt litter er al al ar ulti ulti atel atel depe depend nden en on phot phot auto autotr trop op fo food food and oxyg oxygen en
generat;
.1 to th
l-- to
to thes thesis is co rt ical ical rg fo
lo plas plasts ts in rb th li CO ters ters an
li
er
inly inly in th es ph ti lo ll th th rg th iv ph to th is exit exit th leaf leaf thro throug ug stom stomat ata. a. Vein Vein
suga suga to nonp nonpho hoto tosy synt nthe hetic tic tissu tissue. e. surr surrou ound ndin in ense ense flui flui call called ed th stro stro an an elab elab orate orate memb membran ran syste syste called called thylako thylakoids ids enclo enclosin sin the
73
eC
thylakoi lakoi
space.
Usin evidence from bacteria that-ntilize hydrogen fi (H esiz at ll to ic is ydroge so rc an that plants spli wate as source electron from hydrogen releasin oxygen Scients fi this th is
membrane.
Labe th
nd cate
pa ts
th
diag am of
ch oroplast
a.
es wa r, ra ca dioxide, containe th labele oxygen hotosynthesi is redo proces like respiratio ff re io tr low. tron increase thei pote tial ener when they travel vide this energy
-
Solar rg rt into ca rg light reactions. Light energy absorbed by chlorophyl drives -
xyge
Inquiry
If ly th sidere th equati of respiration
CO
io wa fo ph tosy thesis is th re erse
an te porarily stores ener ized electr ns is released when wate is split. is formed
proces called photophosphorylation. In th Calvin cycle, carbon dioxid is incorporated into existi orga ic co unds carb fixati co re re rb
12
eede
fo th
al in cycle.
INTE Fill in th blanks in this overview of photosynthesis in
chloroplast. Indicate th location of th
processe c.and h.
C h p t r 1 0 P ho t .2 li ti ener to th chemical ener andNADPH
nt
75 re
la
lines different?
lectro neti ener also called electromagneti radiation, travel as rhythmic wa isturbance electrical an ag etic fi lds. Th distance between th crests of th electromagnetic th ir wa le th th ro neti pectru from rt am wa es to long ll ia io 80to 750nm is called visi le li t. Ligh also behave as if it consists of discrete particlescalled phot ns whic ve fi ed quantity en er .Th nt nerg in ph to is in er el re lated to its wavelength.
.
.
. .
. .....
av Absorption
ergy orange (620 nm
lu (480 nm)?
ac on spec ra
or ph os nthesi
hy
le
sp ctroph to et asur th am ts li differen wavelength absorbed by pigment. he ab sorption spectrum of chlorophyl a, th pi en th participates directly in th ligh reactions, show that it ab rb iolet- lu an re li est. cces ry pi ment such as chlorophyl an so carotenoid ab li if wa th th tr rs So in photosynthesis carotenoids functio in photoprotection by absorbin excessiv ligh energy that ight da ag chlorophyl inte wi to iv le le (Thesepigment act as antioxidants.)
ac io spec rumshows he rela iv si
an
ra es of photosyn
le
to
where it
are absorbed. it tate is ta le le th tr to ts tate bital. Isolate chlorophyll molecule als emitphotons of light, called fluorescence as thei electron return to ground state
Light-Harvesting
Phot systems, locate Complexe in th thylak id em ra e, ontain umbe li trv stin co pl es nd reacti center protei complex wit two special chlorophyl molecules and cule in th
li t- ar esti is
co pl ig
sorb to ig
ph to ti
oncy li is re
ro
lakoid membra
le tr
excite el ctro of P6
ly te to in ph to yste II is tr pp
te he hl ro hyll
I) is di tely
chlorophyll
lo
molecule called P700
Describe th components of
photosystem.
mbin ry le tr
thesis of ATP.
it an th
ox ge to
tr
to
rm 02'
is
le tr phot ex it el ctro acceptor This primar
th
to to apture by it rimary le tr electron acceptor passes th elec
erredoxi (F ), fr whic th enzyme AD redu tase transfer electron to NADP+. (Revie this electron path by completing Interactiv Question 10.6.)
