2.9 Photosynthesis

Question 1

Photosynthesis

Answer 1

the process by which cells synthesise organic compounds from inorganic molecules in the presence of sunlight

Question 2

Photosynthesis equation

Answer 2

6CO2 + 6H2O =(light + chlorophyll)> C6H12O6 + 6O2

Question 3

Photosynthesis word equation

Answer 3

carbon dioxide + water => glucose + oxygen

Question 4

What is light energy used for?

Answer 4

create chemical energy (ATP)

Question 5

The electromagnetic spectrum light

Answer 5

Roy G. Biv
red
orange
yellow
green
blue
indigo
violet

Question 6

Chlorophyll

Answer 6

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

Question 7

What light does chlorophyll absorb the most?

Answer 7

blue then red

Question 8

What light does chlorophyll reflect the most?

Answer 8

green

Question 9

Absorption spectrum

Answer 9

indicates the wavelengths of light absorbed by each pigment

Question 10

Action spectrum

Answer 10

indicates the overall rate of photosynthesis at each wavelength of light

Question 11

What are the two steps of photosynthesis?

Answer 11

light dependent reactions convert light energy from the Sun into chemical energy (ATP)
light independent reactions use the chemical energy to synthesise organic compounds

Question 12

Chromatography

Answer 12

an experimental technique by which mixtures can be separated

Question 13

Paper chromatography

Answer 13

uses paper (cellulose) as the stationary bed

Question 14

Thin layer chromatography

Answer 14

uses a thin layer of adsorbent which runs faster and has better separation

Question 15

What conditions is photosynthesis dependent on?

Answer 15

temperature
light intensity
carbon dioxide concentration

Question 16

Effect of temperature on photosynthesis

Answer 16

photosynthesis is controlled by enzymes, which are sensitive to temperature fluctuations
temp increases - reaction increases as more kinetic energy results in more collisions
above a certain temperature the rate of photosynthesis will decrease

Question 17

Effect of light intensity on photosynthesis

Answer 17

as light intensity increases reaction rate will increase, as more chlorophyll are being photo-activated
at a certain light intensity photosynthetic rate will start to stop, as all available chlorophyll are saturated with light
(different wavelengths of light will have different effects)

Question 18

Effect of carbon dioxide concentration on photosynthesis

Answer 18

as carbon dioxide concentration increases reaction rate will increase, as more organic molecules are being produced
at a certain concentration of CO2 photosynthetic rate will plateau, as the enzymes responsible for carbon fixation are saturated

Question 19

How can we measure rate of photosynthesis?

Answer 19

uptake of carbon dioxide
production of oxygen
a change in biomass

Question 20

How to measure carbon dioxide uptake?

Answer 20

place leaf tissue in an enclosed space with water (free of carbon dioxide by boiling and cooling)
carbon dioxide interacts with the water molecules (produces bicarbonate and hydrogen ions) and changes the pH
increased uptake of carbon dioxide will lower the concentration in solution and increase alkalinity

Question 21

How to measure oxygen production?

Answer 21

submerging a plant in an enclosed water-filled space attached to a sealed gas syringe
any oxygen gas produced will bubble out of solution and can be measured by a change in meniscus level on the syringe

Question 22

How to measure biomass?

Answer 22

measure the change in the plant’s biomass (after completely dehydrated)