Saturday, September 29, 2007
Control and Coordination in Plants
Plant shows two types of movements- one dependent on growth and the other independent of growth.
Movements Due to growth or Tropic Movements
A growth movement of a plant part in response to an external stimulus in which the direction of a stimulus determines the direction of response s called tropism. Thus tropism is a directional movement of the part of a plant caused due to its growth. The tropic movements can be either towards the stimulus or away from it e.g. the shoot of a growing plant bends towards the light, while roots of a plant move away from light.
Types of tropism:
1. The movement of a plant part in response to light is called phototropism. The stem of a growing plant bends towards the light (positive phototropism), while roots of a plant move away from light (negative phototropism).
2. The movement of a plant part in response to gravity is called geotropism. The roots of a plant move downwards in the direction of gravity. On the other hand the stem of a plant grow upwards and away from the earth.
3. The movement of a plant part in response to chemicals is called chemotropism. The growth of pollen tubes towards ovules during the process of fertilization.
Movements Due to growth or Tropic Movements
A growth movement of a plant part in response to an external stimulus in which the direction of a stimulus determines the direction of response s called tropism. Thus tropism is a directional movement of the part of a plant caused due to its growth. The tropic movements can be either towards the stimulus or away from it e.g. the shoot of a growing plant bends towards the light, while roots of a plant move away from light.
Types of tropism:
1. The movement of a plant part in response to light is called phototropism. The stem of a growing plant bends towards the light (positive phototropism), while roots of a plant move away from light (negative phototropism).
2. The movement of a plant part in response to gravity is called geotropism. The roots of a plant move downwards in the direction of gravity. On the other hand the stem of a plant grow upwards and away from the earth.
3. The movement of a plant part in response to chemicals is called chemotropism. The growth of pollen tubes towards ovules during the process of fertilization.
4. The movement of a plant part in response to water is called hydrotropism. The roots of a plant always grow towards water.
5. The directional growth movement of a plant part in response to the touch of an object is called Thigmotropism.
There are some plants called climbing plants which have weak stems, cannot stand erect on their own. They have climbing organs called tendrils. Tendrils are thin, thread like structures on the stem or leaves of climbing plants. Tendrils are sensitive to touch. When they come in contact with an object, wind around the object and cling to it. This is due to the growth of a tendril towards the object.Nastic Movements:
In nastic movements the movement of plant part is neither towards the stimulus nor away from the stimulus. This movement is not a directional movement of the plant part with respect to the stimulus. In nastic movements growth may or may not take place.
The folding up of the leaves of a sensitive plant or touch me not plant (Mimosa pudica) on touching is an example of nastic movement. Here stimulus is touch. This information is traveled from cell to cell by electrical chemical means.
This plant has pad like swellings called pulvini at the base of each leaf. The folding up of the leaves of a sensitive plant on touching is due to the sudden loss of water from the pulvini.
Plant cells change shape by changing the amount of water in them, resulting in swelling or shrinking, and in changing shapes.
Hormones in Plants
Different plant hormones help to coordinate growth, development and responses to the environment. They are produced at places away from where they act simply diffuses to the area of action.
Types of Hormones:
1. Auxin: It is produced at the shoot tip. It helps plant to grow. It promotes cell enlargement and cell differentiation in plants
2. Gibberellins: It also helps in the growth of the stem along with Auxin.
3. Cytokinins: It promotes cell division. They are present in large amount in areas of rapid cell division, such as fruits and seeds. It promotes the opening of stomata.
4. Abscisic acid: It inhibits growth. It effects wilting of leaves. It also promotes the closing of stomata.
Monday, September 10, 2007
ASSIGNMENT..CLASS XI
EXCRETION
Explain the following:
1. Skin functions as an accessory excretory organ.
2. Micturtion is a reflex process, but is under some voluntary control.
3. Different parts of a nephron participate in different ways in the formation of urine.
Distinguish between:
