photosynthesis

Question 1

Photosynthesis

Answer 1

Photosynthesis is the process by which cells synthesise organic compound (ex. glucose) from inorganic molecules (CO2 and H2O) in the presence of sunlight

Question 2

Photosynthesis equation

Answer 2

carbon dioxide + water = (light and chlorophyll) = Glucose + oxygen + water

Question 3

chemical energy created

Answer 3

Photsynthetic organisms use the light energy from the sun to create chemical energy (ATP). This energy can be used directly or used to synthesise organic compounds (ex. glucose)

Question 4

relationship of Photosynthesis and cell respiration

Answer 4

1)Photosynthesis in chloroplasts (light energy)
2) Oxygen in organic compounds
3) cell respiration in mitochondria (cellular energy)
4) carbon dioxide and water back to photosynthesis

Question 5

Electromagnetic spectrum

Answer 5

range of all possible frequencies of electromagnetic radiation

Question 6

Colours of the visible spectrum

Answer 6

red, orange, yellow, green, blue, indigo, violet (700nm - 400nm)

Question 7

Chlorophyll

Answer 7

Chlorophyll is a green pigment found in photosynthetic organisms that is responsible for light absorption.
When it absorbs light it releases electrons which are used to synthesise ATP

Question 8

Chlorophyll reflect and absorption colours

Answer 8

Absorbs most strongly: Blue and red
Reflects most strongly: green

Question 9

Pigments

Answer 9

Pigments absorb light as a source of energy for photosynthesis

Question 10

Photosynthesis two step process:

Answer 10

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

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

Question 11

Pigment examples

Answer 11

Chlorophylls
Xanthophyll
Carontenes

Question 12

Chromatography

Answer 12

An experimental technique by which mixtures can be separated

Question 13

law of limiting factors

Answer 13

when a chemical process depends on more than one essential condition being favourable, the rate of reaction will be limited by the factor that is nearest its minimum value.

Question 14

photosynthesis dependant on:

Answer 14

Temperature
Light intensity
Carbon dioxide concentration

Question 15

Temperature

Answer 15

• Photosynthesis is controlled by enzymes, which are sensitive to temperature fluctuations
• As temperature increases reaction rate will increase, as reactants have greater kinetic energy and more collisions result
• Above a certain temperature the rate of photosynthesis will decrease as essential enzymes begin to denature

Question 16

Light Intensity

Answer 16

• Light is absorbed by chlorophyll, which convert the radiant energy into chemical energy (ATP)
• As light intensity increases reaction rate will increase, as more chlorophyll are being photo-activated
• At a certain light intensity photosynthetic rate will plateau, as all available chlorophyll are saturated with light
• Different wavelengths of light will have different effects on the rate of photosynthesis (e.g. green light is reflected)

Question 17

Carbon dioxide concentration

Answer 17

• Carbon dioxide is involved in the fixation of carbon atoms to form organic molecules
• 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 18

Measuring CO2 uptake

Answer 18

Carbon dioxide uptake can be measured by placing leaf tissue in an enclosed space with water
Increased uptake of CO2 by the plant will lower the concentration in solution and increase the alkalinity

Question 19

Measuring O2 Production

Answer 19

Oxygen production can be measured by submerging a plant in an enclosed water-filled space attached to a sealed gas syringe

Question 20

Measuring Biomass