Light Dependent Reactions

Question 1

the primary source of light energy on our planet.

Answer 1

sun

Question 2

Plants utilize all the colors of light except ________ when they
photosynthesize. This reflection of
light makes this the color of plants.

Answer 2

green

Question 3

photosynthetic reaction

Answer 3

6CO2 + 6H2O → (chlorophyll and sunlight) C6H12O6 + 6O2

Question 4

2 stages of photosynthetic reaction

Answer 4

light reaction & calvin cycle

Question 5

structure of chloroplast from outside to inside

Answer 5

intermembrane space - inner membrane - stroma - thylakoid membrane - thylakoid lumen

Question 6

where does light reaction occur

Answer 6

thylakoid (membrane)

Question 7

light reaction sequence

Answer 7

photosystem II - plastoquinone - cytochrome complex (CYT B6-F) - plastocyanin - photosystdm I - ferredoxin - ferredoxin NADP reductase - atp synthase

Question 8

light-dependent reaction electron carriers

Answer 8

plastoquinone
cytochrome complex
plastocyanin
Ferredoxin

Question 9

the enzyme that catalyzes the transfer of 2 electrons from Fd to
NADP+
* This results in taking an H+
from the stroma.

Answer 9

Ferredoxin NADP Reductase (FNR)

Question 10

Powered by the diffusion
of H+ from the lumen to
the stroma, it binds ADP
with inorganic phosphate (Pi) to produce ATP.

• diffusion of H+ - energy - ATP

Answer 10

ATP Synthase

Question 11

how many H+ are required to produce ATP

Answer 11

3

Question 12

the capture of light energy by chlorophyll that results in the release of energized electrons

• its electrons gain energy and move to higher energy levels in the molecule

Answer 12

chlorophyll photoactivation/photoexcitation

Question 13

A thylakoid membrane protein complex comprised of light-
harvesting pigments.

Answer 13

photosystem

Question 14

components of photosystem

Answer 14

• antennae complexes
• reaction center complexes

Question 15

component of photosystem

-light-harvesting system
-light energy or photons excites the electrons in photopigments
and the energy is being
transferred to its neighbor
photopigments.
-composed of different
photopigments (chlorophyll a, b, c, carotenoids) and proteins

Answer 15

antennae complexes

Question 16

contains a special pair of
chlorophyll molecules that
transfer excite electrons to
primary electron acceptor

Answer 16

reaction center complexes

Question 17

two types of photosystem

Answer 17

photosystem 1 and 2

Question 18

what is the special chlorophyll molecule in photosystem II

Answer 18

P680 (effectively absorbs light
with a wavelength of 680nm)

Question 18

the first link in the chain of photosynthesis. It captures photons and uses the energy to extract electrons from water molecules.

• contains an oxygen-evolving complex (OEC, involved in the photolysis of water during the light reaction of photosynthesis. It is a water-oxidizing enzyme that catalyzes the oxidation (loss of electrons) of water into dioxygen, protons, and electrons

Answer 18

photosystem II

Question 19

the primary electron acceptor in Photosystem II

Answer 19

pheophytin

Question 20

provides energy to reduce NADP to NADPH, which is required for carbon fixation and other synthetic processes.

Answer 20

photosystem I

Question 21

the special chlorophyll molecule of photosystem I

Answer 21

P700 (chlorophyll a. is effective in absorbing light with a wavelength of 700nm.)

Question 22

primary acceptor of photosystem I

Answer 22

chlorophyll A

Question 23

Splitting of water molecules into hydrogen ions, electrons, and oxygen gas in the presence of excited chlorophyll.

H2O + light —–> 2H+ + 2e- + O

Answer 23

photolysis

Question 24

series of four protein complexes that couple redox reactions, creating an electrochemical gradient that leads to the creation of ATP in a complete system named oxidative phosphorylation. It occurs in mitochondria in both cellular respiration and photosynthesis.

Answer 24

electron transport chain

Question 24

series of four protein complexes that couple redox reactions, creating an electrochemical gradient that leads to the creation of ATP in a complete system named oxidative phosphorylation. It occurs in mitochondria in both cellular respiration and photosynthesis.

Answer 24

electron transport chain

Question 25

one of the electron acceptors associated with Photosystem II in photosynthesis. It accepts two electrons and is reduced to Plastoquinol and as such acts as an electron and energy carrier in the electron transport process (goes back to being this after the electron is transferred)

Answer 25

plastoquinone

Question 26

functions to mediate the transfer of electrons and of energy between the two photosynthetic reaction center complexes, Photosystem II and Photosystem I, while transferring protons from the chloroplast stroma across the thylakoid membrane into the lumen - where H+ is pumped to the lumen.

