VERY
VERY SHORT ANSWER QUESTIONS (1 Mark)
1. Mention one example of
chemotropism. [2010 (T-I)]
2. Mention the function of hind brain
in humans. [2010 (T-I)]
Answer:Hind brain controls all involuntary actions including bloood pressure, salivation and vomitting.
Answer:Hind brain controls all involuntary actions including bloood pressure, salivation and vomitting.
3. Name and explain the function of
the hormone secreted by the pituitary gland in humans.[2010 (T-I)]
Answer: The pituitary gland secrete Growth hormone that Controls the overall growth of the body, muscles and bones.
4. State the main function of abscisic
acid in plants.[2010 (T-I)]
Answer: Abscisic acid in plant inhibits growth and affects wilting of leaves5. Name the hormone the secretion of which is responsible for dramatic change in appearance in girls when they approach 10-12 years of age. [2008]
Answer: The ovary in females produces the hormone oestrogen which controls the production of eggs and changes during puberty.
VERY SHORT ANSWER QUESTIONS (2 Mark)
VERY SHORT ANSWER QUESTIONS (2 Mark)
6. What are the end
products formed during fermentation in yeast. Under what condition a similar
process takes place in our body that leads to muscle cramps? [2010 (T-I)]
Ans: Yeast breakdown glucose (food) into ethyl alcohol and carbon dioxide and release energy during fermentation.
Under anaerobic (no oxygen) a similar process takes place in our body that leads to muscle cramps
Ans: Yeast breakdown glucose (food) into ethyl alcohol and carbon dioxide and release energy during fermentation.
Under anaerobic (no oxygen) a similar process takes place in our body that leads to muscle cramps
7. Differentiate between
tropic and nastic movements in plants. Give one example of each. [2009]
Ans: Nastic movements are non directional responses to stimuli such as temperature and heat. These are kind of movements do not depend on direction of stimulus such as seismonastic, chemonastic, etc. Example of seismonastic movement is movement of Venus fly trap.
Tropic movement is the response to stimuli that comes from one direction. It is a directional movement. If the movement of the plant part is towards the stimulus, then it is known as positive tropism. If the movement of the plant part is away from the stimulus, then it is known as negative tropism. For example phototropism, Geotropism etc.
Ans: Nastic movements are non directional responses to stimuli such as temperature and heat. These are kind of movements do not depend on direction of stimulus such as seismonastic, chemonastic, etc. Example of seismonastic movement is movement of Venus fly trap.
Tropic movement is the response to stimuli that comes from one direction. It is a directional movement. If the movement of the plant part is towards the stimulus, then it is known as positive tropism. If the movement of the plant part is away from the stimulus, then it is known as negative tropism. For example phototropism, Geotropism etc.
8. Draw the diagram of a
nerve cell and label the following on it: [2009] (a) Nucleus (b) Dendrites
9. Write the name and the
functions of any two parts of the hind brain.
Ans Hind brain :- consists of cerebellum, pons and medulla.
Cerebellum :- controls body movements, balance and posture.
Pons :- controls respiration.
Medulla :- controls heart beat, blood pressure, swallowing, coughing, sneezing, vomiting etc.
Ans Hind brain :- consists of cerebellum, pons and medulla.
Cerebellum :- controls body movements, balance and posture.
Pons :- controls respiration.
Medulla :- controls heart beat, blood pressure, swallowing, coughing, sneezing, vomiting etc.
10. How does
our body maintain blood sugar level? [2010
(T-I)
Ans The pancreas produces the hormone
insulin which controls the blood sugar level. Increase in blood sugar level
causes diabetes. A diabetic patient has to take insulin injections to control
his blood sugar level.
SHORT ANSWER QUESTIONS (3 Marks)
11. A compound of iodine is
compulsorily added to common salt in small quantity.
(a) Why is it important for
us to have iodised salt in our diet.
(b) Name the disease caused
by its deficiency.
(c) Write our symptoms of
the disease. [2010 (T-I)]
Ans: (a) It is important to have iodized salt in our diet because iodine is required for the synthesis of a hormone called thyroxin. Thyroxin is a very important hormone required metabolism, growth and development of body and brain. Iodine deficiency can result in various disorders like goitre, so it is necessary to consume iodized salt.
