2.9 & 8.3

Question 1

what is photosynthesis?

Answer 1

conversion of light energy into chemical energy (ATP)

Question 2

what is the electromagnetic spectrum?

Answer 2

the range of all possible frequencies of electromagnetic radiation

Question 3

what is Chlorophyll?

Answer 3

Chlorophyll is a green pigment found in photosynthetic organisms that is responsible for light absorption

Question 4

what does chlorophyll do?

Answer 4

When chlorophyll absorbs light, it releases electrons which are used to synthesise ATP (chemical energy)

Question 5

what color does chlorophyll absorbs?

Answer 5

Blue and red

Question 6

what color does chlorophyll reflect?

Answer 6

green

Question 7

what does The absorption spectrum show?

Answer 7

indicates the wavelengths of light absorbed by each pigment

Question 8

what does The action spectrum show?

Answer 8

indicates the overall rate of photosynthesis at each wavelength of light

Question 9

Both display two main peaks, what the colors they peak at and what is their number?

Answer 9

a larger peak at the blue region (~450 nm) and a smaller peak at the red region (~670 nm)

Question 10

what are the 2 steps of photosynthesis?

Answer 10

The light dependent reactions and The light independent reactions

Question 11

what does The light independent reactions do?

Answer 11

use the chemical energy to synthesise organic compounds

Question 12

what does The light dependent reactions do?

Answer 12

convert light energy from the Sun into chemical energy (ATP)

Question 13

what comes first light dependent of light independent reactions?

Answer 13

Light Dependent Reactions comes first.

Question 14

what happens in the the Light Dependent Reactions?

Answer 14

1) Light is absorbed by chlorophyll, which results in the production of ATP (chemical energy)
2) Light is also absorbed by water, which is split (photolysis) to produce oxygen and hydrogen
3) The hydrogen and ATP are used in the light independent reactions, the oxygen is released from stomata as a waste product

Question 15

what happens in the the Light Independent Reactions?

Answer 15

1) ATP and hydrogen (carried by NADPH) are transferred to the site of the light independent reactions
2) The hydrogen is combined with carbon dioxide to form complex organic compounds (e.g. carbohydrates, amino acids, etc.)
3) The ATP provides the required energy to power these anabolic reactions and fix the carbon molecules together

Question 16

what is photolysis?

Answer 16

chemical process by which molecules are broken down into smaller units through the absorption of light

Question 17

name 3 pigments

Answer 17

chlorophylls, xanthophyll and carotenes

Question 18

what is Chromatography?

Answer 18

Chromatography is an experimental technique by which mixtures can be separated

Question 19

what are the 3 limiting factors on the rate of photosynthesis?

Answer 19

temperature, light intensity and CO2 concentration

Question 20

how is temperature a limiting factor?

Answer 20

• Photosynthesis is controlled by enzymes, which are sensitive to temperature fluctuations
• As temperature increases reaction rate will increase

Question 21

how is light intensity a limiting factor?

Answer 21

• Light is absorbed by chlorophyll, which convert the radiant energy into chemical energy (ATP)
• As light intensity increases reaction rate will increase

Question 22

how is CO2 concentration a limiting factor?

Answer 22

• Carbon dioxide is involved in the fixation of carbon atoms to form organic molecules
• As carbon dioxide concentration increases reaction rate will increase

Question 23

where do Light Dependent Reactions occur?

Answer 23

discs within the chloroplast called thylakoids

Question 24

what are the 3 steps of the Light Dependent Reactions?

Answer 24

1) Excitation of photosystems by light energy
2) Production of ATP via an electron transport chain
3) Reduction of NADP+ and the photolysis of water

Question 25

what is Cyclic Photophosphorylation?

Answer 25

Cyclic photophosphorylation involves the use of only one photosystem (PS I) and does not involve the reduction of NADP+

Question 26

what is Non-Cyclic Photophosphorylation?

Answer 26

Non-cyclic photophosphorylation involves two photosystems (PS I and PS II) and does involve the reduction of NADP+

Question 27

where does The light independent reactions occur?

Answer 27

fluid-filled space of the chloroplast called the stroma

Question 28

what is the light independent reactions also known as?

Answer 28

the calvin cycle

Question 29

what are the 3 main steps of the calvin cycle?

Answer 29

1) Carbon Fixation
2) Reduction of Glycerate-3-Phosphate
3) Regeneration of RuBP

Question 30

what happens in carbon fixation?

Answer 30

An enzyme, RuBP carboxylase (or Rubisco), catalyses the attachment of a CO2 molecule to RuBP

Question 31

what happens in Reduction of Glycerate-3-Phosphate?

Answer 31

Reduction by NADPH transfers hydrogen atoms to the compound, while the hydrolysis of ATP provides energy

Question 32

what happens in Regeneration of RuBP (Rubisco)?

Answer 32

Of the six molecules of TP produced per cycle, one TP molecule may be used to form half a sugar molecule

Question 33

Name 5 structure of the chloroplast

Answer 33

Thylakoids 
Grana 
Photosystems 
Stroma 
Lamellae

Question 34

what does the stroma do?

Answer 34

central cavity that contains appropriate enzymes and a suitable pH for the Calvin cycle to occur