10. life’s internal secrets - mt-iconnect.commt-iconnect.com/mte_content/mte/notes_question...

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Life’s Internal Secrets10.

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Q.I (A) Choose the correct alternatives and rewrite the complete sentences :1. The organisms which synthesize their own organic food are called as

....................... .(a) autotrophs (b) heterotrophs(c) parasites (d) saprophytes

2. Organisms that depend on other organisms for their food are .......................organisms.(a) autotrophic (b) heterotrophic(c) parasitic (d) saprophytic

3. The alimentary canal begins with the ....................... .(a) stomach (b) oesophagus(c) mouth (d) small intestine

4. Enzyme ....................... breaks down starch into a simple sugar maltose.(a) pepsin (b) salivary amylase(c) pancreatic amylase (d) trypsin

5. The enzyme ....................... digests proteins in the stomach.(a) trypsin (b) pepsin(c) salivary amylase (d) pancreatic amylase

6. The ....................... is the longest part of the alimentary canal.(a) stomach (b) oesophagus(c) small intestine (d) large intestine

7. Unused glucose is stored in the liver in the form of ....................... .(a) starch (b) glycogen(c) proteins (d) fats

8. Cellular or internal respiration takes place in the ....................... of thecells to release energy in the form of ATP.(a) mitochondria (b) cytoplasm(c) nucleus (d) vacuoles

9. In aquatic animals ....................... are the site for uptake of dissolvedoxygen into the blood by diffusion.(a) lungs (b) skin(c) gills (d) trachea

10. The human respiratory tract starts with the ....................... .(a) mouth (b) larynx(c) lungs (d) nostrils

11. The process of transportation of materials in animals is called....................... .(a) assimilation (b) translocation(c) circulation (d) absorption

12. Human heart weighs about ....................... .(a) 500 gm (b) 360 gm(c) 1000 gm (d) 250 gm

13. In plants, the gaseous excretory materials are eliminated by ....................... .(a) transpiration (b) diffusion(c) osmosis (d) translocation

Answers :1. autotrophs 2. heterotrophic3. mouth 4. salivary amylase5. pepsin 6. small intestine7. glycogen 8. mitochondria9. gills 10. nostrils

11. circulation 12. 360 gm13. diffusion

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Q.I (B) Fill in the blanks :*1. ....................... artery takes the blood to the lungs for oxygenation.*2. ....................... is the largest gland in the body.*3. The digested food is absorbed by the ....................... in the small intestine.*4. Lymph flows in ....................... direction.5. The processes that are common to all living organisms are called as the

....................... .6. Food contains several components called as ....................... .7. The crushed food is wetted with saliva secreted by the ....................... .8. Food is converted into simpler molecules with the help of biological catalysts

called as ....................... .9. The food is pushed forward in the canal due to rhythmic contraction and

relaxation of the muscles of the canal called as ....................... .10. ....................... protects the inner lining of the stomach from the action of

acids under normal conditions.11. The exit of the food from the stomach is regulated by the ....................... .12. Carbondioxide enters into the leaves through tiny pores present on the

surface of the leaf called ...................... .13. The heart is covered by the ...................... .14. The basic filtration unit in the kidney is a cluster of thin walled blood

capillaries called as a ....................... .15. Each nephron has a cup shaped thin walled upper end called ...................... .16. Bowman’s capsule contains a bundle of blood capillaries called

....................... .17. In some plants, waste is in the form of calcium oxalate crystals called as

....................... .18. ....................... is the fluid connective tissue in human beings.

Answers :1. Pulmonary 2. Liver3. villi 4. one5. life processes 6. nutrients7. salivary glands 8. enzymes9. peristaltic movement 10. mucus

11. sphincter muscle 12. stomata13. pericardial membrane 14. nephron15. Bowman’s capsule 16. glomerulus17. raphides 18. blood

Q.I (C) Match the following :1. Column I Column II(i) Pepsin (a) Creates alkaline conditions

(ii) Pancreatic amylase (b) Digests proteins(iii) HCl (c) Digests carbohydrates(iv) Bile (d) Creates acidic conditions

(e) Protects the stomachAns. (i - b), (ii - c), (iii - d), (iv - a).

