Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis

You can Download Chemical Messages for Homeostasis Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 10th Standard Biology Solutions Chapter 3 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis

Chemical Messages for Homeostasis Text Book Questions and Answers

Chemical Messages for Homeostasis Question 1.
Which are the hormones you know? List them?
Answer:

  • Insulin
  • Thyroxine
  • Oestrogen

Hormones:
The endocrine glands play a vital role in coordinating and controlling life activities. Secretions of endocrine glands are called hormones. There secretions are chemical substances that belong to different categories such as proteins, peptides, steroids, fatty acids, etc. Endocrine glands do not have particular ducts carry hormones to various tissues. Hence they are known as ductless glands. Hormones are transported through blood. As these substances regulate cellular activities, they can be called chemical messages to cell.

Chemical Messages for Homeostasis Hormones In Target Cells

The cell which are acted upon by hormones are called target cells. Only cells having specific receptors can receive a particular hormone. A hormone-receptor complex is formed by the combination of each hormone molecule and its receptor. Following this, enzymes are activated within the cell. As a result, certain changes occur in cellular activities.
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 1
After Digestion

Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 2
Pancreas helps in the digestive process. It functions as an endocrine gland too. It secretes two hormones namely insulin and glucagon.
The beta cells in the Islets of Langerhans glucagon.

Action of insulin and glucagon:
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 3
HSSLive.Guru

Chemical Message Question 2.
Complete the illustration by including the production of hormones that regulate the level of glucose.
Answer:
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 4
Biology Chapter 3 Question 3.
How is the level of glucose in the blood maintained while fasting? Discuss
Answer:
When the level of glucose increases in blood the cells in the Islets of Langerhans produce insulin which converts the excess glucose into glycogen, protection and lipids.

Diabetes Mellitus

Diabetes is clinically referred to as a condition when the level of glucose before breakfast is above 126 mg/100ml of blood. It is caused either by decreased production of insulin or it$ malfunctioning. Symptoms: Increased appetite and thirst, Frequent urination, Traces glucose in urine Diabetes can be controlled through medicine, diet control and insulin injections.

HSSlive Biology Question 4.
The increase of glucose in blood is said to be diabetes. Shouldn’t one be more energetic if the glucose level in his/her blood rises? What is your opinion? Write them down in your science diary.
Answer:
No. One be more should not energetic if the glucose level in his or her blood. Persons with diabetes experience loss of body weight, weakening of muscles and tiredness.

Regulation Of Metabolism

Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 5

The anabolic and catabolic processes taking place in the body are metabolism. The thyroid gland is the endocrine gland contrails the metabolic process.

Functions of thyroxine:

Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 6

Question 5.
How would be body activities be affected if sufficient amount of thyroxine is not produced?
Answer:

  • Low energy production
  • Bloating of body
  • Slowing down of heartbeat
  • Loss of appetite, lethargy
  • Dry skin

Undersecretion of thyroxine – Hypothyroidism:
The deficiency of thyroxine during the fetal stage or infancy leads to mental retardation and stunted growth. This condition is cretinism. Lack of thyroxine in adults leads to myxoedema.

Symptoms of Hypothyroidism:

  • Low metabolic rate
  • Sluggishness
  • Sleeplessness
  • Increase in body weight
  • Hypertension
  • Oedema

Oversecreation of thyroxine – Hyperthyroidism:
The condition in which all life activities controlled by thyroxine are accelerated due to the excessive production of thyroxine is referred to hyperthyroidism.

Symptoms of Hyperthyroidism:

  • High metabolic rate
  • Rise in body temperature
  • Excessive sweating
  • Increased heartbeat
  • Sleeplessness
  • Weight loss
  • Emotional imbalance

Goitre:
Iodine is essential for the production of thyroxine. The production of thyroxine is obstructed in the absence of iodine. In an attempt to produce more thyroxine; the thyroid gland enlarges. This condition is called goitre.

HSSLive.Guru

Question 6.
What is the importance of thyroxine in controlling life activities?
Answer:
Thyroxine is a hormone that influences metabolism in our body to a great extent.

Question 7.
What are the problems caused by excessive production of thyroxine?
Answer:

  • Energy production increases and body weight decreases
  • Increased heartbeat
  • Increased appetite
  • Shivering of hands and profuse sweating
  • Persistent hyperthyroidism may lead to Graves disease, characterized by exophthalmic goiter.

Question 8.
What are the problems due to thyroxine deficiency?
Answer:
The deficiency of thyroxine retards mental and physical growth of children. This condition is called cretinism. In adults the deficiency of thyroxine results in a disease called myxoedema.

Question 9.
How is iodine related to thyroid gland?
Answer:
Iodine is essential for the production of thyroxine. The production of thyroxine is obstructed in the absence of iodine.

Calcitonin:
It helps in maintaining the level of calcium in blood by depositing excess calcium in bones and by preventing the mixing of calcium with blood, from the bones.

Parathyroid Gland

Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 7

The parathyroid gland is situated behind the thyroid gland. This gland secretes a hormone called parathormone. The function of this hormone is to raise the level of calcium in blood

Question 10.
Complete the illustration showing the maintenance of the level of calcium in blood by the action of calcitonin and parathormones
Answer:
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 8

The hormone only upto youth:
Thymus gland:
The thymus gland is situated just below the sternum. The major function of thymus gland is to control, the activities and maturation of lymphocytes which help to impart immunity. This gland secretes thymosin, which is active during infancy. Hence it is known the ‘youth hormone’.