1. Sweat and Sebum
2. Proximal and Distal convoluted tubule
3. Ascending and descending limbs of loop of Henle.
4. Tubular reabsorbtion and Tubular secretion
5. Cortical and Juxtamedullary nephron.
Short answer type questions
1. What is the osmolarity of human blood?
2. In which three forms animal excrete excess of nitrogen?
3. In which organ urea is produced
4. What constitute the malpighian corpuscles?
5. What are podocytes?
6. Expand GFR, What is the value of GFR per minute and per day?
7. Which enzyme cells of JGA secrete?
8. Name the hormone secreted by atrial wall which inhibits the secretion of rennin from JGA?
9 Write full form of RAAS?
10 What is the function of enzyme rennin?
11 What is meant by Micturtion?
Long answer questions
1. Describe the structure of nephron with a labeled diagram.
2. Describe the role of ADH and counter current systems in forming hypertonic urine.
3. What happens to the role of the kidney filtrate in Descending loop of Henle & Collective tubules in humans?
4. Why is glomerular filtrate hypertonic and hypotonic in descending and ascending limb of loop of Henle respectively? What is the effect of ADH on collecting tubules?
5. How does the PCT of the nephron contribute in homeostasis?
6. .Explain the structure of kidney with the help of neat and labeled diagram.
7. What is the mechanism that provides auto regulation of glomerular filtrate?
8. Name the two groups of nephron on the basis of their position in the kidney. How are they ascending limb of different from each other?
9. Draw a labeled sketch of human urinary system with its associated blood vessels.
10. Both the thin and thick segments of the ascending loop of Henle transport NaCl out to the interstitial fluid. What is the difference in their respective mode of transport?
11. What is the counter current system? Name two such systems associated with excretory system and state their functions.
12. Explain the structure of glomerular filtration membrane. Give the pressures that favours and opposite filtration through membrane
13. With the help of flow chart explain regulation of kidney functions by RAAS.
14. With the help of flow chart explain regulation of kidney functions by ADH.
MOVEMENT AND LOCOMOTION
1. Explain the initiation of muscle contraction. What is the role of sarcoplasmic reticulum, Myosin head and F actin filament during contraction?
2. Name the heaviest and longest bone in the human body?
3. Why does thinning of bones usually start occurring in human females at about 50 years of age?
4. What is the total number of bones present in the left pectoral girdle and left arm in human?
5. How many pairs of ribs are present in men? How do you categories these on the basis of their attachment to the back bone?
6. Trace the events in the muscle fibre from the time it receives the impulse through the neuro muscular junctions up to the contractile process.
7. Explain molecular structure of actin and myosin filament?
8. Draw neat and labeled diagram of contractile unit of muscle fibre?
9. Explain the sliding filament theory of muscle contraction.
10. What is the role of Calcium ions in the contraction of muscle?
11. Name the bones which form the basin – shaped pelvis
12. Give one example of fibrous joint
13. Name the kind of joint in our knee and elbow
14. Name the oxygen storing pigment present in the muscles
15. What is the total number of bones in arms
16. Which bone support shank of the legs
17. Name the triangular bone which forms the knee cap
18. How many vertebras present in the vertebral column? Give their names according to location and number.
19. Name the bones of the pectoral girdle and the cavity in which head of humerus articulates
20. Name the bones of the pelvic girdle and the cavity head of femur fits
21. Write the first vertebrae of vertebral column. How does it articulate with the skull?
Explain the following:
1. Skin functions as an accessory excretory organ.
2. Micturtion is a reflex process, but is under some voluntary control.
3. Different parts of a nephron participate in different ways in the formation of urine.
Distinguish between:
1. Sweat and Sebum
2. Proximal and Distal convoluted tubule
3. Ascending and descending limbs of loop of Henle.
4. Tubular reabsorbtion and Tubular secretion
5. Cortical and Juxtamedullary nephron.
Short answer type questions
1. What is the osmolarity of human blood?
2. In which three forms animal excrete excess of nitrogen?
3. In which organ urea is produced
4. What constitute the malpighian corpuscles?
5. What are podocytes?
6. Expand GFR, What is the value of GFR per minute and per day?
7. Which enzyme cells of JGA secrete?
8. Name the hormone secreted by atrial wall which inhibits the secretion of rennin from JGA?
9 Write full form of RAAS?
10 What is the function of enzyme rennin?
11 What is meant by Micturtion?
Long answer questions
1. Describe the structure of nephron with a labeled diagram.
2. Describe the role of ADH and counter current systems in forming hypertonic urine.
3. What happens to the role of the kidney filtrate in Descending loop of Henle & Collective tubules in humans?
4. Why is glomerular filtrate hypertonic and hypotonic in descending and ascending limb of loop of Henle respectively? What is the effect of ADH on collecting tubules?
