Plant Structures and Their functions

Question 1

Photosynthesis equatioin

Answer 1

carbon dioxide + water –> glucose +oxygen

Question 2

How are photosynthetic organisms the main producers of food for nearly all life on earth?

Answer 2

• During photosynthesis, photosynthetic organisms, such as green plants and algae use energy from the Sun to make glucose
• Some of the glucose used to make up the organisms biomass
• The energy stored in the biomass works its way through the food chain as animals eat them and each other.
• So photosynthetic organisms are the main porducers of food for nearly all life on Earth

Question 3

Where does photosynthesis happen?

Answer 3

• Happens inside of chloroplasts which contain chlorophyll which absorbs light
• Energy is transferred to the chloroplast by light

Question 4

What kind of reaction is photosynthesis?

Answer 4

Endothermic - energy is taken in during the reaction

Question 5

What are the limiting factors of photosynthesis?

Answer 5

• Light intensity
• Concentration of CO2
• Temperature

Question 6

How is temperature a limiting factor of photosynthesis?

Answer 6

Affects the rate of photosynthesis because it affects the enzymes involved…
- If temperature is too low, the enzymes needed for photosynthesis work slower
- If temperature is too high, the enzymes it needs for photosynthesis and other reactions will be denatured (happens at around 45 degrees)

Question 7

How is light a limiting factor of photosynthesis?

Answer 7

• Light transfers the energy needed for photosynthesis
• At first, light intensity and rate of photosynthesis are directly proportional (as the light intensity increases, rate of photosynthesis increases) but is only true up to a certain point

Question 8

The Inverse Square Law
(Light intensity as a limiting factor)

Answer 8

• The square of the distance from the lamp and the light intensity are inversely proportional to each other
• Written as: light intensity = 1/d²
  where d = distance from lamp
• Means that if you halve the distance, the light intensity will be four times greater and if you double the distance, the light intesnity will be four times smaller

Question 9

How is CO² Concentration a limiting factor?

Answer 9

• CO² is one of the raw materials needed for photosynthesis
• As with light intensity, increasing CO² concentration increases the rate of photosynthesis up to a point
• As long as CO² is plentiful in supply, then light or temperature is the limiting factor