During Emergencies

These glands are situated above the kidneys. The outer part of the adrenal gland is known as the cortex and inner part is medulla. The adrenal cortex secretes aldosterone, cortisol and sex hormones. Adrenal medulla secretes epinephrine and norepinephrine.

HSSLive.Guru

Question 11.
The structure of the adrenal glands and the hormones produced by them are illustrated below. On the basis of the indicators given, discuss and write down the notes in the science diary.
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 9
i) Hormones secreted by the adrenal cortex
ii) The function of cortisol
iii) Maintenance of salt-water balance in the body
iv) The function of epinephrine and norepinephrine during emergencies.
Answer:
(i) Aldosterone and sex hormones are the hormones secreted by the adrenal cortex.
ii) The synthesis of glucose from protein and fat controls inflammation and allergy, slows down the action of defense cells.
iii) Aldosterone is the hormone that helps to maintains salt-water balance in the body by restating the lose of Na+ ions and by promoting the elimination of K+ ions through sweat, urine, etc.
iv) Epinephrine acts along with the sympathetic nervous system during emergencies. Thus we can resist or withdraw ourselves from such situations. Norepinephrine acts along with epinephrine.

Biological Clock
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 10
Pineal gland is seen in centre of the brain. It secretes the hormone, melatonin which helps in maintaining the rhythm of our daily activities. The production of melatonin is high at night and low during the day. When the level of melatonin increases we feel sleepy and when it decreases we wake up. This hormone also controls reproductive activities of organisms.

Behind Growth

Pituitary gland is a bibbed gland situated just below the hypothalamus in the brain. The anterior lobe produces tropic hormones which regulate the functions of other glands. The posterior lobe stores the hormones which are produced in the hypothalamus.
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 11
Question 12.
The hormones produced by the anterior lobe is listed in table. Analyse-it and complete the following worksheet in the science diary.
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 12
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 13
Answer:
A – Stimulates the activity of thyroid giand
B – AdrenoCortico Tropic Hormone(ACTH)
C – Gonado Tropic Hormone(GTH)
D – Stimulates the activity of ovaries
E – Production of milk
F – Growth Hormone (GH) or Somatotropic Hormone (STH)

HSSLive.Guru

Question 13.
How the variation in the production of somatotropin affects growth.
Answer:
Somatotropin promotes growth of the body during its growth phase. If the production of this hormone increases during the growth phase, it leads to the excessive growth of the body. This condition is gigantism. It causes another stage called dwarfism when its production decreases during the growth phase. Acromegaly is the condition caused by the excessive production of somatotropin after the growth phase. It is characterized by the growth of the bones on face, jaws and fingers.
The Posterior Lobe of pituitary gland – A storage center
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 14
The hormones oxytocin and vasopressin, which are secreted from the posterior lobe of the pituitary are actually produced in the neuro-secretory cells of the hypothalamus. The posterior lobe stores these two hormones and Releases them into blood when required.

Question 14.
Observe the table and write down your inferences in the science diary.
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 15
Answer:
Oxytocin and vasopressin are secreted from the hypothalamus and stored in the posterior lobe of pituitary gland. Through the connecting nerve fibers they are transported to pituitary gland. Oxytocin facilitates childbirth by stimulating the contraction of smooth muscles in the uterine wall and facilitates lactation. Vasopressin helps in the reabsorption of water in the kidneys.

Question 15.
Observe illustration given below which shows the action of vasopressin in kidneys. Based on the indicators given discuss and write a note in science diary.
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 16
i) The functions of vasopressin in kidneys
ii) The reason for excessive production of urine during the rainy season
iii) The role of vasopressin in preventing loss of water from the body.
iv) Diabetes insipidus
Answer:
i) The hormone vasopressin regulator reabsorption of water and minerals from the glomerular filtrate.. When there is a reduction in the amount of water in blood, the production of vasopression increased. It accelerates the rate of reabsorption of water. When the quantity of water in blood increases the production of vasopressin decreases. As a result, the rate of reabsorption is also reduced.

ii) During rainy season, sweat production reduces. So the water loss through sweat is decreased. It wingcase the quantity of water in our body Comparatively high. Such situations demand elimination of excess water through urine.

iii) The production of vasopressin increases when there is a need to reduce loss of water through urine. As a result of this, more water is reabsorbed to the blood from kidneys, Thereby the loss of water through urine is reduced and regulate water loss in our body.

iv) The rate of resorption of water in the kidney is decreased when there is no sufficient amount of vasopressin. Hence excess amount of urine is excreted. This condition is called diabetes insipidus Symptoms include frequent urination.

Behind Sexual Characteristics

Testes and ovary, the male and female sex organs respectively, secrete different types of hormones.
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 17
Prepare a table by including hormone, centre of production and function:
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 18

Prime Controller

Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 20
Oxytocin and vasopressin are secreted by the hypothalamus. In addition to this hypothalamus controls the pituitary gland by secreting a variety of releasing hormone are inhibitory hormones.

HSSLive.Guru

Question 16.
Observe the illustration given below on the functions of releasing hormones and inhibitory hormones. On the basis of indicatiors discuss and writes it down in the science diary.

Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 21
i) Action of releasing hormone
ii) Influence of tropic hormones in different glands.
iii) Action of inhibitory hormones
Answer:
i) Stimulates the anterior lobe of the pituitary and secretes tropic hormones.
ii) Tropic hormones stimulate the production of hormones of certain other important glands.
iii) Inhibits the production of tropic hormones in the anterior lobe of the pituitary gland.

Chemical Messages For Communication

Pheromones: Pheromones are chemical substances that are secreted in trace amounts to the surrounding in order to facilitate communication among organisms. Pheromones help in attracting mates, to inform the availability of food, to determine the path of travel and to inform about dangers.
Eg:- Musk in the nusk deer, civet on in civet cat, Bombycol in female silkworm.

Plant Hormones

There are certain chemical substances in plant cells to control and co-ordinate life activities. These are also called plant growth regulators.

Question 17.
Observe the illustration, which show plant hormones and their functions and complete the following table suitably.
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 22
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 23
Answer:
a) Cell growth, cell elongation, fruit formation
b) Controls the dormancy of embryo in the seeds, dropping to leaves and fruits wilting of leaves, flowering, etc.
c) Gibberellins
d) Promotes cell division cell growth
e) Ethylene.

Artifical Plant Hormones

Auxins: NaphtheleneAceticAcid (NAA), Indol Butyric Acid (IBA), etc., are used for sprouting and the prevention of dropping of premature fruits. 2.4-D (2, 4-Dichloro phenoxy acetic acid) is used as a weedicide.

Gibberellins: It is used for increasing fruit size in grapes and apple and also for preventing ripening of fruits to assist in marketing.

Abscisic acid: As it accelerates the dropping of fruit, it is used for harvesting fruits at the same time.

Ethylene: Ethylene is used for the flowering of pineapple plants at a time and for the ripening of tomato, lemon, orange, etc. Ethyphon, a chemical which is available in liquid form gets transformed into ethylene when used in rubber trees, and it increases the production of latex.

Chemical Messages for Homeostasis Let Us Assess

Question 1.
Identifying the word-pair relationship and fill in the blank.
Thyroxine: Thyroid gland
Epinephrine:…………..
Answer:
Adrenal gland

Question 2.
Analyze the information given in the box and answer the questions.
X- The production of this hormone is more in night and less in day time.
Y – Hormones from the adrenal gland work along with the sympathetic system.
(a) Identify and name the hormone ‘X’ and its gland.
(b) Identify the hormones indicated as ‘Y’.
Answer:
a) Melatonin pineal gland
b) Epinephrine (Adrenaline)
c) Norepinephrine (Noradrenline)

HSSLive.Guru

Question 3.
Analyse the illustration and complete the table appropriately.
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 24
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 25
Answer:
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 26
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 27

Question 4.
The hormone that helps in the reabsorption of water in the kidneys.
a) TSH
b) ACTH
c) ADH
d) GTH
Answer:
ADH

Chemical Messages for Homeostasis Extended Activities

1. Conduct a seminar on the topic – The role of the Endocrine system in maintaining homeostasis’.
Main points:-

  • Situations which lead to change in homeostasis
  • How is homeostasis reinstated
  • Harmonious co-existence

2. Conduct a debate on ‘Use of artificial plant hormones – problems and possibilities’.

3. Collect information about novel laboratory tests related to diagnosis of diabetes and conduct an exhibition on World Diabetes Day.

Chemical Messages for Homeostasis More Questions and Answers

Question 1.
Correct the sentence if it is wrong
1. Endocrine glands are ductless glands
2. The alpha cells in the Islets of Langerhans secrete insulin.
3. Aldosterone slows down the action of defense cells.
4. Anti Diuretic hormone helps in the reabsorption of water in the kidneys.
5. Hypothalamus secretes inhibitory hormones which stimulate the anterior lobe of the pituitary gland.
Answer:
1. Endocrine glands are ductless glands
2. The beta cells in the islets of Langerhans secrete insulin.
3. Cortisol slows down the action of defense cells.
4. Anti Diuretic hormone helps in the reabsorption of water in the kidneys.
5. Hypothalamus secretes releasing hormones that stimulate the anterior lobe of the pituitary gland.

Question 2.
Endocrine glands are called ductless glands. Why?
Answer:
Endocrine glands do not have particular ducts to carry hormones to various tissues. Hence they are called ductless glands.

Question 3.
Name the hormone-producing centers situated in the brain?
Answer:
Hypothalamus, pituitary, Pineal

HSSLive.Guru

Question 4.
The gland which is active only during infancy?
Answer:
Thymus

Question 5.
Though hormones reach every part of the body through the blood, all hormones do not act upon all cell. Explain the reason.
Answer:|
The cell which are acted upon by hormones are called target cells. Only cells having specific receptors can receive a particular hormone. A hormone-receptor complex is formed by the combination of each hormone molecule and its receptor. Following this, enzymes are activated withfn the cell. As a result, certain changes occur in cellular activities.
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 28

Question 6.
Name the digestive gland which is also functioning as an endocrine gland?
Answer:
Pancreas

Question 7.
What is the normal level of glucose in blood? How is this level maintained?
Answer:
The normal level of glucose is 70-110 mg/100 ml blood. The level of glucose in blood is maintained by the combined action of insulin and glucagon of the Islets of Langerhans tissues of the pancreas. Insulin, released from the beta cells of Islets of Langerhans, helps to reduce blood sugar by accelerating the process of cellular uptake of glucose and Conversion of glucose in to glycogen. When blood glucose level falls, glucagon, released from the alpha cells of Islets of Langerhans, converts glycogen to glucose and synthesizes glucose from amino acids.