Fi in th step ncycli electr fl th diagra belo hemica nerg an reducing powe to th Calvin cycl
Circleth
importan
pr
ucts th
il
usedto
rovi
Chapter 10: li th
to th
re po
plie to
tr
lo
le
le is generated. Th Calvin cycl requires an th itio th li lo electr er ps in il
III
to
electron flow
to suga
Th Calvin cycl turn thre times to fixthre olecules an prod ce on olec le of th three-carbon suga glyceral ehyde- -p osphat (G P) he cycl ivid
Ca xa CO sugar, ribulose bisphosphate (RuBP) in
Mitochondria
Chemiosmosis in it chon ri an in chloroplasts is very similar. Th ke difference is that in respiration, chemical energy from food is transferre to formed to th chemical energy of TP In chloroplasts th electron transp rt chai pu ps
fo th Calvi cycle
tr
si
wh re it is
il
le fo th
(r bisco)
he
nsta le si -carbo
reactio
intermediate
3-phosphoglycerate.
2 . R ed uc t o n
Each
olecul
of 3-phosphoglycerate
bisphosphoglycerate. Tw electron fro
olecul
NADP
of G3 -.
C O a c c ep to r ( R uB P ) : The rearrangefi le le into th thre le cule of RuBP requires thre re P. in le ix quired to synthesize ne 3P (Torevie this pr cess pl te th ry ia ra th al in le in Interactiv Questio 10.9.
78
Un
T wo : T h C e
ro
ro
cy
a.
CALVIN CYCLE
j.
b.
c.
n.
10.4 Alternativ mechanis carbon fixation have evolve in hot, arid climates plants thes
In enters th al in cycl an th firs prod fi ti is ph ph ly te pl ts lo th ir to ta t, to
late -i"]
CO co poun
isco
leaves th chloroplas an
called photorespiration.
What possible explanatio is ther fo photorespiration roce sth sof th carbon ixed in he Ca vi cycle?
is brokendown
Plants
In
plants, CO is firs adde
to 3-carbon The
ap resultin four-carbo ph ll cell th le ls ti tl ke ti th
co poun formed in th esois tran port to le-sheat th in th le creating ig th is will an initiate th alvi cycle.
mesomiddle (mesophyll: th le in id leaf (photosystem: cules)
Structure cl
ke
nt re
ti su in th
id
Knowledge
YOU:':
lr ll la ks gr ph tosy th si re ll dersta this process, however, yo should create your ow pr ti ia ti tlin th ke events of photosynthesis Trac th flow of le tr th to te th pr ctio Pan PH th li reacti
plants?
plants successfull perfor th Calvin cycl plan woul be undergoing photorespiration?
aj step in th pr du ti te wher th ti in th lo pl t. co pare creati to th sk tc in th an we
CA
Plants
Many succulen plants clos thei stom in plants brea
it into variet of organi acids. thes co ig th in le like th pathway, th ta li (C th does no structurally separate carbon fixation from th Calvin cycle; instead, th tw processe ar separate in time. Th Importanc About 50%
of Photosynthesis: th
ic
th it ia la bo skeleton fo synthesi starch, or lost throug
Review
te ia ll th of organi
is tolecules (pro
photorespiration. Abou 160 bil-
duced by photosynthesis
ur ia ra er ap in severa repres tation su ar of this chapter. 2.
Test Your Knowledg MULTIPLE CHOICE: C ho o
auto-
self;-troph
a ns we r
a. light reactions-grana electr
tran port chain-th lakoid
em ra
c. Calvin cycle-stroma d. ATPsynthase-double chloroplast te
is re
ce
P+ is re
food (autotroph: an organism that
other organisms) chlorogreen; -phyll leaf (chlorophyll: photosyntheti pigment in chloroplasts) electroelectricity; magnetmagnetic (electromagn e ti c s pe c tr um : th entire spectrum of radiation) heteroother (heterotroph: an rganis that tain organi food olecules by eating othe organism or their by-products
he on be
location?