5. How does the PCT of the nephron contribute in homeostasis?
6. .Explain the structure of kidney with the help of neat and labeled diagram.
7. What is the mechanism that provides auto regulation of glomerular filtrate?
8. Name the two groups of nephron on the basis of their position in the kidney. How are they ascending limb of different from each other?
9. Draw a labeled sketch of human urinary system with its associated blood vessels.
10. Both the thin and thick segments of the ascending loop of Henle transport NaCl out to the interstitial fluid. What is the difference in their respective mode of transport?
11. What is the counter current system? Name two such systems associated with excretory system and state their functions.
12. Explain the structure of glomerular filtration membrane. Give the pressures that favours and opposite filtration through membrane
13. With the help of flow chart explain regulation of kidney functions by RAAS.
14. With the help of flow chart explain regulation of kidney functions by ADH.
MOVEMENT AND LOCOMOTION
1. Explain the initiation of muscle contraction. What is the role of sarcoplasmic reticulum, Myosin head and F actin filament during contraction?
2. Name the heaviest and longest bone in the human body?
3. Why does thinning of bones usually start occurring in human females at about 50 years of age?
4. What is the total number of bones present in the left pectoral girdle and left arm in human?
5. How many pairs of ribs are present in men? How do you categories these on the basis of their attachment to the back bone?
6. Trace the events in the muscle fibre from the time it receives the impulse through the neuro muscular junctions up to the contractile process.
7. Explain molecular structure of actin and myosin filament?
8. Draw neat and labeled diagram of contractile unit of muscle fibre?
9. Explain the sliding filament theory of muscle contraction.
10. What is the role of Calcium ions in the contraction of muscle?
11. Name the bones which form the basin – shaped pelvis
12. Give one example of fibrous joint
13. Name the kind of joint in our knee and elbow
14. Name the oxygen storing pigment present in the muscles
15. What is the total number of bones in arms
16. Which bone support shank of the legs
17. Name the triangular bone which forms the knee cap
18. How many vertebras present in the vertebral column? Give their names according to location and number.
19. Name the bones of the pectoral girdle and the cavity in which head of humerus articulates
20. Name the bones of the pelvic girdle and the cavity head of femur fits
21. Write the first vertebrae of vertebral column. How does it articulate with the skull?
Friday, September 7, 2007
Activity of salivary amylase
ACHROMIC POINT -It is the point at which starch is completely broken into sugar.Benedict' solution gives brick red colour to sugar.This is the confirmatory test. This shows the starch present in the activity tube is converted into sugar.
Test control tube with benedict's reagent. There will be no change. This shows that
It is salivary amylase which convert starch into sugar.
Wednesday, September 5, 2007
HORMONES IN ANIMALS
HORMONES- THE ENDOCRINE SYSTEN
1. The endocrine system consists of a number of endocrine glands which secrete chemicals known as hormones.
2. Endocrine system helps in coordinating the activities of our body in addition to nervous system.
3. The hormones produced by endocrine glands act as messengers between the nervous system and the organs of our body.
Features of hormones
1. They are secreted by ductless glands called endocrine glands.
2. They are poured directly into the blood.
3. They are secreted in small amounts by the endocrine glands
4. The hormones have their effect at the site different from the sites where they are made.
5. They act on specific tissues or organs called target tissues or organs.
6. They are known as chemical messengers as they modify and regulate the activity of the target tissues or organs.
The endocrine glands present in the human body areas follows:
Endocrine gland Location
1 Pineal Forebrain
2. Hypothalamus Forebrain
3. Pituitary Forebrain
4. Thyroid wind pipe
5. Parathyroid embedded in the
i. Thyroid gland
6. Adrenal Above kidney
7. Pancreas Below the stomach
8. Testis Male sex organ
9. Ovary Female Sex Organ
HYPOTHALAMUS:
1. It is present in the brain.
2. It produces ’releasing hormones’ and ’inhibitory hormones’.
3. The function of hypothalamus is to regulate the secretion of hormones from pituitary gland i.e. hypothalamus controls the pituitary gland.
PITUITARY GLAND:
1. It is also present in the brain.
2. It produces number of hormones. One of the hormones secreted by pituitary gland is growth hormone.
3. The growth hormone controls the growth of the human body. The growth hormone controls the development of bones and muscle.
