PHOTOSYNTHESIS IN HIGHER PLANTS Flashcards
1
Q
PHOTOSYNTHESIS
A
ANABOLIC ENDERGONIC OXIDO REDUCTION
2
Q
EQUATION
A
6CO2 + 12H2O –> C6H12O6 + 6H2O + 6O2
3
Q
% OF DRYMATTER FROM LAND
A
10
4
Q
STARCH PRESENCE
A
BLUE - WITH IODINE
5
Q
KOH USE?
A
ABSORBS THE CO2. USED IN THE EXP TO PROVE THAT CO2 IS NECESSARY FOR PHOTOSYNTHESIS ( MOLL HALF RKN)
6
Q
PRIESTLY
A
1774 - DISCOVERED O2,
KILLED A MOUSE ( SUFFOCATION )
CANDLE EXTINGUISHED
USED MINT PLANT - MOUSE LIVES, CANDLE LIVES
PLANTS RESTORE THE AIR THE MOUSE AND CANDLE REMOVE
7
Q
INGELHOUSZ
A
SUNLIGHT IS ESSENTIAL
- USED HYDRILLA
- NO BUBBLES IS FORMED (IN DARK)
- IN PRESENCE OF SUNLIGHT IT IS ONLY GREEN PARTS OF PLANT WHICH WILL RELASE O2
8
Q
VON SACHS
A
GREEN PARTS - STARCH IS STORED ( CHLOROPHYLL)
9
Q
ENGLEMANN
A
- CLADOPHORA
- SPECTRUM OF LIGHT + AEROBIC BACTERIA( TO DETECT PRESENCE OF O2 EVOLUTION)
- BLUE AND RED LIGHT WAS THE HIGHEST
- GREEN WAS LEAST
10
Q
VAN NIEL
A
PURPLE AND GREEN SULPHUR BACTERIA
H2 RELEASED IS USED TO OXIDISE CO2 TO CH2O
- O2 IS FROM H2O AND NOT FROM CO2
11
Q
RUBEN, KAMEN AND HASSID
A
USED NON RADIOACTIVE, STABLE ISOTOPE OF OXYGEN(O18)
12
Q
PAR Full Form
A
PHOTOSYNTHETICALLY ACTIVE REGION
13
Q
RANGE OF WAVELENGTH
A
400 - 700nm
14
Q
Chlorophyll in the ?
A
mesophyll cells
15
Q
thylakoids
A
third system of membranes in chloroplasts
16
Q
granum
A
stack of thylakoids
17
Q
grana is connected to another by
A
stroma lamallae
18
Q
fluid compartment
A
stroma
19
Q
stroma rkns
A
enzymatic rkn which synthesis sugar and convert to starch
20
Q
CHLOROPHYLL-A
A
BLUE GREEN
21
Q
CHLROPHYLL B
A
YELLOW GREEN
22
Q
CARETOINDS
A
ORANGE YELLOW
23
Q
XANTHOPHYLLS
A
YELLOW
24
Q
CHLORPHYLL TWO PARTS
A
PORYPHRIN HEAD & PHYTOL TAIL, chlorphyll pigment looks like a tadpole
25
PORPHYRIN HEAD
HAS CYCLIC TETRAPHYROLIC STRUCTURE AND WITH NON IONIC MG ATOM
26
PHYTOL TAIL
HAS HYDROPHOBIC PORTION
TAIL ATTACHED TO RING STRUCTURE
27
ACCESORY PIGMENTS
ALL THE PIGMENT OTHER THAN CHLOROPHYLL A
28
why do chloroplasts align themselves vertically along the lateral walls of the mesophyll cells?
This is done under high light intensities so as to protect themselves from photo oxidation. this is also done to easily diffuse gases, and to receive optimum quantity of light.
29
absorbs the light of diff wavelength and transfer the energy to the chlorophyll molecules is called _________
antenna molecules
30
carotenoids protect the plant from heat and photo oxidn and so it is called _________
shield pigment
31
max photoysnthesis at ______
chlorphyll a
32
ps 1
P700
- found in the grana and stroma lamellae
- lies on the outer surface of thylakoids
- participates in cyclic and non cyclic flow of electrons
- no role in splitting of h20
33
ps2
P680
- only grana lamellae
- inner surface of thylakoids
- only non cyclic flow of electrons
- splitting of h20
34
complexes of harvesting molecules
LHC (Light Harvesting Complexes)
35
ARNON
used assimalatory powers for nadph and atp. NADPH is reducing power
36
photophosphylation
process of formation of ATP from ADP and inorganic phosphate ip utilising light energy
37
ets
the process of reduction of NADP+ into NADPH and H+ is called ets
38
redox potential
measure of tendency of chemical species to acquire e- and get reduced
39
cyclic
only PS I is involved
- can happen only with light beyond 680 nm
- NADPH and H are not produced.
