Photosynthesis/ Light reaction stuff

Question 1

Where do light reactions take place?

Answer 1

lumen of the thylakoids

Question 2

Where does carbon fixing take place?

Answer 2

chloroplast stroma (middle bit)

Question 3

What do photosyntheic pigments do and what is the main one that gets excited?

Answer 3

Photosynthetic pigments catch sunlight energy. Chlorophyll a is the main photosynthetic pigment

Question 4

What happens in the antenna complex?

Answer 4

transmit energy from sunlight to chlorophyll a in the reaction center (Chlorophyll a and accessory pigments, chlorophyll b and carotenoids)

Question 5

Where does the electron transport chain start?

Answer 5

photosystem II

Question 6

What happens when Chl* loses an electron?
*=excited

Answer 6

it becomes oxidized (Chl+)

Question 7

What is lost in the electron tranport chain between photosystem l and photosystem ll ?

Answer 7

reducing power

Question 8

How is reducing power reproduced?

Answer 8

The excitation by light of PSI reaction center powers more electron movement across another electron transport chain, ending up in the reduction of NADP+ into NADPH.

Question 9

What does ATP stand for?

Answer 9

adenosine triphosphate (Short term energy storage)

Question 10

What does NADPH stand for?

Answer 10

Nicotinamide adenine dinucleotide phosphate (short term reducing power storage)

Question 11

What happens when there is a high level of light?

Answer 11

Excess energy/electrons end up on oxygen creating- Reactive oxygen species (ROS)

Question 12

How much does the fixation of one carbon dioxide molecule cost in ATP and NADP?

Answer 12

ATP- 3
NADP- 2

Question 13

What is the calvin-benson cycle?

Answer 13

part of the photosynthesis processes responsible for assimilation of atmospheric CO2 into sugar phosphates used in wider metabolism for plant growth and development.

Question 14

What can G3P produced by the Calvin-Benson cycle be used for?

Answer 14

can be used either to make sucrose to be transported to other parts of the plant, or stored temporarily in starch granules.

Question 15

What is hydrolysed to power night metabolism in plants?

Answer 15

sucrose

Question 16

What is the role of rubsico?

Answer 16

It catalyzes the first step in the Calvin cycle, namely the carboxylation of RuBP. It leads to the production of two 3-PGA molecules. RuBisCO also has an affinity for oxygen, thus it binds to some O2 during the photorespiration process

Question 17

What occurs during photorespiration?

Answer 17

Recycling the oxygenation product 2-PG costs energy and releases fixed CO2

Question 18

Where does the calvin benson cycle occur in c4 plants?

Answer 18

bundle sheath cells

Question 19

What does CAM stand for an what do CAM plants do?

Answer 19

Crassulean Acid Metabolism, fix carbon dioxide by CAM pathway or Crassulacean acid metabolism

Question 20

What increases photorespiration?

Answer 20

Temperature