Photosynthesis

Question 1

What is the Light Reaction in photosynthesis?

Answer 1

energy from light is used to create unstorable chemical energy

Question 2

What is the calvin cycle?

Answer 2

AKA stoma reactions, dark reactions

chemical energy from the light reactions is used to create stable, storable chemical energy

Question 3

What is the structure of the Cholroplast?

Answer 3

has many membrane-enclosed compartments inside it that form into sacks

Question 4

What is in the sacs?

Answer 4

the sacs have aqueous interiors, the membrane surrounding them and the squeous solution around the sacks add up to three sites of important processes in photosynthesis

Question 5

what happens in the thylakoid membrane?

Answer 5

The thylakoid membranes of a chloroplast is an internal system of interconnected membranes, that carry out the light reactions of photosynthesis.

Question 6

what happens in the thylakoid space?

Answer 6

The thylakoid space is the space on the inside of the thylakoid. A thylakoid is membrane-bound disc in the chloroplast of plant cells. The membrane of the thylakoid contains enzymes necessary for the light dependent reactions of photosynthesis.

Question 7

what is the stroma?

Answer 7

colorless fluid surrounding the grana within the chloroplast. Within the stroma are grana, stacks of thylakoid, the sub-organelles, the daughter cells, where photosynthesis is commenced before the chemical changes are completed in the stroma.

Question 8

Chloroplast pigment:

what is chlorophylls a and b?

Answer 8

land plants have cholrophyll a and b

different a have methyl group

Question 9

Chloroplast pigment:

what are the three?

Answer 9

chlorophylls a and b

carotenoids

phycobilins

Question 10

carotenoids are responsible for what?

Answer 10

pigments responsible for bright red, yellow and orange hues in many fruits and vegetables

Question 11

phycobilins are responsible for what?

Answer 11

Any of a class of water-soluble, mostly red, orange, and blue pigments found in cyanobacteria and red algae. Phycobilins absorb the blue and blue-green frequencies of light which penetrate deep water, and allow red algae to carry on photosynthesis at greater depths than other organisms.

Question 12

Light spectra:

visible light is what? what is its range?

Answer 12

electromagnetic radiation in the wavelength rage of 380-750nm

Question 13

if a pigment is dissolved in a specific solvent it will have a what?

Answer 13

characteristic absorption spectrum and that spectrum will be unique to that molecule (like a fingerprint)

Question 14

What is a photosystem?

Answer 14

is an assembly of several light harvesting complexes that gather sunlight and pass the energy to a reaction center complex

Question 15

What are the pigments in the photosystem?

Answer 15

chlorophyll a and b

carotenoids

Question 16

pigments in the light-harvesting complex do what?

Answer 16

absorb light and transfer the energy to the reaction center chlorophyll a

Question 17

What happens to the reaction center (chlorophyll a) after absorbing the energy from the light harvesting complex?

Answer 17

the molecules are oxidized

Question 18

the light reaction:

what are the two kinds of electron flow that occur in this reaction?

Answer 18

non-cyclic and cyclic noth of which lead to the synthesis of ATP driven by light (photophosphorylation)

Question 19

what happens in non-cyclic photophosphorylation?

the Z-scheme

Answer 19

electrons move from a weak electron doner (H20) to a weak electron acceptor (NADP+). the movement of electrons also drives the formation of an H+ gradient, which is used to power ATP synthesis

Question 20

What is the problem posed by the Z-scheme?

Answer 20

it makes equal amounts of ATP and NADPH. but the subsequent Calvin cycle reaction needs more ATP than NADPH (3:2 ratio). the solution to the problem is cyclic photophosphorylation. which makes ATP but no NADPH

Question 21

How is the problem of the Z-scheme solved?

Answer 21

the electrons cycle through photosystem 1 only

a given photosystem will flip back and forth from cyclic and non-cyclic electron flow depending on the availability of NAHP+

Question 22

what form of electron flow would a photo system use if there is low NADP+?

Answer 22

cyclic electron flow

Question 23

what form of electron flow would a photo system use if there is high NADP+?

Answer 23

non cyclic electron flow

Question 24

The Calvin Cycle:

What does the Calvin cycle make?

Answer 24

it makes carbohydrate by fixing (reducing) CO2

Question 25

The Calvin Cycle:

how was this cycle discoved?

Answer 25

by Melvin Calvin who used radioactive carbon (14C) as a tracer

Question 26

The Calvin Cycle:

what is the first enzyme?

Answer 26

runisco (RuBP)

Question 27

The Calvin Cycle:

what is the first reaction of the calvin cycle?

Answer 27

RuBP (5C) + CO2 (1C) –> 2x3-phosphoglycerate (2x3c)

Question 28

What is the net gain of the calvin cycle?

Answer 28

3 turns (three carbons fed in) –> 1 glyceraldehyde-3-phosphate

Question 29

What is glyceraldehyde-3-phosphate used for? (5)

Answer 29

sugar, starch, cellulose

AA, protein

Nucleic acid

lipid

secondary metabolites