Chapter 6: Photosynthesis And The Chloroplast

Front 1

Heterotrophs

Back 1

Survived on nutrients from the environment

Front 2

Autotrophs

Back 2

Manufacture organic nutrients from CO2 and H2S

Front 3

_________ of complex molecules from CO2 requires a large input of energy

Back 3

Synthesis

Front 4

Chemoautotrophs

Back 4

Use energy from inorganic molecules

Front 5

Photoautotrophs

Back 5

Use radiant energy to make organic molecules

Front 6

Photosynthesis

Back 6

Converts energy from sunlight into chemical energy stored in carbohydrates

Front 7

Low energy electrons are removed from a _____ molecule

Back 7

Donor

Front 8

First photoautotrophs used ___ as electron source

Back 8

H2S

Front 9

Cyanobacteria used electrons from to produce _____ as a waste product

Back 9

Water

Front 10

Photosynthesis in eukaryotes takes place in the __________

Back 10

Chloroplast

Front 11

Chloroplast

Back 11

A cytoplasmic organelle.

Front 12

Chloroplasts have a double _________

Back 12

Membrane

Front 13

The outer membrane of chloroplast is ________ to large molecules

Back 13

Permeable

Front 14

The inner membrane contains ________, __________, and _____________________

Back 14

light-absorbing pigment

electron carriers

ATP-synthesizing enzymes

Front 15

The inner membrane of a chloroplast is folded into ________ arranged in stacks called _______

Back 15

flattened sacs (thylakoids)

grana

Front 16

Chloroplasts are self-replicating organelles containing their own ___

Back 16

DNA

Front 17

Thylakoid membranes contain a large percentage of glycolipids, which make the membrance highly fluid for ________________

Back 17

Diffusion of proteins complexes

Front 18

Photosynthesis is a redox reaction transferring an electron from ______ to _______

Back 18

Water to Carbon Dioxide

Front 19

Photosynthesis oxidizes ______ to ________

Back 19

Water to Oxygen

Front 20

Respiration reduces ______ to form ______

Back 20

Oxygen to form water

Front 21

Respiration removes high energy electrons from reduced organic substrates to form ____ and _____

Back 21

ATP and NADH

Front 22

Photosynthesis uses low energy electrons to form ___ and ______, which are then used to reduce CO2 to carbohydrate

Back 22

ATP and NADPH

Front 23

Light-dependent reactions (light reactions)

Back 23

Sunlight is absorbed, converting it into ATP and NADPH

Front 24

Light-independent (dark reactions)

Back 24

Use the energy stored in ATP and NADPH to produce carbohydrate

Front 25

Absorption of photons by a molecule makes them go from _____ to ______

Back 25

ground state to excited state

Front 26

Energy in the photon depends on the __________________

Back 26

wavelength of light

Front 27

Molecules absorb specific _______________

Back 27

wavelengths of light

Front 28

Photosynthetic Pigments

Back 28

Molecules that absorb light of particular wavelengths

Front 29

Chlorophyll contains a ________________ that absorbs light and a ____________________ embedding it to the photosynthetic membrane

Back 29

porphyrin ring

hydrophobic tail

Front 30

The alternating single and double bonds along the porphyrin ring form a cloud making it a __________ system

Back 30

conjugated

Front 31

Conjugated bond systems absorb energy of range of ___________

Back 31

wavelengths

Front 32

Besides chlorophyll, there are accessory pigments called __________

Back 32

caratenoids

Front 33

Carotenoids

Back 33

absorb light in the blue-green region of spectrum

Front 34

Each Photosynthetic Unit contains

Back 34

several hundred chlorophyll molecules

Front 35

The reaction-center chlorophyll

Back 35

transfers electrons to an electron acceptor

Front 36

Pigments that do not participate directly in the conversion of light energy are responsible for light absorption called ________ pigments

Back 36

antenna

Front 37

Two large pigment-protein complexes called ___________ act in series to raise electrons from H20 to NADP+

Back 37

photosystems

Front 38

Photosystems II (PSII)

Back 38

Boosts electrons from below energy level of water to a midpoint

Front 39

Photosystem I (PSI)

Back 39

Boosts electrons to a level above NADP+

Front 40

The reaction center of Photosystem II is referred to as ______

Back 40

P680

Front 41

The reaction center of Photosystem I is referred to as ______

Back 41

P700

Front 42

Electrons are transferred to a ____________________________

Back 42

Primary electron acceptor

Front 43

The flow of electrons from H20 to NADP+ is refereed to as the ____________

Back 43

Z scheme

Front 44

Photosystem II uses absorbed light energy to remove ________ and generate a _______________

Back 44

electrons

proton gradient

Front 45

Two proteins, D1 and D2, bind the P680 chlorophyll and perform reactions to ________________

Back 45

oxidize H20

Front 46

Light is harvested by a pigment-protein complex called __________________

Back 46

light-harvesting complex II (LHCII)

