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Published on: 25/09/2019
Plant and Animal Hormones
Download Tamil Nadu 10th Standard Science question papers, model tests, one-mark questions, important questions, and public exam papers in PDF format. Free study materials and answer keys for TN State Board students.
Questions + Answers key
Take MCQ Science Test1.
List the functions of adrenal medulla hormones.
2.
Write a note on mineralocorticoids
3.
Write a note on hormones of posterior pituitary.
4.
Mention the physiological effects of Ethylene.
5.
Mention the physiological effects of ABA.
6.
Which gland secretes digestive enzymes and hormones?
7.
Which hormone is secreted during emergency situation in man?
8.
Which hormone induces parthenocarpy in tomatoes?
9.
Write the name of a synthetic auxin.
10.
Which hormone promotes the production of male flowers in Cucurbits?
1.
Adrenal Medulla:
The adrenal medulla is composed of chromaffin cells. They are richly supplied with sympathetic and parasympathetic nerves.
Hormones of adrenal medulla: It secretes two hormones namely
a. Epinephrine (Adrenaline)
b. Norepinephrine (Noradrenaline)
They are together called as "Emergency hormones". It is produced during conditions of stress and emotion. Hence it is also referred as "flight, fright and fight hormone".
Functions of adrenal medullary hormones:
(i) It promotes the conversion of glycogen to glucose in liver and muscles.
(ii) It increases heart beat and blood pressure.
(iii) It increases the rate of respiration by dilation of bronchi and trachea.
(iv) It causes dilation of the pupil in eye.
(v) It decreases blood flow through the skin.
2.
The mineralocorticoids are secreted by zona glomerulosa of cortex of Adrenal gland.
(i) The chief hormone is Aldosterone.
(ii) It helps to reabsorb sodium ions from the renal tubules.
(iii) It causes increased excretion of potassium ions.
(iv) It regulates electrolyte balance, body fluid volume, osmotic pressure and blood pressure.
3.
The hormones secreted by the posterior lobe (Neurohypophysis) of the pituitary gland are:
Vasopressin or Antidiuretic hormone (ADH), Oxytocin
a. Vasopressin or Antidiuretic hormone (ADH) :
(i) In kidney tubules it increases reabsorption of water. It reduces loss of water through urine and hence the name antidiuretic hormone.
(ii) Deficiency of ADH reduces reabsorption of water and causes an increase in urine output (polyuria). This deficiency disorder is called Diabetes insipidus.
b. Oxytocin: It helps in the contraction of the smooth muscles of uterus at the time of child birth and milk ejection from the mammary gland after child birth.
4.
(i) Ethylene promotes the ripening of fruits.
Eg : Tomato, Apple, Mango,Banana, etc.
(ii) Ethylene inhibits the elongation of stem and root in dicots.
(ii) Ethylene hastens the senescence of leaves and flowers.
(iv) Ethylene stimulates formation of abscission zone in leaves, flowers and fruits. This leads to premature shedding.
(v) Ethylene breaks the dormancy of buds, seeds and storage organs.
5.
(i) ABA stands for Abscisic Acid.
(ii) ABA promotes the process of separation of leaves, flowers and fruits (abscission).
(iii) During water stress and drought conditions ABA causes stomatal closure.
(iv) ABA promotes senescence in leaves by causing loss of chlorophyll.
(v) ABA induces bud dormancy towards the approach of winter in trees like birch.
(vi) ABA is a powerful inhibitor of lateral bud growth in tomato.
6.
Pancreas.
7.
(i) Epinephrine (Adrenaline)
(ii) Norepinephrine (Noradrenaline)
(iii) They are together called as "Emergency hormones" secreted during emergency situation in man.
8.
Gibberellin induces parthenocarpy in tomatoes.
9.
2,4 - Dichlorophenoxy Acetic acid ( (2,4 - D)
10.
Gibberellin promote the production of male flowers in Cucurbits.
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Tamilnadu Stateboard 10th Standard Subjects
Tamilnadu Stateboard Standards