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photosynthesis Flashcards

1
Q

what is the formula for photosynthesis

A

6CO2+ 6H20 +energy—> C6H12O6 + 6O2

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2
Q

main purpose of light dependent reactions

A

-(Photo)
- convert light energy into chemical energy in the form of ATP and NADPH, these chemical energy molecules are used in calvin cycle to assemble sugar molecules

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3
Q

main purpose of light independent reactions

A
  • (synthesis)
  • use chem energy from light dependent to assemble glucose
  • main goal is to assemble glucose
  • calvin cycle
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4
Q

location requirments and products for light dependent reactions

A
  • thylakoid membrane
  • required: sunlight and water
  • products: oxygen, NADPH, ATP
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5
Q

location requirmeents and products for light independent reactions

A
  • stroma
  • requires: ATP, NADPH, CO2 and rubp (enzyme)
  • products: glucose, NADP+ and ADP
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6
Q

role of photosystem 2

A

absorb photons of light energy to energzie and transfer electrons and to create a proton gradeint (H+)

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7
Q

role of photosystem 1

A

prdocue NADPH which is a energy carrier molecules and to generate a proton motive force

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8
Q

where is energy passes in light dependent reactions

A

along electron accepting cholophyll A molecules called reaction center

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9
Q

2 stages of light dependent reactions

A

1: captue solar energy and transfer it to electrons through the splitting of water
2: using energy to make ATP and transferring electrons to make NADPH

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10
Q

what is a photsystem

A

clusters of cholorphyll and other pigments emeded in thylakoid membrane

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11
Q

what is photolysis

A

splitting of water, occurs in thylakoid lumen

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12
Q

what is NADP+

A

coenzyme electron carrier

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13
Q

what is NADPH

A

electron donor that carriers electrons and hydrogen atoms to other molecules

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14
Q

what is chemiosmosis,

A

synthesizing ATP using energy from H+ gradeint
process of ions moving across a semi permeable membrane from higher concentration to a lower one

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15
Q

ATP synthase

A

emeded in thylakoid membrane and porvides the only pathway for H+ to move out

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16
Q

reduction reaction

A

electron transfer in a chemical equation (gain of electron)
oxidizing agent
- always occurs with a oxidation reaction

17
Q

oxidation reaction

A

loss of elctrons
reducing agaent
reacts with oxygen

18
Q

first step in stage 1

A
  • light strikes the cholorphyll photons excite the chlorophyll
  • after chlorophyll captures light energy by absorbing photons and passing energy to electrons it is transfer to reaction center
19
Q

what causes splitting of water

A

light energy
water is dived into hydorgen ions, oxygen and electrons
oxygen is made and realses into atmosphere (exits stroma)
Hyrdogen ions remain in luem

20
Q

electron excitation second step in stage 1

A

electrons are excited and moved from lumen to cholorphyll
- electrons are transferred to PS1 through electron transport chain

21
Q

what is the electron transport chain

A

found along the thylakoid membrane, electron moev along this relasesing energy as they move (redox reaction)
every step down the ETC electrons give up some stored potential energy

22
Q

what happens when electrons reaches PS1

A

it is hit by light and become excited again

23
Q

what is energy realsed by PS1 used for

A

rejoin high energy electrons with hydrogen ions and NADP+ to produce NADPH (final electron acceptor)

24
Q

how do hyrdogen ions difuse into thylakoid membrane

A

cannot diffuse out because membrane is impermebale to them so uses chemiosmmosi
- energy realses from Electron tasnport chain pulls hydrogen ions into thyalkoid membrane (against gradeint)
- creates a + channel and a step gradeinent

25
how is ATP synthesixed in light depndent reactions
using energy from H+ gradeint
26
what is an action spectrum
sjows relative effectvieness of different wavelengths of light for photosynthesis, reflected by a response in the rate oxygen is released
27
what is absorbance spectrum
relative amounds of light of different colors a compound absorbs
28
what are light independent reactions
energy of ATP and reducing power of NADPH are used to reduce CO2 and make glucose occurs in stroma
29
what is G3P
converts CO2 into glucose
30
what is rubisco
enzyme catalszing carbon fixation
31
what happens in carbon fixation
means carbon atom in CO2 is chemically bonded to a pre existing molecule in stroma - this molecule is RuBP (5-carbon molecule) - this results in a six carbon compound that is highly unstable - this immediately breaks down into 2 identical carbon compounds (3-PGA) - these 3-carbon compounds are the first stable products - plants that demonsatte this are called C3 plants CO2+ RuBP--> unstable C6--> 2C3
32
what happens in the reduction part of calvin cycvle
- newly formed 3 carbon compound are in a low energy state - to convert them to high energy they are first activated by ATP and then reduced by NADPH - this results in 1,3 bisphosphoglycerate (1,3-BPG) - pair of electron from NADPh reduced 1,3-BPG into G3P - results in 6 G3P molecules fro 3 CO2 - 1exits cycle to form glucose and other high energy molecules ( 2 G3P forms 1 glucose) - 5 G3P are used in regeneration phase
33
what happens in replacing RuBP stage
- most of reduced G3P molecules are used to make more RuBP, energy supplied by ATP is required to break and reform the chemical bonds to make the 5 carbon RuBP from G3P
34
how many times must the calvin cycle must be completed in order to synthesize one molecules of sugar
6 times
35
of the 12 G3P molecules prudced in 6 cycles what do each of them do
- 10 are used to regenerate RuBP - 2 are used to make glucose
36
light reaction summary
- 6H2O split= photolysis - 6O2 released in atmosphere electron move along teasnport chain - 18 ADP to 18ATP in photosytem 2 from the hydrogen ion gradeint - 12 NADP+ reduced to 12 NADPH on photosytem 1
37
calvin cycle summary
- 6 moleucles of CO2 combine with 6 molecules of RuBP -n12 molecules are PGA are formed - 12 NADPh are oxidized - 18 ATP are consumed - 12 G3P are formed - 10 G3P are changed into RuBP - 2 G3P molecules are converted into glucose
38
how long can plant carry out light independent reaction if place in the dark
until it runs out of ATP and NADPH supplied by light reaction
39
why does plant not immediatly produce glucose when placed in the light
must produced ATP and NADPH - light independent requires products from light dependent

Biology 20 (13 decks)

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