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CHAPTER 9
NUTRITION AND RESPIRATION
EXERCISES
Q 1. Define nutrition. What are the different modes of nutrition?
Ans: Nutrition is a process of intake, as well as utilization of nutrients by an
organism.
Organism can be classified into two groups based on their mode of obtaining food.
1. Autotrophic nutrition: In which organism synthesis organic materials from
the inorganic source. E.g. green plants.
2. Heterotrophic Nutrition: In which energy is derived from the intake and
digestion of the organic substances normally of plant or animal source.
Heterotrophic mode of nutrition are of different types.
Saprophytic nutrition: In which organisms obtain nutrients from the dead and
decaying organic matter ex: fungi and bacteria.
Parasitic nutrition: The organism which obtains food is called the parasite and
organism from which food is absorbed is called the ‘host’. Eg: Few plants like
cuscuta and some animals like plasmodium and roundworm.
Holozoic nutrition: In which the complex organic matter in the form of solid
food is ingested, digested and then absorbed into the cells and utilized.
Eg: Amoeba, frog, human beings.
Q 2. What is the mode of nutrition in fungi?
Ans: Saprophytic nutrition.
Q 3. Name the pigment which can absorb solar energy?
Ans: Chlorophyll.
Q 4. Name the two stages in photosynthesis.
Ans: The two main stages in the process of photosynthesis are : one which is light
dependent called light reaction and the other which is not dependent on light called
dark reaction.
Q 5. Name the factors which affect photosynthesis.
Ans: The factors which affect photosynthesis are:
a) Light: The rate of photosynthesis increases in moderate light intensity and in
red light.
b) Temperature: Increases in temperature initially accelerates the rate but high
temperature inhibits photosynthesis.
c) Water: the rate of photosynthesis decreases is water deficient conditions.
Q6. Define herbivore and carnivore.
Ans: Herbivores: Animals consume only plants for their nutrition Ex: rabbit, deer,
grasshopper.
Carnivores: Animals consume flesh of other animals ex: frog. hawk, tiger.
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Q7 .How does amoeba engulfs its food?
Ans: Amoeba obtains food by phagocytosis. Amoeba engulfs the food by forming
pseudopodia. Two pseudopodia start growing from the opposite sides of amoeba.
They completely encircle the food and their lips touch each other. The membranes
of both the pseudopodia dissolve at the point of touching and the food is encaptured
into the amoeba in a bag known as food vacuole.
Q8. Name the parts of the digestive system of a grasshopper.
Ans: The digestive system of grasshopper consists of foregut, midgut and hindgut.
1) Foregut: It consists of mouth, oesophagus, crop, salivary glands and gizzard.
2) Midgut: It consists of stomach and 6 digestive glands called hepatic caeca.
3) Hindgut: It consists of intestine, rectum which ends into anus.
Q9. What are the functions of the liver and the pancreas?
Ans: 1) Function of liver : Liver secretes bile juice, the bile juice contains bile
pigments and the bile salts. The bile emulsifies present in the food. It facilitates
digestion of fats by the enzymes.
2) Function of pancreas: Pancreas secretes pancreatic juice. The pancreatic juice
contains digestive enzymes. The trypsin enzyme for digesting proteins, pancreatic
amylase for break down of starch and pancreatic lipase to digest fats. Pancreas also
secrete hormones, known as insulin and glucagons.
Q 10. Define breathing.
Ans: The process of letting in oxygen from air into the lungs and carbon dioxide out
of the lungs is called breathing.
Q 11. How is respiration different from breathing?
Ans: Breathing:
1) It is a bio-physical process where oxygen is taken and carbon dioxide is given
out.
2) It does not require enzymes.
3) No energy is released during this process.
4) It occurs at organ level.
5) It is found in higher animals only.
Respiration:
1) It is a bio-chemical process where oxidation of food occurs and carbon
dioxide is released.
2) It occurs in the presence of respiratory enzymes.
3) Energy is released in the form of ATP.
4) It occurs at cellular level.
5) It is found in all animals and plants.
Q12. In which kind of respiration more energy is released?
Ans: In aerobic respiration more energy is released than anaerobic respiration.
Q 13. Which part of roots is involved in exchange of respiratory gases?
Ans: In young roots or parts of roots the exchange of gases takes place through
root hairs between root cells and the soil.
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Older portion of the roots do not have root hairs. The gaseous exchange takes place
through lenticels present in protective layer.
Q14. What are a) stomata and b) lenticels?
Ans:-Stomata is a pore, large numbers of which are present is the epidermis of
leaves and young shoots. They help in exchange of gases.
Lenticels is any of the raised pores in the stems of woody plants, that allow gas
exchange between the atmosphere and the internal tissues.
Q15. Give two points of difference between respiration in plants and respiration in
animals.
Ans: Respiration in plants:
1) Plants do not have respiratory system.
2) Direct diffusion of respiratory gas into the cells.
Respiration in animals:
1) Animals have respiratory system
2) The respiratory gases are transported up to the tissue cells.
Q16. Name the respiratory organs of 1) fish 2) mosquito 3) earthworm 4) dog
Ans: Animal Respiratory organs: i) Fish: Gills
ii) Mosquito: Trachea or air tubes
iii) Earthworm: Skin
iv) Dog: Lungs
Q17. How does air reach every cell of an insect?
Ans: In insects, exchange of gases take place through a tracheal system. There are
present small openings known as spiracles in the body wall of the insects which lead
into the trachea, which further branches into trachioles. The tracheoles and blindly
into the cells. Oxygen is absorbed by the cells and used to oxidize the food. During
expiration, CO2 is expelled out through trachioles, tracheas and finally released
through spiracles.
Ext.air
Q18. From where do the following take in oxygen? (a) prawn b) rat?
Ans: a) Prawn has gills as respiratory organs which draw in oxygen dissolved in
water.
b) Rat has lungs which draw in oxygen from air.
Q19.State the function of epiglottis.
Ans: The function of epiglottis is that at the time of swallowing food, the epiglottis
closes the tracheal opening thereby preventing the food from entering the windpipe.
Q20. Why do the walls of trachea not collapse when there is less air in it?
Ans: The walls of trachea does not collapse when there is less air in it as it is
supported by rings of cartilage.
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Q21. Name the membranes covering the lungs.
Ans: pleural membrane.
Q22. What happens in the carbon dioxide which collects in human tissues?
Ans: Carbon dioxide which collects in human tissues is carried to the alveoli of
lungs for exhalation. It is then pushed out of lungs through trachea and nostrils.
Q23. Why is nutrition necessary for an organism?
Ans: Nutrition is necessary for an organism because it serves as energy source
which is utilised in all physiological activities for growth, development and
maintenance of life.
Q24.Define the following terms:(i) Saprophyte (ii) Parasite (iii)Photosynthesis
(iv) Thylakoids?
Ans:
i)
Saprophytes: the organisms which obtain nutrients from the dead and
decaying organic matter. Ex: fungi, bacteria.
ii)
Parasites: these organisms obtain prepared food from other organisms
called hosts. Ex: plasmodium (malaria parasite)
iii)
Photosynthesis: it is the process by which chlorophyll containing green
plants synthesise their own food from CO2 and H2O in presence of light.
iv)
Thylakoids: the sac like lamellae structures present in the granum of
chloroplast are called thylakoids.
