Class 10th Science Gujarat Board Solution
Exercise- What is called the movement of plant toward the gravity?A. hydrotropism B. geotropism C.…
- The plant part which exhibits negative geotropism is:A. root B. stem C. branch D. leaves…
- The growth of a pollen tube towards the ovule is caused by.... A phototropism B.…
- Bending of the shoot of a plant in response to light is known as.....A. geotropism B.…
- The stimulus in the process of thigmotropism is:A. touch B. gravity C. light D. chemical…
- Which of the following helps in maintaining posture and balance of the human body?A.…
- How many pairs of nerves arise from the spinal cord?A. 21 B. 31 C. 41 D. 51…
- Cerebellum, medulla oblongata and pons are the parts of:A. mid-brain B. hind-brain C.…
- For the synthesis of which of the following hormone iodine is necessary?A. adrenaline B.…
- Which of the following is a mismatched pair?A. adrenaline: pituitary gland B. estrogens:…
- The spinal cord originates from :A. cerebrum B. cerebellum C. medulla oblongata D. puns…
- Which of the following hormone prepares our body for action in emergency situations?A.…
- Which is male sex hormone?A. estrogens B. adrenaline C. testosterone D. progesterone…
- Which of the following endocrine gland does not occur as a pair in the human body?A.…
- Name the plant which shows thigmonesty.
- Give the scientific terms used to represent the following: A. Bending of a shoot towards…
- Give example of the movement of a plant part which is caused by the loss of water.…
- Name the two systems of control and co-ordination in higher animals.…
- Name the three components of a nerve cell.
- Name the most important part of the human brain.
- State one function each of cerebellum and pons.
- Name one hormone secreted by the pituitary gland.
- Where are hormones synthesised in the human body?
- Which gland secretes the growth hormone?
- Name the disease caused by the deficiency of insulin hormone in the body.…
- A. What does a root do in response to gravity? What is this phenomenon known as? B. What…
- A. What does a stem do in response to gravity? What is this phenomenon known as? B. What…
- A. What is a spinal cord? What is its main function? B. Give the functions of medulla…
- A. Name the hormones secreted by the following endocrine glands: (i) Thyroid gland (ii)…
- A. Write the names of the regions of hind-brain. Give functions of each region. B. Mention…
- What does CNS stand for?
- A. What is meant by ‘tropisms’ ? Explain with an example. B. Mention types of tropisms.…
- A. Define phototropism and give one example of it. B. How does phototropism occur in a…
- A. Name the structural and functional unit of nervous system. B. What is autonomous…
- A. What is a reflex action? Explain with the help of an example. B. How involuntary…
- A. Write the names of five endocrine glands found in the human body. Name the hormones…
- What is called the movement of plant toward the gravity?A. hydrotropism B. geotropism C.…
- The plant part which exhibits negative geotropism is:A. root B. stem C. branch D. leaves…
- The growth of a pollen tube towards the ovule is caused by.... A phototropism B.…
- Bending of the shoot of a plant in response to light is known as.....A. geotropism B.…
- The stimulus in the process of thigmotropism is:A. touch B. gravity C. light D. chemical…
- Which of the following helps in maintaining posture and balance of the human body?A.…
- How many pairs of nerves arise from the spinal cord?A. 21 B. 31 C. 41 D. 51…
- Cerebellum, medulla oblongata and pons are the parts of:A. mid-brain B. hind-brain C.…
- For the synthesis of which of the following hormone iodine is necessary?A. adrenaline B.…
- Which of the following is a mismatched pair?A. adrenaline: pituitary gland B. estrogens:…
- The spinal cord originates from :A. cerebrum B. cerebellum C. medulla oblongata D. puns…
- Which of the following hormone prepares our body for action in emergency situations?A.…
- Which is male sex hormone?A. estrogens B. adrenaline C. testosterone D. progesterone…
- Which of the following endocrine gland does not occur as a pair in the human body?A.…
- Name the plant which shows thigmonesty.
- Give the scientific terms used to represent the following: A. Bending of a shoot towards…
- Give example of the movement of a plant part which is caused by the loss of water.…
- Name the two systems of control and co-ordination in higher animals.…
- Name the three components of a nerve cell.
- Name the most important part of the human brain.
- State one function each of cerebellum and pons.
- Name one hormone secreted by the pituitary gland.
- Where are hormones synthesised in the human body?
- Which gland secretes the growth hormone?
