REVIEW QUESTIONS

Our Environment
1.What do you mean by Environment?

2.What is an ecosystem?

3.What are biodegradable substances? Give two examples.

4.What are non - biodegradable substances? Give two examples.

5. Name the two basic components of an ecosystem.
6.Name any three biotic components.
7.Name the a biotic components of an ecosystem.

8. Name some naural ecosystem.

9. Name some man made ecosystem.

10.What are producers? Give example other thangreen plants?

11. What are consumers?Give two examples.

12.What are Herbivores?Give two examples.

13. What areCarnivores?Give two examples.

14.. What areOmnivores?Give two examples.

15. What are decomposers? How do decomposers create a balancein the environment

or

What is the role of decomposers in the ecosystem?

or

Explain how will it affect the environment if the decomposers are removed from the ecosystem.

16. What is a food chain?

17. What are the steps of food chain called?

18. Define food web?

19. Write the food chain operated in a fresh water pond. Mention the food habit of each trophic level.

20. Give an example of a grassland food chain consisting of four organisma at different trophic levels. Give the scientific term used to indicate the first and third trophic level.

21. Draw schematic diagrams of a food chain and a food web.

22.Describe with the help of diagram show energy flows through different trophic levels in a food chain.

23. What will happen if we kill all the organisms in one trophic level?

24. Differentiate between food chain and food web. Give suitable examlples of each.

25. Why we say energy flow in the biosphere is unidirectional?

26. Which food chain are advantageous in terms of energy? Support your answer giving one example.

27. Consider the food chain. Grass-----Deer------Lion What will happen if lions are removed from the above food chain?

28. The amount of energy that will be available to the plants from the sun is 20,000 J. Calculate the amount of energy available to the lion in the following food chain.
Plant----Deer----Lion

29.Calculate the amount of energy that will be available to fish in the following food chain, if 10,000 J of energy is available to small algae from the sun.Small algae---- Zooplankton------ Fish-----Big fish

30. A food chain consists of the following members. If the last member recieves 30 J of energy, make a diagrammatic representation to show the flow of energy.
Snake, Vulture, Plants, and Rat

31. Why number of trophic levels in a food chain is not more then 4 or 5.

32. What is a ten percent law?

33. How will you justify that "vegetarian food habits give us more calories"? Represent it with the help of a 3 step food chain.

34.What is biological magnification?

35. Explain the process of biological magnification?

36. If a harmful chemical enters a food chain comprising snakes, peacock. mice and plants. Which of these organisms is likely to have the maximum concentrations of this chemical in its body.Give reason.

37.What is Ozone?

38. What is the importance of ozone layer?

39.What is ozone depletion?

40.State the effects caused by the depletion of the layer?

41. Give the name of the chemicals which are responsible for thinning of ozone layers.

Assignment-HERIDITY AND EVOLUTON

1. What is heredity? 

The transfer of characters from parents to the next generation. 

2. What is variation?

The tendency of an organism differ from each other is called variation

3. Name the plant on which Mendel performed his experiment? 

Pea plant 

4. Who is called “Father of Genetics”?

Gregor Johann Mendel 

 5. Why did Mandel select pea plant for his experiment? 

1. Pea plant is easy to grow.  

2. Life cycle of pea plant is very short.

3.Controlled breeding is possible.

4. Pea plant shows contrasting pair of characters.

Tall plant.         Short plant

Violet.            White coloured flowers 

Round seeds.   Wrinkled seeds

Yellow.           Green coloured seeds 

6. What are the basic steps of Mendel’s experiment?

 7. Name any four contrasting traits studied by Mendel in garden pea plant.

plant

 8. How do Mendel’s experiments show that traits may be dominant or recessive? 

9. How do Mendel’s experiments show that traits are inherited independently? 

10 What term did Mendel use for what we now call the genes? 

11. Mendel crossed true breeding plants of terminal flower (AA) and axillary (aa) flowers. He found plants of terminal flower appeared in F1 generation. He also carried out F2 generation. Which trait is dominant? What would be the ratio in F2 generation? Show the cross. 

12. The gene for red hair is recessive to the gene for black hair. What will be the hair colour of a person if he inherits a gene for red hair from his mother and a gene for black hair from his father? 