Q25. How do plants obtain food? What are the two phases of photosynthesis?
Ans: Plants obtain food from carbon dioxide and water in the presence of sunlight
inside the chlorophyll containing cells by process called photosynthesis. The
equation involved is:
sunlight
6CO2 +12H2O
C6 H12O6+6H2O+6O2
chlorophyll
Glucose
The two phases of photosynthesis are:
i)
Light reaction or the photochemical phase, which starts with the
absorption of light by the chlorophyll molecules.
ii)
Dark reaction or the biosynthetic phase, where the carbon dioxide is
fixed and is reduced to carbohydrates.
Q26. Name the organelle in which photosynthesis occurs. Discuss the role of
chlorophyll in photosynthesis.
Ans:Photosynthesis takes place in chloroplasts mostly present in green leaves.
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Role of chlorophyll: chlorophyll a and b are most common in plants absorb solar
energy chlorophyll molecules converts- light energy into chemical energy. By
utilizing the light energy chlorophyll molecules form ATP and NADPH which are
used to reduce the CO2 into glucose during the dark reaction.
Q27. Describe the process of nutrition in Amoeba.
Ans: `the process of nutrition in amoeba are as follows:
Ameoba is holozoic in nutrition and feeds on unicellular plants and animals: such as
small ciliates, diatoms, bacteria or algal filaments. When the amoeba comes in
contact with the food particles, it extends the pseudopodia on either side and forms
a food cup. The food material along with some amount of water becomes enclosed in
the food vacuole. The process of ingestion takes about 2-3 minutes and several food
vacuoles may be present at a time.
Q28. Write the differences between:
i)
Herbivore and Carnivore
ii)
Autotroph and heterotroph
Ans:
i) Herbivores animals consume only plants for their nutrition e.g. rabbit, deer,
grasshopper
Carnivores animals consume flesh of other animals. E.g. frog, hawk, tiger.
ii) Autotrophs are the green plants that show the phenomenon of synthesis and
contain chlorophyll whereas heterotrophs are organisms like non-green plants
and animals that are unable to synthesis their own food.
Q29. Describe the process of digestion of food in man.
Ans:Digestion is the process of conversion of large, complex and insoluble organic
molecules into simpler, smaller and soluble molecules.
The process of digestion of food in man starts in the mouth cavity and continues
upto the intestine.
In the mouth, food gets mixed up with saliva secreted by salivary glands. Saliva
contains an enzyme ptyalin which break polysaccharide starch and disaccharide
maltose.
Ptyalin
Starch
Maltose
(Salivary amylase)
The food from the mouth cavity passes into the stomach through the oesophagus.
The gastric glands of the stomach secrete gastric juice, which contains hydrochloric
acid, two protein digesting enzymes - pepsin and rennin, mucus and small amount of
gastric lipase.
Pepsin breaks down proteins into peptones in acidic medium of gastric juice.
Muscles present on the wall of stomach churn and propel and food forward.
The digested food moves from stomach to duodenum of the small intestine.
Duodenum receives juices from liver, i.e. bile and pancreatic juice from pancreas.
The pancreatic juice contains trypsin, amylase and lipase.
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The proteins, fats and carbohydrates are further digested into amino acids, glycerol
and fatty acids, glucose and fructose.
Finally the digestion is completed in the ileum with the secretion of the intestinal
juice by intestinal glands.
The intestinal juice consists of amylolytic, proteolytic and lipolytic enzymes.
Q30. Respiration is a vital function of the body’. Justify.
Ans: respiration is a very vital process because in this process digested food present
in the body cells broken down (oxidised) to release energy. This energy is utilised for
carrying out all biological functions of the cells and the body of the organisms. Thus,
respiration is essential for survived and maintenance of an organism.
Q31.State the differences between breathing and respiration.
Ans: Breathing: (i) It is a bio-physical process where oxygen is taken and carbon
dioxide is given out.
ii) It does not require enzymes.
iii) No energy is released during this process.
iv) It occurs at organ level.
v) It is found in higher animals only.
Respiration:
i)
It is a bio-chemical process where oxidation of food occurs and carbon
dioxide is released.
ii)
It occurs in the presence of respiratory enzymes.
iii)
Energy is released in the form of ATP.
iv)
It occurs at cellular level.
v)
It is found in all animals and plants.
Q32. Give three points of distinction between aerobic and anaerobic respiration.
Ans: Anaerobic respiration:
i)
When oxidation of nutrients occurs without the utilisation of molecular
oxygen, it is called anaerobic metabolism.
ii)
Less amount of energy is produced as oxidation is not complete.
iii)
It occurs in higher organisms.
Aerobic respiration:
i)
When oxidation of food nutrients occurs in the presence of molecular
oxygen, it is aerobic respiration.
ii)
More energy is produced as oxidation is complete.
iii)
It occurs is lower organisms.
Q33. What are stomata and lenticels? What is their role in respiration?
Ans: Stomata or stoma: is a pore, large numbers of which are present in the
epidermis of leaves and young shoots. Each stoma is bordered by two semicircular
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guard cells. Stomata function is to exchange the gas between the plant and the
atmosphere.
Lenticels is any of the raised pores in the stems of woody plants. The pore is formed
by the cork cambium. Which at certain points produce a loose bulky form of cork
that pushes through the outer tissues to create the lenticels. Lenticels function in gas
exchange between the atmosphere and the internal tissues.
Q34. Describe the mode of respiration in an insect with a diagram.
Ans: In insects, exchange of gases take place through a tracheal system. Insects
respire though the spiracles and trachea. The trachea are the fine tubes that are well
distributed in whole body of the insects. The spiracles. lead to trachea, tracheal
trunk and finally it branches into tracheoles. The tracheoles end blindly into the
tissue cells.
During inspiration the abdominal muscles relax and the air is diffused into the
tissues through spiracles and trachea. It reaches directly into the tissue through the
fluid of tracheoles. It oxidises the food in the tissues and carbon dioxide is produced.
During expiration, when its concentration becomes high in the body, the abdominal
muscles contract and the carbon dioxide is expelled out through tracheoles,Trachea
and finally released through spiracles.
( Diagram as per the test book from the page no. 129)
Q36. Draw the respiratory system of human beings.
Ans:
( Diagram as per the test book from the page no. 130)
Q37. Describe the mechanism of breathing in human beings.
Ans: mechanism of breathing: breathing is a complex mechanical process involving
muscular movement that alters the volume of the thoracic cavity and thereby that of
lung.
There are two main steps in breathing - inspiration and expiration.
Inspiration. Inspiration or inhalation is the process by which air is brought into the
lungs. It involves the following steps.
i)
The external intercostals muscles contract causing ribs to pull out and
chest cavity to expand.
ii)
Diaphragm contracts and is a brought down a little. This also expands the
chest cavity.
iii)
There is a contraction of the abdominal muscles. The expansion of chest
cavity creates a partial vacuum and atmospheric air rushes the lung.
Expiration: after the exchange of gases in the lungs, the air has to expelled.
Expulsion of air from the lungs is called expiration.
It involves the following steps:
i)
The inner intercostals muscles contract and diaphragm and the
abdominal muscles relax.
ii)
This leads to a decrease in volume of chest cavity and increases pressure
of lungs.
iii)
The air in the lungs is pushed out through the nose into the atmosphere.
