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biology IB > C1.3 photosynthesis > Flashcards

C1.3 photosynthesis Flashcards

1
Q

general symbol equation photosynthesis

A

6CO2 + 6H20 -> C6H12O6 + 6O2
use of chlorophyll

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2
Q

define photosynthesis

A

transformation of light energy into chemical energy in the form of organic compounds

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3
Q

2 stages of photosynthesis

A

light dependent reaction
light independent reaction

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4
Q

explain in detail stages of photosynthesis

A

LDR-
photolysis of water, h2o reactant o2 is the waste product
photoactivation
and more, where their products are used in LIR
LIR-
co2 is also added and used in calvin cycle to make glucose

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5
Q

describe structure of leaf

A

waxy cuticle
upper epidermis
palisade mesohpyll- packed chloroplasts
vascular bundle= xylem on top and phloem on bottom
spongy layer
lower epidermis; stomata and guard cells

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6
Q

describe chloroplast strucutre

A

outer memebrane
inner membrane
stroma (like matrix)
circular DNA
lamelae= “bridge””
thylakoid- thylakoid lumen + thylakoid membrane, many thylakoids make up a grana (or granum plural)
70s ribosome

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7
Q

what is inside thylakoid membrane

A

PSII
ETC
PSI

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8
Q

describe overall LDR

A

occur on the thylakoid membranes
photolysis of water
photophosphoralation
in: H2O and NADP+
out: O2 NADPH

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9
Q

describe overall LIR

A

occur in the stroma of the chloroplast
carbon fixation
calvin cycle
synthesis of carbohydrate
in: co2 NADPH
out: glucose phosphate NADP+

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10
Q

describe steps in LDR

A
  1. photoactivation of PSII- chlorophyll in PSII absorbs light, light energy taises the energy level of electrons in chlorophyll= photoactivation electrons in photosystem 2 are activated by light
  2. photolysis of water- photoactivated electrons are passed along membrane by electron carriers, electrons replaced through photolysis of water
    hydrogen ions accumulate in thylakoid lumen oxygen is waste product
  3. electron transport chain- energy from photoactivated electron is used to pump protons across thylakoid membrane
  4. photoactivation of PSI= same as step 1

5.NADPH production- NADP+ id reduced into NADPH
electrons are received by ferrodoxin (NADP reductase) and used to reduce NADP with a H ion
NADPH carried to LIR, conc gradient of H protons is maintained
electrons are replaced by electrons lost by PSII, as electrons used for reduction

  1. formation of electrochemical gradient- hydrogen ions accumulate in thylakoid space, generate high H ions concentration gradient
  2. chemiosmosis and ATP production chemiosmosis= diffusion of ions accross selectively permeable membrane through ATP synthase
    flow of H ions through ATP synthase couples ATP and Pi to make ATP
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11
Q

what enzyme is nvovled in photosynthesis

A

rubisco

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12
Q

plant pigments

A

proteins that absorb wavelengths of visible light

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13
Q

what are the 3 plant pigments

A

chlorophylls (green)- most abundant pigment
-darker
-lighters
castenoids (yellow,orange)
-xanothophyll- yellow
-carotenes- orange

protective pigments- attract pollinators protect DNA from UV light
eg. anthocyanins (red, purple, blue)

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14
Q

wavelength of blue light

A

440- 485 mm

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15
Q

wavelength of green light

A

510-565 mm

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16
Q

wavelength of yellow light

A

565-590 mm

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17
Q

wavelength of red light

A

625-740 mm

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18
Q

rf value

A

distance travelled pigment/ distance solvent travelled

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19
Q

anthocyanins

A

attract insects for pollination by abosrbing light in the UV spectrum, serve as a sunscreen to protect plants from sun damage and provide protection against predators because of their foul taste

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20
Q

carotenoids and chlorphyll

A

both serve as light harvesting pigments in the photosynthetic processes of plants

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21
Q

action spectrum

A

this shows the rate of photosynthesis for all the wavelengths of light as a % of the maximum possible rate
involves all photosynthetic pigments= chlorophyll and accessory pigments (caretnoids/ xanthophyll)

22
Q

describe action spectrum graph

A

does not start at x=0, violet/ blue has highest peak then drops at green- yellow color wavelength and then increases a bit to organe-red

x-axis= wavelength of light (mm)
y-axis= % of the max rate of photosynthesis

23
Q

absorption spectrum

A

shows the absorbance of light by photosynthetic pigments for all wavelengths of light