13. In humans, if gene B gives brown eyes and gene b gives blue eyes what will be the colour of eyes of the persons having the following combination of genes? 1) Bb 2) Bb 3) BB

 14. What are genes where are they located in our body?

 15. What do dominant genes and recessive genes mean? Give an example of each 

16. Explain how, characteristic (or traits) are inherited through genes? 17. Study the given data and answer the question following the data. Parental plants cross fertilised and seeds collected 1. Male parent always bore red flowers and female parents always had white flowers 2. 330 seeds sown and observed 3. All 330 gave red flowers in F1 generation 4. Out of 44 seeds 33 seeds gave plants with red flowers and 11 seeds gave plants with white flowers in F1 generation 1. What is the term for this type of cross? 2. What does the data of the column marked F1 indicate? 3. Express the genotype of the a) parents b) F1 progeny c) F2 progeny 18. The genotype of green-stemmed tomato plants is denoted as GG and that of purple-stemmed tomato plants as gg. When these two are crossed, 1. What colour of stem would you expect in their F1 progeny? 2. Give the percentage of purple-stemmed plants if F1 plants are self-pollinated. 3. In what ratio would you find the genotype GG and Gg in the F2 progeny? 

19. How many X – chromosomes are present in the cells of normal female? 20. How many types of gametes do a male produce? 

21. How is the sex of a child determined?

 22. In humans genetically the father or mother determines the sex of a child? 

23. What will be the sex of a child who inherits X- chromosome from the father? 

24. If a sperm carrying Y- chromosome fertilizes an ovum that carries X chromosome what will be sex of the born child?

 25. If a sperm carrying X- chromosome fertilizes an ovum that carries X chromosome what will be sex of the born child? 

26. Name one reptile in each case where higher incubation temperature leads to the development of: a. Male progeny b. Female progeny 

27. Name an animal in which individuals can change sex? What does this indicates? 

28. What is meant by acquired and inherited traits? Explain with one example each. 

29. Why are the traits acquired during the lifetime of an individual not inherited?

 30. Define evolution.

 31. Who gave the idea of evolution of species by natural selection? 

32. Name the various tools of tracing evolutionary relationships which have been used for studying human evolution. 

33. What are homologous organs? Give one example of it. 

34. What are analogous organs? Give one example of it. 

35. Why are wings of birds and bats called as analogous organs? 

36. The forelimbs of frog, reptiles, birds, and a man show the same basic design of bones. What name is given to such organs? 

37. What are fossils? Give any three examples 

38. Explain importance of the fossils in deciding the evolutionary relationships? 

39. How the age of fossils can be estimated? 

40. Answer the following on the basis of the figure given on the page no. 

1 Why the number of green beetle increased in 1st  case? 

2 Why the number of green beetle increased in 2nd case? 

3 What is the cause of evolution in 1st and 2nd case? 

41 What is genetic drift? 

42 What is natural selection? 

43. Is there evolution occurring in the 3rd case? 

44 What is speciation? 

45. How is a new species formed? 

46. What are the factors responsible for speciation? 4

7 Explain why evolution can cot be said to progress from lower forms to higher forms? 

48. How will you conclude that birds are closely related to reptiles? 

49.Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics? 

50.Why are human beings who look so different from each other in terms of size, colour, and looks said to belong to the same species?

 51.What is artificial selection?

 52.How do five varieties of vegetables produced from wild cabbage by the process of artificial selection?

freemindmaps

This is a mindmap for class IX to revise the topic Animalia Kingdom , Plantae Kingdom given in Classification of living organisms.
http://www.freemindshare.com/map/bdpz4DFJNY/
http://www.freemindshare.com/map/adhij6MOVW/

Gibbons

Gibbons are the smallest and lightest apes found in Southeast Asia. There are different species in the gibbon family: white- handed gibbon, white – browed gibbon and white- cheeked gibbon.

The white- cheeked gibbon is the only gibbon that is not strictly monogamous. Other gibbons are faithful. Members of a typical gibbon family include the couple a father, mother, and some young animals. The mother is the dominant animal in the group. When the kids are past adolescence, the parents chase them out of the group, because now they can start their families.