Question 8.
Suppose a person is fasting in a day and takes heavy food on the very next day. How is the level of glucose in his body is maintained in these two days?
Answer:
While fasting glucagon converts glycogen or amino acids into glucose. When taking heavy food insulin enhances cellular uptakes of glucose and converts glucose into glycogen.

Question 9.
Diabetic patients frequently take insulin injections. Give reason?
Answer:
Insulin is helpful to reduce the excess glucose in the blood and to maintain its normal level

Question 10.
If the level of glucose increases one feels hunger, thirsty and fatigue instead of becoming energetic. Give reason?
Answer:
Increasing the level of glucose in blood adversely affects the normal functioning of the cells.

Question 11.
A doctor advised one of his patients to use iodized salt and to include more leafy vegetables and marine items in his diet. What should be reason for this recommendation?
Answer:
To prevent goitre. Deficiency of iodine may cause Goitre, a disorder affects on thyroid gland.

Question 12.
Under secretion of thyroxine: Hypothyroidism
Over secretion of thyroxine: ……………..?
Answer:
Hyperthyroidism

Question 13.
Overproduction, as well as underproduction of the hormone thyroxine, may lead to disorders’. Substantiate.
Answer:
Deficiency of thyroxine (Hypothyroidism) leads to cretinism in infants and myxoedema in adults. Excess production of thyroxine (Hyperthyroidism) leads to a condition, known as the Graves disease.

Question 14.
Persistent hyperthyroidism may leads to ……………. disease characterized by bulging of the eye balls.
Answer:
Graves disease

Question 15.
What is the normal level of calcium in the blood? How is this level maintained?
Answer:
9-11 mg/100 ml blood.
When the level of calcium in blood increases, thyroid gland secretes a hormone named calcitonin. It lowers the level of calcium in blood by depositing excess calcium in bones and by preventing the mixing of calcium with blood form the bones. When the level of calcium in blood decreases, parathyroid gland secretes parathormone. It increases blood calcium by reabsorbing it from the kidneys and also preventing the deposition of calcium in bones.

Question 16.
Complete the flow chart
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 66
Answer:
A. Medulla
B. Aldosterone
C. Cortisol
D. Norepinephrine

Question 17.
Overproduction of parathormone can weaken the bones. Why?
Answer:
The hormone, parathormone prevents the deposition of calcium in bones resulting its weakening.

HSSLive.Guru

Question 18.
The hormone which can be used to prevent allergy and inflammation? Can this hormone be given to diabetic patients? Why?
Answer:
Cortisol of adrenal gland. It cannot be given to diabetic patients as it increases the level of glucose in blood.

Question 19.
The pineal gland is known as the ‘biological clock’ in the body. Why?
Answer:
Melatonin, the secretion of the pineal gland helps to . maintain rhythm of our daily activities. Therefore pineal gland is called as the biological clock.

Qn. 20
What are the hormones of hypothalamus stored in the posterior lobe of pituitary gland? Mention its functions.
Answer:
Oxytocin – Facilitates childbirth by stimulating the contraction of smooth muscles in the uterine wall and also facilitates lactation Vasopressin (Anti Diuretic Hormone) – Helps in the reabsorption of water in the kidneys.

Question 21.
Give reasons.
Some times certain pregnant women need to take oxytocin injection.
Answer:
Oxytocin facilitates childbirth by stimulating the contraction of smooth muscles in the uterine wall. It also facilitates lactation.

Question 22.
Point out the functions of releasing hormones and inhibitory hormones.
Answer:
Releasing Hormones: Stimulate the anterior lobe of the pituitary to secretes tropic hormones and other hormones.
Inhibitory Hormones: Inhibit the production of tropic hormones and other hormones from the anterior lobe of the pituitary gland.

Question 23.
What is the reason behind the difference in the quantity of urine during summer and rainy season?
Answer:
The production of vasopressin is high during summer season where water loss is excessive through sweat. But its production is less during winter and rainy seasons and there is difference in the quantity of urine during summer and rainy seasons.

Question 24.
Why do Vasopressin is known as antidiuretic hormone (ADH)?
Answer:
Because vasopressin retains the quantity of water by inducing the kidneys to reabsorb it.

Question 25.
Complete the following table related with the hormonal functions of our sex organs.
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 30
Answer:
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 31

Question 26.
Identify the hormone defects concern with the following hints.
a) Insulin injection
b) Treatment using thyroxine
c) Food and medicine containing calcium
d) Seafood, vegetable and iodized salt.
Answer:
a) Diabetes
b) Myxoedema
c) Osteoporosis
d) Goiter

Question 27.
How is homeostasis of the body maintained?
Answer:
Homeostasis of the body maintained by the combined action of the quick nervous system and the slow endocrine system.

Question 28.
How are pheromones useful to animals?
Answer:
Pheromones help in attracting mates, to inform the availability of food, to determine the path of travel and to inform about dangers.