2. Column I Column II(i) Salivary amylase (a) Protects the stomach

(ii) Lipase (b) Breaks down starch into maltose(iii) Pancreatic amylase (c) Digests proteins(iv) Trypsin (d) Digests carbohydrates

(e) Breaks down fatsAns. (i - b), (ii - e), (iii - d), (iv - c).


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3. Column I Column II(i) Salivary amylase (a) Pancreas

(ii) Gastric juice (b) Gall bladder(iii) Bile (c) Small intestine(iv) Pancreatic juice (d) Mouth

(e) StomachAns. (i - d), (ii - e), (iii - b), (iv - a).

4. Column I Column II(i) Small intestine (a) Absorption of water and salts

(ii) Mouth (b) Complete digestion(iii) Large intestine (c) Regulates the exit of food(iv) Sphincter muscle (d) Partial digestion

(e) Churns the foodAns. (i - b), (ii - d), (iii - a), (iv - c).

5. Column I Column II(i) Glucose (a) Waste products in plants

(ii) Urea (b) Six carbon molecule(iii) Pyruvate (c) Waste products in animals(iv) Raphides (d) Three carbon molecule

(e) Stored in gall bladderAns. (i - b), (ii - c), (iii - d), (iv - a).

Q.I (D) State whether the following statements are true or false. If falsewrite the corrected statement :

1. Carbohydrates, proteins, fats which are of plant and animal origin areinorganic nutrients.

Ans. False. Carbohydrates, proteins, fats which are of plant and animal originare organic nutrients.

2. Nutrition provides the raw materials to sustain life.Ans. True.

3. Most of the plants are autotrophs.Ans. True.

4. Mushrooms break down the food materials into simple substances insidethe body.

Ans. False. Mushrooms break down the food materials into simple substancesoutside the body and then absorb it.

5. The process is which the soluble digested food is absorbed into the blood isknown as assimilation.

Ans. False. The process is which the soluble digested food is absorbed into theblood is known as absorption.

*6. Aquatic animals breathe at a slower rate than the terrestrial animals.Ans. False. Aquatic animals breathe at a faster rate than the terrestrial animals.*7. In human beings the blood goes to the heart in one cycle once.

Ans. False. In human beings the blood goes to the heart twice in one cycle.*8. Plasma is called as the tissue fluid.

Ans. False. Lymph is called as the tissue fluid.*9. Carbohydrates are the body building nutrients.

Ans. False. Carbohydrates are the energy giving nutrients.*10. Calcium oxalate crystals present in the cells of some plants are called as

resins.Ans. False. Calcium oxalate crystals present in the cells of some plants are

called as raphides.


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11. Pancreatic amylase breaks down starch into maltose.Ans. False. Salivary amylase breaks down starch into maltose.12. Mucus protects the inner lining of the stomach from the action of acids.

Ans. True.13. Liver is the largest gland in the body.

Ans. True.14. Liver secretes gastric juice.

Ans. False. Liver sectretes bile juice.15. Desert plants take up carbon dioxide at night.

Ans. True.16. Nitrogen is essential for photosynthesis.

Ans. False. Nitrogen is essential for protein synthesis.17. A human adult at rest, on an average breathes about 20-22 times per

minute.Ans. False. A human adult at rest, on an average breathes about 12-20 times

per minute.18. Mammalian RBCs carry out only anaerobic respiration.

Ans. True.19. Cellular respiration takes place in the cytoplasm of the cells.

Ans. False. Cellular respiration takes place in the mitochondria of the cells.20. Blood pressure is greater in veins than in arteries.

Ans. False. Blood pressure is greater in arteries than in veins.21. Translocation is a simple physical process.