- Name the disease caused by the deficiency of insulin hormone in the body.…
- A. What does a root do in response to gravity? What is this phenomenon known as? B. What…
- A. What does a stem do in response to gravity? What is this phenomenon known as? B. What…
- A. What is a spinal cord? What is its main function? B. Give the functions of medulla…
- A. Name the hormones secreted by the following endocrine glands: (i) Thyroid gland (ii)…
- A. Write the names of the regions of hind-brain. Give functions of each region. B. Mention…
- What does CNS stand for?
- A. What is meant by ‘tropisms’ ? Explain with an example. B. Mention types of tropisms.…
- A. Define phototropism and give one example of it. B. How does phototropism occur in a…
- A. Name the structural and functional unit of nervous system. B. What is autonomous…
- A. What is a reflex action? Explain with the help of an example. B. How involuntary…
- A. Write the names of five endocrine glands found in the human body. Name the hormones…
Exercise
Question 1.What is called the movement of plant toward the gravity?
A. hydrotropism
B. geotropism
C. chemotropism
D. phototropism
Answer:•The movement of plants towards water is hydrotropism.
•The movement of plants towards gravity is known as geotropism.
•The movement of plants towards chemical stimulus is known as chemotropism.
•The movement of plants towards light is phototropism.
Question 2.The plant part which exhibits negative geotropism is:
A. root
B. stem
C. branch
D. leaves
Answer:Stem shows negative geotropism because it shows its growth against the force of gravity.
This is a picture showing geotropism.
Question 3.The growth of a pollen tube towards the ovule is caused by....
A phototropism
B. hydrotropism
C. gravitropism
D. chemotropism
Answer:The growth of pollen tube towards the ovule is caused in response to a chemical stimulus i.e the chemicals released by the ovule during the time of fertilization.
This is a picture showing chemotropism. Growth of pollen tube Observed in response to chemicals secreted by ovule
Question 4.Bending of the shoot of a plant in response to light is known as.....
A. geotropism
B. phototropism
C. thigmotropism
D. photonasty
Answer:The movement of plant in response to light is known as phototropism
This is a picture showing phototropism. Growth of stem in response to light.
Question 5.The stimulus in the process of thigmotropism is:
A. touch
B. gravity
C. light
D. chemical
Answer:In Thigmotropism, the word ‘thigmo’ means touch, hence the movement of plant part in response to touch is thigmotropism.
This is a picture showing the process of thigmotropism. Here, the stimulus is touch.
Question 6.Which of the following helps in maintaining posture and balance of the human body?
A. cerebellum
B. cerebrum
C. medulla oblongata
D. pons
Answer:Cerebellum is involved in maintaining body postures and co-ordinating body movments.
Question 7.How many pairs of nerves arise from the spinal cord?
A. 21
B. 31
C. 41
D. 51
Answer:31 pairs of nerves arise from the centre of spinal cord.
Question 8.Cerebellum, medulla oblongata and pons are the parts of:
A. mid-brain
B. hind-brain
C. fore-brain
D. spinal cord
Answer:This is because hind brain has 3 parts. Cerebellum present on the dorsal side of pons, while medulla and pons are present on the ventral side.
Question 9.For the synthesis of which of the following hormone iodine is necessary?
A. adrenaline
B. auxin
C. thyroxine
D. insulin
Answer:Because the deficiency of iodine can cause the deficiency of thyroxine hormone.
•Adrenaline is secreted by adrenal gland.
•Auxin is a plant hormone.
•Insulin is a hormone secreted by pancreatic glands which metabolizes sugar.
Question 10.Which of the following is a mismatched pair?
A. adrenaline: pituitary gland
B. estrogens: ovary
C. pancreas: insulin
D. progesterone: ovary
Answer:•Adrenalin hormone also known as fight or flight hormone is secreted by the adrenal gland.
•Ovary produces two female sex Hormones which are Estrogen and Progesterone which are responsible for controlling the development of female sex organs and controlling the changes taking place in uterus during menstrual cycle respectively
•Pancreas contain Islets of Langerhans that synthesize insulin
Question 11.The spinal cord originates from :
A. cerebrum
B. cerebellum
C. medulla oblongata
D. puns
Answer:Spinal cord originates from the posterior side of medulla.
Question 12.Which of the following hormone prepares our body for action in emergency situations?