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Q38. Explain the mechanism of gaseous exchange between tissue and blood
Ans. Exchange of respiratory gases, i .e. Oxygen and carbon dioxide
Occurs between the blood and tissues. In tissues, oxygen is used up for
their activities and carbon dioxide is released. The blood from lungs has
high concentration of oxygen and low concentration of carbon dioxide.
Due to this difference in concentration in oxygen and
Carbon dioxide, the exchange of gases takes place between tissue and
blood.
CHAPTER 10
TRANSPORTATION AND EXCRETION
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EXERCISES
Q1.what is transpiration?
Ans: The loss of water in the form of vapour from the aerial parts of the plant is
known as transpiration.
Q2. Name the two kinds of cells of xylem?
Ans: Tracheids and Vessels.
Q3. Why is transportation of materials necessary?
Ans: All living organisms need to transport materials from one part of the
body to another. All these materials like food, water, oxygen, carbohydrates
and hormones etc,, are essential for the organisms to survive. Therefore,
transportation of materials is essential.
Q4. Name the various cells through which water moves upwards to reach the
leaves?
Ans: Epidermis of root hairs
root cortex
Endodermis
Xylem.
Q5. State the term for transfer of food from leaves to other parts of the plant?
Ans:Translocation.
Q6. Name system responsible for transportation of materials in human
beings.
Ans: Circulatory system.
Q7. List the components of blood
Ans;Components of blood are:
(i)
Plasma
(ii)
Blood corpuscles or blood cells.
(a) Red blood corpuscles (RBCs)or Erythrocytes.
(b) White blood corpuscles (WBCs)or Leucocytes.
(c) Blood platelets or thrombocytes.
Q8. What makes Red blood corpuscles red?
Ans: Hemoglobin makes RBCs red.
Q9. Why are white blood corpuscles called "soldiers" of the body?
Ans: White blood corpuscles can fight with disease germs present in the body
carried by blood and help to maintain a healthy body. So, they are called as
"soldiers" of the body.
Q10. Name the four blood groups in human beings.
Ans: The four blood groups in human in beings are A, B, AB, and O.
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Q11. Point out two differences between an artery and a vein?
Ans:
Artery
Vein
1. Arteries carry blood from the
1. Veins carry blood from body
heart to the body organs.
organs to the heart.
2. Arteries have thick walls.
2. Veins have comparatively thin
3. There are no valves in the
walls.
3. There are valves in the veins.
arteries.
Q12. name the largest artery in our body?
Ans: Aorta.
Q13. What is the meaning of the term “double circulation”?
Ans: The deoxygenated blood comes to the heart through Veins. It is
oxygenated in the lungs and comes back to the heart. From heart oxygenated
blood is distributed to all parts of the body. Since blood flows twice through
the heart, it is called “double circulation”.
Q14. What is the other term for "extra cellular fluid”?
Ans: Lymph.
Q15. Define excretion?
Ans: Excretion is the process of elimination of metabolic waste products from
the body of an organism.
Q16. name the parts of the body responsible for excretion in:
(i)
Amoeba
Ans: -Contractile vacuole.
(ii)
Earthworm
Ans: - Nephridia.
Q17. What is the nephrostome?
Ans: The funnel like structure at the one end of nephridum in earthworm is
called nephrostome.
18. From where does waste collect into the excretory part of the amoeba?
Ans: The waste material is present in the cytoplasm in amoeba. This waste
along with water enters the contractile vacuole.
Q19. Where are the nephridia found in an earthworm?
Ans: Nephridia are found attached to the septa of the earthworm.
Q20.what happens to the useful substances, which flow into nephridia along
with the waste?
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Ans: Useful substances like glucose,etc.are absorbed by cells lining the
tubules and passed into the blood.
Q21. Name the excretory unit of a kidney?
Ans: Nephron.
Q22.Where is urine carried through the ureters?
Ans: The urine is carried through ureters into the urinary bladder.
Q23. What is urethra?
Ans: Urethra is the muscular tube or duct by which urine is discharged from
the urinary bladder in mammals.
Q24. What happens to glucose which enters the Nephron along the filtrate?
Ans: The fluid part of the filtrate is diffused into the uriniferous tubule while
the useful part like glucose remains there which is again carried by renal
veins.
Q25.State the two vital functions of the human kidney.
Ans: Two vital functions of human kidney are as follows:
(a).Excretion. Metabolic wastes is excreted in the form of urine.
(b).Osmoregulation. Maintenance of water quantity in all the parts of the
body.
Q26. Name the procedure used in the working of an artificial kidney.
Ans:Dialysis.
Q27. what is the need of special tissues or organs for transport in plants and
animals?
Ans:The special type of tissues or organs are necessary to perform special
type of vital functions.Such as like digestion ,respiration and excretion are
carried out by the living bodies. The cells in animals require oxygen,water
and food .whereas in plants,carbon dioxide, water and oxygen are required.
These substances required by living organisms are to be distributed
throughout the body, thus there is a need for transportation system with
special tissue or organs in plants and animals.In plants, there is a system of
vascular channels, the xylem and phloem, while in animals blood vascular
system is present.
Q28.Describe transport of the following materials in plants:
(i).water
(ii). Minerals
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(iii) Food
Ans: Transport of water and mineral in plants. Water and minerals are
dissolved in it and move upto leaves from root through tracheids and vessels.
Tracheids and vessels are the two kinds of elements of xylem water and
minerals flow from one tracheids to another tracheid.In flowering plants both
tracheids and vessels or only vessels conduct water and
minerals.
Q29.What do you mean by ‘translocation’ with respect to transport in
plants?
Ans:Translocation is the process of transport of food from leaves to other
parts of the plant body through phloem.It is necessary because every part of
the plant needs energy to do its functions for which it requires food.
Q30.What is blood?Describe its composition.
Ans:Blood has a fluid matrix called plasma, and three kinds of cells.these
cells are (1)Red blood corpuscles (2)white blood corpuscles and (3)Blood
platelets.
Plasma is colourless and contains a lot of water and many proteins. Blood
looks red because of the red coloured pigment haemoglobin present in the red
blood cells. Normal mature red blood cells are circular in shape and do not
contain nuclei. Haemoglobin performs a very important function of carrying
oxygen from lungs to tissues and carbon dioxide from tissues to lungs.
Red blood cells have a life span of about 120 days.
White blood cells are lesser in number than the red blood cells. They
protect the body from infections. They are capable of squeezing out of
capillaries to destroy foreign matter. White blood cells also manufacture
antibodies which
are responsible for Immunity. Blood platelets are
fragments of cells. They do not possess nuclei. They participate in the
coagulation of blood . Blood cells are manufactured in the bone marrow
from cells called stem cells.
Q31. Write a note on mechanism of blood clotting.
Ans: Clotting of blood is a complex process which requires factors. As blood
flows out of a damaged blood vessel, blood platelets release Thromoboplastin.
Thrombin then catalyses the conversion of fibrinogen present in plasma into
fibrin. Fibrin forms a mesh into which red blood corpuscles get entangled
and form a blood clot.
Release
Injured tissues + blood platelets
Thromboplastin
Prothrombin
Thrombin
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Fibrinogen
Fibrin
Q33.Hema’s blood group is A,Vivek’s blood group is O,and Shidha’s blood
group is AB. Who can receive blood from whom and donate blood to whom?