Ans. False. Translocation is not a simple physical process.22. Urea is formed in the kidneys.

Ans. False. Urea is formed in the liver.23. The right kidney is placed slightly lower than the left kidney.

Ans. True.24. The effect of transpiration pull is important during the day.

Ans. True.25. An average person has around 10 litres of blood.

Ans. False. An average person has around 5 litres of blood.26. Enzyme pepsin digests fats in the stomach.

Ans. False. Enzyme pepsin digests proteins inthe stomach.

Q.I (E) Find the odd man out :1. Nutrition, Respiration, Crystallization, Transportation.

Ans. Crystallization. It is not a life process whereas the others are life processes.2. Skin, Heart, Kidneys, Lungs.

Ans. Heart. It is a circulatory organ whereas the others are excretory organs.3. Gum, Urea, Resins, Rubber.

Ans. Urea. It is a waste product formed in animals whereas the others arewaste products formed in plants.

4. Nitrogen, Phosphorus, Sugar, Magnesium.Ans. Sugar. It is an organic nutrient whereas the others ae inorganic nutrients.

5. Yeast, Mushroom, Mucor, Cuscuta.Ans. Cuscuta. It shows parasitic mode of nutrition whereas the others show

saprophytic mode of nutrition.6. Ticks, Lice, Leech, Yeast.

Ans. Yeast. It shows saprophytic mode of nutrition whereas the others showparasitic mode of nutrition.

7. Mouth, Stomach, Liver, Small intestine.Ans. Liver. It is a digestive gland whereas the others are digestive organs.


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8. Hydrochloric acid, Enzyme pepsin, Mucus, Salivary amylase.Ans. Salivary amylase. It is present in saliva whereas the others are present

in gastric juice.9. Trypsin, Pepsin, Pancreatic amylase, Lipase.

Ans. Pepsin. It is an enzyme present in gastric juice whereas the others areenzymes present in pancreatic juice.

10. Pharynx, Larynx, Trachea, Lungs.Ans. Lungs. They are respiratory organs whereas the rest are parts of respiratory

tract.

Q.I (F) Write the correlated terms :1. Able to move : Movement :: Respond and react : ....................... .

Ans. Sensitivity.2. Produce offsprings : Reproduction :: Grow to adult size : ....................... .

Ans. Growth.3. Take food to stay alive : Nutrition :: Get rid of waste matter : ....................... .

Ans. Excretion.4. Salivary glands : Saliva :: Liver : ....................... .

Ans. Bile.5. Proteins : Amino acids :: Fats: ....................... .

Ans. Fatty acids.6. Pepsin : Gastric juice :: Trypsin : ....................... .

Ans. Pancreatic juice.7. Water : Xylem :: Food: ....................... .

Ans. Phloem.8. Proteins : Body building nutrients :: Carbohydrates : ....................... .

Ans. Energy giving nutrients.9. External respiration : Physical process :: Internal respiration :

....................... .Ans. Biochemical process.10. Six carbon compound : Glucose :: Three carbon compound : ....................... .

Ans. Pyruvate.11. Day time : Transpiration pull :: Night time : ....................... .

Ans. Root pressure.

*Q.I (G) Given below are the end products of differents reactions involvingglucose :

Write the reaction number in front of the following :1. Anaerobic reaction 2. Reaction in human muscles3. Aerobic respiration 4. Reaction in plant cells5. Reaction in liver.

Ans. 1. Anaerobic reaction = 5, 2. Reaction in human muscles = 4,3. Aerobic respiration = 3, 4. Reaction in plant cells = 1,5. Reaction in liver = 2.

GLUCOSE5

1

2

34

Glycogen

CO2 + H2OLactic acid

CO2 + Ethanol

Starch


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Q.II Define the following :1. Nutrition.

Ans. The process of intake of nutrients and its utilization by an organism iscalled nutrition.