A. testosterone
B. growth hormone
C. adrenaline
D. insulin
Answer:•This hormone is secreted by the adrenal gland. Medulla part of this gland secretes adrenalin hormone, which is called fight or flight hormone.
•Insulin is secreted by the pancreas.
•Testosterone is secreted by the testis.
•Growth hormone is secreted by pituitary gland.
Question 13.Which is male sex hormone?
A. estrogens
B. adrenaline
C. testosterone
D. progesterone
Answer:Testosterone is secreted by the male reproductive part testis, hence it is the male sex hormone.
Question 14.Which of the following endocrine gland does not occur as a pair in the human body?
A. adrenal
B. pituitary
C. testis
D. ovary
Answer:The rest of the three glands – adrenal, testis and ovary occur as a pair in human body. Pituitary gland, also known as the master gland is only one in number.
Question 15.Name the plant which shows thigmonesty.
Answer:Mimosa is the plant which shows thigmonesty.
The leaves of the plant folds up in response to a touch.
A picture showing response of mimosa plant.
Question 16.Give the scientific terms used to represent the following:
A. Bending of a shoot towards light.
B. Growing of roots towards the earth.
C. Growing of a pollen tube towards ovule.
D. Bending of roots towards water.
E. Winding of tendril around a support.
Answer:A. Positive phototropism. The growth of shoot takes place in the direction of light, that is towards the stimulus. Hence, positive phototropism.
Picture showing positive and negative phototropism.
B. Positive geotropism. The stimulus in the case of geotropism is gravity. As the growth of roots is towards the earth, i.e. under the force of gravity. Hence, positive geotropism.
C. Chemotropism. The growth of pollen tube is in response to the chemicals released by the ovule during fertilization.
D. Hydrotropism. The movement of plant part in response to water is known as hydrotropism.
E. Thigmotropism. Movement of plant part in response to touch is known as thigmotropism.
Question 17.Give example of the movement of a plant part which is caused by the loss of water.
Answer:Thermometry. The movement is caused due the loss of water in in the pulvinus part of the leaf. When we touch the leaves of the ‘mimosa’ plant, they fold up in response to the touch.
Question 18.Name the two systems of control and co-ordination in higher animals.
Answer:Nervous system and Endocrine system are the two systems of control and co-ordination in higher plants.
Question 19.Name the three components of a nerve cell.
Answer:The three components of a nerve cell are:
1. Cell body-Made up cytoplasm and nucleus, Have lots of fibers stretching out known as nerve fibers
2. Dendrites- Perform the role of picking up the message that sets of chemical reaction
3. Axon-Performs the role of passing the message to next nerve cell
Question 20.Name the most important part of the human brain.
Answer:Cerebrum is the most important part of human brain as it performs so many functions like visual reception, auditory reception, muscular activities, etc.
Question 21.State one function each of cerebellum and pons.
Answer:Function performed by:
1. Cerebellum- It maintains the balance of body and postures.
2. Pons- It regulates the process of respiration
Question 22.Name one hormone secreted by the pituitary gland.
Answer:Pituitary gland, also known as the master gland is associated with the secretion of many different hormones. It consists of three different lobes, structurally. Growth hormone is secreted by the anterior lobe of pituitary gland. Under-secretion of growth hormone from childhood results in a disorder known as dwarfism while over-secretion causes dwarfism.
Picture showing gigantism and dwarfism.
Question 23.Where are hormones synthesised in the human body?
Answer:Hormones are synthesized by specialized cells in the glands of human body. They are also known as chemical messengers because they act at a particular target site in the body. Endocrine glands pour their secretion into the blood, hence they are also known as ductless glands.
Question 24.Which gland secretes the growth hormone?
Answer:Pituitary gland is associated with the secretion of growth hormone. The anterior lobe of the pituiatary gland secretes many different hormones like FSH( Follicle stimulating hormone), LH (leutenising hormone), Prolectin and growth hormone.
Picture showing location of pituitary gland in human brain.
Question 25.Name the disease caused by the deficiency of insulin hormone in the body.
Answer:The disease caused by the deficiency of insulin hormone in the human body is diabetes. Insulin is secreted by the specialized cells of pancreatic glands known as Islets of langerhans. Insulin controls the blood sugar level in blood. Diabetes causes large amount of sugar level in the blood and urine. That is why, diabetic patients should take less amount of sugar in diet.
Diagram showing working pancreas in the body
Question 26.A. What does a root do in response to gravity? What is this phenomenon known as?