Ans: Shikha can receive blood from all, i.e. from Hema as well as from Vivek
can donate blood to all, i.e, to Hema as well as Shikha . Hema can donate her
blood to Shikha only.
Q34.What are antigens and antibodies?
Ans:Antigen is a protein which generate the body to produce antibodies.
Antibody is a specialised plasma protein produced by certain white blood
cells(lymphocytes) in response to entry into the body or a foreign
substance,i.e., antigen, in order to rend it harmless.
Q35. Draw the human heart and label its parts.
Ans: Diagram as per the text book from the page no 137, fig.10.6.
Q36. State differences between artery vein and capillary.
Ans: Differences between:
Artery
(i)
(ii)
(iii)
(iv)
Vein
Artery
is
thick-walled.
Lumen
is
small.
Valves absent.
Blood flows
from heart to
different
organs.
(i)
(ii)
(iii)
(iv)
Capillary
Vein is thin
walled.
Lumen is big.
Valves
present.
Blood flows
from different
organs
to
heart.
(i)
(ii)
(iii)
(iv)
Extremely
thin walled.
Lumen is very
small.
Valves absent.
Blood flows
from arteries
to veins.
Q 37. Write a note on lymphatic system in human beings stating two major
functions of lymph.
Ans: Lymph. Lymph is also a circulatory fluid. It circulates through a system
of lymphatic capillaries called lymphatic system. Lymph is a light yellow fluid
containing lymphocyte cells. Lymph flows only in one direction, which is
from tissue to heart. Lymphatic system contains, lymph glands, lymph nodes
with lymph vessels.
Q38. Describe the mechanism of excretion in amoeba and earthworm.
Ans: AMOEBA: Amoeba is unicellular. IT lives in fresh water and removes
waste and excess water by simple diffusion through the contractile vacuole.
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Waste produced in the cell and surplus water enters into contractile vacuole
from the cytoplasm. As more and more water and waste collect, the
contractile vacuole increases in size and moves close to the plasma
membrane, contractile vacuole bursts and releases the contents in the
surrounding water.
EARTHWORM:- Nephridia, the excretory organs of earthworm, are
attached to the septa. A nephridium is an assembly of long tubules lined by
cilia. One end of nephridium has la funnel like structure, the nephrostome.
The other end has an opening, called nephrostome. The other end has an
opening, called nephridiopore, through which waste fluid is drained outside.
Fluid from body cavity carrying waste enters the nephrostome. Cilia in the
tubule, beast to move the fluid through the nephridium. During its passage
through nephridium, useful substances like, cells lining the tubules and
passed into blood reabsorb glucose, etc.. Fluid with waste moves out of
nephridiopore.
Q39. Draw and label the parts of the human excretory system.
Ans: Diagram as per the textbook from the page no 140, fig. 10.14.
Q40. What is osmoregulation? How does it take place in humans?
Ans: Osmoregulation is the process of regulating the water content and the
concentration of salts in the body of an animal.
In human body, osmoregulation is brought about by kidneys, which performs
these functions:
(1). It removes waste materials.
(2). It carries out reabsorption of useful materials as well as control the level
of water and dissolved substances in the blood and tissue fluid, thereby
maintaining a constant osmotic potential within the body.
Q41. Briefly describe the mechanism of urine formation.
Ans:- Mechanism of Urine formation:- Urine is formed in the kidneys. There
are numerous excretory units called nephrons, and each nephron is very thin
thread like structures with its one end bearing a cup-shaped structure known
as Bowman’s capsule. A thin network of blood vessels known as glomerulus is
present in the Bowman’s capsule, which consists of afferent and efferent
arterioles. Urine is formed in town stages called filtration and reabsorption.
In filtration, blood is filtered into kidney tubules to form a clear fluid
containing the waste substance urea, and many useful substances like glucose
and amino acids. The filtration occurs in the glomeruli. The useful
substances are reabsorbed from the filtrate back into the blood leaving only
urea and other substance in the kidney tubules.
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Q42. Which is the major nitrogenous waste product in a human being? How is it
removed from the body?
Ans: Urine contains urea, uric acid and ammonium carbonate in human
beings. All these products are removed from the body through kidneys in the
form of urine.
CHAPTER 11
CONTROL AND COORDINATION
EXERCISES:
Q.1.what is a neuron?
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Ans.A Neuron is an elongated branched cell that is fundamental unit of the
nervous system and is specialized for conduction of nerve impulse.
Q.2.Name any two types of tropism?
Ans:- (i) Phototropism : Movement towards the light.
(ii) Geotropism
: Movement towards downward.
Q.3. What is a phytohoromone? Name any two phytohormones?
Ans:- Phytohormones can be defined as as a chemical substance which is produced
naturally in plants and are capable of translocation and regulating one are more
physiological process when present in low concentration.
Some phytohormones are :
(i) Auxins
(ii) Cytokinin
(iii) Gibberellin (iv) Abscisic Acid.
Q.4. Mention the receptors for light and sound in animals?
Ans:- (i) Photo receptors : They receive light.
(ii) phono receptors : They receive sound
Q. 5. How does control and coordination take place in plants?
Ans. In plants the control system is not specialized. The control and co-ordination in
plants is performed by chemical substances known as plants hormones or
phytohormones.
Q. 6. Mention names of various phytohormones?
Ans. Various phytohormones are:
(i) Auxins
(ii) Gibberellins
(iii) Cytokinins
and (v) Ethylene.
(iv)
Abscisic
Acid
Q. 7. Discuss phototropism.
Ans. Phototropism: When a growing plant is illuminated by a unidirectional light, it
responds by bending towards the light.
Q. 8. Differentiate between tropic and nastic movements.
Ans. Tropic movementsNastic movements(i) Direction of movement is in
direction of the stimulus. (ii) Growth takes place. (iii) Movements are slow,
phototropism, geotropism.(i) Direction of movement is not determined by
direction of stimulus. (ii) Growth does not take place. (iii) Movements are fast,
seismonasty.
the
e.g.
the
e.g.
Q. 9. Draw the diagram of a neuron.
Ans. Diagram as per the textbook from the page No. 145.(Fig. No. 11.3)
Q. 10. Draw a neat diagram of the nervous system in an insect.
Ans. Diagram as per the textbook from the page No. 144, (Fig. No. 11.2).
Q.11. Describe the central nervous system in human beings?
Ans:-The central nervous system in human beings consists of brain and spinal cord.
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(a) Brain - Brain is the highest coordinating centre in the body. It is
covered by meanings which is made up of three layers. It is protected by
cranium. Brain is broadly divided into:
(i)
Forebrain - The forebrain includes cerebrum and olfactory lobes.
Cerebrum is the largest part of the brain. It consists of two
cerebral hemispheres. Sensory and motor receptors are present in
the brain. These are various regions for reception of vision
(occipital lobe), reception of sound (temporal lobe), touch, smell,
temperature (parietal lobe) and muscular activities (frontal lobe).
Olfactory lobes are one pair and receive olfactory nerves .
(ii)
Mid brain -It is the small portion of the brain that connects
cerebrum with the other parts of the brain and spinal cord.
(iii) Hind brain - It consists of cerebellum, Pons and medulla
oblongata. Cerebellum is responsible for coordination and
adjustment of movement and posture. Pons regulates respiration.
Medulla oblongata regulates swallowing, coughing, sneezing and
vomiting.