2. Mode of nutrition.Ans. The way by which an organism obtains its food is called as mode of nutrition.

3. Autotrophic nutrition.Ans. Autotrophic nutrition is the mode of nutrition in which organisms synthesize

their own organic food.4. Respiration.

Ans. The process of release of energy from the assimilated food is calledrespiration.

5. Cellular or internal respiration.Ans. Cellular respiration is a biochemical process in which the simple nutrients

like glucose are utilized within the cells to release energy.6. Transportation.

Ans. The process by which the substance synthesized or absorbed in one part ofthe body is moved to the other part of the body is called transportation.

7. Circulation.Ans. The process of transport of materials in animals is called circulation.

8. Blood pressure.Ans. The force exerted by the blood on the wall of a blood vessel is called blood pressure.

9. Transpiration.Ans. The loss of water in the form of water vapour from the aerial parts of the

plants, like stomata of leaves, is known as transpiration.10. Digestion.

Ans. The process of breaking down of complex organic food into simpler solublesubstances is called digestion.

11. Assimilation.Ans. The process in which the absorbed food is transported into tissues and

cells of the body where it is used to produce energy or for growth anddevelopment or stored for future use is called as assimilation.

12. Egestion.Ans. The process in which the undigested and unabsorbed residues of food are

thrown out of the body is called as egestion.

Q.III (A) Give scientific reasons :1. Amphibians and reptiles have three chambered heart.

Ans. 1. Amphibians and reptiles are cold blooded animals.2. The body temperature of cold blooded animals varies according to the

environmental temperature.3. Such animals can tolerate some mixing of oxygenated and deoxygenated

blood.4. Therefore, amphibians and reptiles have three chambered heart.

2. Digestion of food starts in the mouth itself.Ans. 1. In the mouth, the food is crushed and wetted with saliva secreted by

the salivary glands so the food can smoothly pass through the softlining of the alimentary canal.

2. The food that we take is of complex nature.3. It is converted into simpler molecules with the help of biological catalysts

called as enzymes.4. Enzyme salivary amylase breaks down starch into a simple sugar

maltose.5. Thus digestion of food starts in the mouth itself.


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3. Rate of breathing is faster in aquatic animals.Ans. 1. An animal living in water uses oxygen dissolved in water.

2. The solubility of oxygen in water is much lower.3. So, the amount of oxygen available is much lesser than air.4. Hence the rate of breathing is faster in aquatic animals.

4. Human heart has four chambers.Ans. 1. In humans, oxygen and carbon dioxide both have to be transported by

the blood.2. The heart has different chambers, the left and the right, to prevent

oxygen rich blood from mixing with the blood containing carbon dioxide.The left half carries oxygenated blood and the right half carriesdeoxygenated blood.

3. Such separation allows a highly efficient supply of oxygen to the body.4. This is essential in animals that have high every needs like humans,

which constantly use energy to maintain their body temperature.5. Each half is further divided into two chambers. The upper one is called

atrium and the lower one is termed as ventricle.6. Therefore, the human heart has four chambers.

*5. It is necessary to separate oxygenated blood from the deoxygenatedblood in mammals.

Ans. 1. Mammals have high energy requirement for maintaining their bodytemperature.

2. For obtaining this energy, oxygen rich blood has to reach the cells.3. This is possible only if oxygenated and deoxygenated blood remain

separate.4. Therefore, it is necessary to separate oxygenated blood from the

deoxygenated blood.*6. Translocation is needed in all higher plants.

Ans. 1. Food manufactured in the cells of the leaves has to be transported toeach cell of the plant. Besides amino acids, excess food has to be takento the storage organs like roots, fruits and seeds.