The gibbons usually spend their life in the high canopy of tropical rain forests, rarely venturing on the ground. On the trees they prefer to eat small pulpy fruits, buds young leaves and some invertebrates.
The white- cheeked gibbon’s posses an opposable thumb that is used for climbing or grooming but not for swinging from branch to branch. They can move biped ally along branches or on the ground using their arms for balance. In fact, their small body size and long arms are designed to feed from terminal branches and for brachiating through the forest that is for winging from hand hold under branches and vines, using their long fingers as hooks.
Most of the gibbons today are threatened with extinction, because their habitat is being destroyed more and more.

Types of movements in plants

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.

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.

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?

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.

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.

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?

NERVOUS SYSTEM

CENTRAL NERVOUS SYSTEM

The central nervous system consists of brain and spinal cord.

Human Brain
À Brain is the highest coordinating centre in the body.
À It is present in the bony box in the skull called cranium. It is surrounded by three membranes called meninges.
À The space present between the membranes is filled with a cerebrospinal fluid that protects the brain from mechanical shocks and acts like a cushion.
À The brain is divided into three regions- forebrain, midbrain and hindbrain.

Human Brain It consists of three parts

Forebrain
1.Cerebrum
2Hypothalamus


2.Midbrain

3.Hindbrain
1.Cerebellum
2.Pons
3. medulla oblongata

Cerebrum1. It is the most complex and largest part of the brain.
2..It is the site of our faculties such as learning, reasoning, intelligence, personality and memory. All our thoughts, sensations, actions and movements are controlled by the cerebrum.

3.The cerebrum has different areas for performing different functions.
1. Sensory area: The information is received from the sense organs like eyes, ears, nose, tongue, and skin and gives sensation of feelings.
2. Motor areas: Instructions are sent to various organs or muscles to do various types of activities.

3. Association areas: They register and store information and respond by interpreting past experiences, they are associated with reasoning, learning and intelligence.
4. In cerebrum five lobes are present to control specific activities.

1. Occipital lobe…Visual reception
2. Temporal lobe…Auditory reception
3. Parietal lobe……Perception of general sensation like touch, smell, temperature and conscious association.
4. Frontal lobe……Muscular activities, both voluntary and involuntary. It also includes speech, thought and memory etc.

HYPOTHALAMUS
Controls and regulate body temperature, hunger, thirst, blood pressure etc.

MIDBRAIN

The midbrain controls reflex movement of the head, neck and trunk in response to visual and auditory stimuli.
It also controls eye muscles, change in pupil size and shape of the eye lens.
HINDBRAIN

Cerebellum…..
1. Controls and coordinates precise and accurate movements such as walking in a straight line, riding a bicycle and picking up a pencil, etc.
2. It also helps in maintaining posture and balance of the body.
Pons…..It acts as a bridge carrying all sensory and motor neurons between brain and spinal cord.
Medulla Oblongata…..1. Posterior most part of the brain. Continues into spinal cord.
2.Have reflex centers to control activities like swallowing, coughing, sneezing, vomiting, heart beat, swallowing and breathing etc.

REFLEX ACTION

REFLEX ACTION

Reflex action is a rapid automatic and involuntary response to a stimulus which is not under the control of the brain.
If we unknowingly touch a hot object, we immediately move our hand away from it. So moving our hand away on touching a hot plate is an example of reflex action.
A knee jerk, coughing, yawning, blinking of eyes, sneezing, salivation, movement of diaphragm during breathing are all examples of reflex actions.


REFLEX ARC





The nerve pathway involved in a reflex action is called a reflex arc.
If we unknowingly touch a hot object, this heat is sensed by a heat receptor (Thermo receptor) in our hand.
The receptor starts an impulse in a sensory neuron, which transmits the message to the spinal cord.
The impulse is passed to the relay neuron, which is in turn passes to motor neuron.
The motor neuron passes the impulse to a muscle in our arm.
The muscle of arm is an effector organ because it responds to the stimulus.

Stimulus → Receptor → Sensory neurons
↓
Effector organs ← motor neurons ← spinal cord

Dear students this is the diagram of reflex arc.