Question 29.
A farmer says pest control is made possible using pheromones. Can you say how?
Answer:
Artificial pheromones are used for pest control in agricultural field.

HSSLive.Guru

Question 30.
Identify the plant hormone that performs the following functions.
a) flowering and growth of leaves
b) ripening of fruits
c) dropping of leaves and fruits
d) growth of terminal bud.
Answer:
a) Gibberellin
b) Ethylene
c) Abscisic acid/ ethylene in excess amount.
d) Auxin

Question 31.
Site examples of situations where artificial plant hormones are applied widely.
Answer:
Ethylene is used for the flowering of pineapple plants at a time and for the ripening of tomato, lemon, orange, etc.
Ethyphon, a chemical which is available in liquid form gets transformed into ethylene when used in rubber trees, and it increases the production of latex.

Auxins: Naphthalene Acetic Acid (NAA), Indol Butyric Acid (IBA) etc. are used for sprouting and the prevention of dropping of premature fruits. 2,4- D (2, 4-Dichloro phenoxy acetic acid) is used as a weedicide.

Gibberellins: Used for increasing fruit size in grapes and apple and also for preventing ripening of fruits to assist in marketing.

Abscisic acid: As it accelerates the dropping of fruit, it is used for harvesting fruits at the same time.

Question 32.
The following figure shows the relationship of hypothalamus with an endocrine gland. (Model 2016)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 32
a) Write down the name of endocrine gland marked as X
b) Write down the name of hormone produced the A and B.
c) Mention the functions of hormones produced the B.
Answer:
Answer:
a) Pituitary gland
b) A – Tropic hormone
B – Oxytocin and vasopressin
c) Oxytocin helps to contraction of smooth muscles and vasopressin helps in the reabsorption of water in the kidneys.

Question 33.
Artificial hormones should be handled with care. What is your opinion?
Answer:
This statement is correct. Though artificial hormones are useful they should be handled with care as they are chemicals, which may cause health and environmental issues.

Question 34.
…………….. is used for increasing fruit size in grapes and apple.
Answer:
Gibberellins

Question 35.
………….. is a plant hormone, used for harvesting fruits in a field at the same time.
Answer:
Abscisic acid

Question 36.
The quantity of urine excreted by a person in different seasons is given below. Analyse-it and answer the following questions. (Model 2016)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 33
a) Write down the climate B and C
b) Analyse the difference shown in B and C and write down its reasons.
c) Which hormone is responsible for the excretion of excess water through urine.
Answer:
a) B – Rainy season or winter season, C – Summer season
b) In rainy season production of vasopressin is less it decreases the reabsorption of water in the kidneys. So raises the quantity of urine. In summer season production of vasopressin increases. It increases the reabsorption of water in kidneys and lowers the quantity of urine.
c) ADH or vasopressin

Question 37.
Given below is the blood test result of a person. Analyze the result and answer the following questions? (Model 2016)
Glucose – 200mg/100ml
Calcium -11 mg/100ml
a) Name the disease of the man mentioned in the test report.
b) Write down the name of hormone which related to this disease.
c) What is the cause of this disease?
Answer:
a) Diabetes mellitus
b) Insulin
c) It is caused either by the decreased production of insulin or its malfunctioning

Question 38.
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 34
a) Complete the table based on the hormone somatotropin (Model 2014)
b) This hormone is not a tropic hormone. Why?
Answer:
a) (i) X-dwarfism 1) become dwarfs due to stunted growth of bones
ii) Y – gigantism 2) Growing tall with a heavy body
iii) Z-acromegaly 3) enlargement of internal organs and thickening of bones, especially in hands feet and face.

b) Somatotropin does not induce any other endocrine gland to release its hormone

Question 39.
The quantity of urine excreted by a person in different seasons is given below. Analyse-it and answer the following questions. (Model 2014)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 35
a) Which is the coldest season?
b) Which hormone is responsible for the variation in quantity of urine?
c) How this hormone regulates water level of the body.
Answer:
a) Season 3
b) ADH/Vasopressin
c) This hormone promotes reabsorption of water from renal tubules when normal level of water in blood decreases. The rate of reabsorption of water in the kidney is decreased when there is no sufficient amount of vasopressin.

Question 40.
Some hormones are given below. Make them into 4 pairs. Give reasons for pairing. (Model 2014)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 36
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 37
basis pairing:- Products of same gland

Question 41.
Observe the chart (March 2013)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 38
Write down the climate A and B
Answer:
A-Summer season
B – Rainy season or winter

HSSLive.Guru

Question 42.
Changes in the number of hormones produced will affect our bodily activities. Write down the changes occur in our body by the increase and decrease of the hormones given below.
a) Parathormone
b) Vasopressin
Answer:
a) Increase of parathormone – Bones fragile stones in urinary tract, high blood calcium
Decrease of parathormone – Blood calcium level decrease and it leads to tetany

b) Vasopressin
Production of vasopressin increases It accelerate the rate of reabsorption of water from kidney. So the loss of water through urine is reduced.
Production of vasopressin decreased The rate of reabsorption is reduced and more water discharged out through urine.

