C1.3 HL

Question 1

Describe the arrangement of pigments into photosystems in membranes.

Answer 1

Chloroplast - Granum - Thylakoid - Thylakoid membrane - Photosystem with chlorophyll pigment (capture light electrons excited)

Question 1

Outline the advantage of pigments being arranged in photosystems as opposed to being dispersed.

Answer 1

causes the excitation and the release of e- that will provide energy for the rest of the light-dependent phase of photosynthesis.

Question 2

Outline each photosystems: include where the replace lost electrons, peak absorbance of the reaction center of chlorophyll molecules, what they produce/function

Answer 2

PSII —> ATP
-P680 (best wavelength for absorbing)
- electron from photolysis
PSI —> reduced NADP
-P700
-electron from PSII

Question 3

Photosystems as arrays of _____ molecules that can generate and emit excited ______.

Answer 3

pigment, electrons

Question 4

Outline advantages of different types of pigment molecules being arranged within a photosystem.

Answer 4

• more pigment = more photons of light absorbed
• increases range of wavelengths
• efficient energy transfer to the reaction center

Question 5

Describe the role of photosystem II in photolysis.

Answer 5

• pigment chlorophyll absorb light
  -excited electron moves down ETC
• water splits and gives 2 electrons to PSII to replace lost electrons (happens twice to make oxygen gas)

Question 6

Photolysis of water at photosystem II contributes to the _________ in the thylakoid lumen.

Answer 6

proton gradient (inc. of H+)

Question 7

Outline the role of photosynthesis of the “Great Oxygenation Event” on early Earth.

Answer 7

-oxygenation of atmosphere
-increase in biodiversity after early life formed

Question 8

Outline the evidence for the “Great Oxygenation Event” provided by banded iron formations.

Answer 8

The increase in oxygen allowed it to react with iron to form several layers of iron oxide sediments.

Question 9

Sketch a cross section of the thylakoid membrane, inclusive of photosystem II, ATP synthase, an electron transport chain (with Pq) and photosystem II.

Answer 9

(view diagram/interactive)

Question 10

Define chemiosmosis and photophosphorylation.

Answer 10

Chemiosmosis - ATP synthase pump H+ (high to low- facilitate diffusion)
Phosphorylation - Kinetic energy allows ADP + Pi to convert to ATP

Question 11

electrons generated by photosystem II pass from ________ through a chain of electron carrier molecules.

Answer 11

plastoquinone (Pq)

Question 12

The energy _____ by the movement of electrons is used to __________ across the thylakoid membrane, from the ____ into the thylakoid lumen.

Answer 12

released, pump protons (H+), stroma

Question 13

The result of the electron transport chain is a ______, with a high concentration of protons in the _______.

Answer 13

proton gradient, thylakoid lumen

Question 14

Compare the flow of electrons in cyclic vs noncyclic photophosphorylation.

Answer 14

(ONLY PS1)Cyclic photophosphorylation- electrons get expelled by photosystem I and they return to the system.
- (BOTH PHOTOSYSTEMS) non-cyclic photophosphorylation, the electrons that are expelled by the photosystems do not return.

Question 15

the photoactivation of the reaction center _______ in photosystem I _____ electrons which pass through a different electron transport chain.

Answer 15

chlorophyll, excites

Question 16

Outline the flow and function of electrons from photosystem I in cyclic photophosphorylation.

Answer 16

-as excited electron travels ETC it uses energy to pump protons into thylakoid lumen
- ATP synthase uses facilitated diffusion to transfer protons into the stroma
-Kinetic energy: ADP +Pi –> ATP molecules are produced.

Question 17

Outline the flow and function of electrons from photosystem I in non-cyclic photophosphorylation.

Answer 17

-excited electron leaves PSII (P680)
-electron leaves PSI (P700)and enters NADP reductase enzyme embedded within the membrane
-Both NADPH and ATP molecules are produced.

Question 18

In noncyclic photophosphorylation, the electrons of ________ are used to reduce _____ to form NADPH.

Answer 18

photosystem I, NADP+

Question 19

State the function of the enzyme NADP reductase.

Answer 19

use electrons to reduce NADP+ to form NADPH for Calvin cycle

Question 20

The light dependent reactions convert ________ into chemical energy in the form of ___ and ________.

Answer 20

light energy, ATP, reduced NADP (=NADPH)

Question 21

In cyclic phosphorylation, water is ______ and NADPH is _______. The main action of this is _______. Product: _____

Answer 21

not required, not synthesized, hydrogen ions being pumped into lumen and stroma, ATP

Question 22

______ is an electron carrier in Photosynthesis

Answer 22

NADP

Question 23

Describe the structure of the thylakoid grana and stroma lamellae.

Answer 23

thylakoid grana - stack of pancakes
stroma lamellae - connect thylakoids of two different grana. increase the efficiency of photosynthesis - keep distance so that thylakoids do not clutter together.

Question 24

Outline how the thylakoid functions as a system of interacting parts.

Answer 24

The NADPH and ATP produced are used in the Calvin cycle

Question 25

State the location of the light-dependent reactions of photosynthesis, including photoactivation, photolysis, electron transport chain, chemiosmosis, and reduction of NADP.

Answer 25

thylakoid membranes