Dear students If diagram of reflex arc is asked

SENSE ORGANS

Animals have five sense organs.
1. Photoreceptor - respond to light……..eyes
2. Phonorceptor - respond to sound……ears
3. Olfactory receptor - respond to smell…….nose
4. Chemoreceptor - respond to chemicals…tongue
5. Thermo receptor - respond to heat ……..skin

CONTROL AND COORDINATION IN HUMANS

Control and Coordination in Humans

There are two types of coordination of activities in humans. These are:
Nervous system
Endocrine system
In human beings, nervous system and endocrine system work together to control and coordinate all our activities such as our physical actions, our thinking processes and our emotional behavior.
Human Nervous System
Nervous system is composed of two main components:
Central nervous system(CNS): It includes brain and spinal cord
Peripheral system (PNS): It includes all the nerves arise from brain (cranial nerves) and spinal cord (spinal nerves).These nerves are present outside the CNS and connect brain and spinal cord to all parts of the body.

STRUCTURE OF A NEURON

Nervous system is made of special cells called neurons. The neurons carry messages in the form of electrical impulses or nerve impulses. A neuron has three components:
Cell body or cyton
Dendrites
Axon.
Cell body or cyton

1. The cell body contains a nucleus and cytoplasm. In the cytoplasm are embedded different cell organelles like mitochondria, Golgi apparatus, endoplasmic reticulum etc. 2.From the cell body extend out two kinds of protoplasmic extensions the cell body – dendrites and axons.
Dendrites
Dendrites are short and branched processes. They carry the impulse towards the cell body.

Axon
1. It is a long process, may be several centimeters long. It conducts nerve impulses away from the cell body.
2. The axon has an insulating and protective sheath of myelin around it.
Neurons are of three types:
Sensory neurons: They carry nerve impulses from receptors to the central nervous system. They carry stimulus from receptors.
Receptors → CNS
Motor neurons: They take nerve impulses from CNS to effector organs that may be a muscle or gland.
CNS → Effector
Interneuron or relay neurons: They are found only in CNS and make links between sensory and motor neurons.

SYNAPSE

3. There is no physical connection between the neurons at synapse and so the impulse has to pass through the synapse to be passed on to other neurons.


How do we detect that we are touching a hot object?

All information from our environment is detected by the tips of dendrite of nerve cells. These receptors are usually located in our sense organs, such as the inner ear, the nose, the tongue, the skin and the eyes.
1. Hot object is a stimulus. When a stimulus acts on a receptor, a chemical reaction is set off that creates electrical impulse.
2.This impulse travels from the dendrite to the cell body and then travel along its axon.
3.At the end of axon synapse is present; a microscopic gap between two neurons, thus electrical impulse can not directly pass between two neurons.
4. At the end of axon, the releases small amount of a chemical substance called acetylcholine into the synapse. This chemical substance starts a similar electric impulse in the dendrite of the next neuron. As acetylcholine transmits impulse of one neuron to another so it is called as neurotransmitter.
5. In this way it can be transmitted to a third neuron and so on. Finally reaches to the brain. The motor neurons bring message from the brain in the form of electrical impulse to the effector organs like muscles and glands.

Transport of materials in plants

TRANSPORT OF FOOD AND OTHER SUBSTANCES IN PLANTS

1.Leaves make food by the process pf photosynthesis. The food made by leaves is in the form of simple sugar (glucose). Other types of substances are called plant hormones are released from the tips of roots and shoots. Now every part of the plant needs food and other substances. So these substances are to be transported to all the parts of the plants like roots, stems, growing

regions etc. The movement of food from leaves to other parts of the plant is called Trans location. In plants, phloem Trans locates the food and other substances.

2.Phloem consists of sieve tubes and companion cells. Sieve tubes are living cells which contain cytoplasm but do not have nucleus. So its function is supported by companion cell. Each sieve tube has a companion cell next to it.

3.Food is prepared in the Mesophyll cells of a leaf. Food is trans located in the form of sucrose. The movement of water and dissolved minerals in xylem is always upward (from soil to leaves). The movement of food can be upward as well as down ward depending upon the needs of the plants.




The mechanism of transport of food in a plant.:-

1.The movement of food in the phloem takes place by utilizing energy. The areas where the nutrients are stored known as sink (e.g. root) and where they originate as source ( leaf). The movement of food is always from the source to the sink.

2.At source, leaves food is prepared in the form of glucose. Glucose is converted into sucrose. Sucrose enters into the phloem at the expense of energy from ATP.

3.The osmotic concentration of phloem will increase. Water now enters into sieve tubes by the ocess of osmoses due to which the hydrostatic pressure in the phloem tissue rises.

