MINERAL NUTRITION
2020 MARCH
1. Define hydroponics. Write one advantage of it. (2)
Answer:
The
technique of growing plants in a defined nutrient solution (without soil) is
known as hydroponics.
It is
used to identify the essential elements required for plants and their
deficiency symptoms.
2019 JULY IMPROVEMENT
1. Observe the diagram given below.
a. Identify the type of plant culture.
b. Write any two uses of this type of plant culture. (Score 2)
Answer:
a) Hydroponics.
b) It is used to identify essential elements required for plants and their deficiency symptoms.
For commercial production of vegetables such as tomato, seedless cucumber & lettuce.
2019 MARCH
1. Observe the elements given below.
Copper, Phosphorus, Boron, Magnesium, Potassium, Manganese, Chlorine.
Choose
microelements from the above. (2)
Answer:
Manganese,
copper, boron, chlorine.
2018 JULY IMPROVEMENT
1. The element is said to be deficient when present below the critical
concentration. What is critical concentration? State any two kinds of
deficiency symptoms shown by plants. (2)
Answer:
It is the concentration of the essential element below
which plant growth is retarded.
Deficiency symptoms: Chlorosis, Necrosis, Stunted growth etc.
2. Amides contain more nitrogen than the amino acids. Name two important
amides found in plants and explain their formation. (2)
Answer:
Asparagine & Glutamine.
They
are formed from aspartic acid and glutamic acid by addition of another amino
group to each.
2018 MARCH
1. Plants are adversely affected by manganese toxicity. Mention the effects
of manganese toxicity in plants.
Answer:
Chlorosis,
Necrosis, Brown spots surrounded by chlorotic veins etc.
2017 JULY (IMPROVEMENT)
1. Ammonia is used to synthesise amino
acids in plants by two ways. Name the two ways of synthesis of amino
acids. (2)
Answer:
a) Reductive amination b) Transamination
2017 MARCH
1. The root nodules of leguminous plants
contain two necessary biochemical compounds for N2 fixation.
Identify these compounds. (2)
Answer:
Nitrogenase enzyme/Mo-Fe protein & leg-haemoglobin.
2016 MARCH
1. The plants show deficiency symptoms
when the concentration of an essential element is below the critical
concentration. Write any four deficiency symptoms shown by plants. (2)
Answer:
Chlorosis, necrosis,
delay flowering and inhibition of cell division.
2015 SEPTEMBER (IMPROVEMENT)
1. Steps of conversion of atmospheric nitrogen to ammonia by nitrogen fixing
bacteria are given below.
Name the key enzyme in
that reaction and point out the relationship between the key enzyme and leg-haemoglobin.
(2)
Answer:
Nitrogenase enzyme.
Nitrogenase is
highly sensitive to the molecular oxygen. So it requires anaerobic conditions
to protect from oxygen. For this, leg-haemoglobin acts as an oxygen scavenger.
2015 MARCH
1. Even though more than sixty elements are found in different plants, all
are not essential. Write any two criteria for the essentiality of an element.
(2)
Answer:
· An element must be needed for normal growth and reproduction.
· The requirement of an element must be specific. i.e., deficiency of an element cannot be met by another element.