(b)Goitor is caused by its deficiency
(c) The neck of person appear to be swellen
Ans: (a) It is important to have iodized salt in our diet because iodine is required for the synthesis of a hormone called thyroxin. Thyroxin is a very important hormone required metabolism, growth and development of body and brain. Iodine deficiency can result in various disorders like goitre, so it is necessary to consume iodized salt.
(b)Goitor is caused by its deficiency
(c) The neck of person appear to be swellen
12. What is reflex action?
Describe the steps involved in reflex action. [2009]
Ans: Reflex Action is defined as an unconscious, automatic and involuntary response of efforts, i.e., muscles and glands, to a stimulus, which is monitored through the spinal cord.
Mechanism of Reflex Action: It involves the following steps:
(i)Receptor organ like skin perceives the stimulus and activates a sensory nerve impulse.
(ii)Sensory organ carries message in the form of sensory impulse to the spinal cord.
(iii)The spinal cord acts as modulator. The neurons of spinal cord transmit the sensory nerve impulse to motor neuron.
(iv) Motor nerve conducts these impulses to the effectors like leg muscles which responds by pulling back the organ away from the harmful stimulus.
Ans: Reflex Action is defined as an unconscious, automatic and involuntary response of efforts, i.e., muscles and glands, to a stimulus, which is monitored through the spinal cord.
Mechanism of Reflex Action: It involves the following steps:
(i)Receptor organ like skin perceives the stimulus and activates a sensory nerve impulse.
(ii)Sensory organ carries message in the form of sensory impulse to the spinal cord.
(iii)The spinal cord acts as modulator. The neurons of spinal cord transmit the sensory nerve impulse to motor neuron.
(iv) Motor nerve conducts these impulses to the effectors like leg muscles which responds by pulling back the organ away from the harmful stimulus.
13. What is ‘hydrotropism’?
Describe an experiment to demonstrate ‘hydrotropism’? [2009]
Ans: The growth of the root of plant in response to water or moisture
Experiment:
1. Take two plastic troughs say A and B
2. Fill each one of them with two-thirds of soil
3. Place the seedling in the soil in trough A
4 Place the similar seedling in trough B, place a small clay pot inside the soil.
5. Water the soil in the trough A daily and uniformly
6. Do not water the soil in trough B, but put some water in the clay pot placed in the soil.
7. Leave both the troughs for a few days. On examining the roots later, it will be found that the root in trough B has bent towards the clay pot that is source of water. Roots in trough A grew normally straight. Thus roots show the hydrotropism.
Ans: The growth of the root of plant in response to water or moisture
Experiment:
1. Take two plastic troughs say A and B
2. Fill each one of them with two-thirds of soil
3. Place the seedling in the soil in trough A
4 Place the similar seedling in trough B, place a small clay pot inside the soil.
5. Water the soil in the trough A daily and uniformly
6. Do not water the soil in trough B, but put some water in the clay pot placed in the soil.
7. Leave both the troughs for a few days. On examining the roots later, it will be found that the root in trough B has bent towards the clay pot that is source of water. Roots in trough A grew normally straight. Thus roots show the hydrotropism.
14. What is ‘phototropism’?
How does it occur in plants? Describe an activity to demonstrate phototropism.
[2009]
Ans: The growth movements in plants in response to light as stimulus is said to be phototropism
Activity: To demonstrate phototropism in plants.
Requirements: A potted plant,
Procedure: Take a potted plant and keep it in the sunlight in a horizontal position and observe the growth of roots and shoots.
Observation: The shoots of the plant grow towards sunlight and roots away from sunlight
Conclusion: Roots are negatively phototropic and shoots are positively phototropic
15. What are ‘hormones’? State one function of each of the following hormones: [2009]
Requirements: A potted plant,
Procedure: Take a potted plant and keep it in the sunlight in a horizontal position and observe the growth of roots and shoots.
Observation: The shoots of the plant grow towards sunlight and roots away from sunlight
Conclusion: Roots are negatively phototropic and shoots are positively phototropic
15. What are ‘hormones’? State one function of each of the following hormones: [2009]
(i) Thyroxin (ii) Insulin
Ans: Thyroxin (secreted by thyroid gland)
The hormone called thyroxin helps in coordinated growth. It regulates carbohydrate, fat, and protein metabolism in our body. The deficiency of this hormone results in the enlargement of the thyroid gland or goitre.