4.This high pressure produce in the phloem tissues allow the movement of food to all parts of the plants having low pressure in their tissues. At sink, sucrose move from the phloem into the storage site or growing parts of the plants. Water will also move out from phloem. Hydro static pressure will decrease in phloem at sink.

5.A pressure gradient is set up in the phloem with high pressure at source and low pressure at sink. So the phloem sap with food will move from source to the sink. The phloem transports food according to the need of the plant e.g., in spring even the sugar stored in the roots or stem tissue of a plant would be transported through phloem to the buds which need energy to grow.

Transport of water in plants
Plants need raw materials like CO2, water and minerals for photosynthesis and for various other purposes such as making of proteins. For plants soil is the richest source of water and minerals. Roots absorb these substances and transport to the various parts of the plant. The water and minerals dissolved in it move through special tissue present in plants called xylem. Xylem consists of two kinds of elements called tracheids and vessels. Vessels and tracheids of the roots, stems and leaves are interconnected to form a continuous system of water conducting channels reaching all parts of the plant.

1. The cells of root actively take up ions from the soil. This creates a difference in the concentration of these ions between the root and soil. Inside the root the concentration of ions is more than the soil. Cell of the root is hypertonic in nature. So water moves cosmetically into the root from the soil. Water reaches then to the xylem this result in hydrostatic pressure in the xylem. This pressure is known as root pressure that forces the water up in the plant.

2. However, this pressure is not enough to move water in tall plants. To move water in tall plants, plants use another process known as transpiration pull.

3. According to transpiration pull, water is lost in the form of water vapours through the stomata. Stomata take water from the deeper cells. Finally the water is taken from the xylem vessels of the leaf.

4. The water is in the xylem behaves like a solid column because of strong force of attraction between water molecules.

5. The evaporation of water molecules from the cell of the leaf creates a suction which pulls water from the xylem cells of root. The lose of water in the form of vapour from the aerial parts of the plant is known as transpiration.

SIGNIFICANCE OF TRANSPRATION

1 It helps in the absorption and upward movement of water and minerals from roots to the leaves.
2 It also helps in the temperature regulation. It protects the plant from heat injury.

How water is transported at night in plants.?

Ans:- During the day, when the stomata are open, the transpiration pull becomes the major driving force in the movement of water in the xylem. During night, when stomata are closed, the transport of water is through root pressure.

structure of human heart

Heart is a pumping organ that keeps the blood continuously moving in the blood vessels. It is a blunt conical organ of about 12cm long and 9 cm broad. Its narrow apex is pointed downward and to the left. Heart is enclosed in a doubled walled sac, called pericardium. In between the two layers fluid filled space; the fluid is called pericardia l fluid and it prevents any friction between the heart walls and the surrounding tissues.

Human heart consists of four chambers. The two upper chambers are called atria (or auricles) and the two lower ones the ventricleTwo auricles are separated by an interatrial septum.
Two ventricles are separated by an interventricular septum Septum prevents the mixing of oxygenated blood and deoxygenated blood. The right auricle and right ventricle guarded by tricuspid valves. The left atrium and left ventricle are guarded by bicuspid valve. Both the valves are attached to chordae tendinae, the tough strands of connective tissue which in turn are attached to the papillary muscles of ventricles.

Heart is made of special muscles cells called cardiac muscles Bicuspid and tricuspid valves allows only unidirectional flow of blood i.e. from atria to ventricles Ventricles are far thicker walled than atria because ventricles pump out the blood with force to the different parts of the body, Left ventricles are far thicker walled than right ventricles as it is pumping the blood to different parts of the body a right ventricle is only up to lungs From right atrium the deoxygenated blood enters the right ventricle through tricuspid valves From right ventricle the deoxygenated blood is pumped out through pulmonary artery to lungs for oxygenation. Oxygenated blood from left atrium enters the left ventricles through bicuspid valve. From left ventricle, the oxygenated blood is pumped out into aorta, the largest artery which takes the blood to the body. In the tissues a capillary network allows the exchange of gases and food substances. Finally the deoxygenated blood flows through venules and then veins. This blood is returned to the right atrium through inferior and superior vena cava and inferior vena cava pour deoxygenated blood to the right atrium. Pulmonary veins from lungs pour oxygenated blood into left atrium. Right atrium pours deoxygenated blood into right ventricles right ventricles. Left atrium pours oxygenated blood into left ventricle.
CARDIAC CYCLE

