Nutrition in plants

Question 1

What is photosynthesis and what type of reaction is it.

Answer 1

Plants use light as energy. The reaction of that traps the light energy is called photosynthesis. ( endothermic reaction).

Question 2

How does photosynthesis work.

Answer 2

photosynthesis takes place in the leaves of a plant which have green chemical chlorophyll that absorbs light energy. Firstly the plant take CO2 and H2O into the leaf. Light energy is absorbed by chlorophyll. It converts CO2 and H20 to oxygen and glucose.

Question 3

Word and chemical equation for photosynthesis.

Answer 3

carbon dioxide + water —light—> oxygen + glucose

CO2 + H2O —> O2 + C6H12O6

Question 4

What do the plants use the glucose they produce for?

Answer 4

As a source of energy in respiration/ convert it into starch for storage, into lipids for an energy source in seeds, into cellulose to make cell wall or amino acids when combined with nitrogen and other mineral ions absorbed by roots.

Question 5

Why is photosynthesis important?

Answer 5

Because the conversion of light energy to chemical energy provides energy for all consumers as the chemical energy in bonds can be passed on to other organisms when they eat

Question 6

Factors Affecting Photosynthesis

Answer 6

temperature, light intensity and carbon dioxide concentration.

Question 7

How does temperature affect Photosynthesis

Answer 7

As temperature increases, the rate of photosynthesis increases as the reaction is controlled by enzymes.
As the reaction is controlled by enzymes, this trend only continues up to a certain temperature beyond which the enzymes begin to denature and the rate of reaction decreases

Question 8

How does light intensity affect Photosynthesis

Answer 8

The more light a plant receives, the faster the rate of photosynthesis.
trend will continue until some other factor required for photosynthesis prevents the rate from increasing further because it is now in short supply

Question 9

How does the carbon dioxide concentration affect Photosynthesis.

Answer 9

The more carbon dioxide that is present, the faster the reaction can occur
This trend will continue until some other factor required for photosynthesis prevents the rate from increasing further because it is now in short supply

Question 10

What minerals do plant require for growth

Answer 10

magnesium and nitrate

Question 11

How are minerals absorbed into the plant

Answer 11

Plants obtain these elements in the form of mineral ions actively absorbed from the soil by root hair cells

Question 12

Function and deficiency of magnesium

Answer 12

Is needed for production of chlorophyll

deficiency= causes yellowing between vein of leaves.

Question 13

Function and deficiency of nitrate

Answer 13

Is a source of nitrogen which is required to make amino acids to build and protect DNA
deficiency = causes stunted growth.

Question 14

Investigating the effect of changing light intensity on the rate of photosynthesis

Answer 14

1. Take a boiling tube and place it 10cm away from an LED light ( as LED don’t give away much heat).
2. Fill the boiling tube with sodium hydro carbonate solution which releases CO2 that is required for photosynthesis
3. Place a pond weed into the boiling tube with the cut end on top.
4. let it rest for 5 minutes to acclimatise to the boiling tube.
5. You should start to see bubbles starting to be produced.
6. Start a stop watch and count the number of bubbles produced in one minute.
7. Repeat twice and measure the mean number of bubbles produced at that distance.
8. Repeat the whole experiment now at different lengths, 20cm 30cm 40cm.
   * The more bubbles produced per minute, the faster the rate of photosynthesis*

Question 15

What is a more accurate way to Investigating photosynthesis using a water plant

Answer 15

1. Fill a beaker up with sodium hydro carbonate.
2. place a pond weed with cut side on top with a funnel over it.
3. place a measuring cylinder over the funnel to catch the bubbles.
4. Use the measuring cylinder to measure the volume of oxygen produced.
5. Repeat twice at the same distance eg.10
6. Repeat the whole experiment now at different lengths, 20cm 30cm 40cm.

Question 16

Investigating the production of starch and the need for chlorophyll

Answer 16

1. Take a leaf from a plant and boil it in water for 30 seconds to kill and break down the cell walls.
2. Then take the leaf and place it in a boiling tube with ethanol in it and place into the beaker with the boiling water for 10minutes.
3. Make sure the the Bunsen burner is off as ethanol is very flammable.
4. The chlorophyll will come out into the ethanol therefore the leaf losing it’s colour.
5. Take out the leaf and rinse it in some cold water and spread it out on a white tile.
6. Drop some iodine solution on the leaf.
7. If the leaf turns blue black that means there is strach present in the leaf therefore it is photosynthesising.
8. If some areas don’t have starch they will remain orange as no photosynthesises is taking place there.