2. Photosynthesis is
ot
ro ca co cl ar co cise
reat concep ap to confir your understand in th he io ti thesis in ph tophosphorylation.
littin
or
tu into
embran
surroundin
koid redo proces in whic
an
wate is
ce
ADP+ an
nd RuBPis
idiz
wate ar reduced.
d.
tsas id zi reducing agent.
e.
is re ce is oxidized.
an
idiz
wate th electr
ts
tr nsport ch in
Unit
80
"holes filled by electron from
fore blue ligh as
lo
wa te wa
co
in
a. photosystem
re en
b. phot system II
ed ig
re
c. water.
ed ig
d. NADPH. re
light.
e. accessory pigments.
e. is absorbed faster by chlorophyl a. spectr photometer ca
se
a. th absorption spectr b. th acti
easure
perf rmin
substa ce
of isible li ht
ab ig
th splittin
an
wate
in
e.
le 68
10
th 70
create
lakoid force.
ri ig duri th da
al in cycl at night. co poun in th
in th le
ra
ee
th ir to at
cl
in
th
lectrons that flow thro gh th tw hotosystem have thei highes otential energy in a. water.
chlorophyl afte photoexcited electron pass to NADP+. ro proton-motiv
by
d. usin carb xylate tofixCO to ribulos bisphosphate (RuBP).
olec les.
fferen en rg
th
ci
into four-carbo ll whic el as cells.
sheat
for
a. drivin
hotorespiratio
ixin into rg ic thes acid then releas
e. th efficiency of photosynthesis. sponsibl
lant av id
su stance
spectrum
th wavele gt
to
9.
to
e. anch ring chloro hyll center. Be rp io ec ru fo kn wn pigmen olecule. What colo woul this pigmen ap ea to you?
68 c. NADPH. d. th electron transpor chain. e. photoexcited P700 ts provided with
ak
ar
ra
rk if
Pan b. an artificially induce
proton gradient
c. organi acid or four-carbo
co pounds
source of hydrogen
th io ic plast, H+diffuses throug fr
is th
ro
b. fr
chloro TPsynthase koid
ac
th th lakoid spac into th stro a.
c. from th intermem rane spac into th
atrix.
fl
space. fr a.
iole
c.
lu
d. yellow
re
7. Noncycli electron flow alon with chemiosmosis in th chloroplas result in th production a. ATPonly. ~~
Pan
:;.:.'~
':
atri into plants th
ro
alvi cycl
ke b.
nl
cc rs when th stomat
c. take plac in th d. take plac in th
esophyll cells. undle-sheath cells.
e. uses PE carboxylas instea it greate affinity fo
c.
Pan
d.
TPan
e.
TP,NADPH an 02'
02'
ar closed
of rubisc becaus
Chapter 10:
produc
on
olecul
c. chloroplas d. trom hloroplast
glucose?
cyclic electron flow
15.
proteins cytoplasmi streaming, an othe cellular activities come directly from
produc
by cyclic elec ro
port hain is no in olve d. oxidativ
flow
in cyclic elec ro
fl w.
phosphorylation.
e. photophosphorylation.
a. th ee
ol cule of gluc se toNADPH
3-phosphoglycerate. d. on G3 an
synthesi
th ee our-ca bo
an respiratio
he el ct on ransport
e. ransfe el ct on from phog ce at to roduce G3
in ermediates
tosynthesi
is that in phot synthesi
a.
hain
to 1,3-bispho
an in cellular respiration?
in bo in both
c.
in respiration D+ or AD
re pi at on in respira-
from th oxidatio proton-motiv ofATP.
foo molecules
forc drives th phosphorylatio
tion Us
h e o ll ow in g
indicate if th
o r q ue s o n
ol owin
23
even
h ro ug h 2 8
occu du in
b. photosynthesis needed
bo
espira io
d. neithe respiratio
an photos nthesi no photosynthesis
aldehyde-3-phosphate). glucose.
fC
fN
a. nucleu b. cytoso