1.contraction of atria.
right atrium recieves blood from vena ceva and pours into right ventricle. left atrium recieves blood from pulmonary vein and pours into left ventrical.
2.Contraction of both ventricles (Atria start relaxing):
from right ventricle, deoxygenated blood flows to the lungs through pulmonary artery.From left ventricle pours blood into aorta sends blood to the various parts of the body.

structure of heart

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Review questions-circulatory system

REVIEW QUESTIONS
Give one word for the following:
1. A blood vessel that transports oxygenated blood from lungs to heart.
2. A blood vessel that poured blood into right atrium.
3. Covering of heart.
4. The thinnest blood vessel
5. The cells of blood responsible for clotting of blood.
6. The blood vessel which carry blood back to the heart from lungs
7. The largest artery of the heart.
8. The blood vessels which connect arteries to veins
9. A non nucleated cell present in human blood.
10.
Differentiate between the following:
1. Artery and vein
2. Red blood cell an White blood cell
3. Blood and lymph
Short answer questions
1. What is the meaning of double circulation?
2. Draw the human heart and label its parts.
3. Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
4. How many chambers are there in the heart of (1).an amphibian, (2).mammal, and (3) a fish?
5. Describe the circulatory system in a fish.
6. How do amphibians tolerate mixing of blood?
7. List three differences between an artery and vein.
8. What is lymph? Why it is called extra cellular fluid?
9. Why is lymph important for the body?
10. How is lymph returns back to the blood?
Long answer questions:
1. Explain various types of blood cells.
2. Explain how oxygenated blood from lungs is sent to all parts the body
3. Explain the structure of heart with the help of well labeled diagram.

Blood vessels

BLOOD VESSELS

• Arteries and veins are the main blood vessels.

1. Have thick walls to withstand the pressure of the blood and a small lumen
2. Carry blood from heart to different organs.
3. Do not have valves
4. Carry oxygenated blood to the whole body except pulmonary artery.
5. Situated deeper in the tissues

Veins:

1. Have thinner walls and a large lumen.
2. Carry blood from organs towards the heart.
3. Have valves to prevent the back flow of blood.
4. Carry deoxygenated blood to the lungs except pulmonary vein.
5. Situated superficially.

Capillaries: Have extremely thin walled and very narrow lumen. They do not have valves Blood flows with low pressure. Allow exchange of gases food materials and waste. Capillaries join together to form venules then they join to form veins.

Lymphatic system

Lymphatic system is an open circulatory system. It consists of lymphatic capillaries Lymphatic vessels, lymph nodes and lymphatic organs. Lymph flows in one direction only i.e. from tissue to heart.

Capillaries have very fine pores through which blood plasma filters out and starts flowing into the inter cellular spaces. This fluid is called extracellular fluid. A part of this fluid enters into the lymph capillaries. The fluid inside the lymph capillaries is called lymph. Lymph is yellow fluid which contains blood plasma minus blood proteins.

Lymph enters into lymph capillaries which join together to form large lymph vessels The lymph vessels finally drains lymph into large veins.

Functions of lymph

1. It takes up excess fluid that has diffused out from the blood capillaries and puts it into blood.
2. It has lymphocytes which fight against germs and bacteria and produce antibodies to fight against infections.
3. It absorbs and carries digested fats from the intestine.
   

ciculatory system

Circulatory system

Blood circulatory system of man consists of following components:
Blood
Blood vessels
Heart

BLOOD
Functions of Blood
1. Transport of nutrients
2. Transport of respiratory gases
3. Transport of waste products
4. Transport of hormones
5. Transport of water, inorganic ions and elements.
6. Regulation of body temperature
7. Protection from diseases

Composition of blood
i) IT is red coloured fluid connective tissue that circulates in the body.
ii) It looks red in colour due to pigment hemoglobin present in red blood cells.
iii) It has two components:
a. Plasma
b. Cells

Blood plasma: It is a pale yellow fluid that forms 55% of blood. It contains water, plasma proteins, inorganic compounds, food waste, hormones, enzymes and other compounds.