B. What does a stem do in response to light? What is this phenomenon known as?
Answer:(A) The root grows towards the stimulus, that is it responds under the force of gravity positively.
This phenomenon is known as positive geotropism.
(B) The stem shows growth in response to the light, that is towards the light. This phenomenon is known as positive phototropism.
Question 27.A. What does a stem do in response to gravity? What is this phenomenon known as?
B. What does a root do in response to light? What is this phenomenon known as?
Answer:(A) A stem grows in opposite direction to the stimulus of gravity, that is, gravitational force attracts the plant parts towards itself but the stem grows upwards, which means against the force of gravity. This is known as negative geotropism.
(B) The response of root towards light is in opposite direction,that is it grows downwards, towards the dark. Hence, the phenomenon is known as negative phototropism.
Question 28.A. What is a spinal cord? What is its main function?
B. Give the functions of medulla oblongata.
Answer:(A) Spinal cord is a cylindrical structure which originates from the posterior extension of medulla oblongata( a part of hind brain). Function- It contain nerve fibres which help in the transfer of information from spinal cord to brain (known as ascending nerves) and from brain to spinal cord(known as descending brain).
(B) Function of medulla- It controls various involuntary activities like breathing, heartbeat, peristalsis movement of alimentary canal, blood pressure.
It also controls the main centre of reflex action like coughing, sneezing, vomiting, etc.
Question 29.A. Name the hormones secreted by the following endocrine glands:
(i) Thyroid gland
(ii) Parathyroid glands
(iii) Pancreas
(iv) Adrenal glands
B. Write the functions of testosterone and estrogen hormones.
Answer:(A)
(B) Functions of testosterone- To control the development of sex organs and secondary sexual characters like deeper voice, adam’s apple, moustache. They are also involved in the production of sperms.
Functions of ovary- The function of estrogen is to control the development of sex organs and secondary sexual characters like soft skin, mammary gland,etc. The function of progesterone is to maintain the changes in uterus during menstrual cycle and also the production of ova.
Question 30.A. Write the names of the regions of hind-brain. Give functions of each region.
B. Mention the functions of cerebrum.
Answer:(A) the regions of hind brain:-
1. Medulla- It controls various involuntary activities like breathing, heartbeat, peristalsis movement of alimentary canal, blood pressure.
It also controls the main centre of reflex action like coughing, sneezing, vomiting, etc.
2. Cerebellum- It maintains the balance of body and postures.
3. Pons- It regulates the process of respiration
(B) The cerebrum has 4 lobes. Each lobe performs specific functions:
1. Occipital lobe- performs the function of visual reception (to see).
2. Temporal lobe- performs the function of auditory reception (to hear)
3. Parietal lobe- performs the function of reception of general smell, touch and temperature.
4. Frontal lobe- controls specific muscular activities like thought, speech and memory.
Question 31.What does CNS stand for?
Answer:CNS stands for Central Nervous System. It includes brain and spinal cord.
Question 32.A. What is meant by ‘tropisms’ ? Explain with an example.
B. Mention types of tropisms. Define each type of tropism. Write the name of stimulus in each case.
C. How do tropism differ from nastism?
Answer:(A) When a plant part gets moved in response to an external stimuli or directional stimuli, then it is known as tropism. If the growth of plant part is towards the stimulus then it is called positive tropism and when the growth is away from the stimulus, then it is called the negative tropism.
Example- Growth of stem towards the light is an example of positive phototropism. The plant part – stem grows in the response to light.
(B) There are 5 common types of tropism:
1. Phototropism- The movement of plant part in response to light is known as phototropism. The stimulus in this case is –light.
2. Hydrotropism- The movement of plants towards water is hydrotropism. The stimulus is water.
3. Geotropism- The movement of plants towards gravity is known as geotropism. The stimulus in geotropism is gravity.
4. Chemotropism- The movement of plants towards chemical stimulus is known as chemotropism. The stimulus is chemicals.
5 Thigmotropism- The movement of plants towards light is phototropism. The stimulus in thigmotropism is touch.
(C)
Question 33.A. Define phototropism and give one example of it.
B. How does phototropism occur in a plant stem ? Explain with the help of labelled diagrams.
C. What is meant by positive phototropism and negative phototropism? Give one example of each type.
Answer:(A) The movement of plant part in response to light is known as phototropism.