4. If there is deficiency of this hormone in childhood, it leads to dwarfism. On the other hand, if is secreted in large amount then the person becomes giant.
THYROID GLAND:
1. It is attached to the wind pipe our body.
2. It produces a hormone called thyroxin. Iodine is necessary for the thyroid gland to make thyroxin hormone.
3. Thyroxin regulates carbohydrate, protein and fat metabolism of the body.
4. The deficiency of iodine in the diet of a person produces less thyroxin hormone and causes a disease known as goiter. One of the symptoms in this disease is a swollen neck.
PANCREAS:
1. The pancreas is present just below the stomach in the body. Pancreas secrets the hormone called insulin.
2. Insulin regulates the level of sugar in the blood. If it is secreted in less amount the sugar level in the blood rises, person suffers from diabetes. Diabetes causes many harmful effects.
TESTES:
1. Testes are the male sex organs. They also function as endocrine gland. Testis produces male sex hormone called testosterone.
2. Testosterone controls the development of male sex hormone and the changes which occur during puberty at the age of 13 to 14 years like deeper voice, moustache, beard, and more body hair.
OVARIES:
Ovaries are the male sex organs. They also function as endocrine gland. Ovary makes two hormones called estrogen and progesterone.
ESTROGEN: It controls the development of female sex organs, and the changes which occur during puberty at the age of 10 to 12years like feminine voice, mammary glands etc.
PROGESTERONE: It is a pregnancy hormone. It also causes ovulation (release of ovum).
ADRENAL GLAND:
1. It is an emergency hormone or hormones of Fight or Flight. The adrenal gland secrets a hormone called adrenalin.
2. It prepares the body to face emergency conditions of physical stress like danger, anger, excitement; etc.
3. It is secreted in small amounts all the time but in large amounts when a person is frightened. When we are faced with a dangerous situation this hormone….
1. The target organ is heart so heart beat increases, resulting in supply of more oxygen in our muscles.
2. The blood to the digestive system and skin is reduced due to contraction of muscles around small arteries in theses organs.
3. Increase blood flow to our skeletal muscles.
4. Increase in the breathing rate.
5. Allows more supply of glucose into the blood to give us a lot of energy quickly to fight or flight from the frightening situation.
1. The endocrine system consists of a number of endocrine glands which secrete chemicals known as hormones.2. Endocrine system helps in coordinating the activities of our body in addition to nervous system.
3. The hormones produced by endocrine glands act as messengers between the nervous system and the organs of our body.
Features of hormones
1. They are secreted by ductless glands called endocrine glands.
2. They are poured directly into the blood.
3. They are secreted in small amounts by the endocrine glands
4. The hormones have their effect at the site different from the sites where they are made.
5. They act on specific tissues or organs called target tissues or organs.
6. They are known as chemical messengers as they modify and regulate the activity of the target tissues or organs.
The endocrine glands present in the human body areas follows:
Endocrine gland Location
1 Pineal Forebrain
2. Hypothalamus Forebrain
3. Pituitary Forebrain
4. Thyroid wind pipe
5. Parathyroid embedded in the
i. Thyroid gland
6. Adrenal Above kidney
7. Pancreas Below the stomach
8. Testis Male sex organ
9. Ovary Female Sex Organ
HYPOTHALAMUS:
1. It is present in the brain.
2. It produces ’releasing hormones’ and ’inhibitory hormones’.
3. The function of hypothalamus is to regulate the secretion of hormones from pituitary gland i.e. hypothalamus controls the pituitary gland.
PITUITARY GLAND:
1. It is also present in the brain.
2. It produces number of hormones. One of the hormones secreted by pituitary gland is growth hormone.
3. The growth hormone controls the growth of the human body. The growth hormone controls the development of bones and muscle.
4. If there is deficiency of this hormone in childhood, it leads to dwarfism. On the other hand, if is secreted in large amount then the person becomes giant.
THYROID GLAND:
1. It is attached to the wind pipe our body.
2. It produces a hormone called thyroxin. Iodine is necessary for the thyroid gland to make thyroxin hormone.
3. Thyroxin regulates carbohydrate, protein and fat metabolism of the body.
4. The deficiency of iodine in the diet of a person produces less thyroxin hormone and causes a disease known as goiter. One of the symptoms in this disease is a swollen neck.