(b) Spinal cord - Medulla oblongata extends downwards, enclosed in
vertebral column to form cylindrical structure known as spinal cord. It is
also covered by meninges. It is the reflex centre of the body.
Q.12. What is ganglion?
Ans. Ganglion is referred to a mass of nervous tissue containing many cell bodies
and synapses usually enclosed in a connective tissue sheath.
Q.13. Mention the function of the fore brain.
Ans. Fore brain includes cerebrum and olfactory lobes. Different areas perform
different function. The cerebrum has sensory areas where information is received
from the sense organ called receptors. Similarly cerebrum has motor areas from
where instructions are sent to the various muscles of the body called effectors to do
the various jobs.
There are specific reasons in cerebrum for each kind of stimulus and
response ,e.g, i)occipital lobe:is the region for sight,i.e visual
ii)reception temporal lobe: Is the region for hearing, i.e auditory reception .
iii)frontal lobe :Is the region for speech ,facial muscular activities and higher
mental activities
iv)Parietal lobe:Is the region for taste,smell ,touch ,temperature and conscious
association
v)Olfactory lobe :In the fore brain lie below the cerebrum. They contain olfactory
receptors which are the organs of smell.
Q.14.Write the functions of any one part of hind brain?
Ans) These are following parts of hind brain
i)Cerebellum ,ii)pons iii)medulla
Functions of Cerebellum. It regulates and co-ordinates movements and posture of
the body. It helps in adjustment of the body balance.
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Q.15. What is the autonomic nervous system?
Ans:- The autonomic nervous system consists of a pair of chains of nerves and
ganglia found on either side of the backbone. It controls the in involuntary actions
of many internal organs like heart, blood vessels and glands. The autonomic
nervous system consists of two parts - sympathetic and parasympathetic.
Q.16.Define reflex action with suitable examples?
Ans:- Reflex Action is defined as an unconscious, automatic and involuntary
response of effectors, i.e, muscles and glands, to a stimulus, which is monitored
through the spinal cord.
e.g., Knee-jerk reflex, movement of diaphragm, coughing, sneezing, yawning and
blinking of eyes are all reflex action.
Q.17. Name the hormones secreted by thyroid, parathyroid and pancreas.
Ans:- Thyroid
--Thyroxine
Parathyroid -Calcitonin
Pancreas
--Insulin and glucagon
Q18.List the functions of testosterone and estrogen?
Ans:- Functions of Testosterone.
(iv)
Regulation of male accessory sex organs.
(v)
Regulation of secondary sexual characters like moustache, beard
and voice.
Functions of Estrogen.
(i)
Regulation of female accessory sex organs.
(ii)
Regulation of secondary sexual characters like mammary gland,
hair pattern and voice.
(iii) Maintenance of Pregnancy.
Q.19. Write names of three hormones secreted from pituitary?
Ans:- (i) Trophic hormones. (2) Prolactin. (3) Oxytocin. (4) Vasopressin.
(5) Growth hormone.
Q.20.Nervous and hormonal system together perform the function of control and
co-ordination in human beings. Justify the statement.
Ans:- Both the systems control, co-ordinate the various functions in human body.
Nervous system control various functions by the units called neurons. Neurons
receive the information by sensory nerves and transfer them through motor actions.
The hormones are the chemicals secreted by endocrine glands.The endocrines
glands do not have ducts, so they are called ductless glands. Hormones also control
the functions of various organs of the body. In this way it is true that the nervous
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system and hormonal system in human body together perform the functions of
control and coordination.
Chapter -12
REPRODUCTION
EXERCISES
Q1. Name the various types of asexual reproduction?
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Ans:Various types of the asexual reproduction are
(a)Fission (b) Budding (c) Spore formation (d) regeneration and (e)
Vegetative regeneration.
Q2.Differentiate between Binary fission and multiple fission.
Ans: Binary fission: It involves division of the organism into two equal
halves.This method of reproduction occurs regularly among protozoans, eg:
Ameoba, Paramoecium.
Multiple fission: It involves division of the organism into more than two
equal halves. Eg:plasmodium.
Q3:List two advantages of vegetative propagation?
Ans: Advantages of the vegetative propagation:
(i)It is useful in propagating the plants which do not reproduce viable
seeds or produce very few seeds.
(ii) The plants produced by vegetative propagation have exactly the
same characters that of the parent plant i.e.it helps in preserving the
characters of the parent plant.
Q4:name the male and female gametes in animals.
Ans: In animals: (a)Male gamete is sperm.
(b)Female gamete is egg or
ovum.
Q5: Define fertilisation?
Ans: Fertilisation is defined as the process of fusion of a male gamete with
a female gamete to form
zygote during sexual reproduction.
Q6:Define sexual reproduction?
Ans: Sexual reproduction is a type of reproduction in which the two sexes,
namely male and Female are involved.
Q7: Mention any two functions of ovary?
Ans: Functions of human ovary:
(i) It produces ovum, the female gamete.
(ii) It secretes estrogen and progesterone hormones.
Q8:What is syngamy?
Ans:The process of the fusion of the male gamete with the female gamete is
called syngamy.
Q9:Where does fertilization take place in human females?
Ans:Fallopian tube.
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Q10:Define menopause.
Ans: The age at which the menstruation stops and a women loses her
ability to bear the child is called menopause.
Q11:Discuss briefly the different types of reproduction?
Ans:There are two types of reproduction viz.asexual
and sexual
reproduction.
Asexual reproduction: In this mode of reproduction the certain body
cells or certain organs of the organism undergo repeated mitotic
divisions and form two or more new individuals similar to the parent
organism. The asexual reproduction includes fission, budding,spore
formation, regeneration and vegetative propagation.
Sexual reproduction: In this type of reproduction involvement of male
sex and female sex is essential. It includes fusion of the male gamete
(sperm) and female gamete (egg or ovum) called
Fertilization.
Q12: Describe asexual reproduction in amoeba.
Ans:- In amoeba, asexual reproduction takes place by Binary Fission. During
Binary fission, the nucleus of Amoeba divides into two daughter
nuclei. The nuclear division is followed by the appearance of
constriction the cell membrane which gradually deepens and divides
the Amoeba into two daughter Amoeba.
Q13: Explain various steps of budding in yeast.
Ans:- Budding in Yeast:- Yeast asexually reproduce by budding. During
budding, a small protuberance appears on the upper part of an adult
yeast cell. This gradually grows in size. From the newly formed bud
another bud appears at the tip. The budding in this way may continue
for 3-4 times forming a chain of yeast cells.
Q14: What are the various methods of vegetative propagation? Discuss any
one method with example.
Ans:- Various methods of vegetative propagation are:
(i)
Cutting
(ii)
Layering and
(iii) Grafting
Grafting:- In this method a cutting of desired plant called scion is
taken and grafting over the stump of another plant called stock. The
stock has well developed root system in the soil. Scion and stock are well
tied up. After some time, the scion and stock get joined due to activity of
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cambium. The stock supplies the water and minerals to the scion. This
bears fruits of desired qualities on maturity.
Example: Mango.
Q15: Define the terms unisexual and bisexual giving one example of each.
Ans:- Unisexual organism: In majority of animals like human beings, male
and female sex organs are in different individuals, such organism which
possesses only one kind of reproductive organs in its body, i.e. male or female
is called an Unisexual organism.