Example- Growth of stem towards the light is an example of positive phototropism. The plant part – stem grows in the response to light.
(B) In plant, the stem shows positive phototropism because it grows in the direction of light. The stimulus in phototropism is light.
(C)
Question 34.A. Name the structural and functional unit of nervous system.
B. What is autonomous nervous system? What is its function?
C. What is voluntary nervous system? Explain the working of voluntary nervous system with an example.
Answer:(A) Nerve cell is the structural and functional unit of nervous system.
Picture showing structure of nerve cell showing the parts of it.
(B) The part of nervous system that control the functions of the body without any need of our conscious, such as breathing, heartbeat and digestive processes, is known as autonomous nervous system.
Functions- It control and regulates the processes like breathing, sweating, digestion, heart rate.
(C) Somatic nervous system – a type of peripheral nervous system is also known as voluntary nervous system.
Example- Reflex action.
When we touch a hot pan. The afferent neuron take the information from body to the central nervous system. The brain processes the information. The efferent neurons then take the information from the brain to the body back in the form of muscle contraction, so that we can move our hand away from hot pan.
Question 35.A. What is a reflex action? Explain with the help of an example.
B. How involuntary actions and reflex actions differ from each other?
Answer:(A) Reflex action is the simplest form of response of nervous system. It is an automatic process that occurs when we touch a hot pan, cut or hand through knife, yawning, etc.
Example- When we touch a hot pan.
•The afferent neuron take the information from body to the central nervous system.
•The brain processes the information.
•The efferent neurons then take the information from the brain to the body back in the form of muscle contraction, so that we can move our hand away from hot pan.
Diagram showing reflex arc. Reflex arc is the neural pathway involved in reflex action.
(B)
Question 36.A. Write the names of five endocrine glands found in the human body. Name the hormones secreted by each gland.
B. Name the gland which controls the secretion of hormones of pituitary gland.
C. How does our body response when adrenaline is secreted in large amounts into the blood?
D. Name the disease which occurs in adults due to the deficiency of iodine in the diet. What is the main symptom of this disease ?
Answer:(A)
(B) Hypothalamus gland controls the secretion of hormones of pituitary gland.
(c) When adrenaline hormone is secreted in large amount into the blood, it raises the heartbeat and blood-pressure, due to which more glucose go into the blood. Thus the glucose provides energy to fight back in a situation. This is why it is also known as emergency hormone.
(D) Goitre is the disease which occurs in adults due to deficiency of iodine in the diet.
The main symptom is the enlargement of the thyroid gland.
Diagram showing the disease of goitre. It is caused due to the deficiency of iodone.
What is called the movement of plant toward the gravity?
A. hydrotropism
B. geotropism
C. chemotropism
D. phototropism
Answer:
•The movement of plants towards water is hydrotropism.
•The movement of plants towards gravity is known as geotropism.
•The movement of plants towards chemical stimulus is known as chemotropism.
•The movement of plants towards light is phototropism.
Question 2.
The plant part which exhibits negative geotropism is:
A. root
B. stem
C. branch
D. leaves
Answer:
Stem shows negative geotropism because it shows its growth against the force of gravity.
This is a picture showing geotropism.
Question 3.
The growth of a pollen tube towards the ovule is caused by....
A phototropism
B. hydrotropism
C. gravitropism
D. chemotropism
Answer:
The growth of pollen tube towards the ovule is caused in response to a chemical stimulus i.e the chemicals released by the ovule during the time of fertilization.
This is a picture showing chemotropism. Growth of pollen tube Observed in response to chemicals secreted by ovule
Question 4.
Bending of the shoot of a plant in response to light is known as.....
A. geotropism
B. phototropism
C. thigmotropism
D. photonasty
Answer:
The movement of plant in response to light is known as phototropism
This is a picture showing phototropism. Growth of stem in response to light.
Question 5.
The stimulus in the process of thigmotropism is:
A. touch
B. gravity
C. light
D. chemical
Answer:
In Thigmotropism, the word ‘thigmo’ means touch, hence the movement of plant part in response to touch is thigmotropism.
This is a picture showing the process of thigmotropism. Here, the stimulus is touch.
Question 6.
Which of the following helps in maintaining posture and balance of the human body?
A. cerebellum
B. cerebrum
C. medulla oblongata
D. pons
Answer:
Cerebellum is involved in maintaining body postures and co-ordinating body movments.
Question 7.
