C3 photosynthesis

Question 1

Photoautotroph

Answer 1

An organism capable of undertaking photosynthesis.

Question 2

Photosynthesis

Answer 2

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

Question 3

Mesophyll cell

Answer 3

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

Question 4

Chloroplast

Answer 4

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

Question 5

Chlorophyll

Answer 5

A chemical found in the thylakoids of chloroplasts. It is responsible for absorbing light energy in photosynthesis.

Question 6

Stoma (pl. stomata)

Answer 6

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

Question 7

Xylem

Answer 7

Vascular tissue in plants responsible for transporting water and minerals from the roots to the leaves.

Question 8

Light-dependent stage

Answer 8

The first stage of photosynthesis, where light energy splits water molecules into oxygen and hydrogen inside the thylakoid membranes. AKA the light-dependent reactions.

Question 9

Thylakoid

Answer 9

A flattened sac-like structure housed inside the chloroplast. Each thylakoid is made up of a chlorophyll-containing membrane enclosing a lumen. Thylakoids are the location of the light-dependent stage of photosynthesis.

Question 10

Granum (pl. grana)

Answer 10

A stack of thylakoids.

Question 11

NADPH

Answer 11

A coenzyme that is a proton (H+) and electron carrier in photosynthesis.

Question 12

ATP

Answer 12

Adenosine triphosphate, a high-energy molecule that, when broken down, provides energy for cellular processes.

Question 13

Inputs of light-dependent stage

Answer 13

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

Question 14

Outputs of light-dependent stage

Answer 14

• 6 oxygen (O2) molecules
• 12 NADPH
• 18 ATP

Question 15

Photolysis

Answer 15

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

Question 16

Steps in the light-dependent stage

Answer 16

1) Sunlight excites an electron within chlorophyll.
2) Water absorbed by a plant’s root hairs is split into O2 and H+ as it donates one electron to the chlorophyll.
3) The excited electron and H+ ion from water lead to the production of the coenzymes NADPH and ATP.
4) The oxygen is released out of the chloroplast, and the coenzymes are ready for the second stage of photosynthesis.

Question 17

Biochemical pathway

Answer 17

A series of steps (which may occur at different locations within a cell or, in the case of eukaryotic organisms, in different cells) from initial reactants to a final product and each step is facilitated by enzymes and coenzymes.

Question 18

Enzymes & coenzymes in photosynthesis

Answer 18

Catalyse most of the reactions in photosynthesis, and ensure reactions are sped up and controlled so plants can metabolise efficiently.

Question 19

ATP synthase enzyme

Answer 19

Catalyses the reaction ADP + Pi -> ATP

Question 20

Light-independent stage

Answer 20

The second stage of photosynthesis where carbon dioxide is used to form glucose in the stroma of a chloroplast. AKA the Calvin cycle, the dark stage, or the light-independent reactions.

Question 21

Stroma

Answer 21

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

Question 22

Inputs of light-independent stage

Answer 22

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

Question 23

Outputs of light-independent stage

Answer 23

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

Question 24

Steps in the light-independent stage

Answer 24

1) CO2 collected from the stomata in leaves enters a cyclic reaction.
2) The carbon, from CO2, undergoes reactions powered by ATP and NADPH to produce a series of carbon-based molecules.
3) Eventually, a specific carbon molecule is reached that goes on to contribute to the formation of glucose, with water also being produced in this stage.

Question 25

ATP coenzyme

Question 26

NADPH coenzyme