Bisexual organism: In most flowering plants and certain animals like
tapeworm, earthworm, and starfish: a single individual has both male and
female sex organs in its body. Such organism is called Bisexual organism.
Q16: Mention the reproductive parts of a flower.
Ans:- Stamen (male) and carpel (female).
Q17: what is pollination? Describe cross pollination.
Ans:- Pollination: The transfer of pollen grains from anther to stigma is
called pollination.
Cross Pollination: The transfer of pollen from the anther of one flower
to the stigma of another flower of a different plant of the same species is
called Cross Pollination. In this case, pollen grains of the same flower do not
pollinate its stigmas. In Cross Pollination, the transfer of pollen grains may
take place through some agency like wind, insect, bird or other agencies.
Q18: Describe double fertilisation in plants.
Ans:- During fertilisation in plants, the following events takes place
:
(i)
One of the male gamete fuses with the female gamete present in
the embryo sac.
(ii)
The other male gamete fuses with the two polar nuclei in the
embryo sac.
The first fusion product gives rise to the zygote while the second one
forms the endosperm.
The process of two fusions occuring in the embryo sac is called double
fertilization.
Q19: What are the male and female gonads in human beings? Mention their
functions.
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Ans:- Male gonads are testes and female gonads are ovaries in
human beings.
Functions of Testes:
(i)
Testes produce sperms, the male haploid gametes.
(ii)
Testes are responsible for secondary sexual characters.
(iii) They produce male sex, i.e., testosterone.
Functions of ovaries:
(i)
They produce female sex hormones, i.e., estrogen
progesterone.
(ii)
They produce ova, the female haploid gamete.
(iii) They are responsible for secondary sexual characters.
and
Q20: Mention secondary sexual characters in human male and female?
Ans:- Secondary sexual characters in human male are moustaches, beard,
facial and pubic hairs, etc.and in female are development of mammary
gland, skinless hairy, feminine voice.
Q21: Write names of one male and one female sex hormones?
Ans: Male sex hormone is testosterone and female sex hormone is Estrogen.
Q.22:Describe menstrual cycle?
Ans:The periodic discharge of blood, mucus and uterine lining through the
vaginal opening is called as Menstruation. It occurs every 28-30 days and
lasts for 4-7 days. The ovarian follicle matures rapidly. The cell multiplies
and the centre of the follicle degenerates. Around the 14th day, before the next
menstrual cycle the follicle ruptures to release (discharge) the ovum.
This process of release of ovum is known as ovulation. Simultaneously,
the inner wall of uterus thickens, then uterine lining starts degenerating .At
the end of 28th day, this unfertilised egg rejected along with the uterine lining.
If fertilization takes place, then the embryo implants itself in the uterus.
Q 23: Differentiate between menarche and menopause.
Ans: - Menarche is the beginning of menstruation at puberty. Which also,
marks the starting of reproductive life of a woman, whereas menopause is the
stoppage of menstrual flow at the age of 45-50 years when a women loses her
ability to bear children.
Q24 what is ovulation?
Ans: The process of release of the maturing ovum from the mature follicle in
the ovary is called ovulation.
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Q25 write whether true (T) or false (F)
(i)
Fertilization is the fusion of sperm and ovum.
(ii)
Duration of menstrual cycle in human female is 20 days
(iii) Onset of menstruation is termed menopause.
(iv) In human beings, male attains puberty little late than females.
(T)
(F)
(F)
(T)
Q26: Fertilization is possible if copulation has taken place during the middle
of the menstrual cycle. Give reason.
Ans: - Reason: - In a normal woman ovulation (release of ovum) takes place
in mid of the menstrual cycle i.e.14th day. Thus, egg is available during
ovulatory period to sperms for fertilization.
Q27: Mention the methods used for regulation of childbirth.
Ans: Methods for Regulation of childbirth are:
(i)
Barrier Method
(ii)
Chemical Method
(iii) Use of IUCDs
(iv) Surgical method
Q28: Write the full form of IUCD, AIDS, HIV, OC.
Ans :- The full form of:(i)
IUCD is Intrauterine Contraceptive Device.
(ii)
AIDS is Acquired Immunodeficiency Virus
(iii) HIV is Human Immunodeficiency Virus.
(iv) OC is Oral Contraceptive.
Q29: Describe the surgical method of birth control.
Ans: The surgical methods of birth control is the permanent method for
prevention of childbirth. This can be done in males as well as females.
In case of males a small portion of vas deference is removed or tied which is
known as vasectomy. Similarly, in case of females as small portion of
fallopian tube is removed or tied which is known as tubectomy.
Q30: Define sexually transmitted disease and give two examples.
Ans: The diseases, which spread from infected person to a healthy person by
sexual contact, are called sexually transmitted diseases (STDs). For example
Gonorrhea, syphilis,Trichomonasis, AIDS.
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CHAPTER - 13
HEREDITY AND EVOLUTION
EXERCISES
Q.1. What is heredity?
Ans:- Heredity refers to the transmission of characters or traits from the parents to
their offspring.
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Q.2. Name the plant on which Mendel performed his experiments?
Ans:- Garden Pea (Pisum sativum.)
Q.3. Define variation?
Ans:-Variation refers to the differences in the characters or traits about the
individuals of a species.
Q.4. Define a gene?
Ans:- Gene is a small segment of DNA on a chromosome occupying specific position
in which is a hereditary determinant or unit of a biological function.
Q.5.Write the expanded form of DNA?
Ans:- DNA - Deoxyribonucleic Acid.
Q.6. What are the components of chromosome?
Ans:- Each chromosome is double or replicated and consists of two thread like
structures called chromatids attached to each other at centromere.
.Each chromatid has a number of dense areas arranged linearly which are known
as chromomeres. They represent the areas of active genes.
.Internally each chromosome has two spirally coiled threads called chromonemata
embedded in matrix. These are DNA molecules.
Q.7. What is a retrovirus?
Ans:- A virus having RNA (Ribonucleic acid) as genetic (heredity) material is called
Retrovirus. For example, Human immunodeficiency virus (HIV) is a retrovirus.
Q.8. What is sex chromosome?
Ans:- A chromosome which is associated with sex determination is called sex
chromosome.
Q.9. How is sex determined in human beings?
Ans:- Sex is determined at the time of fertilisation and the two sexes are produced in
approximately equal numbers. A human male has XY sex-chromosomes and
produces two types of sperms (heterogametic). Either with X-chromosome or with
Y-chromosome.
A human female has XX sex-chromosomes and produce ova of one type
(homogametic) all with X-chromosomes.
Parents
Gametes
Male XY
XY
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Female XX
X
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Progeny
XX
Female (50%)
XY
Male (50%)
Q.10. What do you understand by evolution?
Ans:-Evolution is the sequence of gradual changes which takes place in the
primitive organisms over million of years in which new species are produced.
Q.11. Define homologous organs?
Homologous organs are those organs which have the same basic structure and
developmental origin but have different functions and appearance.
Ans:- e.g., The forelimb of a frog, a bird and a man seem to be built from the same
basic design of bones, but they perform different functions.
Q.12. Explain Darwin’s theory of evolution?
Ans:- According to Darwin’s theory of evolution:
(i)
There is natural variation within any population and some individuals
have more favourable variations than others..
(ii)
Population remains fairly constant even though all species produce a
large number of off springs.