How many pairs of nerves arise from the spinal cord?
A. 21
B. 31
C. 41
D. 51
Answer:
31 pairs of nerves arise from the centre of spinal cord.
Question 8.
Cerebellum, medulla oblongata and pons are the parts of:
A. mid-brain
B. hind-brain
C. fore-brain
D. spinal cord
Answer:
This is because hind brain has 3 parts. Cerebellum present on the dorsal side of pons, while medulla and pons are present on the ventral side.
Question 9.
For the synthesis of which of the following hormone iodine is necessary?
A. adrenaline
B. auxin
C. thyroxine
D. insulin
Answer:
Because the deficiency of iodine can cause the deficiency of thyroxine hormone.
•Adrenaline is secreted by adrenal gland.
•Auxin is a plant hormone.
•Insulin is a hormone secreted by pancreatic glands which metabolizes sugar.
Question 10.
Which of the following is a mismatched pair?
A. adrenaline: pituitary gland
B. estrogens: ovary
C. pancreas: insulin
D. progesterone: ovary
Answer:
•Adrenalin hormone also known as fight or flight hormone is secreted by the adrenal gland.
•Ovary produces two female sex Hormones which are Estrogen and Progesterone which are responsible for controlling the development of female sex organs and controlling the changes taking place in uterus during menstrual cycle respectively
•Pancreas contain Islets of Langerhans that synthesize insulin
Question 11.
The spinal cord originates from :
A. cerebrum
B. cerebellum
C. medulla oblongata
D. puns
Answer:
Spinal cord originates from the posterior side of medulla.
Question 12.
Which of the following hormone prepares our body for action in emergency situations?
A. testosterone
B. growth hormone
C. adrenaline
D. insulin
Answer:
•This hormone is secreted by the adrenal gland. Medulla part of this gland secretes adrenalin hormone, which is called fight or flight hormone.
•Insulin is secreted by the pancreas.
•Testosterone is secreted by the testis.
•Growth hormone is secreted by pituitary gland.
Question 13.
Which is male sex hormone?
A. estrogens
B. adrenaline
C. testosterone
D. progesterone
Answer:
Testosterone is secreted by the male reproductive part testis, hence it is the male sex hormone.
Question 14.
Which of the following endocrine gland does not occur as a pair in the human body?
A. adrenal
B. pituitary
C. testis
D. ovary
Answer:
The rest of the three glands – adrenal, testis and ovary occur as a pair in human body. Pituitary gland, also known as the master gland is only one in number.
Question 15.
Name the plant which shows thigmonesty.
Answer:
Mimosa is the plant which shows thigmonesty.
The leaves of the plant folds up in response to a touch.
A picture showing response of mimosa plant.
Question 16.
Give the scientific terms used to represent the following:
A. Bending of a shoot towards light.
B. Growing of roots towards the earth.
C. Growing of a pollen tube towards ovule.
D. Bending of roots towards water.
E. Winding of tendril around a support.
Answer:
A. Positive phototropism. The growth of shoot takes place in the direction of light, that is towards the stimulus. Hence, positive phototropism.
Picture showing positive and negative phototropism.
B. Positive geotropism. The stimulus in the case of geotropism is gravity. As the growth of roots is towards the earth, i.e. under the force of gravity. Hence, positive geotropism.
C. Chemotropism. The growth of pollen tube is in response to the chemicals released by the ovule during fertilization.
D. Hydrotropism. The movement of plant part in response to water is known as hydrotropism.
E. Thigmotropism. Movement of plant part in response to touch is known as thigmotropism.
Question 17.
Give example of the movement of a plant part which is caused by the loss of water.
Answer:
Thermometry. The movement is caused due the loss of water in in the pulvinus part of the leaf. When we touch the leaves of the ‘mimosa’ plant, they fold up in response to the touch.
Question 18.
Name the two systems of control and co-ordination in higher animals.
Answer:
Nervous system and Endocrine system are the two systems of control and co-ordination in higher plants.
Question 19.
Name the three components of a nerve cell.
Answer:
The three components of a nerve cell are:
1. Cell body-Made up cytoplasm and nucleus, Have lots of fibers stretching out known as nerve fibers
2. Dendrites- Perform the role of picking up the message that sets of chemical reaction
3. Axon-Performs the role of passing the message to next nerve cell
Question 20.
Name the most important part of the human brain.
