A thorough understanding of Class 10 Biology Notes Kerala Syllabus Chapter 4 Important Questions Chemoreception in Organisms can improve academic performance.
SSLC Biology Chapter 4 Important Questions Chemoreception in Organisms
Chemoreception in Organisms Class 10 Important Questions
Question 1.
Examine the statement and reason and choose the correct answer.
Statement: Auxins accumulate in the shaded part of the plant stem, which causes the stem to bend towards the light.
Reason: Auxins increase cell elongation in the cells where they accumulate.
(A) Both statement and reason are correct. The reason is the correct explanation of the statement.
(B) Both statement and reason are correct. The reason is an incorrect explanation of the statement.
(C) Statement is correct. Reason is incorrect.
(D) Statement is incorrect. Reason is correct.
Answer:
(A) Both statement and reason are correct. The reason is the correct explanation of the statement.
Question 2.
Find the correctly matched set from the given answers.
| (A) Auxin | (i) Breaks seed dormancy. |
| (B) Gibberellin | (ii) Regulates tropic movements. |
| (C) Cytokinin | (iii) Causes the shedding of mature leaves and fruits. |
| (D) Abscisic Acid | (iv) Stimulates cell differentiation. |
(a) A – iv, B – ii, C – i, D – iii
(b) A – ii, B – i, C – iv, D – iii
(c) A – iii, B – iv, C – i, D – ii
(d) A – i, B – iii, C – ii, D – iv
Answer:
(b) A – ii, B – i, C – iv, D – iii
| (A) Auxin | (ii) Regulates tropic movements. |
| (B) Gibberellin | (i) Breaks seed dormancy. |
| (C) Cytokinin | (iv) Stimulates cell differentiation. |
| (D) Abscisic Acid | (iii) Causes the shedding of mature leaves and fruits. |
Question 3.
Choose the correct answer.
Statement 1: Auxins help in the maturation and ripening of leaves, flowers, and fruits.
Statement 2: Gibberellins maintain seed dormancy.
(A) Both Statement 1 and 2 are correct.
(B) Both Statement 1 and 2 are incorrect.
(C) Statement 1 is incorrect, Statement 2 is correct.
(D) Statement 1 is correct, Statement 2 is incorrect.
Answer:
(B) Both Statement 1 and 2 are incorrect.
Question 4.
Examine the statement and reason and choose the correct answer.
Statement: Insulin and Glucagon are the hormones that help in regulating the blood glucose level. Reason: Insulin increases the blood glucose level, and Glucagon decreases the blood glucose level.
(A) Both statement and reason are correct. The reason is the correct explanation of the statement.
(B) Both statement and reason are correct. The reason is an incorrect explanation of the statement.
(C) Statement is correct. Reason is incorrect.
(D) Statement is incorrect. Reason is correct.
Answer:
(C) Statement is correct. Reason is incorrect.
Question 5.
Find the correctly matched set from the given answers.
| (A) Thyroid Gland | (i) Calcitonin |
| (B) Pancreas | (ii) Epmephrine |
| (C) Adrenal Medulla | (iii) Glucagon |
| (D) Pineal Gland | (iv) Melatonin |
(a) A – iv, B – ii, C – i, D – iii
(b) A – ii, B – i, C – iv, D – iii
(c) A – iii, B – iv, C – i, D – ii
(d) A – i, B – iii, C – ii, D – i
Answer:
(d) A – i, B – iii, C – ii, D – i
| (A) Thyroid Gland | (i) Calcitonin |
| (B) Pancreas | (iii) Glucagon |
| (C) Adrenal Medulla | (ii) Epmephrine |
| (D) Pineal Gland | (i) Calcitonin |
Question 6.
Find the odd one out. Write the common characteristic of the others.
Cortisol, Nor-epinephrine, Aldosterone, Androgens
Answer:
Nor-epinephrine. The others are Corticosteroids (or hormones secreted by the Adrenal Cortex).
Question 7.
Complete the statement.