(iii) This is due to ‘competition’ or struggle for existence between same and
different species.
(iv)
The struggle for survival within population eliminates the unfit
individuals and those with ‘favourable variations’ survive and pass on
these variations to their progeny to continue. This is called natural
selection.
(v)
The favourable variations are accumulated over a long time period
leading to the origin of a new species.
Q13. Define genetics. What is the contribution of Mendel in this branch of biology?
Ans:- genetics is the branch of biology which deals with the study of heredity and
variation.
Contribution of Mendel : Mendel done his experiments on garden pea(pisum
sativum) and discovered the scientific principles which govern patterns of
inheritance i.e. the principle of inheritance. He explained the contrasting characters
are controlled by units which he called Factors. Today these factors are called genes.
Q14. Where are the genes located? What is the chemical nature of gene?
Ans:- Genes are located on chromosomes. Chemically, genes are made of
DNA(deoxy ribonucleic acid).
Q15. During which stage of cell division can chromosome be seen? Write the
features of prokaryotic and eukaryotic chromosome.
Ans:- Chromosomes can be seen during the metaphase stage of the cell division.
FEATURES OF:
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PROKARYOTIC CHROMOSOME: Prokaryotes (bacteria) have a single
chromosome. The chromosome is circular and made up of a DNA molecule
associated with a few proteins.
EUKARYOTIC CHROMOSOME: Eukaryotes contain many chromosomes. Each is
made up of a DNA molecule and more number of basic proteins. The chromosomes
are not circular but rod shaped.
Q 16. Who provided the evidence of DNA as a genetic material? Write the names of
components of DNA?
Ans:- Griffith, Avery , McLeod and McCarty established that DNA is the genetic
material.
Components of DNA: A DNA molecule consists of two polynucleotide chains. Each
nucleotide consists of (a) nitrogenous base (Adenine/guanine/Thymine or Cytosine)
,a pentose sugar(deoxyribose) and a phosphate group.
Q17.What do you understand by the double helical structure of DNA? Who
proposed this structure?
Ans:-J.D.Watson & F.H.C.Crick proposed the double helical structure of DNA.
The important features of the model are:
i)DNA molecule consists of two polynucleotide strands forming a double helix.
Each helical turn has a length of 3.4nm in which ten nucleotides present.
ii)Each polynucleotide stand has a backbone of sugar and phosphate. The
nitrogenous base is attached to the sugar.
iii)The nitrogenous bases of the two stands of a double helix form a pair with the
help of hydrogen bonds. Adenine pairs with Thymine ,whereas the guanine pairs
with Cytosine. Such a specific pairing of the bases is called complimentary pairing.
A and T are complimentary to each other and G is complimentary to C. The
hydrogen bonding between the nitrogenous bases holds the two strands together as
a result of which the base pairs remains stacked between the two strands.
This structure can be compared with the steps of a spiral staircase.
Q18.Describe the different types of chromosomes.
Ans:- depending on the position of the centromere,a chromosome may have either
equal arms, or one long and one short arm. Accordingly, four types of chromosomes
are known :
Metacentric:It is a chromosome with the centromere near the middle and the two
arms are almost equal in length.
Sub-metacentric:In this type of chromosome the centromere is situated closer to one
end. As a result , one arm of the chromosome is long and one is slightly short.
Acrocentric:It is the type of the chromosome which has the centromere near the end.
In this case one arm is very long and the other one is very short.
Telocentric:In this type of the chromosome, the Centromere is situated at the tip of
the chromosome.
Q19.How many types of nitrogenous bases are present inDNA?Name them.
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Ans:-In DNA two types of nitrogenous bases are present. These are (i)PURINES
which are adenine and guanine (ii)PYRIMIDINES which are Thymine and
cytosine.
Q.20.How do embryological studies provide evidence for evolution?
Ans:- The similarities in embryonic development reinforce the idea of evolution
from common ancestors. The sequence of embryonic development in different
vertebrates shows striking similarities. Notochord and gill clefts appear in the
embryos of all vertebrates.
Q.21. Define evolution. And Describe the contribution of Lamarck?
Ans:- Evolution is the sequence of gradual changes which takes place in the
primitive organisms over millions of years in which new species are produced.
Contribution of Lamarck:
(i)
Lamarck proposed a theory called “The Theory of inheritance of
Acquired Characters” to explain the origin and evolution of species.
(ii)
The theory was explained in his book ‘Philosophic Zoologique.
Q.22. What are homologous organs? How do they provide evidence in support of
evolution?
Ans:- Homologous organs are those organs which have the same basic structure and
developmental origin but have different functions and appearance.
Homologous organs support evolution:
(i)
The similarities of structure and origin of organs indicate that all
vertebrates had common ancestors. For example, the forelimbs of
humans, whale and bat show structural similarities but functional
dissimilarities. Forelimbs in humans used for grasping or holding the
things, in whale for swimming and in bat for flying.
(ii)
All the organs and systems of the vertebrates show fundamental
similarities i.e. homology, which indicate towards common ancestry.
Thus, homologous point that organic evolution has taken place.
(iii)
Q.23. Define the following terms?
(i)
Vestigial organs: Vestigial organs are those organs, which are
rudimentary and functionless in the evolved forms but are well
developed and functional in the ancestral forms. Eg: Vermiform
appendix in human beings.
(ii)
Analogous organs : Are those organs which have different basic
structure and developmental origin but have similar appearance
and perform similar functions. Eg: The wings of and insect and a
bird have different structures, but they perform the same function
of flying.
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CHAPTER - 16
ENVIRONMENT AND ENVIRONMENTAL PROBLEMS
EXERCISES
Q.1. Define pollution?
Ans:- Pollution is defined as the undesirable change in the physical, chemical or
biological characteristics of our land, air or water, which harmfully affect human
lives or the lives of other species.
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Q.2. Define pollutants?
Ans:- The agents of substances that cause undesirable change leading to
environmental pollution are called pollutants.
Q.3. Write two natural sources of air pollution?
Ans:-Forest fire and dust storm.
Q.4. Write the harmful effect of ozone depletion?
Ans:- (i) Due to depletion of ozone layer, more ultra violet (UV) radiation will reach
the earth. UV radiations cause skin cancer, damage to eyes and immune system.
(iii) Ozone layer depletion may lead to variation in rainfall, ecological
disturbances and dwindling of global food supply.
Q.5. Name two mechanical devices for controlling?
Ans:- (i) Gravity or earth settle down the particles.
(ii)Fabric filters also help in separating particles.
Q.6. What are fabric filters?
Ans:-The particulate matter present in polluted air are passed through a porous
medium of woven fabrics and gets collected in the filtration bag known as fabric
filters.
Q.7. Define point source of water pollution?
Ans:-Point sources are those sources of water pollution which are fixed at a place
and have a specific location for discharging pollutants into a particular water body.
These include factories, power plants, underground coal mines and oil wells situated
close to the water sources.
Q.8. Write three characteristics of potable water?
Ans:- (i) It should be transparent, colorless and odorless.
(ii) It should be free from harmful chemicals and bacteria.
(iii) It should contain sufficient dissolved oxygen.
Q.9. Define eutrophication?
Ans:- Eutrophication is the process in which extra nutrients are added to a water
body leading to tremendous growth of algal plants resulting in the reduction of
dissolved oxygen.
Q.10. How can you reduce the volume of waste?