Answer:
Cerebrum is the most important part of human brain as it performs so many functions like visual reception, auditory reception, muscular activities, etc.
Question 21.
State one function each of cerebellum and pons.
Answer:
Function performed by:
1. Cerebellum- It maintains the balance of body and postures.
2. Pons- It regulates the process of respiration
Question 22.
Name one hormone secreted by the pituitary gland.
Answer:
Pituitary gland, also known as the master gland is associated with the secretion of many different hormones. It consists of three different lobes, structurally. Growth hormone is secreted by the anterior lobe of pituitary gland. Under-secretion of growth hormone from childhood results in a disorder known as dwarfism while over-secretion causes dwarfism.
Picture showing gigantism and dwarfism.
Question 23.
Where are hormones synthesised in the human body?
Answer:
Hormones are synthesized by specialized cells in the glands of human body. They are also known as chemical messengers because they act at a particular target site in the body. Endocrine glands pour their secretion into the blood, hence they are also known as ductless glands.
Question 24.
Which gland secretes the growth hormone?
Answer:
Pituitary gland is associated with the secretion of growth hormone. The anterior lobe of the pituiatary gland secretes many different hormones like FSH( Follicle stimulating hormone), LH (leutenising hormone), Prolectin and growth hormone.
Picture showing location of pituitary gland in human brain.
Question 25.
Name the disease caused by the deficiency of insulin hormone in the body.
Answer:
The disease caused by the deficiency of insulin hormone in the human body is diabetes. Insulin is secreted by the specialized cells of pancreatic glands known as Islets of langerhans. Insulin controls the blood sugar level in blood. Diabetes causes large amount of sugar level in the blood and urine. That is why, diabetic patients should take less amount of sugar in diet.
Diagram showing working pancreas in the body
Question 26.
A. What does a root do in response to gravity? What is this phenomenon known as?
B. What does a stem do in response to light? What is this phenomenon known as?
Answer:
(A) The root grows towards the stimulus, that is it responds under the force of gravity positively.
This phenomenon is known as positive geotropism.
(B) The stem shows growth in response to the light, that is towards the light. This phenomenon is known as positive phototropism.
Question 27.
A. What does a stem do in response to gravity? What is this phenomenon known as?
B. What does a root do in response to light? What is this phenomenon known as?
Answer:
(A) A stem grows in opposite direction to the stimulus of gravity, that is, gravitational force attracts the plant parts towards itself but the stem grows upwards, which means against the force of gravity. This is known as negative geotropism.
(B) The response of root towards light is in opposite direction,that is it grows downwards, towards the dark. Hence, the phenomenon is known as negative phototropism.
Question 28.
A. What is a spinal cord? What is its main function?
B. Give the functions of medulla oblongata.
Answer:
(A) Spinal cord is a cylindrical structure which originates from the posterior extension of medulla oblongata( a part of hind brain). Function- It contain nerve fibres which help in the transfer of information from spinal cord to brain (known as ascending nerves) and from brain to spinal cord(known as descending brain).
(B) Function of medulla- It controls various involuntary activities like breathing, heartbeat, peristalsis movement of alimentary canal, blood pressure.
It also controls the main centre of reflex action like coughing, sneezing, vomiting, etc.
Question 29.
A. Name the hormones secreted by the following endocrine glands:
(i) Thyroid gland
(ii) Parathyroid glands
(iii) Pancreas
(iv) Adrenal glands
B. Write the functions of testosterone and estrogen hormones.
Answer:
(A)
(B) Functions of testosterone- To control the development of sex organs and secondary sexual characters like deeper voice, adam’s apple, moustache. They are also involved in the production of sperms.
Functions of ovary- The function of estrogen is to control the development of sex organs and secondary sexual characters like soft skin, mammary gland,etc. The function of progesterone is to maintain the changes in uterus during menstrual cycle and also the production of ova.
Question 30.
A. Write the names of the regions of hind-brain. Give functions of each region.
B. Mention the functions of cerebrum.
Answer:
(A) the regions of hind brain:-
1. Medulla- It controls various involuntary activities like breathing, heartbeat, peristalsis movement of alimentary canal, blood pressure.
It also controls the main centre of reflex action like coughing, sneezing, vomiting, etc.