Growth hormone (GH) (secreted by the pituitary gland)
Growth hormone (GH) is involved in the growth and development of the human body. The secretion of this hormone should be properly maintained in the body. Over secretion of this hormone results in abnormal growth of the body known as gigantism. On the other hand, its low secretion results in dwarfism.
Insulin (secreted by pancreas)
The pancreas secretes a hormone called insulin, which regulates the blood sugar level in the human body.
It increases the permeability of the cell membrane for glucose and accelerates the passage of glucose into the cells from the bloodstream.
Ans: Thyroxin (secreted by thyroid gland)
The hormone called thyroxin helps in coordinated growth. It regulates carbohydrate, fat, and protein metabolism in our body. The deficiency of this hormone results in the enlargement of the thyroid gland or goitre.
Growth hormone (GH) (secreted by the pituitary gland)
Growth hormone (GH) is involved in the growth and development of the human body. The secretion of this hormone should be properly maintained in the body. Over secretion of this hormone results in abnormal growth of the body known as gigantism. On the other hand, its low secretion results in dwarfism.
Insulin (secreted by pancreas)
The pancreas secretes a hormone called insulin, which regulates the blood sugar level in the human body.
It increases the permeability of the cell membrane for glucose and accelerates the passage of glucose into the cells from the bloodstream.
LONG ANSWER QUESTIONS (5 Marks)
16. (a) Name two hormones secreted by pancreas. Write one function of each hormone.
16. (a) Name two hormones secreted by pancreas. Write one function of each hormone.
(b) How does our body
respond when alternative is secreted into the blood.
(c) Write an example to
explain feedback mechanism for regulation of hormonal secretion. [2010 (T-I)]
Ans: (a) Two hormones secreted by pancreas are insulin and glucagon.
Both regulate the levels of glucose in our body.Glucagon helps in elevating the amount of glucose in the blood while insulin decreases the level of glucose in the blood stream.
(b) When someone is in danger or in emergency then adrenal gland secrete adrenaline hormone. It is secreted directly into the blood and is transported to different parts of the body. It speeds up the heartbeat and hence supplies more oxygen to the muscles. This results in increasing breathing rate and blood pressure which enable them to fight with such urgent situation.
(c) Feedback means that some element in the physiological response to a hormone feeds back to the endocrine gland either directly or indirectly and affects its secretion rate. The feedback may be negative or positive.
For example insulin regulates the amount of blood glucose. When the level of blood glucose is high, insulin secretion is turned on by the pancreas which acts on target tissues like liver to convert excess sugar into glycogen. When the blood glucose concentration is normal the insulin secretion is stopped.
Both regulate the levels of glucose in our body.Glucagon helps in elevating the amount of glucose in the blood while insulin decreases the level of glucose in the blood stream.
(b) When someone is in danger or in emergency then adrenal gland secrete adrenaline hormone. It is secreted directly into the blood and is transported to different parts of the body. It speeds up the heartbeat and hence supplies more oxygen to the muscles. This results in increasing breathing rate and blood pressure which enable them to fight with such urgent situation.
(c) Feedback means that some element in the physiological response to a hormone feeds back to the endocrine gland either directly or indirectly and affects its secretion rate. The feedback may be negative or positive.
For example insulin regulates the amount of blood glucose. When the level of blood glucose is high, insulin secretion is turned on by the pancreas which acts on target tissues like liver to convert excess sugar into glycogen. When the blood glucose concentration is normal the insulin secretion is stopped.
Chemical Co-ordination in plants VALUE BASED QUESTION
1. A young boy met an accident while riding a bike. Petrolling police found the boy and brought him to a hospital for treatment. After the accident, the boy lost his memory completely. Left side of his body also suffered from paralysis.
a) What values were shown by police persons?
b) Which injured body part can cause paralysis?
c) What precaution should one take while riding a two-wheeler?
2. Mr. Bora has a habit to iron his shirt every morning before going to office. One morning he forgot to keep the hot iron in proper place and left for office. His two year old daughter touched the iron and her hand got burnt. Mrs. Bora immediately put the hand of her daughter under a running tap as a first aid.
a) What value was shown by Mrs. Bora?
b) How do we react when we touch a hot object?
c) What other materials commonly cause burn injury?
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