Ans:- The volume of the waste can be reduced by incineration (burning the wastes
at high temperature). From biodegradable wastes, bio gas and manure can be
prepared which costs much less than fuel and fertilizers.
Q.11. Name two materials which can recycled?
Ans:- Metals, papers , plastics can be recycled.
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Q.12. How can you make a balance between environment and development?
Ans:- To maintain a balance between environment and development:
(i) It is essential to adopt sustainable development. It is also necessary to meet
the needs of present generation without foreclosing the options for future
generation.
(ii) Human beings should live in harmony in nature.
(iii) Technologies which are environmentally sound and based on maximizing
recycling and efficient use of resources should be adopted.
Q.13. How does development affect the environment?
Ans:- development affects the natural environment for socio-economic
considerations. It leads to degradation of environment. Some of human activities
harm to the environment are :
(i) Urbanization: Old villages, hills, beaches etc. have been converted into cities and
big towns.
(ii) Industrialization: To set up Industries for development agriculture land has
been used.
(iii) Construction of big dams and mining have also caused degradation of natural
environment.
Q.14.Define conservation?
Ans:- conservation of environment may be defined as activities which can provide
individual or commercial benefits but at the same time prevent excessive leading to
environmental damage.
Q.15. Write two conservation practices?
Ans: Conservation practices:
(i) Judicious use of fertilizers, intensive cropping, proper irrigation and
drainage.
(ii) Establishment of national parks and conservation forests, or
(iii) Planting trees in place those removed for various purposes.
Q.16. What is environmental pollution? Name three non- biodegradable pollutants
that are harmful to human beings.
Ans: Environmental pollution is the un desirable change in physical, chemical and
biological characteristics of water and land.
The three non-biodegradable pollutants, harmful to human beings are insecticides,
DDT and plastics.
Q.17. How does water get polluted?
Ans. Water gets polluted by two types of sources. These are:
(i)Point sources: These sources are located near water bodies and discharge
pollutants directly into the water source. For example, factories power plants, coal
mines ,oil wells etc, pour their wastes into rivers, lakes e.t.c.
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(ii)Non-point sources: They are scattered and do not discharge any problems in
a particular water source. These include run-off from the roads, fields, lawns,
construction sites, logging areas e.t.c.
Q.18. Describe the various pollutants in the atmosphere?
Ans. Classification of pollutants. All pollutants can be classified into two groups-Bio
degradable and non-biodegradable pollutants.
(i)Biodegradable pollutants are the pollutants which are broken down into the
simpler, harmless substances in nature in due course of time by the action of
microorganisms like certain bacteria, e.g. Domestic waste products ,urine and faecal
matter, sewage, agricultural residue, paper, wood, cloth and cattle dung.
(ii)Non-bio degradable pollutants are those pollutants, which cannot be broken
down into simpler, harmless substances in nature. These pollutants may be solid,
liquid and gaseous form and may enter into the food chain and harm organisms,
e.g., DDT, plastics, polythene bags, insecticides, pesticides, mercury, lead, arsenic,
aluminium, radioactive wastes, e.t.c.
Q.19. What is soil erosion? What are its causes and what are its effects? How can it
be checked?
Ans: Soil erosion is the removal and thinning of the fertile topsoil from a region due
to climatic and physical processes, such as high rainfall and wind, Soil erosion
occurs easily where the soil is not covered by vegetation.
Causes of soil erosion:
(i)Wind causes soil erosion by carrying away the topsoil particles.
(i)rain causes soil erosion on unprotected topsoil by washing it down.
(iii) Improper farming and tilling the field for long time causes soil erosion.
(iv)Human beings cause soil erosion by clearing trees, plants and other vegetation.
(v)Frequent flooding of river causes soil erosion by removing the topsoil of the fields
near the riverbanks.
Effects of soil erosion:
(i)It can turn green forests into deserts and spoil the environment.
(ii)It can lead to excessive scarcity of as food crops do not grow well.
(iii)It can cause land slides in hilly areas.
(iv)It can cause sudden floods in low lying areas causing loss of life and property.
Prevention of soil erosion: (i) It can be prevented by intensive cropping.
(ii)It can be prevented by providing proper drainage canals around the fields.
(iii)Soil erosion in hilly areas can be prevented by practicing terrace farming.
(iv)It can be prevented by planting trees and sowing grasses.
(v)It can be prevented by constructing strong embankments along the riverbanks.
Q.20 Explain the following terms with suitable examples:
(i)Acid rain: Acid rain is that rain which contains small amount of acids in it,
formed from the gases like sulphur dioxides and nitrogen oxides present in polluted
air. it causes damage to living and non-living things.
(ii)Ozone depletion:
(a)causes of ozone depletion:
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The use of chlorofluorocarbons in aerosol propellants, refrigerators and fire
extinguishers.
(b)Effects of ozone depletion:
(1)The ultra violet rays enter through the depleted ozone of the ozone layer and
affect the living organisms.
(2)UV-rays cause skin cancer in human beings.
(iii)Global warming or green house effect : The phenomena of trapping infrared
radiations of sun and causing heating effect is called green house effect.
Q.21. What are occupational disorders? Give examples?
Ans: There are certain diseases which are related to one’s occupation. These are
caused by the constant use of certain substances that sneak into air and then enter
into our body. Examples are Silicosis, Asbestosis, Byssinosis, Pneumoconiosis.
Q.22. What is eutrophication? Mention its harmful effects?
Ans:- Eutrophication is the process in which extra nutrients are added to a water
body leading to tremendous growth of algal plants resulting in the reduction of
dissolved oxygen.
Harmful effects of Eutrophication: The reduction of dissolved oxygen and poisonous
industrial wastes affects the fish population and deprives us from one of our sources
of food. Eutrophication also kills other animals living in fresh water.
Q.23. Explain main types of sources of water pollution?
Ans:- (i)Point sources: These sources are located near water bodies and discharge
pollutants directly into the water source. For example, factories power plants, coal
mines ,oil wells e.t.c. pour their wastes into rivers, lakes e.t.c.
(ii)Non-point sources: They are scattered and do not discharge any problems in
a particular water source. These include run-off from the roads, fields, lawns,
construction sites, logging areas e.t.c.
Q.24. Write in brief about :
(i)
UASB : Its full form is up flow anaerobic sludge blanket. It is a reactor in
which the anaerobic bacteria degrade the biodegradable material present in
wastewater. In this process foul odour of wastewater is removed and
methane (CH4) is released. UASB reduces the pollution load up to 85%.
(ii)
Sustainable development: To maintain a balance between environment and
development, it is necessary to strive for sustainable development to meet
the needs of present generation without foreclosing the options for future
generation without foreclosing the options for future generation. To achieve
this, one has to consider different aspects of development. Conservation,
sustainability and biological diversity are interrelated. If human beings have
to survive, they have to live in harmony with nature.
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Q.25. What are environmental laws? State the need for enforcing them?
Ans:- The laws that have been enacted to conserve and protect the environment are
called environmental laws. These laws have been enacted to protect the
environment from pollution and to conserve the natural resources.
Need for enforcing Environmental Laws:
(i)
To conserve natural resources including wild life and,
(ii)
To control pollution of air, water and soil.
PREPARED BY :
D. RAVI
PGT, BIOLOGY
JNV WARGAL, MEDAK DIST.
502279
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