Module 8 (Photosynthesis)

Question 1

What is photosynthesis?

Answer 1

The conversion of light energy to chemical energy

Question 2

What is the energy yield of photosynthesis in the form of carbohydrates?

Answer 2

4% of light energy is converted into carbohydrates

Question 3

Photic zone

Answer 3

The area in the ocean where photosynthesis can still occur

Question 4

Two stages of photosynthesis

Answer 4

• Light capture
• Carbon fixation

Question 5

Reduction in photosynthesis

Answer 5

CO2 is reduced to form carbohydrate molecules

Question 6

Oxidation in photosynthesis

Answer 6

Water is oxidized to form oxygen and hydrogen ions, electrons are taken in

Question 7

Thylakoid

Answer 7

Flattened membrane sacs in the chloroplast

Question 8

Lumen

Answer 8

Space inside the thylakoid membrane (fluid filled)

Question 9

Grana

Answer 9

Orderly stacks of thylakoids

Question 10

Stroma

Answer 10

Space surrounding thylakoids
(location of carbon fixation)

Question 11

Light dependent reactions

Answer 11

Sunlight energy converted into chemical energy, produces ATP and NADPH

Question 12

Light -independent reaction

Answer 12

ATP and NADPH used to synthesize carbohydrates (occurs in stroma)

Question 13

How is light absorbed?

Answer 13

When photons are absorbed, the compound is converted to a higher-energy state, transfers energy to another molecule

Question 14

Chromophore

Answer 14

Chemical group capable of absorbing light of wavelengths

Question 15

Why are plants green?

Answer 15

Because the pigment chlorophyll isn’t good at absorbing green wavelengths of light (absorbs red and blue)

Question 16

Parts of chlorophyll

Answer 16

Porphyrin ring (light absorption)
Phytol side chain (side chain with hydrophobic properties, for inserting chlorophyll into thylakoid membrane)

Question 17

Accessory pigments

Answer 17

Found in thylakoid membrane, absorb light from regions of the visible spectrum that are poorly absorbed by chlorophyll

Question 18

Reaction center

Answer 18

A pair of chlorophyll molecules that receives the passed energy (NOT ELECTRONS)

Question 19

Electron acceptor

Answer 19

Reaction center chlorophyll passes an electron to an electron acceptor

Question 20

Photosystem II is also known as…

Answer 20

PSII

Question 21

Photosystem I is also known as…

Answer 21

PSI

Question 22

Photosynthetic electron transport chain

Answer 22

Drives the formation of ATP and NADPH

Question 23

Z scheme

Answer 23

Energy trajectory of photosynthetic electron transport

Question 24

Flow of electrons (in photosynthesis)

Answer 24

H2O->PSII->PSI->NADP+

Question 25

Proton gradient in photosynthesis

Answer 25

Created as electrons flow along Z pathway - High in lumen, low in stroma

Question 26

ATP produced in the chloroplast...

Answer 26

Stays in the chloroplast

Question 27

Plastoquinone

Answer 27

Carries electrons from PSII to cytochrome b6f complex

Question 28

Plastocyanin

Answer 28

Carries electrons from the cytochrome b6f complex to PSI by diffusing through the thylakoid lumen

Question 29

Cytochrome b6f complex

Answer 29

Protein that electrons pass through between PSII and PSI

Question 30

NADP+ reductase

Answer 30

Takes the electron from the photosynthetic transport chain and converts NADP+ to NADPH

Question 31

Purpose of Calvin Cycle

Answer 31

Takes a low potential energy carbon compound (CO2) and converts it into a higher-energy carbon compound

Question 32

Three steps of calvin cycle

Answer 32

Carboxylation, Reduction, Regeneration

Question 33

Carboxylation

Answer 33

First step of carbon fixation - CO2 is reacted with RuBP to form a 6 carbon molecule (catalyzed by rubisco), which is then broken down into two PGA molecules (3C)

Question 34

Reduction ## Footnote Carbon Fixation

Answer 34

PGA is phosphorylated by ATP to produce triose phosphates, which are then reduced by NADPH and only one can leave the calvin cycle

Question 35

RuBP

Answer 35

Ribulose 1,5-bisphosphate

Question 36

Regeneration

Answer 36

Five triose phosphate molecules are used to regenerate RuBP using the input of ATP, produces three RuBP to be used in carboxylation

Question 37

Excess carbohydrates in a plant produced from the calvin cycle is converted into storage....

Answer 37

As starch

Question 38

Two possible possibilities of evolution to produce two photosystems

Answer 38

Horizontal gene transfer and gene duplication (and divergence)

Question 39

Horizontal gene transfer

Answer 39

Passing along genetic information from one cyanobacterium to another

Question 40

Gene duplication and divergence

Answer 40

PSII duplicates and then diverges (one becomes PSI)