PANCREAS:
1. The pancreas is present just below the stomach in the body. Pancreas secrets the hormone called insulin.
2. Insulin regulates the level of sugar in the blood. If it is secreted in less amount the sugar level in the blood rises, person suffers from diabetes. Diabetes causes many harmful effects.
TESTES:
1. Testes are the male sex organs. They also function as endocrine gland. Testis produces male sex hormone called testosterone.
2. Testosterone controls the development of male sex hormone and the changes which occur during puberty at the age of 13 to 14 years like deeper voice, moustache, beard, and more body hair.
OVARIES:
Ovaries are the male sex organs. They also function as endocrine gland. Ovary makes two hormones called estrogen and progesterone.
ESTROGEN: It controls the development of female sex organs, and the changes which occur during puberty at the age of 10 to 12years like feminine voice, mammary glands etc.
PROGESTERONE: It is a pregnancy hormone. It also causes ovulation (release of ovum).
ADRENAL GLAND:
1. It is an emergency hormone or hormones of Fight or Flight. The adrenal gland secrets a hormone called adrenalin.
2. It prepares the body to face emergency conditions of physical stress like danger, anger, excitement; etc.
3. It is secreted in small amounts all the time but in large amounts when a person is frightened. When we are faced with a dangerous situation this hormone….
1. The target organ is heart so heart beat increases, resulting in supply of more oxygen in our muscles.
2. The blood to the digestive system and skin is reduced due to contraction of muscles around small arteries in theses organs.
3. Increase blood flow to our skeletal muscles.
4. Increase in the breathing rate.
5. Allows more supply of glucose into the blood to give us a lot of energy quickly to fight or flight from the frightening situation.
Monday, September 3, 2007
ASSIGNMENT
CONTROL AND COORDINATION
Write one word for the following:
1. Nerve cells that transmits information from brain to effectors organs.
2. An electric signal passing through the neurons.
3. Fluid that protects the brain from mechanical shocks.
4. A lobe of cerebrum for auditory reception.
5. Part of the brain contains respiratory centre.
6. The structural and functional unit of nervous system.
7. The control centre of reflex actions?
Differentiate between the following
1. Dendrites and axon.
2. Sensory and motor neurons
3. Cerebrum and cerebellum
4. Spinal and Cranial nerves
Short answer questions
1. What is a synapse? How are messages carried across a synapse?
2. What is cranium? What is its function?
3. The human brain can be broadly divided into three regions. Name these three regions.
4. State one function each of cerebellum and pons.
5. Where is the medulla located in the brain? Write its functions.
6. Where does cerebro-spinal fluid present in our body? Mention any two of its function.
7. What is meant by receptors and effectors? Give two examples of each.
8. Name the types of nerves which constitute peripheral nervous system?
9. What is the difference between a reflex action and walking?
10. Which part of the brain maintains posture and equilibrium of the body?
11. How do we detect the smell of an agarbatti (incense stick)?
12. What is the role of brain in reflex action?
13. Which signals will get disrupted in case of a spinal cord injury?
14 How are involuntary actions and reflex actions different from each other?
Write one word for the following:
1. Nerve cells that transmits information from brain to effectors organs.
2. An electric signal passing through the neurons.
3. Fluid that protects the brain from mechanical shocks.
4. A lobe of cerebrum for auditory reception.
5. Part of the brain contains respiratory centre.
6. The structural and functional unit of nervous system.
7. The control centre of reflex actions?
Differentiate between the following
1. Dendrites and axon.
2. Sensory and motor neurons
3. Cerebrum and cerebellum
4. Spinal and Cranial nerves
Short answer questions
1. What is a synapse? How are messages carried across a synapse?
2. What is cranium? What is its function?
3. The human brain can be broadly divided into three regions. Name these three regions.
4. State one function each of cerebellum and pons.
5. Where is the medulla located in the brain? Write its functions.
6. Where does cerebro-spinal fluid present in our body? Mention any two of its function.
7. What is meant by receptors and effectors? Give two examples of each.
8. Name the types of nerves which constitute peripheral nervous system?
9. What is the difference between a reflex action and walking?
10. Which part of the brain maintains posture and equilibrium of the body?
11. How do we detect the smell of an agarbatti (incense stick)?
12. What is the role of brain in reflex action?
13. Which signals will get disrupted in case of a spinal cord injury?
14 How are involuntary actions and reflex actions different from each other?
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