Answer 26

cytochrome complex

Question 27

a copper-containing protein that plays a role in the electron transport process associated with photosynthesis. It serves as an electron transfer agent between the cytochrome complex which follows Photosystem II and the entry point to Photosystem I of the non-cyclic electron transfer process.

Answer 27

plastocyanin

Question 28

they transfer electrons from photoreduced Photosystem I to ferredoxin NADP(+) reductase in which NADPH is produced for CO(2) assimilation.

Answer 28

ferredoxin

Question 29

During the light-dependent reactions, an electron that's excited in ______ is passed down an electron transport chain to _____ (______ energy along the way). In here, the electron is excited again and passed down the second leg of the electron transport chain to a final electron acceptor, producing ______

Answer 29

PSII, PSI, losing, NADPH

Question 30

what drives the reduction of NADP+ to NADPH via the enzyme FNR.

Answer 30

electron transport

Question 30

what drives the reduction of NADP+ to NADPH via the enzyme FNR.

Answer 30

electron transport

Question 31

Transfer of light energy absorbed by chlorophyll to molecules of ATP. -the conversion of ADP to ATP using the energy of sunlight by activation of PSII.

Answer 31

photophosphorylation

Question 32

(the "standard" form of the light-dependent reactions), electrons are removed from water and passed through PSII and PSI before ending up in NADPH. This process requires light to be absorbed twice, once in each photosystem, and it makes ATP - Both Photosystem I and II are involved. - P680 is the active reaction centre. -Electrons travel in a non – cyclic manner. - Electrons from Photosystem I are accepted by NADP. - Both NADPH and ATP molecules are produced. - Photolysis of water is present. - NADPH is synthesized. - Oxygen is evolved as a by-product - This process is predominant in all green plants.

Answer 32

non-cyclic photophosphorylation

Question 33

the process in which organisms (like prokaryotes), just accomplish the conversion of ADP to ATP for immediate energy for the cells. - the excited electrons in PSI transported by ferrodoxin and cytochrome back to PSI. -Only Photosystem I is involved. - P700 is the active reaction centre. - Electrons travel in a cyclic manner. - Electrons revert to Photosystem I - ATP molecules are produced. - Water is not required. - NADPH is not synthesized. - Oxygen is not evolved as the by-product - This process is predominant only in bacteria.

Answer 33

cyclic photophosphorylation

Question 34

input in light-dependent reaction

Answer 34

12H2O + 12NADP+ + 18ADP + 18Pi + light energy and chlorophyll

Question 35

output of light-dependent reaction

Answer 35

6O2 + 12NADPH + 18ATP

Question 36

what is atp and nadph used for in photosynthesis

Answer 36

The ATP and NADPH from the light-dependent reactions are used to make sugars in the next stage of photosynthesis, the Calvin cycle.

Question 37

an energy diagram for electron transfer in the "light reactions" of plant photosynthesis. It applies equally well to photosynthesis by algae and cyanobacteria. The vertical energy scale shows each molecule's ability to transfer an electron to (i.e., to reduce) the next one from left to right.

Answer 37

z-scheme

Question 38

which photosystem is only present in humans and other primitive bacteria (no NADPH, instead of H2o, hydrogen sulfates)

Answer 38

photosystem 1

Question 39

the only bacteria that can produce photosynthesis and has both photosystems

Answer 39

cyanobacteria

Question 40

which photosystem comes first

Answer 40

PSII comes first in the path of electron flow, but it is named as second because it was discovered after PSI

Question 41

which part of the chloroplast has a high concentration of H+

Answer 41

lumen

Question 42

why is there an electron produced in the photolysis of water

Answer 42

to say there is a reaction (oxidation, subreaction) The electrons released from the photolysis of water are used to replace the electrons lost by the photosystem II. Photosystem II replaces the electrons that are lost by the photosystem I. Photosystem I provides the electrons for the production of NADPH.

Question 43

refers to the process of moving ions (e.g. protons) to the other side of a biological membrane, and as a result, an electrochemical gradient is generated. This can then be used to drive ATP synthesis. - movement of H+ across ATP synthase

Answer 43

chemiosmosis

Question 44

what happens in light reaction (5)

Answer 44

- Chlorophyll Photoactivation - Photolysis of Water - Linear Electron Flow - Reduction of NADP+ - Photophosphorylation