B1.4 Photosynthesis

Question 1

Biomass

Answer 1

The total mass of organisms in a given area

Question 2

chlorophyll

Answer 2

green pigment in chloroplast which traps energy from the Sun

Question 3

endothermic

Answer 3

a chemical reaction in which energy is transferred from the surrounding to the reacting mixture

Question 4

limiting factors

Answer 4

factors which can prevent an increase in the rate of photosynthesis

Question 5

photosynthesis

Answer 5

process by which producers make food - carbon dioxide and water react to form glucose and oxygen

Question 6

producers

Answer 6

Organisms that make their own food through the process of photosynthesis

Question 7

stage 1 (of photosynthesis)

Answer 7

the light dependant stage of photosynthesis where energy transferred from light is used to split water molecules into oxygen gas and hydrogen ions

Question 8

stage 2 (of photosynthesis)

Answer 8

the light independent stage of photosynthesis where carbon dioxide gas combines with the hydrogen ions produced in stage 1 of photosynthesis to make glucose

Question 9

Photosynthesis word and symbol eqation

Answer 9

carbon dioxide + water -> glucose + oxygen

6CO2 + 6H2O -> C6H12O6 + 6O2

Question 10

Where does photosynthesis occur?

Answer 10

In the plant’s chloroplasts

Question 11

What happens to glucose produced (in photosynthesis)

Answer 11

the plant uses some of the glucose it makes immediently in respiration. Other glucose molecules are converted into other sugar molecules such as fructose. Glucose that is not needed straight away is converted to starch. This provides a store of energy and can be used at night for respiration when the plant is not photosynthesising.

Question 12

How do you test for starch?

Answer 12

Take the leaf you are about to test and, using forceps, place it in a beak of boiling water to kill it. Then place the leaf, using forceps, into a boiling tube of ethanol to remove all the chlorophyll . Then wash the leaf with water to remove the ethanol and soften the leaf, then place it on a white tile. Add a few drops of iodine solution and if the plant turn into a blue-black colour, starch is present in that leaf.

Question 13

How can you destarch a plant?

Answer 13

You can do this by keeping the plant in the dark for a minimum of 24 hrs

Question 14

How can you probe chlorophyll is needed for photosynthesis?

Answer 14

Variegated leaves only have chlorophyll in some areas of the leaf. To prove chlorophyll is need place the the variegated plant in some sunlight for several hours then test one of its leaves for the presence of starch.