24
Q

describe absorption spectrum graph for chlorophyll

A

peak at violet and blue (highest) then flat for green and yellow and then increase for orange/ red

x-axis= wavelength of light (mm)
y-axis= % absorption of light

25
what conclusions can be drawn by overlaping action and absorption spectrum
both have same pattern pf absorbance and reflection action spectrum has a lower absorbance in the green yellow wavelength ( min point lower) due to xanophyll majority of action spectrum is performed by chlorophyll accessory pigments play smaller role on the action spectrum
26
what are the two types of LDR that can happen
cyclic or non cyclic
27
describe non cylicc LDR
non cyclic photoactivation involves PSII and PSI produces oxygen NADPH and ATP happens during regular enviornmental conditions follows Z diagram electrons lost by each PS are replaced by a different pathway PSII= photolysis of water PSI=PSII
28
describe cyclic LDR
cyclic photoactivation involves only PSI produces ATP happens in enviornments with reduction light and/ or CO2 follows A diagram decrease in photosynthesis (low glucose and low o2) reduces aerobic respiration reduces ATP formation electrons lost by PSI return to PSI emergency reaction for plants under stressful environemental conditions enables plants to ease ATP to survive until enviornment returns optimum conditions
29
describe cyclic LDR diagram
photons absorbed by PSI, electrons raised to higher energy state electron carriers carries the 2 electrons to another electron carrier, which carries them to ETC where ATP is produced, remaining electrons return to PSI
30
compare simply non cyclic and cyclic LDR
non- cyclic source of electrons: PSI=PSII PSII= photolysis of water destination of electrons PSII=PSI PSI=NADP reductase products= useful- ATP NADPH waste- O2 photosystems involved= PSII, PSI cyclic source of electrons PSI destination of electrons PSI products- useful- ATP photosystems involved PSI
31
in the LDR what is the importance of light
photolysis photophosphorylation photoactivation
32
in the LIR what is the importance of co2
carbon fixation G3P reduction glucose formation
33
whats another name for the LIR
calvin cycle
34
describe basis of calvin cycle
glucose phosphate (6c) is produced which is either stroed as starch which is used for growth (as cellulose) or used in respiration co2, ATP and NADPH are used ATP and NADPH (reduced form of NADP) were produced by LDR
35
where does the calvin cycle happen
completely in stroma
36
explain general 4 steps of calvin cycle
1- carbon fixation 2- reduction 3- regeneratio of RuBp 4- glucose formation
37
explain carbon fixation (first step) of calvin cycle
RUBP is carboxylated with CO2, catalysed by enzyme rubisco the 6G product immediately splits into 2x glycerare 3 phosphate (G3P) -cycle starts with 5c compound called RuBp -enzyme rubisco catalyses attachmenet of co2 molecule to the RuBP - 6c unstable compound breaks down into 2x 3C compounds (G3P)
38
descibre second step of calvin cycle= reduction
glycerate 3 phosphate (G3P) is converted into triose phosphate using NADPH and ATP while 2xATP convertes into 2x ADP (returns to the LDR) and its hydrolysis provides energy 2xNADPH is oxidised into 2X NADP+ (RETURNS TO ldr) transferibng hydrogen atoms to the compoound, this reduces the 2xGRP
39
descirbe thir step fof calvin cycle = regeneration of RuBp
the 2X triose phosphate if regenerated into RuBp which recquires eneergy dervied from the hydrolysis of ATP= ATP-> ADP remaning five tisoe phsophate molecules are recombined to regenerate stocks of RuBp
40
descirbe fourth step of calvin cycle = glucose formation
of the six molecules of triose phosphate per cycle 1 of them may be used to form half a sugar molecule hence two cycles are recquired to produce a single glucose monomer and 6 cycles to produce starch starch is formed by condensation
41
how is hydrogen used in photosynthesis to convert co2 to glucose obtained
splitting of water molecules
42
what is a limitting factor which affects rate of photosynthesis
temperature and co2 concentration
43
what are the products of LDR reactions
reduced NADP = NADPH and ATP
44
what happens in the calvin cycle with the entry og inroganic gas molecule
inorganic gas molecule= co2 which binds to active site of the enzyme rubisco which catalyses reaction of carbon fixation
45
what are ways you can measure photosynthesis
oxygen production= count bubbles or colelct with a gas syringe place acquatic plants submerged in water in a closed space with a gas syringe attached carbon dioxide uptake, you can use hydrogen carbonate indicator= measure presence of co2 place plant in closed space with water co2 reacts with water produceing bicarbonate and hydrogen ions increases acidity of solution increased co2 uptake= increased ph change in biomass, indirect measurment glucose prouction can be inderactly measured by a chnage in plants dry biomass, starch level in a plant can be identified by staining with iodine solution this can be quantitated using a colorimeter
46
what are the strucutres in a chloroplast
thylakoing membrane and grana thylakoid space/ lumen stroma 70s ribosome
47
descibre adaptations of thylakoing membrane and stroma
thylakoids provide large surface area for light absorption and LDR, chlorophyll and other pigments molecules are grouped together to form the photosystems which are embbeded in the membrane along with e- carriers folds in the thylakoid allow photosystems and e- carreirs to be close together
48
descibre adaptations of thylakoid space/ lumen
space collects H+ for chemiosmosis the low volume enables H+ gradient to generate rapidly H+ flows back to the stroma down H+ gradient through ATP sythase channels (embbeded in thylakoid membranes) to produce ATP
49
descibre adaptations of stroma
contains rubisco for carboxylation of RuBp along with all the other enzymes recquired for calvin cycle
50
descibre adaptations of 70s ribosomes
synthesizes proteins of the ETC and enzymes for LDR (atp synthase) and LIR (rubisco)
51

biology IB (24 decks)

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