Photosynthesis

Question 1

What are autotrophs?

Answer 1

Organism that are capable of self-nourishment through being able to harness the energy related by chemical reactions in chemosynthesis

Eg. Most plants and certain bacteria and protists

Question 2

What are the 2 types of autotrophs?

Answer 2

Photoautotrophs

Chemoautotrophs

Question 3

What are photoautotrophs?

Answer 3

Green plants and algae, use light energy to synthesis their own organic materials.

Question 4

What are chemoautotrophs?

Answer 4

Mainly bacteria, able to harness the energy released in exergonic chemical reactions to synthesise their organic food.

Question 5

What are the 10 structures of a cross-section leaf?

Answer 5

Wax cuticle
Upper epidermis 
Mesophyll (palisade mesophyll and spongy mesophyll) 
Substomatal Air space
Lower epidermis 
Stoma
Guard Cell with Chloroplasts 
Leaf veins

Question 6

What is Photosynthesis?

Answer 6

A series of chemical reactions by which plants use light energy captured by chloroplasts to break down carbon dioxide and water to synthesise oxygen, glucose and water.

Question 7

What is the chemical formula for photosynthesis?

Answer 7

6CO2 + 12H20 –> C6H12O6 + 6O2 + 6H2O

Carbon + Water –> Glucose + Oxygen + Water

Question 8

What are the 3 photosynthetic pigments in green plants?

Answer 8

Chlorophyll
Carotenoids
Xanthophyll

Question 9

What colours do Chlorophyll absorb and reflect?

Answer 9

They absorb wavelengths of blue and red light.

They reflect green light, leaves appear green.

Question 10

What colours do Carotenoids reflect and absorb?

Answer 10

They reflect orange light and absorb blue-violet light

Question 11

What colours do Xanthophyll reflect and absorb light?

Answer 11

They reflect yellow light and they absorb blue-violet light.

Question 12

What are the two main stages of Photosynthesis?

Answer 12

Light dependent stage

Light independent stage

Question 13

Where does the light dependent stage occur?

Answer 13

Light energy is absorbed by the pigments of the thylakoid membrane.

Question 14

What the reactants and products of the light dependent stage?

Answer 14

Water –> H+ + O2 + ATP

Electrons within the Chlorophyll become energised, this energy splits water molecules (H2O) into Hydrogen ions (H+) and Oxygen gas (O2), ATP is also formed.

Question 15

Where does the light independent stage occur?

Answer 15

Occurs in the stroma of the chloroplast, glucose is produced.

Question 16

What are the reactants and products of the light independent stage?

Answer 16

CO2 + Hydrogen ions(H+) + ATP –> C6H12O6

Carbon dioxide gas, hydrogen ions and ATP from the light dependent stage, provide energy for the conversion of CO2 to Glucose molecules.

Question 17

What activity occurs in the chloroplasts during the daylight?

Answer 17

Glucose is converted into starch or sucrose
Sucrose is the most easily transported to move around the plant via phloem
Starch is stored briefly in the stroma during the day

Question 18

What is starch?

Answer 18

Storage form of glucose

Question 19

What activity in the chloroplast occur in the evening/night?

Answer 19

Cells convert starch to sucrose for export to other cells in leaves, stem and roots that lack chloroplast.

Question 20

How is photosynthesis and cellular respiration interdependent with each other?

Answer 20

As the glucose and oxygen that is made in photosynthesis (outputs), are the inputs of aerobic respiration and the outputs of aerobic respiration (CO2 and H2) are the inputs of of photosynthesis.