1. Define hydroponics. Write one advantage of it. (2)
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.
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)
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.
1. Observe the elements given below.
Copper, Phosphorus, Boron, Magnesium, Potassium, Manganese, Chlorine.
Choose microelements from the above. (2)
Manganese, copper, boron, chlorine.
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)
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)
Asparagine & Glutamine.
They are formed from aspartic acid and glutamic acid by addition of another amino group to each.
1. Plants are adversely affected by manganese toxicity. Mention the effects of manganese toxicity in plants.
Chlorosis, Necrosis, Brown spots surrounded by chlorotic veins etc.
1. Ammonia is used to synthesise amino acids in plants by two ways. Name the two ways of synthesis of amino acids. (2)
a) Reductive amination b) Transamination
1. The root nodules of leguminous plants contain two necessary biochemical compounds for N2 fixation. Identify these compounds. (2)
Nitrogenase enzyme/Mo-Fe protein & leg-haemoglobin.
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)
Chlorosis, necrosis, delay ﬂowering and inhibition of cell division.
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)
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.
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)
· 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.