2. Cerebellum- It maintains the balance of body and postures.
3. Pons- It regulates the process of respiration
(B) The cerebrum has 4 lobes. Each lobe performs specific functions:
1. Occipital lobe- performs the function of visual reception (to see).
2. Temporal lobe- performs the function of auditory reception (to hear)
3. Parietal lobe- performs the function of reception of general smell, touch and temperature.
4. Frontal lobe- controls specific muscular activities like thought, speech and memory.
Question 31.
What does CNS stand for?
Answer:
CNS stands for Central Nervous System. It includes brain and spinal cord.
Question 32.
A. What is meant by ‘tropisms’ ? Explain with an example.
B. Mention types of tropisms. Define each type of tropism. Write the name of stimulus in each case.
C. How do tropism differ from nastism?
Answer:
(A) When a plant part gets moved in response to an external stimuli or directional stimuli, then it is known as tropism. If the growth of plant part is towards the stimulus then it is called positive tropism and when the growth is away from the stimulus, then it is called the negative tropism.
Example- Growth of stem towards the light is an example of positive phototropism. The plant part – stem grows in the response to light.
(B) There are 5 common types of tropism:
1. Phototropism- The movement of plant part in response to light is known as phototropism. The stimulus in this case is –light.
2. Hydrotropism- The movement of plants towards water is hydrotropism. The stimulus is water.
3. Geotropism- The movement of plants towards gravity is known as geotropism. The stimulus in geotropism is gravity.
4. Chemotropism- The movement of plants towards chemical stimulus is known as chemotropism. The stimulus is chemicals.
5 Thigmotropism- The movement of plants towards light is phototropism. The stimulus in thigmotropism is touch.
(C)
Question 33.
A. Define phototropism and give one example of it.
B. How does phototropism occur in a plant stem ? Explain with the help of labelled diagrams.
C. What is meant by positive phototropism and negative phototropism? Give one example of each type.
Answer:
(A) The movement of plant part in response to light is known as phototropism.
Example- Growth of stem towards the light is an example of positive phototropism. The plant part – stem grows in the response to light.
(B) In plant, the stem shows positive phototropism because it grows in the direction of light. The stimulus in phototropism is light.
(C)
Question 34.
A. Name the structural and functional unit of nervous system.
B. What is autonomous nervous system? What is its function?
C. What is voluntary nervous system? Explain the working of voluntary nervous system with an example.
Answer:
(A) Nerve cell is the structural and functional unit of nervous system.
Picture showing structure of nerve cell showing the parts of it.
(B) The part of nervous system that control the functions of the body without any need of our conscious, such as breathing, heartbeat and digestive processes, is known as autonomous nervous system.
Functions- It control and regulates the processes like breathing, sweating, digestion, heart rate.
(C) Somatic nervous system – a type of peripheral nervous system is also known as voluntary nervous system.
Example- Reflex action.
When we touch a hot pan. The afferent neuron take the information from body to the central nervous system. The brain processes the information. The efferent neurons then take the information from the brain to the body back in the form of muscle contraction, so that we can move our hand away from hot pan.
Question 35.
A. What is a reflex action? Explain with the help of an example.
B. How involuntary actions and reflex actions differ from each other?
Answer:
(A) Reflex action is the simplest form of response of nervous system. It is an automatic process that occurs when we touch a hot pan, cut or hand through knife, yawning, etc.
Example- When we touch a hot pan.
•The afferent neuron take the information from body to the central nervous system.
•The brain processes the information.
•The efferent neurons then take the information from the brain to the body back in the form of muscle contraction, so that we can move our hand away from hot pan.
Diagram showing reflex arc. Reflex arc is the neural pathway involved in reflex action.
(B)
Question 36.
A. Write the names of five endocrine glands found in the human body. Name the hormones secreted by each gland.
B. Name the gland which controls the secretion of hormones of pituitary gland.
C. How does our body response when adrenaline is secreted in large amounts into the blood?
D. Name the disease which occurs in adults due to the deficiency of iodine in the diet. What is the main symptom of this disease ?
Answer:
(A)
(B) Hypothalamus gland controls the secretion of hormones of pituitary gland.
(c) When adrenaline hormone is secreted in large amount into the blood, it raises the heartbeat and blood-pressure, due to which more glucose go into the blood. Thus the glucose provides energy to fight back in a situation. This is why it is also known as emergency hormone.
(D) Goitre is the disease which occurs in adults due to deficiency of iodine in the diet.
The main symptom is the enlargement of the thyroid gland.
Diagram showing the disease of goitre. It is caused due to the deficiency of iodone.