The chemical substances secreted by organisms belonging to the same species into the surroundings for communication are ……………………………
Answer:
Pheromones
Question 8.
Identify the word-pair relationship and complete the missing part. Also, write the relationship between the word-pairs.
Biological Clock: Melatonin:: Chief Controller: ………………………….
Answer:
Hypothalamus. The relationship is Hormones and their characteristics/function.
Question 9.
Name the hormone producing centres situated in the brain?
Answer:
Hypothalamus, pituitary, Pineal
Question 10.
The gland which is active only during infancy?
Answer:
Thymus
Question 11.
Name the digestive gland which is also functioning as an endocrine gland?
Answer:
Pancreas
Question 12.
Diabetic patients frequently take insulin injection. Give reason?
Answer:
Insulin is helpful to reduce the excess glucose in the blood and to maintain its normal level.
Question 13.
Under secretion of thyroxine : Hypothyroidism
Over secretion of thyroxine : …………………..?
Answer:
Hyperthyroidism
Question 14.
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 15.
Why do Vasopressin is known as anti diuretic hormone (ADH)?
Answer:
Because vasopressin retains the quantity of water by inducing the kidneys to reabsorb it.
Question 16.
How is homeostasis of the body maintained?
Answer:
Homeostasis of the body is maintained by the combined action of the quick nervous system and the slow endocrine system.
Question 17.
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.
Question 18.
Analyse the table and identify the correct pair.
| a) Decrease in somatotropin during growth phase. | Dwarfism |
| b) Increase in somatotropin during growth phase. | Acromegaly |
| c) Increase in somatotropin after growth phase. | Gigantism |
Answer:
a) Decrease in somatotropin during growth phase. – Dwarfism
Question 19.
Choose the correct statements
a) Aldosterone maintains the salt water level.
b) Vasopressin helps to control inflammation and allergy
c) Prolactin promotes the growth of the body.
Answer:
a) Aldosterone maintains the salt water level.
Question 20.
Name the gland which seen at the centre of brain, write its function.
Answer:
Pineal gland, melatonin the hormone produces by this gland helps to maintain the rhythm of over daily activities.
Question 21.
Complete the illustration.
Answer:
(a) Development of brain in newborn babies and children.
(b) Helps to maintain the health of the heart, skin, reproductive system, etc.
Question 22.
Select the correct statements from the ones given below.
(A) Synthetic gibberellins are used to promote rooting in stem cuttings.
(B) Synthetic auxins are also used as weedicides.
(C) Synthetic ethylene is used for stem elongation in sugarcane.
(D) Synthetic auxins are used to promote rooting in stem cuttings.
(E) Synthetic gibberellins are used to increase fruit size in grapevines.
(F) Ethylene is used to ripen fruits like bananas and tomatoes simultaneously .
Answer:
B, D, E, F
Question 23.
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 within the cell. As a result, certain changes occur in cellular activities.
Question 24.
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 in to glycogen.
Question 25.
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 26.
Over production of parathormone can weaken the bones. Why?
Answer:
The hormone, parathormone prevents the deposition of calcium in bones resulting its weakening.
Question 27.
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 28.
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. There fore pineal gland is called as the biological clock.
Question 29.
What are the hormones of hypothalamus stored in the posterior lobe of pituitary gland? Mention its functions.
Answer:
Oxytocin – Facilitates child birjh 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 30.
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 31.
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 32.
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 witlv care as they are chemicals, which may cause health and environmental issues.
Question 33.
Observe the chart
Write down the climate A and B
Answer:
A – Summer season
B – Rainy season or winter
Question 34.
Observe the illustration given below and explain how hormones act in target cells.
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.
Question 35.
Observe the diagram and answer the questions.
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 36.
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 insulin
- Destruction of Beta Cells
- Inactive insulin
Question 37.
Given below are a few statements related to hormones. Pick out the correct ones.
a) Estrogen helps to maintain embryo in the uterus.
b) Progesteron facilitates child birth.
c) Prolactin helps in the production of milk.
d) Oxytocin facilitates lactation.