2. This process is called translocation and it takes place through phloemin upward as well as downward direction.

3. Translocation allows the phloem to move material according to theplant’s needs.

4. In the flowering season, sugar stored in the roots or stems is translocatedto the buds for growing them into flowers.

5. Therefore, translocation is needed in all higher plants.*7. The plants are kept in dark before determining the factors essential for

photosynthesis.Ans. 1. When the plants are kept in dark all the starch that was previously

prepared gets used up and the plant gets destarched.2. Then when the plant is again kept in sunlight, again photosynthesis

takes place and new starch is formed.3. So, it becomes easy for us to perform various tests to determine the

factors essential for photosynthesis.4. If this is not done the starch already present in the plant will always

give positive results and it will be difficult for us to determine thefactors.

5. Therefore, the plants are kept in dark before determining the factorsessential for photosynthesis.

*8. Breathing rate increases during vigorous exercising.Ans. 1. When we exercise vigorously, the muscles of the body run out of energy.

So, the body has to produce more energy.


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2. So, more oxygen is needed to obtain energy to keep exercising.3. Therefore, to fulfill this demand for more oxygen, breathing rate

increases during vigorous exercising.9. The walls of the arteries are thick and elastic.

Ans. 1. Arteries carry blood from the heart to the various part of body.2. They have to tolerate the force exerted by the blood which is under

high pressure exerted by the heart.3. Therefore the walls of the arteries are thick and elastic to avoid their

rupture due to the force exerted by the blood.10. Effect of root pressure is important during night.

Ans. 1. The transport of water in plants takes place due to root pressure andtranspiration pull.

2. Transpiration pull occurs more during the day when the stomata areopen.

3. Hence effect of root pressure is important during night as the stomataare closed during night.

11. Unwanted and harmful waste products need to be eliminated from thebody.

Ans. 1. Biochemical reactions constantly occur in the cells of the livingorganisms.

2. These reactions produce several unwanted harmful products like urea,uric acid, ammonia etc.

3. These products if allowed to accumulate or remain in the body forlonger period may cause serious damage, sometimes leading to death.

4. Therefore, these unwanted and harmful waste products need to beeliminated from the body.

Q.III (B) Answer the following questions in short :*1. How are fats digested in the human body ?

Ans. 1. Liver, the largest gland in the body secretes bile juice which is storedin the gall bladder.

2. Whenever food enters the small intestine, the gall bladder releasesbile into it through a duct.

3. Bile makes the food alkaline and breaks the large fat globules intosmaller ones, this increases the enzyme action.

4. Pancreas secretes digestive juice. It has digestive enzymes like lipasewhich help to break down fats.

5. Various intestinal juices are also secreted by the walls of the smallintestine to complete the digestion process of converting fats into fattyacids.

*2. What would be the consequences of deficiency of haemoglobin in thehuman body ?

Ans. 1. Haemoglobin present in the RBCs of the blood carry oxygen to all thetissues of the body.

2. If haemoglobin was absent in the human body and oxygen would haveto move only by diffusion from lungs to toes, it would take three yearsfor the oxygen to reach to the toes from the lungs.

3. Deficiency of haemoglobin leads to a condition called anaemia in whichthe person experiences symptoms like headache, tiredness, weakness,breathlessness etc.

*3. How do plants get rid of their excretory products ?Ans. 1. Plants do not have definite excretory system or organ for removal of

wastes.2. Gaseous excretory materials are eliminated by diffusion.


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3. Many plant waste products are stored in the vacuoles of the leaves,flowers, fruits and even in the bark that falls off. Other waste productsare stored as resins and gums in old xylem.

4. Plants also excrete some waste substances in the soil around them.5. In some plants, waste is in the form of calcium oxalate crystals called

as raphides. These are needle shaped and therefore hurt and causeitching.

6. Some plant wastes are very useful to human beings. Eg. rubber latex,gum, resins and essential oils like eucalyptus or sandalwood oil.

4. How are nutrients classified based on their functions ?Ans. Based on their functions nutrients are divided into three types :

1. Energy giving nutrients : Carbohydrates, fats.2. Body building nutrients : Proteins.3. Protective and regulating nutrients : Vitamins and minerals.

