Photosynthesis: Light Reaction

Question 1

Photosynthetic organisms use this energy to synthesize complex carbon compounds.

Answer 1

solar energy

Question 2

Light may appear as both __ and __.

Answer 2

particle; wave

Question 3

The distance between successive wave crests is called ___.

Answer 3

wavelength

Question 4

The number of wave crests that pass an observer in a given time is called ____.

Answer 4

frequency

Question 5

The light wave is a ___ electromagnetic wave.

Answer 5

transverse

Question 6

Light as a particle is called a __.

Answer 6

photon

Question 7

Energy in a photon

Answer 7

quantum

Question 8

The energy (E) of a photon depends on the frequency of the light. True or False?

Answer 8

True; known as Planck’s Law

Question 9

Explain the relationship between (1) energy and frequency, and (2) energy and wavelength.

Answer 9

e = hv
e = hc/λ

Question 10

Molecules that absorb light

Answer 10

pigments

Question 11

Colors that chlorophyll absorb and reflect

Answer 11

blue and red: absorbed
green and yellow: reflected

Question 12

Transitions to an excited state occur only when the energy exactly matches the energy gap between the ground state energy and the excited state energy.

Answer 12

law of quantum mechanics

Question 13

When excited, chlorophyll may return to its ground state and release photon. This is called ___.

Answer 13

fluorescence

Question 14

When excited, chlorophyll may return to its ground state, but no release of photon, which is known as ___.

Answer 14

relaxation

Question 15

Chlorophyll may also transfer the energy to another molecule when excited. This is called ___.

Answer 15

energy transfer

Question 16

The energy of the chlorophyll’s excited state causes chemical reactions. This is known as ___.

Answer 16

photochemistry

Question 17

All pigments are found in the chloroplast. True or False?

Answer 17

true

Question 18

Plants, algae, and cyanobacteria : chlorophyll
as
anaerobic photosynthetic bacteria :

Answer 18

bacteriochlorophyll

Question 19

Number of rings found in a chlorophyll that are similar with the heme and cytochrome; known as ____.

Answer 19

four; porphyrin rings

Question 20

Element that is central to the porphyrin ring.

Answer 20

magnesium; fe in heme

Question 21

Long hydrophobic tail in a chlorophyll with 20 hydrocarbons.

Answer 21

phytol tail

Question 22

Chlorophyll a & b : ____
Chlorophyll c, d, & f : ____

Answer 22

green plants
protists and cyanobacteria

Question 23

Chlorophyll a absorbs _____.
Chlorophyll b absorbs _____.

Answer 23

violet and orange
blue and yellow

Question 24

Tetraterpene (C40) molecules derived from eight isoprene units responsible for coloration, assembly of light-harvesting complexes, and protection of photosynthetic apparatus from photooxidative damage; accessory light‐harvesting pigments.

Answer 24

carotenoids

Question 25

Site of biophysical and biochemical reactions of photosynthesis.

Answer 25

chloroplast

Question 26

Third membrane system of chloroplast

Answer 26

thylakoid membrane

Question 27

Two complexes in pigments

Answer 27

antenna pigments; reaction center complex

Question 28

Photosystems are made up of ___.

Answer 28

LHC Proteins + pigments

Question 29

Photosystems are embedded in the ____.

Answer 29

thylakoid membrane

Question 30

energy transfer: ____ electron transfer: ____

Answer 30

antenna pigments reaction center

Question 31

Proteins associated with antenna pigments which are structurally related.

Answer 31

light-harvesting complex

Question 32

PS II is associated with ___; PS I is with ___.

Answer 32

LHC II; LHC I

Question 33

Two types of reaction center on the nature of electron acceptor

Answer 33

type I, type II

Question 34

An RC based on electron acceptor that reduces a Fe-S cluster and is present in green sulfur bacteria.

Answer 34

type I

Question 35

An RC based on electron acceptor that reduces quinone and is present in purple bacteria.

Answer 35

type II

Question 36

Dimeric multi-subunit protein super complex.

Answer 36

PS II

Question 37

A large multi-subunit complex which is approximately made up of 15 proteins.

Answer 37

PS I

Question 38

RC in PS I

Answer 38

P700

Question 39

RC in PS II

Answer 39

P680

Question 40

PS II is a light-driven ___.

Answer 40

water-plastoquinone oxidoreductase

Question 41

PS I is a light-driven ____.

Answer 41

plastocyanin-ferredoxin oxidoreductase

Question 42

What are the four major protein complexes in the thylakoid?

Answer 42

1. PS II 2. cytochrome b6f 3. PS I 4. ATP synthase

Question 43

PS II is located in the ____.

Answer 43

granal thylakoid

Question 44

Cytochrome b6f is evenly distributed in the thylakoid. True or False?

Answer 44

true

Question 45

PS I & ATP synthase are in the ____.

Answer 45

stromal thylakoid

Question 46

Dimers that transfer electrons from plastoquinol to plastocyanin.

Answer 46

cytochrome b6f

Question 47

Small, water-soluble, and copper-containing protein that transfers electrons between the cytochrome b6f complex and P700.

Answer 47

plastocyanin

Question 48

Plastocyanin is found in the ____.

Answer 48

lumenal space

Question 49

In certain green algae and cyanobacteria, a c-type cytochrome is sometimes found instead of plastocyanin.

Answer 49

true

Question 50

ATP Synthase has two segments: ___ and ___.

Answer 50

CF0 and CF1

Question 51

Transmembrane segment; participates in translocating protons across the membrane to the catalytic portion of the enzyme.

Answer 51

CF0

Question 52

Hydrophilic segment on the stromal surface; involved in the actual conversion of ADP and Pi to yield ATP, using energy stored in the proton gradient.

Answer 52

CF1

Question 53

Chloroplast ATP synthase is a 400‐kDa enzyme that contains __ different subunits.

Answer 53

nine

Question 54

Proton translocation + Phosphorylation of ATP

Answer 54

chemiosmosis

Question 55

What are the three nucleotide‐binding sites on the enzyme?

Answer 55

1. o-site 2. l-site 3. t-site

Question 56

Nucleotide-binding site that is available to bind ADP and Pi; open.

Answer 56

o-site

Question 57

Nucleotide-binding site wherein ADP and Pi are loosely bound; loose.

Answer 57

l-site

Question 58

Nucleotide-binding site where ATP is formed; tight.

Answer 58

t-site

Question 59

The movement of H+ across the membrane drives rotation of the γ subunit in the enzyme, causing conformation changes that interconvert the 3 sites.

Answer 59

true

Question 60

Decreased efficiency for photosynthesis due to high intensities of light

Answer 60

photoinhibition

Question 61

Processes that dissipate excess absorbed light energy harmlessly as heat resulting in de‐excitation of the singlet state of chlorophyll in the antenna of PSII.

Answer 61

nonphotochemical quenching (npc)

Question 62

Carotenoids that have been implicated in NPQ

Answer 62

xanthophylls and lutein

Question 63

QB⁻

Answer 63

semiquinone

Question 64

QBH₂

Answer 64

plastoquinol

Question 65

A₁

Answer 65

phylloquinone

Question 66

Types of chloroplast electron transfers and subsequent phosphorylation: ▪ Non-cyclic/linear electron transfer = linear photophosphorylation ▪ Cyclic electron transfer = cyclic photophosphorylation

Answer 66

true

Question 67

Products of Light Reaction

Answer 67

ATP and NADPH