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Plant And Animal Hormones Book Back Questions 10th Science Lesson 16

10th Science Lesson 16

16] Plant And Animal Hormones

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Do You Know?

Phenyl Acetic Acid (PAA) and Indole 3 Acetonitrile (IAN) are natural auxins. Indole 3 Butyric Acid(IBA), Indole-3-Propionic Acid, α-Naphthalene Acetic Acid (NAA), 2, 4, 5-T (2, 4, 5 Trichlorophenoxy Acetic Acid) are some of the synthetic auxins.

The branch of biology which deals with the study of the endocrine glands and its physiology is known as ‘Endocrinology’. Thomas Addison is known as Father of Endocrinology. English physiologist W.M. Bayliss and E.H. Starling introduced the term hormone in 1909. They first discovered the hormone secretin.

Melatonin is a hormone produced by the pineal gland. It is known as a ‘time messenger’. It signals night time information throughout the body.

Exposure to light at night, especially short-wavelength light, can decrease melatonin production interrupting sleep. Suppression of melatonin has been implicated in sleep disturbances and related metabolic disorders.

Edward C. Kendal in 1914 first crystallised thyroxine hormone. Charles Harrington and George Barger identified the molecular structure of thyroxine in 1927. Thyroid gland requires “120 µg” of iodine everyday for the production of thyroxine.

Human insulin was first discovered by Fredrick Banting, Charles Best and MacLeod in 1921. Insulin was first used in treatment of diabetes on 11th January 1922.

The cortisol hormones of adrenal cortex serve to maintain the body in living condition and recover it from the severe effects of stress reactions. Thus an increased output of cortisol is “life saving” in “shock conditions”. It is also known as life-saving hormone.

Choose the best answers:

1. Gibberellins cause:

(a) Shortening of genetically tall plants

(b) Elongation of dwarf plants

(c) Promotion of rooting

(d) Yellowing of young leaves

2. The hormone which has positive effect on apical dominance is:

(a) Cytokinin

(b) Auxin

(c) Gibberellins

(d) Ethylene

3. Which one of the following hormones is naturally not found in plants?

(a) 2, 4-D

(b) GA3

(c) Gibberellins

(d) IAA

4. Avena coleoptile test was conducted by

(a) Darwin

(b) N. Smit

(c) Paal

(d) F.W. Went

5. To increase the sugar production in sugarcanes they are sprayed with _______________

(a) Auxin

(b) Cytokinin

(c) Gibberellins

(d) Ethylene

6. LH is secreted by

(a) Adrenal gland

(b) Thyroid gland

(c) Anterior pituitary

(d) Hypothalamus

7. Identify the exocrine gland

(a) Pituitary gland

(b) Adrenal gland

(c) Salivary gland

(d) Thyroid gland

8. Which organ acts as both exocrine gland as well as endocrine gland?

(a) Pancreas

(b) Kidney

(c) Liver

(d) Lungs

9. Which one is referred as “Master Gland”?

(a) Pineal gland

(b) Pituitary gland

(c) Thyroidgland

(d) Adrenalgland

Fill in the blanks:

1. ________________ causes cell elongation, apical dominance and prevents abscission.

  1. Auxin
  2. Ethylene
  3. Abscisic acid
  4. None of the above

2. ______________ is a gaseous hormone involved in abscission of organs and acceleration of fruit ripening.

  1. Auxin
  2. Ethylene
  3. Abscisic acid
  4. None of the above

3. _______________ causes stomatal closure.

  1. Auxin
  2. Ethylene
  3. Abscisic acid
  4. None of the above

4. Gibberellins induce stem elongation in _________________ plants.

  1. Pea and chickpea
  2. Pea and corn
  3. Pea and maize
  4. None of the above

5. The hormone which has negative effect on apical dominance is __________________

  1. Auxin
  2. Ethylene
  3. Abscisic acid
  4. Cytokinin

6. Calcium metabolism of the body is controlled by ________________

  1. Parthormone
  2. Auxin
  3. Thormone
  4. None of the above

7. In the islets of Langerhans, beta cells secrete _____________

  1. Parthormone
  2. Auxin
  3. Thormone
  4. Insulin

8. The growth and functions of thyroid gland is controlled by ________________

  1. Hormone T5 and T6
  2. Hormone T3 and T4
  3. Hormone T2 and T3
  4. Hormone T1 and T6

9. Decreased secretion of thyroid hormones in the children leads to ______________

  1. Azar Azar
  2. Cretinism
  3. Marasmus
  4. None of the above

Match Column I with Columns II and III:

Column I Column II Column III
Auxin Gibberellafujikuroi Abscission
Ethylene Coconut milk Intermodal elongation
Abscisic acid Coleoptiles tip Apical dominance
Cytokinin Chloroplast Ripening
Gibberellins Fruits Cell division

Match the following hormones with their deficiency states:

Hormones – Disorders

(a) Thyroxine – Acromegaly

(b) Insulin – Tetany

(c) Parathormone – Simple goitre

(d) Growth hormone – Diabetes insipidus

(e) ADH – Diabetes mellitus

State true or false. If false, correct the statement:

1. A plant hormone concerned with stimulation of cell division and promotion of nutrient mobilization is cytokinin.

2. Gibberellins cause parthenocarpyin tomato.

3. Ethylene retards senescence of leaves, flowers and fruits.

4. Exopthalmicgoiter is due to the over secretion of thyroxine.

5. Pituitary gland is divided into four lobes.

6. Estrogen is secreted by corpus luteum.

Consider the statements given below and choose the correct option:

Direction: In each of the following questions a statement of assertion (A) is given and a corresponding statement of reason (R) is given just below it. Mark the correct statement as.

(a) If both A and R are true and R is correct explanation of A

(b) If both A and R are true but R is not the correct explanation of A

(c) A is true but R is false

(d) Both A and R are false

1. Assertion: Application of cytokinin to marketed vegetables can keep them fresh for several days.

Reason: Cytokinins delay senescence of leaves and other organs by mobilisation of nutrients.

2. Assertion (A) : Pituitary gland is referred as “Master gland”.

Reason (R) : It controls the functioning of other endocrine glands.

3. Assertion (A) : Diabetes mellitus increases the blood sugar levels.

Reason (R) : Insulin decreases the blood sugar levels.


Choose the best option:

1.Promotion of rooting 2. Auxin 3. 2,4-D 4. F.W. Went 5. Ethylene 6. Anterior pituitary 7. Salivary gland 8. Pancreas

9. Pituitary gland

Fill in the blanks:

1.Auxin 2. Ethylene 3. Abscisic Acid 4. Corn and pea 5. Cytokinin 6. Parathormone 7.

  1. Insulin 8. Hormone T3 and T4 9. Cretinism

Match the following:



Coleoptile tip

Apical dominance
Ethylene Fruits Ripening
Abscisic acid Chloroplast Abscission
Cytokinin Coconut milk Cell division
Gibberellins Gibberella fujikuroi Intermodal elongation


5. Diabetes insipidus

True or False:

  1. True
  2. True
  3. False – Ethylene hastens the senescence of leaves, flowers and fruits.
  4. True
  5. False – The Pituitary gland is composed of two lobes and performs different functions.
  6. False – Estrogen is produced by the Graafian follicles of the ovary.

Reason and Assertion:

1.Both A and R are true and R is correct explanation of A

2. Both A and R are false

3.Both A and R are true and R is correct explanation of A

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