5. How are nutrients classified based on their chemical nature ?Ans. On the basis of chemical nature, nutrients are of two types :

1. Inorganic nutrients : Plants get their nutrients from inorganicsubstances present in the soil and atmosphere through leaves androots. They convert it into organic compounds through the process ofphotosynthesis. These compounds are used for growth and to formvarious parts of the plant.

2. Organic nutrients : They include carbohydrates, proteins and fats whichare of animal and plant origin.

6. Describe the mechanism of breathing in human beings.Ans. A human adult at rest, on an average breathes about 12-20 times per

minute i.e. 28800 times per day. The mechanism of breathing in humanbeings involves two processes : Inhalation and Exhalation.1. Inhalation : When the muscular diaphragm of the body relaxes, volume

of the thoracic cavity increases and air pressure inside the cavitydecreases. The air from outside enters the lungs through the nostrilsand the alveolar sacs are filled with air rich in oxygen.

2. Exhalation : When the diaphragm contracts or becomes convex, thethoracic cavity decreases in volume. Lungs come to their original size,forcing the air outside the lungs through the same path but in theopposite direction.

7. Describe the exchange of gases in aquatic animals.Ans. 1. An animal living in water uses oxygen dissolved in water.

2. The solubility of oxygen in water is much lower. So the amount ofoxygen available is much lesser than air, hence the rate of breathingis faster in aquatic animals.

3. Fish take in water through the mouth and release it over the gills.4. Gills are the site for uptake of dissolved oxygen into the blood by diffusion.

8. What happens to the food in the mouth ?Ans. 1. The alimentary canal begins with the mouth.

2. A variety of food items have to pass through the digestive tract. So, thefood is processed in the mouth to generate particles with small size.

3. Such crushed food is wetted with saliva secreted by the salivary glandsso the food can smoothly pass through the soft lining of the alimentarycanal.

4. The food that we take is of complex nature. It is converted into simplermolecules with the help of biological catalysts called as enzymes. Enzymesalivary amylase breaks down starch into a simple sugar maltose. Thusdigestion starts in the mouth itself.


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9. What happens to the food in the large intestine ?Ans. 1. The undigested food and the residue of the digested food pass into the

large intestine (about 1.5 m long).2. This part of the intestine does not have any digestive function as the

digestion is already completed.3. The walls of the large intestine have villi which absorb most of the

water and salts.4. The rest of the material is removed from the body through the anus.

Here, the exit is regulated by the muscle called sphincter.10. What is respiration ? What are its types ?

Ans. The process of release of energy from the assimilated food is calledrespiration. Depending upon the availability of oxygen, respiration is of twotypes :1. Aerobic respiration : It occurs in the presence of oxygen.2. Anaerobic respiration : It occurs in the absence of oxygen.

11. What is respiration ? Explain the phases of respiration.Ans. The process of release of energy from the assimilated food is called

respiration. Respiration is a complex process which involves two distinctphases as follows :1. Breathing or external respiration : Breathing involves movement which

brings the air into the lungs and expels the air containing more ofcarbon dioxide from the lungs to the outer environment. Externalrespiration is a physical process.

2. Cellular or internal respiration : It takes place in the mitochondria ofthe cells to release energy in the form of ATP. It is a biochemicalprocess.

12. Can you recognize this plant? It is a heterotroph. It growsin soil which has very less nitrogen. Find out how thisplant gains nitrogen.

Ans. 1. This plant is pitcher plant (Nepenthes).2. It is an insectivorous plant.3. This plant can synthesize its carbohydrate food through

photosynthesis.4. However, it grows in nitrogen-deficient habitats.5. So, it depends on insects and small animals to fulfil its

nitrogenous protein requirement.

13. Herbivores (grass eating) animals need longer small intestine. Carnivoreslike tigers (meat eating) have shorter small intestine. Which type offood is difficult to digest)?

Ans. 1. Herbivores eat grass which has high cellulose content. It needs moretime for digestion as it is difficult to digest.