Blood Cells: There are three types of blood cells.
i. Red blood cells or erythrocytes i. White blood cells or leucocytes
ii. Blood platelets or thrombocytes

All blood cells together form about 45% of blood and float in the blood plasma.


Red blood cells :

1. Circular and biconcave shape


2. Without nucleus


3. Cytoplasm has hemoglobin, a red pigment that gives red colour to these cells.


4. Transport oxygen from lungs to tissues and help in transport of carbon dioxide from tissues to lungs. Protect the body against diseases and infections.


5. Number varies from 4.5-5 million /cubic mm.

White blood cells :

• Round or irregular shape


• Distinct nucleus


• 3.Cytoplasm is colourless without hemoglobin.


• Protects the body against diseases and infections.


• Number is much less than red blood cells. Varies from 7000-10,000/cubic mm.




• 
  Blood platelets
  1. Irregularly shape, fragments of cells
  2. Without nucleus
  3. Cytoplasm is colouless
  4. Help in clotting of blood.
  5. Number is around 2,50,000/cubic mm.
  
  In infants red blood cells are formed in the red bone marrow of stem cells. In adults red blood cells are formed in the red bone marrow of stem cells of the bones of skull, ribs, sternum, vertebrae and pelvic bones. Life span of red blood cells is about120 days after which they are destroyed in spleen or liver.

parrot flower

Impatiens psittacina
The R are Thailand Parrot Flower means "parrot like".
Hooker examined specimens grown at the Royal Botanical Garden Kew in Britain but did his original work on the plant in India. It is however unclear whether Hooker drew his work from a live specimen or preserved flowers. Hooker mentions in his description plants seen at the Kew in London. The plants in England did not produce seed, possibly due to the lack of pollinators.
.
Impatiens psittacina Facts:
Size: Plant grows to app. 6 feet (1.8) meters
Leaf: Broad, sharply pointed, to 2 1/2 inches (6 cm)Flower size: App. 3 to 4 inches (8 to 10cm)Stem thickness: To 1/2 inch (1.5cm)Bloom season: October/November in Thailand
Growing conditions: Tropical, humid& moist
The curved "beak", which is the backwards pointing nectar tube at the back of the corolla, and "string from the shoulders" are there.

EVALUATION SHEET

CLASS-X11
SUBJECT BIOLOGY
TOPIC-PHOTOSYNTHESIS


Q1. What is the structural difference between Chl.a & Chl.b?

Q2. Where are the pigments forming the photo system located in the chloroplast?

Q3. Mention two conditions under which only PS-1 works.


Q4. Photorespiration posses a threat to plants, yet it occurs in angiosperms why?

Q5. How does the enzyme Rubisco act as carboxylase and oxygenase respectively?

Q6. Specify how C4 photosynthetic pathway increases CO2 concentration in bundle sheath cells of sugarcane?

Q7. What would happen to the rate of photosynthesis in C3 plants, if the CO2 concentration level almost doubles from its present level in the atmosphere?

Q8. How many molecules of ATP are required to produce one molecule of glucose in C4 plants? Give reasons.

Q9. Give the full form of Rubisco. Where is it present in C4 plants?

Q10. What is the significance of photolysis of water in photophosphorylation? What happens to each product of the process?

Q13.Two groups (A and B) of bean plants of similar size and same leaf were placed in identical conditions. Group A was exposed to light of wavelength 400-450 nm and Group B to light of wavelength of 500-550nm. Compare the photosynthetic rate of the two groups giving reason.

Q14.What is the law of limiting factor? How would the rate of photosynthesis be affected if the soil water becomes limiting? Explain

Q15.When and why does photorespiration take place in plants? How does this process result in a loss to the plants?

Q16 Why does the rate of photosynthesis decreases at higher light intensities? What plays a protective role in such situations?

Q17. Draw a schematic diagram of C4cycle.

Q18Where in the chloroplast does non- cyclic photophosphorylation take place? Draw schematic diagram and answer the following questions:

How does PSII regain its electrons?
Name the primary acceptor of electron of PSII in plants.
Name the enzyme which helps in the reduction of NADP.
What are antennae molecules?

Q19.Explain the mechanism of photorespiration with the help of schematic diagram. Name the cell organelles involved in the process. In what way does it loss to C3 plants?