Plant Nutrition - Part 1 (T2)

Question 0

Briefly outline the process of photosynthesis..

Answer 0

• green plants absorb light energy from the sun using the green pigment chlorophyll, located in the chloroplasts of their leaves
• then they use light to combine carbon dioxide with water to produce glucose
• glucose is then either used in respiration so converted into starch and stored
• oxygen is produced as a by product and released into the atmosphere

Question 1

What three main factors can limit the rate of photosynthesis?

Answer 1

• temperature
• concentration of carbon dioxide
• intensity of light

Question 2

As well as light and water, what is also required for the healthy growth of plants?

Answer 2

Mineral ions such as nitrates and phosphates. If there is a deficiency then plants with not grow properly, even with plenty of light and water.

Question 3

What are the three most important element plants require to stay alive?

Answer 3

• carbon
• hydrogen
• oxygen

Question 4

Where can plants get hydrogen and oxygen from?

Answer 4

Water

Question 5

Where can plants get carbon and oxygen from?

Answer 5

From carbon dioxide and oxygen in the atmosphere.

Question 6

Why are fertilisers used?

Answer 6

In addition to carbon, hydrogen and oxygen, plants need 13 mineral nutrients for healthy growth. These come from the soil, are dissolved in water and absorbed through the roots of the plant.

However, these are. Not always present in the required quantities so fertilisers need to be used.

Question 7

What are the three most important mineral ions for plant growth?

Answer 7

• nitrogen
• phosphorus
• potassium

Question 8

What four nutrients are often lacking from the soil and what do they do?

Answer 8

NITROGEN - for making amino acids which are then needed to make proteins.
PHOSPHORUS - for making chlorophyll required for photosynthesis. It is involved in the formation of all oils, sugars and starches.
POTASSIUM - used in the building of proteins, photosynthesis, fruit quality and disease reduction.
MAGNESIUM - needed to form chlorophyll and required for photosynthesis.

Question 9

Describe nitrate deficiency..

Answer 9

Leaves will turn yellow and plant will have stunted growth. The stunted growth is a result of the lack of proteins as nitrates are needed to form amino acids which are needed to form proteins.

Question 10

Describe potassium deficiency..

Answer 10

Older leaves become mottled or spotted and leaf edges become dry and scorched. Dead spots begin to appear, stems are weak and root systems are poor.

Question 11

What is the word equation for photosynthesis?

Answer 11

Carbon dioxide + water (+light energy) -> glucose + oxygen

“light energy” is shown in brackets because it is not a substance