Question 43.
Rearrange B, C and D according to the data given A
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 39
Answer:
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 40

Question 44.
“It is now that I understand why the cock crows early in the morning every day”. Anu said this during a classroom discussion on the rhythm of physiological activities.
a) Which is the hormone that regulates such activities?
b) Which gland secretes this hormone.
c) Write down more examples for such activities
Answer:
a) Melatonin
b) Pineal gland
c) It regulates the rhythm of life, reproductive activities of organisms with definite reproductive periods.

Question 45.
Fill up the blanks (Model 2012)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 41
Answer:
a) Thyroxine
b) Thyroid
c) Insulin
d) Diabetes
e) Pituitory gland
f) Dwarfism

Question 46.
Fill up the blanks
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 42
Answer:
a) – Gibberellin
b) – Helps in the ripening of fruits
c) – Abscisic acid

Chemical Messages for Homeostasis SCERT Questions and Answers

Question 1.
Observe the illustration given below and explain how hormones act in target cells.
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 43
Answer:
The cell which are acted upon by hormones are called target cells. Only cells having specific receptors can receive a particular hormone. A hormone-receptor complex is formed by the . combination of each hormone molecule and its receptor. Following this, enzymes are activated within the cell. As a result, certain changes occur in cellular activities.

HSSLive.Guru

Question 2.
Some statements relate to endocrine system are given below. (Question Pool 2017)
A. Hormones are the secretions of endocrine glands.
B. Hormones are transported through lymph.
C. Hormones are transported through blood.
D. All the harmonies produced by the endocrine glands are proteins.
a) Choose the correct statement.
b) Imagine that particular hormone is not entering a particular cell. What may be the reason? Formulate two hypotheses.
Answer:
a) A, C
c) Receptors of that hormone in not in the cell

Question 3.
Examine the graph indicating the blood glucose level of different individuals before breakfast. (Question Pool 2017)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 44
a) Which individual is affected by diabetes mellitus?
b) Write two actions of insulin to prevent the rise in the level of glucose in blood.
c) Why do people having diabetes mellitus experience extreme fatigue?
Answer:
a) (B)
b) 1. Enhances the entry glucose into the cell.
2. Converts glucose to glycogen in liver and muscles.
c) Sufficient quantity of glucose i not reaching the cell. Energy production decreases. Excess amount of glucose is eliminated through urine.

Question 4.
Case sheets of two patients are given below. Analyze them and answer the questions. (Question Pool 2017)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 45
a) Which are the diseases whose symptoms are indicated above?’
b) Write the reasons for the diseases.
Answer:
a) Case -1 cretinism;
Case – 2 graves disease

b) Case -1 reasons
Deficiency of thyroxine during foetal stage and infancy.
Case-2 reasons
1. Persistent hyperthyroidism
2. Excessive production of thyroxine.

Question 5.
Analyse the table given below. Rearrange column Band C according to the indicators in Column A. (Question Pool 2017)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 46
Answer:
1 – (b) – (r)
2 – (c) – (p)
3 – (a) – (q)

Question 6.
Honey bees and termites live in colonies. (Question Pool 2017)
a) Name the chemical substance which helps them to live together.
b) Mention two uses of these chemical substances.
Answer:
a) Pheromones
b) 1. attracting mates
2. informing availability of food
3. determining the path of travel
4. informing the dangers

Question 7.
Observe the diagram and answer the questions. (Question Pool 2017)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 47
a) Which endocrine gland does ‘X’ indicate?
b) Which are the two hormones produced by the gland to control the physical activities with the sympathetic system?
Answer:
a) Adrenal gland
b) Epinephrine, Norepinephrine

Question 8.
Maintenance of the level of calcium in the blood is illustrated below. Analyse-it and answer the following questions. (Question Pool 2017)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 48
a) Name the hormone indicated as X’.
b) Which gland produces the hormone ‘Y’?
c) Write another activity performed by ‘X’ to raise the level of calcium in blood.
Answer:
a) Parathormone
b) Thyroid gland
c) Helps in the reabsorption of calcium from kidneys.

Question 9. (
Observe the diagram of the endocrine gland given below and answer the question. (Question Pool 2017)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 49
a) Name the part indicated as A and B.
b) Name the hormones synthesized by A. Explain their action.
Answer:
a) A Medulla
B Cortex
b) Epinephrine, Norepinephrine
Epinephrine – Helps to tide over emergency situations
Norepinephrine – acts along with epinephrine

Question 10.
An individual loses large quantities of water through urine (Question Pool 2017)
a) Which could be the disease?
b) Analyze the conditions that lead to this disease.
Answer:
a) Diabetes insipidus
b) ADH is synthesized by hypothalamus.
ADH increases the reabsorption of water into the kidney.
Synthesis of ADH decreases.

HSSLive.Guru

Question 11.
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 50
a) Identify X and Y. (Question Pool 2017)
b) What is the function of ‘Y’?
Answer:
a) Portal vein – X
Posterior lobe of pituitary – Y
b) Stores the hormones vasopressin and oxytocin synthesized by hypothalamus and releases them into blood when required.

Question 12.
Given in the table below is to growth hormone. Complete the table suitably. (Question Pool 2017)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 51
Answer:
a) dwarfism
b) Excessive production of growth hormone during the growth phase.
c) Excessive production of somatotropin after the growth phase.
d) Growth of the bones on face, jaws and fingers.

