Photosythesis

Question 1

Define Photosynthesis

Answer 1

process by which green plants and certain other organisms transform light energy into chemical energy
equation: 6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2

Question 2

State the main photosynthetic pigment

Answer 2

Chlorophyll: absorbs light energy,
Blue and red are the two wavelengths most effectively absorbed by chlorophyll
reflects green light which makes plants green
Light contains photons which contain energy

Question 3

Outline the difference in absorption of red, blue, and green light by chlorophyll

Answer 3

Red: long wave length
Blue: short wave length
Both red and blue are absorbed

Green wavelength is reflected

Question 4

Describe the splitting of water molecules (photolysis)

Answer 4

During the light reaction of photosynthesis the absorption of light by the chlorophyll results in the loss of the electron from it, to fulfill the electron requirement, the water molecule splits and donates the electron to chlorophyl.

Question 5

Explain what the light-dependent reactions involve

Answer 5

convert light energy to chemical energy
Occur in the thylakoid membranes
Reduce NADP+ to NADPH (with energy absorbed from light)
Give off O2 as a by-product
Generate ATP through photophosphorylation

Question 6

Explain was the light-independent reactions involve (Calvin-Cycle) (FRQ)

Answer 6

=carbon-fixation reactions that create a carbohydrate; ATP and NADPH from the light reaction are used to reduce CO2 to glucose

Question 7

Explain the relationship between the structure of the chloroplast and its function

Answer 7

-Intermembrane space- similar to mitochondria
Double-membrane
-Thylakoids: location of light-dependent reactions, contain
-Grana: a stack of thylakoid to maximize light absorption, containing chlorophyll (absorb light energy)
-Stroma: space outside the thylakoids, location of Calvine Cycle

Question 8

Carbon Fixation (1st phase of Calvin cycle)

Answer 8

Each molecule of CO2 is attached to a five-carbon sugar ribulose biphosphate (RuBP)
The reaction is catalyzed by RuBP carboxylase
makes a six-carbon sugar that splits into two molecules of a three-carbon sugar, 3-phosphoglycerate is formed

Question 9

Reduction (2nd phase of Calvin Cycle)

Answer 9

ATP and NADPH are used to reduce 3-phosphoglycerate to triose phosphate (G3P)

Question 10

Regeneration of CO2 Acceptor (3rd phase of Calvin Cycle)

Answer 10

ATP is used to rearrange triose phosphate to RuBP

Question 11

Non-Cyclic Electron Flow (FRQ)

Answer 11

-electrons are removed from the water and passed through PSII and PSI before ending up in NADPH.
Light excites electrons in photosystem II
-Water is split to replace the electron
-Electrons pass to photosystem I via ETC
-ATP is created by photophosphorylation
-Electrons are passed from photosystem I to Calvin cycle via NADPH

Question 12

Cyclic Electron Flow

Answer 12

-Electrons continue to only flow through photosystem I
-electrons follow a different, circular path and only ATP (no NADPH) is produced.

Question 13

Graph of Limiting Factors

Answer 13

(look at google sides)

Question 14

location of photosynthesis

Answer 14

chloroplast- site of photosynthesis

Question 15

3 aspects of Photosystems (FRQ)

Answer 15

1. antenna complex = pigments that absorb light energy and pass it from molecule to molecule
2. reaction-center chlorophyll = molecule that can transfer electrons to start reactions
3. Primary electron acceptor = traps electrons from the reaction-center chlorophyll

Question 16

Photosystem 2 (occurs first)

Answer 16

appears sooner than photosystem I in the process of photosynthesis.
contains chlorophyll a molecule known as P680
absorbs light wavelengths of 680 nm
Located in the inner surface of the thylakoid membrane
Photolysis of water occurs
involve in non-cyclic electron flow

Question 17

Photosystem 1 (occurs second)

Answer 17

-has a chlorophyll a molecule known as P700
-absorbs light at wavelength of 700nm
-located in the outer surface of the thylakoid membrane
-photolysis of water does not occur
-involve in both non-cyclic and cyclic electron flow

Question 18

chemiosmosis

Answer 18

electron travels down ETC, losing energy as it goes. Some of the released energy drives the pumping of H+ ions from the stroma into the thylakoid interior, building a gradient.
As H+ ions flow down their concentration gradient and into the stroma, they pass through ATP synthase, driving ATP production
the proton gradient that is created provides the energy for ATP synthase to create ATP from ADP