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Biology 20 > photosynthesis > Flashcards

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
Q

how is ATP synthesixed in light depndent reactions

A

using energy from H+ gradeint

26
Q

what is an action spectrum

A

sjows relative effectvieness of different wavelengths of light for photosynthesis, reflected by a response in the rate oxygen is released

27
Q

what is absorbance spectrum

A

relative amounds of light of different colors a compound absorbs

28
Q

what are light independent reactions

A

energy of ATP and reducing power of NADPH are used to reduce CO2 and make glucose
occurs in stroma

29
Q

what is G3P

A

converts CO2 into glucose

30
Q

what is rubisco

A

enzyme catalszing carbon fixation

31
Q

what happens in carbon fixation

A

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
Q

what happens in the reduction part of calvin cycvle

A
  • 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
Q

what happens in replacing RuBP stage

A
  • 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
Q

how many times must the calvin cycle must be completed in order to synthesize one molecules of sugar

A

6 times

35
Q

of the 12 G3P molecules prudced in 6 cycles what do each of them do

A
  • 10 are used to regenerate RuBP
  • 2 are used to make glucose
36
Q

light reaction summary

A
  • 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
Q

calvin cycle summary

A
  • 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
Q

how long can plant carry out light independent reaction if place in the dark

A

until it runs out of ATP and NADPH supplied by light reaction

39
Q

why does plant not immediatly produce glucose when placed in the light

A

must produced ATP and NADPH
- light independent requires products from light dependent

Biology 20 (13 decks)

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