Front 47

Harvested energy is passed from LHCII to ___________________________ within PSII

Back 47

inner-antenna molecules

Front 48

Excited P680 transfers energy to an electron acceptor generating ______ and _______

Back 48

P680+ and Pheo-

Front 49

P680+ and Pheo- are transferred to opposite sides of the thylakoid membrane where Pheo- passes an electron to _________________

Back 49

Plastiquinone (PQ)

Front 50

Plastiquinone (PQ) passes the electron to __________, then moved to the ___________ of the membrane

Back 50

Another PQ

stromal side

Front 51

The Flow of Electron from Water to PSII

Back 51

The redox potential of P680+ pulls electrons from water (photolysis)

Formation of O2 requires four electrons from H20

Four electrons required to form O2 are transferred in cycles through P680+ to four Mn ions and one Ca ion that form the oxygen-evolving complex

Protons produced in photolysis are retained in the thylakoid lumen

Oxygen produced is released as a waste product into the environment

Front 52

From PSII to PSI

Back 52

Production of O2 leads to formation of 2 molecules of PQH2

Reduced PQH2 then diffuses through thylakoid membrane and binds cyochrome b6f and releases protons the lumen of thylakoid

Electrons from cytochrome b6f are passed to another carrier plastocyanin

Plastocyanin transfers electrons to P700+

Front 53

PSI Operations: The production of NADPH

Back 53

The PSI consists of a reaction core center of 12–14 different polypeptides and a complex of protein-bound pigments called LHCI.
Photons harvested by antenna pigments in PSI (LHCI) oxidizes chlorophyll a, forming P700*.
Absorption of light leads to production of P700+ and Ao–.
Redox potential of P700+/Ao– reduces NADP.
The reduction of NADP+ to NADPH is catalyzed by ferredoxin-NADP+ reductase.
Some electrons passed to ferredoxin end up reducing nitrate, ammonia or sulfate to form other important biological molecules.

Front 54

Photosynthetic Electron Transport

Back 54

For every 8 photons absorbed:

2H20 + 2NADP+ => O2 + 2NADPH

Electron transport also produces a proton gradient across the thylakoid membrane

Front 55

The machinery for ATP synthesis in a chloroplast is similar to that of ________________________

Back 55

mitochondrial enzymes

Front 56

The ATP synthase consists of a _____ and a ______

Back 56

head (CF1)

base (CF0)

Front 57

The CF1 heads project outward into the stroma, keeping with the orientation of the _________________

Back 57

proton gradient

Front 58

Protons move into the lumen through the CF0 base of the _______

Back 58

synthase

Front 59

The movement of protons during photo-synthesis does not create a significant change in the membrane potential since other ions are ______________________________

Back 59

transported simultaneously

Front 60

The movement of electrons during the formation of oxygen is called __________________________ because the ions move in a linear path

Back 60

noncyclic photophosphorylation

Front 61

Cyclic photophosphorylation is carried out by PSI __________ of PSII

Back 61

independently

Front 62

C_3 plants

Back 62

Plants that produce a 3 carbon intermediate as the first compound to be identified during carbon dioxide fixation

Front 63

The condensation of RuBP and the splitting of the 6 carbon molecule are catalyzed by 1 enzyme:

Back 63

Rubisco (ribulose biphosphate carboxlase)

Front 64

Calvin Cycle

Back 64

• Carboxylation of RuBP to form PGA
• Reduction of PGA to glyceraldhyde 3 phosphate (GAP) using NADPH and ATP from light reactions
• Regeneration of RuBP

Front 65

Carbohydrate Synthesis in C_3 plants

Back 65

• The GAP Molecules can be exported into the cytosol in exchange for phosphate ions and used to synthesize sucrose
• Conversion of 6 molecules of CO2 to 1 6-carbon sugar molecules requires 12 molecules of NADPH and 18 molecules of ATP

Front 66

Redox Control is light _______

Back 66

dependent

Front 67

Key enzymes of Calvin Cycle are only active when ________ and _________ are produced by photosynthesis

Back 67

ATP and NADP

Front 68

Some electrons used to reduce NADP+ are transferred to thioredoxin, which are accepted to ________________________________________

Back 68

reduce disulfide bridges (-S-S-) in selected Calvin Cycle enzymes

Front 69

In the _______, thioredoxin reduction ceases and enzymes go back to oxidized state and are inactivated

Back 69

dark

Front 70

Photorespiration

Back 70

uptake of O2 and release of CO2

Front 71

Glycolate produced during photorespiration is shuttled to the _________

Back 71

peroxisome

Front 72

Peroxisomal enzymes convert glycolate to glyoxylate and then glycine, resulting in the loss of ____

Back 72

CO2

Front 73

C4 pathway involves the production of ____________________________, which then combines with CO2 to produce 4-carbon compounds oxaloacetate

Back 73

Phosphoenolpyruvate (PEP)

Front 74

CAM plants

Back 74

Carry out light reactions and CO2 fixation at different times of the day using the enzyme PEP carboxylase