C3 photosynthesis

Question 1

What is a photoautotrough?

Answer 1

an organism capable of undertaking photosynthesis

Question 2

What is photosynthesis?

Answer 2

the process of capturing light energy to power the production of glucose and oxygen from carbon dioxide and water

Question 3

What is a mesophyll cell?

Answer 3

a plant cell type found in leaves that contain large amounts of chloroplasts

Question 4

How are electrons in the chlorophyll replaced?

Answer 4

sun excites electrons in the chlorophyll
splits water into hydrogen ions which provides to electrons which replace the lost electrons in the chlorophyll

Question 5

What is a chloroplast?

Answer 5

a membrane-bound organelle only found in plant and photoautotroph cells that is the site of photosynthesis

Question 6

What is a stoma?

Answer 6

a small pore on the leaf’s surface that opens and closes to regulate gas exchange

Question 7

What is the xylem?

Answer 7

a small pore on the leaf’s surface that opens and closes to regulate gas exchange

Question 8

What is the equation for water being split?

Answer 8

2H2O → O2 + 4H+ + 4e–

Question 9

What are the inputs for the light dependent stage of photosynthesis?

Answer 9

12 water (H2O) molecules
12 NADP+
18 ADP + Pi.

Question 10

What are the outputs for the light dependent stage of photosynthesis?

Answer 10

6 oxygen (O2) molecules
12 NADPH
18 ATP.

Question 11

Where does the light dependent stage of photosynthesis occur?

Answer 11

Chlorophyll filled thykaloid membranes that make up the grana in a choloroplast

Question 12

What are the steps in the light dependent stage of photosynthesis?

Answer 12

1. Light energy energises chlorophyll which pumps H+ and splits water
2. Oxygen released
3. H+ and e– generate NADPH and ATP
4. NADPH and ATP are inputs for the light-independent stage

Question 13

What occurs in step 1 of the light dependent stage of photosynthesis?

Answer 13

Inside the thylakoid, light energy excites electrons in chlorophyll. The pigment electrons move away from chlorophyll and hits water molecules, which causes water to split into oxygen and two H+ (photolysis). Hydrogen ions build on one side of the thykaloid membrane then diffuse into the intermembrane space where ATP synthase acts as a channel.

Question 14

Why doesn’t green light cause photosynthesis?

Answer 14

shorter wavelengths hit and excites electrons but green wavelength wont

Question 15

Why do electrons become excited?

Answer 15

When light energy hits the nucleus it moves the electrons more than usual.

Question 16

What occurs in step 2 of the light dependent stage of photosynthesis?

Answer 16

The oxygen is released from the chloroplast. It will either diffuse out of stomata and into the environment or be used as an input for aerobic cellular respiration.

Question 17

What occurs in step 3 of the light dependent stage of photosynthesis?

Answer 17

As the H+ ions move through the concentration gradient it spins ATP synthase and causes ADP and Pi to bind in ATP synthase active site making ATP (H+ is a cofactor) NADP then picks up the H+ ions and becomes NADPH

Question 18

What occurs in step 4 of the light dependent stage of photosynthesis?

Answer 18

ATP and NADPH coenzymes then move on to the light-independent stage

Question 19

What are the inputs of the light independent stage of photosynthesis?

Answer 19

6 carbon dioxide (CO2) molecules
12 NADPH
18 ATP.

Question 20

What are the outputs of the light independent stage of photosynthesis?

Answer 20

glucose (C6H12O6)
6 water (H2O) molecules
12 NADP+
18 ADP + Pi.

Question 21

Where does the light independent stage of photosynthesis occur?

Answer 21

In the stroma (mesophyll cell)

Question 22

What is the stroma?

Answer 22

the fluid substance that makes up the interior of chloroplasts. It is the site of the light-independent stage of photosynthesis

Question 23

What is photolysis?

Answer 23

the process in which molecules are broken down by the action of light

Question 24

What are the steps in the light independent stage?

Answer 24

1. Carbon dioxide molecules enter the Calvin cycle
2. NADPH molecules donate their hydrogen ions and electrons, and ATP molecules release energy
3. Carbon molecules continue to change and rearrange
4. create the output water

Question 25

What is the first step of the light independent stage?

Answer 25

Carbon dioxide molecules enter the Calvin cycle and undergo initial reactions. During these changes, the carbon from CO2 combines with a five-carbon molecule, then splits into 2 x three-carbon molecules, which continue along the cycle.

Question 26

What is the second step of the light independent stage?

Answer 26

NADPH molecules formed in the light-dependent reactions donate their hydrogen ions and electrons, and ATP molecules break into ADP and Pi to release energy to facilitate further changes to the carbon molecules.

Question 27

What is the third step of the light independent stage?

Answer 27

Carbon molecules continue to change and rearrange as they move around the cycle. Eventually, one specific three-carbon molecule is created and leaves the cycle, going on to contribute to the formation of glucose. Overall, six CO2 molecules must enter the cycle to produce glucose (carbon dioxide = one carbon; glucose = six carbons)

Question 28

What is the fourth step of the light independent stage?

Answer 28

Some of the oxygen molecules leftover from the breaking of CO2 at the beginning of the cycle combine with hydrogen ions from NADPH to create the output water

Question 29

What is the purpose of photosynthesis?

Answer 29

The production of glucose is the main outcome of photosynthesis. The plant, through a series of reactions over the two stages, has now converted sunlight energy into chemical energy stored within the bonds of a glucose molecule. The glucose is transported out of the chloroplast for cellular respiration or conversion into complex carbohydrates