Answer:
c) Prolactin helps in the production of milk., d) Oxytocin facilitates lactation.
Question 38.
Analyse the statements given below and write the reason.
a) Oxytocin is injected in pregnant women during childbirth, (delivery)
b) Feels sleepy during night, wakesup when day breaks.
Answer:
a) Facilitates child birth 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 39.
Choose the correct statement related to pheromones from those given below.
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 silk worm.
Answer:
b) This is the message to attract mates, determining the path of travel etc., d) Bombycol is the pheromone secreted by the female silk worm.
Question 40.
Teacher: The TSH hormone synthesised 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.
Ammu: Can all the hormones synthesised 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 41.
Choose the correct statement.
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) Thyroid stimulating hormone stimulates the activity of the thyroid gland., c) Synthesis of insulin increases if the blood glucose level rises.
Question 42.
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?
Answer:
Each hormone act only its target tissue, where specific receptors present to accept the same
Question 43.
Indicators related to the endoxine glands are given below. Analyse them and answer the questions.
• Act dining emergencies
• Act along with sympathetic system
a) Identify the gland
b) Which is the hormone synthesised by this gland?
Answer:
a) Adrenal gland
b) Epinephrine
Question 44.
Analyse the statements given below and write the reason.
a) Feels sleepy during night-wakesup when day breaks.
b) All hormones are being transported through the blood and reach all cells of the body but all hormoned are not functioning in all cells why?
Answer:
a) When the level of melatonin increases at night, we feel sleepy we wakeup when the level of melatonin decreases during the day.
b) Each hormone act only its target tissue, where specific receptors present to accept the same hormone.
Question 45.
Complete the table.
| Plant Hormone | Function |
| Synthetic Auxins | ………… (A) ………… |
| ………… (B) ………… | Used to increase fruit size in grapevines and for stem elongation in sugarcane. |
| Synthetic Ethylene | ………… (C) ………… |
Answer:
(a) Used to induce root formation in stem cuttings.
Also used as a weedicide (2, 4 – D)
(b) Synthetic gibberellins
(c) In agricultural sector, ethylene is used to make fruits ripen uniformly for harvest at the same time. Ethylene is used to ripen bananas and tomatoes simultaneously.
Question 46.
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 47.
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 48.
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 49.
Complete the following table related with the hormonal functions of our sex organs.
| Sex organs | Hormones | Functions |
| Testis | ||
| Ovaries |
Answer:
| Sex organs | Hormones | Functions |
| Testosterone | Sperm production, control secondary | |
| Testis | sexual characters in males such as change in voice, growth of hair etc. | |
| Ovaries | Estrogen | Control ovulation, Menstrual cycle, growth of sex organs in females. |
| Progesterone | Control ovulation, menstrual cycle and implantation of embryo in the uterus. |
Question 50.
Given below is the blood test result of a person. Analyse the result and answer the following questions?
| Glucose – 200mg/100ml Calcium – 11mg/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 51.
The quantity of urine excreted by a person in different seasons is given below. Analyse it and answer the following questions.
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 excreation of excess water through urine.
Answer:
a) B – Rainy season or winter season, C – Summer season
b) In rainy season production of vassopressin is less it decreases the reabsorbtion of water in the kidneys. So raises the quantity of urine. In summer season production of vasopressin increases. It increases the reabsorbtion of water in kidneys and lowers the quantity of urine.
c) ADH or vasopressin
Question 52.
The following figure shows the relationship of hypothalamus with an endocrine gland.
a) Write down the name of endocrine gland marked as X
b) Write down the name of hormones produced in A and B.
c) Mention the functions ofhormones produced in B.
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 53.
“It is now that I understand why the cock crows early in the morning everyday”. Anu said this during a class room discussion on the rythm 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, reporductive activities of organisms with definite reproductive periods.
Question 54.
Fill up the blanks
Answer:
a) Thyroxine
b) Thyroid
c) Insulin
d) Diabetes
e) Pituitary gland
f) Dwarfism
Question 55.
