Light Dependent Reaction (Q2)

Question 1

Flow of electrons through the photosystems and other molecular components built into the thylakoid membrane

Answer 1

Linear Photophosphorylation/linear electron flow

Question 2

Two stages of photosynthesis

Answer 2

Light-dependent reaction and light-independent reaction

Question 3

This stage of photosynthesis requires sunlight, occurs in the thylakoid membrane, and involves two photosystems and the electron transport chain.

Answer 3

Light-dependent reaction

Question 4

What is the goal of light dependent reaction?

Answer 4

To create ATP and NADPH by energizing photosynthesis through sunlight

Question 5

Large protein complexes of proteins and pigments that harvest light

Answer 5

Photosystems (PSII and PSI)

Question 6

The photosystem is composed of:

Answer 6

1. Reaction-center complex
2. Light-harvesting complexes

Question 7

A reaction-center complex consists of:

Answer 7

1. Special chlorophyll A molecules
2. Primary electron acceptor

Question 8

Consists of various pigment molecules that harvest light photons

Answer 8

Light-harvesting complex

Question 9

Special pair of chlorophyll a molecules in Photosystem II

Answer 9

P680

Question 10

Special pair of chlorophyll a molecules in Photosystem I

Answer 10

P700

Question 11

What do the numbers on the photosystem names mean?

Answer 11

Reflects the order of discovery of the photosystem

Question 12

Four parts of the light-dependent reaction

Answer 12

1. Light absorption in PSII
2. ATP synthesis
3. Light absorption in PSI
4. NADPH formation

Question 13

What explains the concept of how energy is transferred from one pigment molecule to another until it reaches the special pair of chlorophyll a molecules?

Answer 13

Resonance energy transfer

Question 14

What happens when a chlorophyll molecule absorbs a photon?

Answer 14

It causes a transition of the chlorophyll molecule from its ground state to excited state.

Question 15

Primary electron acceptor of PSII

Answer 15

Pheophytin

Question 16

Primary electron acceptor of PSI

Answer 16

A0

Question 17

Chlorophyll a molecules of PSII

Answer 17

P680, best absorbs light with a wavelength of 680 nm (red part of spectrum)

Question 18

Chlorophyll a molecules of PSI

Answer 18

P700, best absorbs light with a wavelength of 700 nm (far-red part of spectrum)

Question 19

Process of breaking water molecules using the energy provided by light

Answer 19

Photolysis

Question 20

End products of photolysis

Answer 20

2 electrons, 2 hydrogen ions, and 1 oxygen atom

Question 21

The electrons from photolysis are supplied one by one to the _____.

Answer 21

Special pair of chlorophyll a molecules

Question 22

The hydrogen ions from photolysis are stored in the _____.

Answer 22

Thylakoid lumen

Question 23

Strongest biological oxidizing agent that greatly facilitates the transfer of electrons from the split water molecule

Answer 23

P680

Question 24

Three components of the electron transport chain connecting the electron flow between PSII and PSI

Answer 24

1. Plastoquinone (electron carrier)
2. Cytochrome complex
3. Plastocyanin (protein)

Question 25

What causes the electron transport chain to release free energy?

Answer 25

Redox reactions

Question 26

Movement of hydrogen ions down their electrochemical gradient in order to start ATP synthesis

Answer 26

Chemiosmosis

Question 27

What is the name of the enzyme that hydrogen ions go through during chemiosmosis?

Answer 27

Transmembrane enzyme ATP synthase

Question 28

Protein that helps in passing electrons down to the electron transport chain after being excited in PSI

Answer 28

Ferredoxin

Question 29

Electrons from ferredoxin are transferred to _______ and is turned into _______ with the help of the enzyme _______ and through the process of _______. It also requires _______ ions from the stroma.

Answer 29

NADP+, NADPH, NADP+ reductase, reduction, hydrogen

Question 30

How many electrons are needed to reduce NADP+ into NADPH?

Answer 30

2 electrons

Question 31

Process wherein electrons loop back to the first part of the electron transport chain, repeatedly cycling through PSI instead of ending up in NADPH.

Answer 31

Cyclic photophosphorylation

Question 32

Does cyclic photophosphorylation produce NADPH?

Answer 32

No, only ATP.

Question 33

Five reasons why cyclic photophosphorylation happens

Answer 33

1. Organisms with single photosystems 2. Mutations 3. Too little NADP available 4. High ATP needs 5. Photoprotection

Question 34

Reactants of light dependent reaction

Answer 34

1. H2O 2. ADP 3. NADP+ 4. Pi (inorganic phosphate) 5. Light

Question 35

To produce one glucose molecule, how many water molecules are needed?

Answer 35

12

Question 36

To produce one glucose molecule, how many NADP+ are needed?

Answer 36

12

Question 37

To produce one glucose molecule, how many NADPH are needed?

Answer 37

12

Question 38

To produce one glucose molecule, how many O2 molecules are needed?

Answer 38

6

Question 39

To produce one glucose molecule, how many ADP are needed?

Answer 39

18

Question 40

To produce one glucose molecule, how many ATP are needed?

Answer 40

18

Question 41

To produce one glucose molecule, how many inorganic phosphate molecules are needed?

Answer 41

18

Question 42

When excited electrons fall back to the ground state, photons are given off and releases an afterglow called ______.

Answer 42

fluorescence

Question 43

If illuminated, an isolated solution of chlorophyll will fluoresce, giving off ______ and ______.

Answer 43

light, heat