Photosynthesis

Question 1

What is Photosynthesis?

Answer 1

process in which autotrophic organisms convert solar energy into chemical energy

Question 2

What is an Autotroph?

Answer 2

a “self feeder”

Question 3

Photoautotrophic

Answer 3

using specifically sunlight to make organic molecules

Question 4

Heterotroph?

Answer 4

“other feeder,” relies on other organisms for food and oxygen (aka plants)

Question 5

what kind of process is phtosynthesis

Answer 5

a redox reaction

Question 6

what is the electron carrier in photosynthesis?

Answer 6

NADP+ / NADPH

Question 7

Photosynthesis is a two step process, the first step being…

Answer 7

light reaction

Question 8

in the light reaction, we will….

Answer 8

1.) convert light into chemical energy
2.) split water to produce electrons and O2
3.) Reduce NADP+ to NADPH
4.) Generate ATP

Question 9

What is the second step in the process?

Answer 9

the calvin cycle “synthesis”

Question 10

in the calvin cycle, what happens?

Answer 10

1.) Carbon Fixation
2.) Reduces carbon with electrons from NADPH
3.) uses ATP to synthesize sugar from fixed and reduced Carbon

Question 11

what are the reactants of the light reaction?

Answer 11

light, water. NADPH and ADP + Pi come from calvin cycle, but also enter

Question 12

products of light reactions?

Answer 12

ATP, NADPH, O2

Question 13

what are the reactants of the calvin cycle?

Answer 13

CO2, ATP, NADPH

Question 14

what are the products of the calvin cycle?

Answer 14

NADP+, ADP + Pi, Sugar (G3P)

Question 15

Pigments

Answer 15

substances that absorb visible light

Question 16

whats the relationship between pigment color and the color they absorb?

Answer 16

the color of the pigment is the color that it doesnt absorb…ie, color left behind

Question 17

what is the key pigment?

Answer 17

Chlorophyll a

Question 18

what is the main accessory pigment?

Answer 18

Chlorophyll b

Question 19

what is the accessory pigment that actually is not green?

Answer 19

Carotenoids, they are orange / yellow color

Question 20

What is meant by chlorophyll excitation by light?

Answer 20

the photons energy is transferred to an electron, which is then excite to a higher orbital

Question 21

what does a photosystem consist of?

Answer 21

a reaction center complex, and light harvesting complexes

Question 22

what is a reaction center complex?

Answer 22

consists of proteins bound to chlorophyll a molecules and a primary electron acceptor.

Question 23

what are light harvesting complexes?

Answer 23

contain various pigment molecules bound to proteins to capture light. THINK OF THEM AS AN ANTENNAE FOR THE RCC

Question 24

where do light reactions start?

Answer 24

photosystem II

Question 25

what is the source of electrons used in the light reactions?

Answer 25

water

Question 26

so whats the big picture thus far?

Answer 26

light reactions use light energy to create ATP and NADPH, which provide chemical energy (THE ATP) and reducing power (THE NADPH) for the Calvin Cycle

Question 27

where do the protons get pumped to and from where?

Answer 27

from the stroma to the thylakoid

Question 28

Once the electrons reach PSI, where do they go?

Answer 28

they will move to a 2nd transporter, then to NADP+, which will then be reduced by the enzyme NADP+ Reductase

Question 29

what is the enzyme that reduces NADP+?

Answer 29

NADP+ reductase

Question 30

where does the calvin cycle occur?

Answer 30

Stroma

Question 31

what is G3P?

Answer 31

glyceraldehyde-3-phosphate

Question 32

what are the 3 steps to the calvin cycle?

Answer 32

Carbon Fixation, Reduction, Regeneration of RuBp

Question 33

what happens in the carbon fixation phase?

Answer 33

CO2 molecules will be covalently linked to a 5-C sugar, RuBp, then the CO2 acceptor, by the enzyme RUBISCO, forming 3-C molecules

Question 34

What is RuBp?

Answer 34

Ribulose bisphosphate (sugar)

Question 35

what is RUBISCO?

Answer 35

ribulose bisphosphate carboxylase oxygenase

Question 36

what happens in reduction phase of the calvin cycle?

Answer 36

3-phosphogylcerate is reduced using NADPH and ATP to form G3P. Two G3P are then made per CO2 fixed, making a total of 6 G3P per 3CO2

Question 37

What happens in the regeneration phase?

Answer 37

the five remaining G3P molecules re rearranged to form 3 RuBp molecules