Question 13.
Given below is a doctor’s comment at a seminar conducted as part of Diabetic day.
“In diabetic patients, the blood glucose level before breakfast is above 126mg/100ml.
Analyse the statement and enlist the reasons.
Answer:

  • Decreased production of insulin
  • Malfunctioning of insuline
  • Destruction of Beta Cells
  • Inactive insulin

Question 14.
Given below are a few statements related to hormones. Pick out the correct ones. (Question Pool 2017)
a) Estrogen helps to maintain embryo in the uterus.
b)Progesterone facilitates childbirth.
c) Prolactin helps in the production of milk.
d) Oxytocin n faci itates I a citation.
Answer:
c, d

Question 15.
Analyze the statements given below and write the reason. (Question Pool 2017)
a) Oxytocin is injected in pregnant women during childbirth, (delivery)
b) Feels sleepy during night, wakeup when day breaks.
Answer:
a) Facilitates childbirth by stimulating the contraction of smooth muscles in the uterine wall.
b) When the level of melatonin increases at night, we feel sleepy,
We wake up when the level of melatonin decreases during the day.

Question 16.
Analyse the table and identify the correct pair. (Question Pool 2017)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 52
Answer:
a) Somatotropin decreases during growth phase – dwarfism

Question 17.
Observe the table, re-arrange column Band C according to column A.
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 53
Answer:
1 – (b) – (S)
2 – (d) – (P)
3 – (a) – (Q)

Question 18.
A farmer named Balan cultivated oranges in his orchard. Now the trees are full of oranges. The price of oranges is Rs. 80/kg. (Question Pool 2017)
A) This farmer wants to harvest all fruits together.
B) Ripen them together.
a) Suggest two artificial plant hormones to satisfy the A, B needs of the farmer.
b) Uncontrolled use of plant hormones must be controlled. Evaluate this statement.
Answer:
A) a) A – Abscisic acid
B – Ethylene
b) Though artificial hormones are useful they should be handled with care as they are chemicals. Uncontrolled use of it may cause health and environmental issues.

HSSLive.Guru

Question 19.
Analyse the indicators and answer the question given below. (Question Pool 2017)
Indicators
Accelerates the growth and development of the brain in the foetal stage and infancy.
a) Which hormone are the indicators about?
b) Construct a flow chart relating the action of hypothalamus and pituitary in the synthesis of this hormone.
Answer:
a) Thyroxine
b)

Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 54

Question 20.
Artificial plant hormones are used extensively in the agricultural sector. (Question Pool 2017)
Write the name and function of two artificial plants. hormones belonging to the category, auxin.
Answer:
NAA- Sprouting, prevention of premature fall of fruits.
IBA – -do-
2, 4 – D – Weedicide

Question 21.
Artificial plant hormones are used extensively in the agricultural sector. Write a short note on the advantages and disadvantages of these (Question Pool 2017)
Answer:
Advantages:

  • Sprouting
  • Prevents premature fall of fruits
  • Medicinal action
  • Increases size of fruits
  • Ripening of fruits
  • Increases production of latex in rubber trees
  • Harvesting fruits at the same time.
  • Prevents early ripening of fruits

Disadvantages:

  • Environmental issues
  • Health issues

Question 22.
Choose the correct statement related to pheromones from those given below. (Question Pool 2017)
a) Pheromones are chemical substances secreted inside the body for communication.
b) This is the message to attract mates, determining the path of travel, etc.
c) Musk in the civet cat is a pheromone.
d) Bombycol is the pheromone secreted by the female silkworm.
Answer:
b, d

Question 23.
Analyze the box given below and complete the table suitably. (Question Pool 2017)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 67
Answer:
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 56

Question 24.
Indicators related to the endocrine glands are given below. Analyze them and answer the questions. (Question Pool 2017)
1. Situated just below the sternum.
2. Active during infancy.
But constricts at puberty.
a) Name this endocrine gland?
b) Which is the hormone synthesized by this gland?
c) Write the function of this hormone.
Answer:
a) Thymus gland
b) Thymosin
c) Controls the activities and maturation of lymphocytes which help to impart immunity.

HSSLive.Guru

Question 25.
Given below is the illustration showing the hormones synthesized by the anterior lobe of the pituitary gland. Complete it Suitably. (Question Pool 2017)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 57
Answer:
a) Stimulates thyroid gland
b) ACTH
c) Production of milk
d) Enhances growth

Question 26.
Teacher: The TSH hormone synthesized by the pituitary gland acts on the thyroid gland. It is transported to the thyroid gland through blood. All hormones are transported like this through blood. (Question Pool 2017)
Amirtu: Can all the hormones synthesized by the pituitary gland reach the thyroid gland and act there? What is your answer for Ammu’s doubt?
Answer:
Receptors to receive other hormones synthesized by the pituitary gland are absent in the thyroid gland.