Some statements related to endocrine system are given below.
A. Hormones are the secretions of endocrine glands.
B. Hormones are transported through lymph.
C. Hormones are transported through blood.
D. All the hormones 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 hypothesis.
Answer:
a) A, C
c) Receptors of that hormone is not in the cell
Question 56.
Indicators related to the endocrine glands are given below. Analyse them and answer the questions.
• Situated just below the sternum.
• Active during infancy.
But constricts at puberty.
a) Name this endocrine gland?
b) Which is the hormone synthesised by this gland?
c) Write the function of this hormone.
Answer:
a) Thymus gland
b) Thymosine
c) Controls the activities and maturation of lymphocytes which help to impart immunity.
Question 57.
Identity the word pair relationship and complete the following.
a) Alphacells: Glucagon
Beta Cells: …………………
b) Prolactin: Production of milk
……………: Facilitate lactation
c) Parathyroid: Parathormone
Thyroid: ……………….
Answer:
a) Inslulin
b) Oxytocin
c) Calcitonin
Question 58.
Mention the functions of the following plant hormones.
a) Gibberellins
b) Abscisic acid
c) Ethylene
Answer:
a) Stimulates breakdown of stored food to facilitate germination, Sprouting of leaves.
b) Dormancy of embryo, dropping of ripened leaves and fruits.
c) Ripening of leaves and fruits, excess amount of ethylene causes dropping of leaves and fruits.
Question 59.
Classify the following statements into the appropriate categories.
(A) Metabolic rate increases.
(B) Weight loss
(C) Intolerance to cold
(D) Decreased heart rate
(E) Increased body weight
(F) Increased heart rate
(G) Metabolic rate decreases.
(H) Excessive sweating, anxiety.
| Hyperthyroidism | Hypothyroidism |
Answer:
Hyperthyroidism – A, B, F, H
Hypothyroidism – C, D, E, G
Question 60.
Complete the illustration.
(a) Maintains glucose homeostasis, Suppresses the Immune responses, Resists inflammation
and allergy of the body
(b) Androgens
(c) Aldosterone
(d) Helps in maintaining equilibrium of minerals in the body, Regulates blood pressure
Question 61.
Identify the hormone defects concern with the following hints.
(a) Insulin injection
(b) Treatment using thyroxine
(c) Food and medicine containing calcium
(d) Sea food, vegetable and iodised salt.
Answer:
(a) Diabetes
(b) Myxedema
(c) Osteoporosis
(d) Goitre
Question 62.
Identify the plant hormone that perform 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) Gibberelline
(b) Ethylene
(c) Abscisic acid / ethylene in excess amount.
(d) Auxin
Question 63.
Artificial plant hormones are used extensively in the agricultural sector. Write a short note on the advantages and disadvantages of these.
Answer:
Advantages
- Sprouting
- Prevents premature fall of fruits
- Weedicidal 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 64.
Pick the odd one out. Write the common features of the others.
a) Increases metabolic rate, increases energy production regulate growth in children, promotes production of milk.
b) Goitre, Acromegaly, Hypothyroidism, Hyper thyroidism.
c) Cortisol, Vasopressin,Epinephrine, Norepine phrine.
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 are plant hormones
Question 65.
Observe the illustration and answer the following questions?
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 child birth by the contraction 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
Question 66.
Make suitable word pairs from the words given below.
Dwarfism, Cretinism, Insulin,
Vasopressin, Diabetes insipidus,
Somatotropin, Vasopressin,
Diabetes mellitus, Thyroxine
Answer:
Diabetes mellitus – Insulin
Diabetes insipidus – Vasopressin
Somatotrophin – Dwarfism
Thyroxine – Cretinism
Question 67.
Given in the table below is related to growth hormone. Complete the table suitably.
| Disease | Condition of Hormone | Symptoms |
| (a) ………………… | Deficiency of growth hormone during growth phase | Stunted growth |
| Gigantism | (b) ………………… | Excessive growth of the body |
| Acromegaly | (c) ………………… | (d) ………………… |
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.