Photosynthesis 1 Flashcards

1
Q

Pigment

A

any substance that absorbs light
energy

The color that something is, is what it reflects

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2
Q

Chloroplast pigments:

A

Chlorophyll
Carotenoids

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3
Q

Chlorophyll

A

green (reflect green)
* Absorb in red, violet, and blue regions of spectrum

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4
Q

Carotenoids

A

red, orange, yellow
A)carotenes: red, orange, yellow
B)xanthophylls: pale yellow

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5
Q

Action Spectrum for Photosynthesis

A

-Shows the relative effectiveness of different
wavelengths of light in promoting photosynthesis

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6
Q

Absorption Spectrum of a pigment shows

A

the
wavelengths of light that are absorbed by a
pigment.

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7
Q

If one compares the Action Spectrum of a
process with Absorption Spectra, one can get
an idea of

A

what pigments play a role in the
process.

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8
Q

When one compares
the action spectrum for
photosynthesis with the
absorption spectra for
chlorophylls a and b and
for carotenoids

A

they
overlap supporting that
chlorophylls and
carotenoids absorb light
for photosynthesis.

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9
Q

When isolated chlorophyll (no longer in chloroplasts) absorbs
light,

A

the energy levels of electrons are elevated.
– These electrons are said to be in an excited state.
– The excited electrons drop back to the ground state, and
energy is released as fluorescence; and some
energy is lost as heat

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10
Q

light=

A

fluorescence

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11
Q

When chlorophyll absorbs light energy while in chloroplast
membranes or other photosynthetic membranes:

A

– The excited electrons do not drop back down to the
ground state, but are transferred to electron carriers.
– The energy is trapped and stored in chemical bonds

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12
Q

Adenosine triphosphate (ATP) =

A

Energy
currency of cell.

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13
Q

Plants make ATP using

A

light as an energy
source.

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14
Q

Photosynthesis Takes place in

A

membranes of chloroplasts or
in membranes of photosynthetic prokaryotic
organisms

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15
Q

where does the Light-Dependent Reactions happen in

A

thylakoid membranes of chloroplasts

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16
Q

step 1 of Light-Dependent Reactions

A

Water molecules split apart, releasing electrons and
hydrogen ions; oxygen gas released.

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17
Q

step 2 of light dependent reactions

A

Electrons pass to electron carriers of electron
transport system.

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18
Q

step 3 of light dependent reactions

A

NADP (nicotinamide adenine dinucleotide
phosphate) is reduced, forming NADPH (reduced
nicotinamide adenine dinucleotide phosphate)
– used in light-independent reactions

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19
Q

Hydrogen ions play major role in

A

ATP production

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20
Q

Light-Independent Reactions happens where specifically in the chloroplast

A

In stroma of chloroplasts

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21
Q

Calvin cycle step 1

A

Carbon dioxide combines with RuBP (ribulose
bisphosphate)

22
Q

what drives calvin cycle

A

– ATP and NADPH from light-dependent reactions
provide energy to drive Calvin cycle

23
Q

Calvin cycle step 2

A

– The energy from ATP and NADPH becomes trapped
in chemical bonds of carbohydrates that are
produced

24
Q

Two types of photosynthetic units:

A

Photosystem I and Photosystem II

25
Q

Photosystem I (PS I)
antenna pigments

A

– About 200 molecules of chlorophyll a (blue-green)
– Some chlorophyll b (yellow-green)
– Carotenoids

26
Q

Photosystem I (PS I) reaction center

A

P700

27
Q

P700

A

Pigment at 700 nm: a special type of chlorophyll with an absorption peak at 700 nm
– The only chlorophyll in PS I that can use the trapped light energy

28
Q

Photosystem II (PS II)
Antenna pigments and reaction center

A

(chlorophyll a & b; and carotenoids)

p680

29
Q

Oxygen Evolving Complex (OEC)

A

sites where water is split

30
Q

When something is reduced

A

it gains an electron or
electrons and sometimes protons (hydrogen atoms)

31
Q

When something is oxidized

A

it gives up an electron or
electrons and sometimes protons (hydrogen atoms)

32
Q

Oxidation of one compound usually coupled with

A

reduction of another compound

33
Q

Photosystem l step 1

A

Antenna pigments absorb and pass light energy to reaction center P700

34
Q

photosystem 1 step 2

A

Light energy absorbed by P700 boosts electrons to higher energy levels.

35
Q

photosystem 1 step 3

A

Electrons passed in a series of oxidation-reduction reactions, to iron-sulfur acceptor
molecule Fe-S, then to ferredoxin, then to FAD (flavin adenine dinucleotide).
* NADP reduced to NADPH.

36
Q

photosystem 1 step 4

A

Now there is an electron gap in PS I.
* Electrons removed from P700 replaced by electrons from Photosystem II.

37
Q

photosystem 2 step 1

A

Antenna pigments absorb and pass light energy to P680 at the
reaction center
– Light energy absorbed by P680 boosts electrons to higher
energy levels.

38
Q

photosystem 2 step 2

A

Electrons are passed to the acceptor molecule pheophytin, then
to PQ (plastoquinone), then along electron transport system in a
series of oxidation-reduction reactions to photosystem I

39
Q

Photolysis

A

Water-splitting,occurs at the Oxygen Evolving
Complex (OEC) at Photosystem II

40
Q

step 3 of photosystem 2

A

Photolysis
Electrons extracted from water replace electrons lost by P680.

41
Q

what is produced from photosystem 2

A

One molecule of oxygen, 4 protons and 4 electrons produced
from two water molecules.

42
Q

Chemiosmosis step 1

A

Protons build up in thylakoid space
due to splitting of water molecules
and as a result of protons being
ferried across membrane during
oxidation-reduction reactions of
electron transport.

43
Q

chemiosmosis step 2

A

Proton gradient results in proton
motive force (like stored energy in a
battery). The only way protons can
leave the thylakoid space is through
special ATPases in thylakoid
membrane

44
Q

chemiosmosis step 3 Movement of protons across
membrane =

A

source of energy for
synthesis of ATP
https

45
Q

André Jagendorf

A

Jagendorf conducted
the experiments that
showed that
chemiosmosis occurs in
chloroplasts

46
Q

Peter Mitchell had
determined the

A

chemiosmosis results in
ATP synthesis in
mitochondria.

47
Q

sucrose

A

transport form of carbohydrate in plants

48
Q

a disaccharide=

A

1 glucose+1 fructose

49
Q

starch

A

storage carbohydrate in plants (monomer=glucose)

50
Q

Inputs of the
Light Reactions

A

light
water

51
Q

Products of the
Light Reactions

A
  • ATP
  • NADPH
  • Oxygen from the splitting of
    water