- synthesises ATP only
- operates under low intensity of light, anaerobic conditions, low co2
- occurs in stroma lamellae
- doesn't take part in photosynthesis except in some bacteria
40
non cyclic
PS I and II take part
- happens in granal thylakoids
- required an external e donor
- NADPH and H are produced
- takes place under optimum light, aerobic conditions
- connected with photolysis of water and liberation of oxygen occurs
- PASSES THRU ets of cytochromes
(NON CYLCIC ALSO CALLED AS Z SCHEME )
41
who proposed z scheme
hill and bendall
42
chemiosmotic hypothesis
explained by P Mitchell
explains how ATP is synthesised in the chloroplast and how it is linked to the development of a proton gradient across the membrane of the thylakoid
43
what leads to development of proton gradient
Photolysis of water towards thylakoid lumen
2. Transfer of H from stroma to lumen as electrons move towards photosystems, via electron carriers
3. NADPH reductase happens towards the stroma and it requires H+
- decrease in ph of the lumen
44
ATPase enzyme
this enzyme consists of two parts
1. CF0 this is embedded in the membrane and forms a transmembrane channel that carried out facilitated diffusion of protons across the membrane
2. CF1 this protrudes on the stroma side of the membrane
45
REQUIREMENTS
1. a proton pump which pumps protons across the membrane into the lumen
2. ATPase enzyme which has CF0 part, which provides a transmembrane channel for facilitated diffusion of protons across the membrane
3. Proton gradient
4. A membrane.
46
wHERE IS OEC LOCATED
INNER THYLAKOID
47
OEC FUNCTION
OXYGEN EVOLVING COMPLEX HELPS IN SPLITTING OF H2O
48
CALVIN CYCLE PROCESS
it is a five carbon ketose sugar called ribulose biphosphate or RuBP. The enzyme for CO2 fixation is ribulose biphosphate carboxylase oxygenase which can bind both CO2 and O2. It is the most abundant enzyme on earth. It has a higher affinity for CO2 than for O2. BE4 they discoverd rubisco they thought it would be 2 carbon compound since it was a c3 cycle
49
diff process in c3 cycle
1. Carboxylation- Rubisco catalyses the carboxylation of RuBP by CO2
2. Reduction- formation of glucose
3. Regeneration- regeneration of CO2 to continue the cycle
in- 18 ATP, 12 NADPH, 6 CO2
out- 18 ADP, 12 NADP, 1 glucose
50
features of c4
1. dry tropical plants
2. special leaf anatomy - kranz
3. can tolerate higher temperatures
4. do not undergo photorespiration
5. have bundle sheath cells
6. can tolerate saline conditions due to the presence of organic acids which lowers their water potential
7. can perform photosynthesis even when their stomata are closed due to presence of CO2 fixing enzyme pepcase
8. concentric arrangement of cells in leaf produces a smaller area in relation to volume for better water usage
51
bundle sheath
1. have large number of chloroplasts
2. have thick walls impervious to gaseous exchange
3. no grana
4. no intercellular spaces
this is called kranz anatomy, kranz means wreath
52
c4 pathway also called
hatch slack pathway
53
the plants in c4
sugarcane, maize, sorghum, amaranthus
54
initial product
double fixation of co2 occurs
- 4 C compound - OAA formed in mesophyll converted to malic or asparatic in the mesophyll cell itself
55
c4 process explanation
primary acceptor of co2 - PEP9 phosphoeol pyruvate) - mesophyll cells
56
co2 fixation enzyme
PEPcase
57
co2 is broken in
bundle sheath cells
58
CO2 released undergoes
c3 cycle
59
what does mesophyll and bundle sheath cells lack
mesophyll lacks rubisco and has PEPcase
bundle sheath lacks PEPcase and has abundant rubisco
60
3 carbon compound formed in bundle sheath is transported to
mesophyll where they are converted to PEPcase by PEPsynthetase, regeneration requires 2 ATP
61
atp consumed
2 in c4 cycle
3 in c3
total : 5 per co2
since 6 co2 is used so 30 ATP is consumed
62
photorespiration
this is a process involving the loss of CO2 and is initiated in the chloroplasts
when there are high concentration of O2 rubisco acts as an oxygenase and binds to o2 so decreasing CO2 fixation. 1 molecule of PGA and phosphoglycolate(2C) is formed.
this results in the release of co2 with utlisation of ATP.(25% loss)
o2 is first utilized in chloroplast and then in the peroximes
63
why doesnt it occur in c4
these plants have a mechanism which increases intracellular co2 concentration. when c4 acid is broken down in bundle sheath cells it realeases co2 forcing rubisco to act as a carboxylase.
64
3 organelles involved in the c2 cycle or photorespiration
mitochondria - co2 is lost
chloroplast
peroximes
64
65
law of limitng factors
blackmann 1905
it states that
if a chemical process in affected by more than one factor, it's rate will be determined by the factor that is closest to it's minimal value.
66
oxygenic photosynthesis
used as a source of reducing power in cyanobacteria. photolysis of water results in release of O2 as a by product and as it involves oxygen release it is called oxygenic.
example Oscillatoria
67
anoxygneic photosynthesis
in bacteria evolution of oxygen has not been demonstrated as they can't use water. they use H2S instead.
68
carotenoids absorb which fractions of the visible spectrum of light?
violet and blue
69
which is the first electron acceptor in PS I?
iron sulphur protein
70
which complex of mitochondrial ETS possesses two copper centres?
complex 4
71
The LHC are made up of hundreds of pigment molecules bound to ________
proteins
72
how many molecules form the reaction centre
1 molecule of chloropjyll a
73
In chemiosmosis, the primary acceptor of electron transfers its electron to?
H+ carrier
74
By which transport method does the CF(0) of ATP Synthase carry protons back to stroma?
facilated diffusion
75
How many molecules of PGA are produced upon the fixation of 1 molecule CO2?
2
76
Plants of which region show C4 Pathway?
dry tropical
77
Photosyntheic number?
also caled as assimalation number
- relation btw the chlorophyll and photosyntheis
78
variagated leaves
croton
