Samacheer Kalvi 10th Science Unit 16 Book Back Questions with Answers:
Samacheer Kalvi 10th Std Science Book Back 1 Mark and 2 Mark Questions with Answers PDF in Science uploaded and available below. 10th Standard New Science Syllabus 2022 – Biology 16 Plant and Animal Hormones Science Book Back Answers available for both English and Tamil mediums. Tamil Nadu Samacheer Kalvi 10th Science Book Portion consists of 23 Units. Science Book Contain Physics 01- 06, Chemistry 07 – 11, Biology 12 – 22 and Visual Communications 23 units. Check Unit-wise and Full Class 10th Science Book Back Answers/ Guide 2022 PDF format for Free Download for both English and Tamil Medium. Samacheer Kalvi 10th Science Book back Solutions/Answers below:
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Samacheer Kalvi 10th Science Book Subject One Mark, Two Mark Guide questions and answers are available below. Check Science Book Back Questions with Answers. Take the printout and use it for exam purposes.
10th Science Book Back Answers
Unit 16 – Plant and Animal Hormones
I. Choose the best answer:
1. Gibberellins cause:
a) Shortening of genetically tall plants b) Elongation of dwarf plants
c) Promotion of rooting d) Yellowing of young leaves
Ans : (b) Elongation of dwarf plants
2. The hormone which has a positive effect on apical dominance is:
a) Cytokinin b) Auxin c) Gibberellin d) Ethylene
Ans : (b) Auxin
3. Which one of the following hormones is naturally not found in plants:
a) 2, 4–D b) G A 3 c) Gibberellin d) IAA
Ans : (a) 2, 4–D
4. Avena coleoptiles est was conducted by
a) Darwin b) N. Smit c) Paal d) F.W. Went
Ans : (d) F.W. Went
5. To increase the sugar production in sugarcanes they are sprayed with
a) Auxin b) Cytokinin c) Gibberellins d) Ethylene
Ans : (d) Ethylene
6. LH is secreted by
a) Adrenal gland b) Thyroid gland c) Anterior pituitary d) Hypothalamus
Ans : (c) Anterior pituitary
7. Identify the exocrine gland
a) Pituitary gland b) Adrenal gland c) Salivary gland d) Thyroid gland
Ans : (c) Salivary gland
8. Which organ acts as both exocrine gland as well as endocrine gland
a) Pancreas b) Kidney c) Liver d) Lungs
Ans : (a) Pancreas
9. Which one is referred to as “Master Gland”?
a) Pineal galnd b) Pituitary gland c) Thyroid gland d) Adrenal gland
Ans : (b) Pituitary gland
II. Fill in the blanks
1. causes cell elongation, and apical dominance and prevents abscission. Ans: Auxin
2. is a gaseous hormone involved in the abscission of organs and acceleration of fruit ripening.
Ans: Ethylene
3. causes stomatal closure. Ans: Abscisic acid
4. Gibberellins induce stem elongation in plants. Ans: Rosette
5. The hormone which has a negative effect on apical dominance is. Ans: Cytokinin
6. Calcium metabolism of the body is controlled by. Ans: Parathormone
7. In the islets of Langerhans, beta cells secrete. Ans: Insulin.
8. The growth and functions of the thyroid gland are controlled by. Ans: Hormone T3 and T4
9. Decreased secretion of thyroid hormones in children leads to _____. Ans: Cretinism.
III. Match the following:
Question 1.
(a) Match the Column I with Columns II and III.
| Column I | Column II | Column III |
| Auxin | Gibberella fujikuroi | Abscission |
| Ethylene | Coconut milk | Intermodal elongation |
| Abscisic acid | Coleoptile tip | Apical dominance |
| Cytokinin | Chloroplast | Ripening |
| Gibberellins | Fruits | Cell division |
Answer:
| Column I | Column II | Column III |
| Auxin | Coleoptile tip | Apical dominance |
| Ethylene | Fruits | Ripening |
| Abscisic acid | Chloroplast | Abscission |
| Cytokinin | Coconut milk | Cell division |
| Gibberellins | Gibberella fujikuroi | Intermodal elongation |
(b) Match the following hormones with their deficiency states.
| Hormones | Disorders |
| 1. Thyroxine | (a) Acromegaly |
| 2. Insulin | (b) Tetany |
| 3. Parathormone | (c) Simple goitre |
| 4. Growth hormone | (d) Diabetes insipidus |
| 5. ADH | (e) Diabetes mellitus |
Answers:
1. (c) Simple goitre
2. (e) Diabetes mellitus
3. (b) Tetany
4. (a) Acromegaly
5. (d) Diabetes insipidus
IV. True or False (Correct the Statement if it is false)
1. A plant hormone concerned with stimulation of cell division and promotion of nutrient mobilization is cytokinin.
Ans: True.
2. Gibberellins cause parthenocarpy in tomatoes. Ans: True.
3. Ethylene retards the senescence of leaves, flowers, and fruits.
Ans: False. Ethylene hastens the senescence of leaves, flowers, and fruits.
4. Exophthalmic goiter is due to the over secretion of thyroxine. Ans : True.
5. Pituitary gland is divided into four lobes.
Ans: False. Pituitary gland is divided into two lobes.
6. Estrogen is secreted by the corpus luteum.
Ans: False. Estrogen is secreted by Graafian follicles.
V. Assertion and Reason
Direction: In each of the following questions, a statement of Assertion is given and a corresponding statement of reason is given just below it. Of the statements given below, mark the correct answer as
a) If both A and R are true and R is the correct explanation of A.
b) If both A and R are true but R is not the correct explanation of A.
c) If A is true but R is false.
d) If both A and R are false.
1. Assertion: Application of cytokinin to marked vegetables can keep them fresh for
several days.
Reason: Cytokinins delay senescence of leaves and other organs by mobilization of nutrients.
Ans : (a) Both A and R are true and R is the correct explanation of A
2. Assertion (A): Pituitary gland is referred as the “Master gland”.
Reason (R): It controls the functioning of other endocrine glands.
Ans : (a) Both A and R are true and R is the correct explanation of A
3. Assertion (A):- Diabetes mellitus increases blood sugar levels.
Reason (R):- Insulin decreases blood sugar levels.
Ans : (b) Both A and R are true but R is not the correct explanation of A
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