B1.2 Photosynthesis and Plants - Photosynthesis Practicals

Question 1

Photosynthesis

Answer 1

A process where plants and algae synthesise glucose from carbon dioxide and water, using light energy from the sun

Question 2

Glucose (C6H12O6)

Answer 2

The main chemical product of photosynthesis that has many different uses in a plant, including respiration

Question 3

Insoluble starch

Answer 3

A complex carbohydrate made from the products of photosynthesis and used for storage

Question 4

Chloroplast

Answer 4

An organelle found in plant and algae cells where photosynthesis occurs

Question 5

Chlorophyll

Answer 5

A green pigment in plants that absorbs light energy used to carry out photosynthesis

Question 6

Light intensity effect

Answer 6

Photosynthesis rate increases as more energy is available, up to a certain point

Question 7

Carbon dioxide concentration effect

Answer 7

Photosynthesis rate increases as more carbon is available to synthesise glucose, up to a certain point

Question 8

Photosynthetic rate

Answer 8

The rate at which plants take in carbon dioxide, water and the energy from sunlight to produce glucose

Question 9

Testing leaves for starch

Answer 9

Plant leaves can be tested for the presence of starch using iodine solution, after the leaf has been intensely heated and submerged in ethanol

Question 10

Iodine test for starch

Answer 10

Iodine solution will change colour from orange to blue-black in the presence of starch

Question 11

Starch results for plants kept in light conditions

Answer 11

Plants store glucose as starch in the leaves, plants that are kept in the light will photosynthesise and store starch so their leaves will change colour to blue-black

Question 12

Starch results for plants kept in the dark

Answer 12

Plants in the dark will be unable to photosynthesise meaning glucose will not be made and stored as starch, so iodine will not change colour

Question 13

Starch results for variegated leaves

Answer 13

Leaves that are variegated have patches absent of chlorophyll, these regions will not cause iodine to change colour as photosynthesis cannot occur here

Question 14

Investigating photosynthesis in pondweed

Answer 14

Aquatic plants produce observable bubbles of oxygen when photosynthesising near light, a possible factor that could be investigated

Question 15

Pondweed bubbles

Answer 15

Indicate the presence of oxygen which is a product of photosynthesis, the more bubbles produced the greater the rate of photosynthesis

Question 16

Light intensity and rate of photosynthesis in pondweed

Answer 16

The closer the pondweed is to a light source, the greater the light intensity which should increase the rate of photosynthesis, a higher light intensity should produce more oxygen bubbles

Question 17

Data loggers and sensors

Answer 17

Oxygen and carbon dioxide sensors can be used to detect levels of theses gases during an experiment, the data can then be visualised on a data logger

Question 18

Sodium hydroxide

Answer 18

A basic solution that can break down carbon dioxide

Question 19

Effect of plant kept enclosed near sodium hydroxide

Answer 19

A plant kept in a sealed bag with a nearby source of sodium hydroxide will be unable to photosynthesise due to a lack of carbon dioxide, this can be tested using sensors or by carrying out a starch test on a leaf

Question 20

Results of starch test of leaf near sodium hydroxide

Answer 20

Leaves kept near sodium hydroxide will not photosynthesise and will not be able to store starch, the leaf will not cause iodine to change colour to blue-black