Question 27.
Plant hormones and their functions are given in two boxes below. Pair them suitably (Question Pool 2017)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 58
Answer:
(a) – (iv)
(b) – (ii)
(c) – (i)
(d) – (iii)

Question 28.
The problems faced by two farmers are below. Suggest two artificial plant hormones to overcome this. (Question Pool 2017)
Satheesh: Excessive growth of weeds in the agricultural field.
Saneesh: Premature fall of fruit in the mango orchard.
Answer:
Satheesh: 2, 4- D
Saneesh: NAA /IBA

Question 29.
Observe the illustration given below and answer the questions. (Question Pool 2017)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 59
a) Write the names of the hormones ‘X’ and Y\
b) Mention two actions that take place in A and B.
c) Name the gland which synthesises X and Y.
Answer:
a) X-Insulin; Y-Glucagon
b) A-Converts glycogen to glucose
B – Converts glucose to glycogen
c) Pancreas

Question 30.
Identify the word pair relationship and fill in the blanks. (Question Pool 2017)
a) Civet cat:………………
Silkworm: Bombycol
b) Breaks up stored food: Gibberellins
helps in fruit ripening: ……………….
c) Vasopressin: Diabetes insipidus
Insulin: ………………
d) Dwarfism: somatotropin
Myxoedema: ………………..
Answer:
a) Civetone
b) Ethylene
c) Diabetes mellitus
d) Thyroxine

Question 31.
Pick the odd one out. Write the common features of the others. (Question Pool 2017)
a) Increases metabolic rate, increases energy production regulates growth in children, promotes production of milk.
b) Goitre, Acromegaly, Hypothyroidism, Hyperthyroidism.
c) Cortisol, Vasopressin, Epinephrine, Norepinephrine.
d) Ethylene, Cytokinin, Auxin, Pheromones.
Answer:
a) Increases the production of milk: all others are the activities of thyroxine.
b) Acromegaly: All others are disorders/diseases, related to thyroid gland
c) Vasopressin: All others are hormones of adrenal gland
d) Pheromones: All others plant hormones

HSSLive.Guru

Question 32.
Choose the correct statement. (Question Pool 2017)
a) Synthesis of vasopressin increases if the level of water in the blood increases.
b) Thyroid-stimulating hormone stimulates the activity of the thyroid gland.
c) Synthesis of insulin increases if the blood glucose level rises.
d) Deficiency of thyroxine causes cretinism in adults.
Answer:
b, c

Question 33.
Maintenance of the level of calcium in blood is illustrated below. Analyse-it and answer the questions. (Question Pool 2017)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 60
a) Which are the hormones indicated as ‘X’, ‘Y’?
b) Write the actions performed by ‘X’ in the bone and ‘Y’ in the kidney.
c) How does the deficiency of ‘Y’ affect the process of blood clotting?
Answer:
a) X – Calcitonin: Y – Parathormone
b) Action of X : Deposits excess calcium in bones.
Action of Y : Reabsorbs calcium into the blood in the kidney.
c) Deficiency of Y decreases the level of calcium in blood.
As calcium is required for blood clotting, the clotting process becomes slow.

Question 34.
Make suitable word pairs from the words given below. (Orukkam – 2017)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 61
Answer:
Vasopressin- Diabetes insipidus
Dwarfism – Somatotropin
Cretinism – Thyroxin

Question 35.
Complete the illustration using the words given in the box. (Orukkam – 2017)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 62
Answer:
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 64

Question 36.
Observe the illustration and answer the following questions? (Orukkam – 2017)
Kerala Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis - 65
a) Identify the parts marked as A , B and C ?
b) Name the hormones indicated as 1, 2, 3, 4 and 5?
c) What are the functions of the hormones Oxytocin and Prolactin?
d) What are the abnormalities caused by the difference in the production rate of the hormone marked as 1?
Answer:
a) A-Anterior lobe of pituitary
B – posterior lobe of pituitary
C – Hypothalamus

b) 1 – Somatotropin /growth hormone
2 – Vasopressin /ADH
3 – Tropic hormones
4, 5 – TSH/ACTH

c) Oxytocin facilitates childbirth by the contrac¬tion of smooth muscles in the uterine wall and also facilitates lactation. Vasopressin helps in the reabsorption of water in the kidney to prevent water loss through urine.

d) Dwarfism, Gigantism and Acromegaly

HSSLive.Guru

Question 37.
Identify the word pair relationship and complete the following. (Orukkam – 2017)
a) Alpha cells: Glucagon
Beta Cells: …………….
b) Prolactin: Production of milk
……………….: Facilitate lactation
c) Parathyroid: Parathormone
Thyroid
Answer:
a) Insulin
b) Oxytocin
c) Calcitonin

Question 38.
All hormones are being transported through the blood and reach all cells of the body, but all hormones are not functioning in all cells. Why? (Orukkam – 2017)
Answer:
Each hormone act only its target tissue, where spe¬cific receptors present to accept the same hormone.

Question 39.
The increased or decreased level of thyroxin may disrupt the homeostasis of the body. Explain? (Orukkam – 2017)
Answer;
Due to hypothyroidism (eg. cretinism) low metabolic rate, sluggishness, sleeplessness, increase in body weight, hypertension, oedema, etc.
Due to hyperthyroidism (eg. Graves disease) high metabolic rate, increased heartbeat, rise in body tem¬perature, sweating, sleeplessness, loss of weight, emotional imbalance.

Question 40.
Bees and termites are maintaining the colony life by using some chemical substances as chemical messages. (Orukkam – 2017)
a) What are these chemical substances?
b) Write the other uses of these chemical substances?
c) Give other examples for these chemical substances?
Answer:
a) Pheromones
b) To attract mates, to inform about food or dangers, to live in colonies, to follow one afterthe other.
c) Civetone in civet cat, Bombycol in female silkworm moth.

Leave a Comment