HORMONES
Human Hormones
Pituitary gland is an endocrine [ductless] gland. The hormones of pituitary gland stimulate testes and ovaries to produce their hormones. It also stimulates thyroid and adrenals to secrete their hormones. Pituitary gland produces growth hormone necessary for normal growth of a person.
Other endocrine glands are thyroid [secretes thyroxin controls metabolism of carbohydrates, proteins and fats lack of which causes goiter]; pancreas [produce insulin lack of which causes diabetes] and adrenals [produce adrenalin which helps adjust to stress].
Plant Hormones
Auxins: These are indole compounds. Helps the cells grow longer, rooting of stems, promote flowering, prevent early dropping of fruits and leaves but enhance dropping of old leaves. It is also used as weed killer of dicots.
Gibberellins: helps in the growth of stems, elongation of fruits. All are acidic.
Cytokinins: Promote cell division.
Ethylene: Hastens ripening of fruits by increasing their respiration rate.
Abscisic acid: inhibits growth, leads to wilting of leaves.
Miscellenous
Thyroxin causes morphosis of tadpoles into frogs. Thyroxin needs iodine, so if the water in which tadpoles swims don’t have iodine. The tadpoles can’t become fr
Quiz
Score more than 80% marks and move ahead else stay back and read again!
Q1:Endocrine glands are not
1.Ductless
2.Pituary
3.Thyroid
4.Pancreas
ANS.1
Q2: Adrenalin is for
1.Pleasure
2.Tension
3.Anxiety
4.Adjust to stress
ANS.4
Q3: Ethylene is for
1.inhibits growth
2.leads to wilting of leaves.
3.Promote cell division
4.Hastens ripening of fruits by increasing their respiration rate.
ANS.4
Q4:Thyroxin synthesis needs
1.iodine
2.protein
3.vitamin
4.carbohydrates
ANS.1
Q5: Auxins don’t help in
1.rooting of stems
2.cells grow longer
3.promote flowering, prevent early dropping of fruits and leaves
4.weed enhancer.
ANS.4