Photosynthesis

Question 1

What is the main function of photosynthesis?

Answer 1

Producing carbohydrates

Question 2

Sunlight is what type of energy?

Answer 2

Electromagnetic

Question 3

All the energy from sun is used during photosynthesis.

Answer 3

False. 60% is out of the visible range and unavailable for plants to use. The rest of it is lost to other processes such as photorespiration.

Question 4

Where are Chloroplasts located?

Answer 4

Mesophylls

Question 5

Where will the light dependent and dark reactions occur in the chloroplast?

Answer 5

Light dependent will happen in the thykaloid lumen and dark reactions (Calvin Cycle) will happen in the stroma

Question 6

What is the photosynthesis equation?

Answer 6

6CO2 + 6H2O + light → C6H12O6 + 6O2.

Question 7

Cite the processes involved in the light dependent reaction, in order:

Answer 7

Photosystem II
Electron Transport Chain I
Photosystem I
Electron Transport Chain II
ATP synthesis

Question 8

What is the role of the light dependent reaction?

Answer 8

To generate chemical energy from light and water

Question 9

Cite the order of events responsible for charging NADP:

Answer 9

Light - H2O oxidation - PSII - Pq - Cy - Pc - Light - PSI - Fe - NADP reductase

Question 10

What is the electron energy being used for during the light dependent reaction?

Answer 10

To create a proton gradient in the thykaloid lumen; it is pumping protons into the cell

Question 11

What is the main difference between PSI and PSII?

Answer 11

PSI is about charging NADP+ and PSII is about creating a proton gradient

Question 12

What is ATP synthase’s main function?

Answer 12

It phosphorylates ADP, trapping the energy in there, creating ATP

Question 13

What will cause the protons to flow through ATP synthase?

Answer 13

The proton gradient

Question 14

What is the Calvin Cycle main function?

Answer 14

To create 3-carbon sugars from carbon dioxide and ATP/NADPH

Question 15

What are the steps for the Calvin Cycle?

Answer 15

Carbon fixation (carboxylation), reduction of 3-PGA to G3P, regeneration of CO2 acceptor (RUBP)

Question 16

What is the carboxylation (carbon fixation) phase?

Answer 16

It is where 3 molecules of CO2 are bound to RuBP (ribulose biphosphate) with the help of Rubisco

Question 17

What is the reduction phase?

Answer 17

In the reduction phase we transform the compound created during carboxylation into glyceraldehyde-3-phosphate (G3P), which is the basic sugar.

Question 18

What happens in the regeneration phase?

Answer 18

Some of the G3P created is used to regenerate RuBP in order to keep the cycle happening.

Question 19

What is photorespiration?

Answer 19

It is when Rubisco accidentally accepts oxygen to RuBP instead of carbon dioxide.

Question 20

Suppose you discovered a mutant strain of spinach in which the thykaloid membranes were slightly permeable to protons and thus allowed a slow leakage of protons. How would this leakage affect the yield of ATP and/or NADPH from the light dependent reactions?

Answer 20

ATP yield would decrease

Question 21

Which is the role of Rubisco in the Calvin Cycle?

Answer 21

To incorporate CO2 from the atmosphere into an organic molecule.

Question 22

What is another vital function of Cytochrome b6f?

Answer 22

It couples the transport of electrons with the pumping of protons from the stroma into the thylakoid lumen

Question 23

What is the energy in NADPH and ATP being used for during the light independent cycle?

Answer 23

To assemble carbohydrates in the stroma