2. Carnivores eat meat which is easier to digest.3. Therefore, herbivores need longer small intestine and carnivores need

shorter small intestine.

Q.III (C) Write short notes for the following :1. Autotrophic nutrition.

Ans. 1. Autotrophic nutrition is the mode of nutrition in which organismssynthesize their own organic food.

2. They use simple inorganic substances present in the surroundings forthis process.

3. Such organisms are called autotrophs. Most of the plants are autotrophs.


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2. Heterotrophic nutrition.Ans. 1. Heterotrophic nutrition is the mode of nutrition in which organisms

depend on other organisms for their food. Such organisms are calledheterotrophs.

2. Different organisms use different strategies to obtain food dependingupon their body design, organization, functioning and also availabilityof food material. Eg. :(a) Fungi like yeast, mushroom and some carnivorous plants break

down the food material into simple substances outside the bodyand then absorb it.

(b) Some organisms take in whole food and then break it down tosimple substances inside their bodies and then absorb it. Eg. humanbeing, cat, cow etc.

(c) Some animals and plants derive nutrition from other plants oranimals without killing them but during the process they harm thehost plant or animal. Eg. cuscuta, ticks, lice, leeches, tapewormsetc.

3. Lymph.Ans. 1. When blood flows in the capillaries, some amount of water, proteins

and dissolved solutes are filtered out from the blood plasma into thetissue spaces. This forms the tissue fluid.

2. This fluid is similar to blood plasma except that it has very less amountof proteins in it because the capillary wall is impermeable to plasmaproteins.

3. Some amount of this fluid enters small channels called lymph vesselsand the fluid now is known as lymph.

4. This light yellow fluid flows only in one direction that is from the tissuesto the heart.

4. Haemodialysis.Ans. 1. Many factors like injury, infections or restricted blood flow to kidneys

reduce the activity of kidneys.2. This leads to accumulation of poisonous wastes in the body which may

lead to death.3. In case of kidney failure, an artificial device is used to remove the

nitrogenous waste products from the blood. This process is calledhaemodialysis.

4. At one time 500 ml of blood is passed through the dialyzing machine.The purified blood is pumped back into the body of the patient.

5. Blood pressure.Ans. 1. The force exerted by the blood on the wall of a blood vessel is called

blood pressure.2. This pressure is greater in the arteries than the veins.3. The pressure in the artery during ventricular contraction is called the

systolic pressure and the pressure in the artery during ventricularrelaxation is called diastolic pressure.

4. The normal systolic pressure is 120 mm of Hg and the diastolic pressureis 80 mm of Hg.

5. Blood pressure is measured by an instrument called assphygmomanometer. High blood pressure is called as hypertension.


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Q.IV (A) Distinguish between :1. Arteries and Veins.

Ans.

2. Aerobic respiration and Anaerobic respiration.Ans.

3. Autotrophic nutrition and Heterotrophic nutrition.Ans.

4. Photosynthesis and Respiration.Ans.

Autotrophic nutrition

1. Autotrophic nutrition is the modeof nutrition in which organismssynthesize their own organicfood.

2. Autotrophs use simple inorganicsubstances present in thesurroundings for this process.

3. Autotrophs possess chlorophyll.

4. All green plants followautotrophic mode of nutrition.

Heterotrophic nutrition

1. Heterotrophic nutrition is themode of nutrition in whichorganisms depend on otherorganisms for their food.

2. Heterotrophs use differentstrategies to obtain food.

3. Heterotrophs do not possesschlorophyll.

4. All animals and fungi followheterotrophic mode of nutrition.

Photosynthesis

1. Photosynthesis is the process inwhich food (glucose) issynthesized.

2. During photosynthesis energy istrapped in the food.

3. It occurs only during day time i.e.in the presence of light.

4. It is carried out only by greenplants.

Respiration

1. Respiration is the process inwhich food (glucose) is oxydized.

2. During respiration energy isreleased from the food.

3. It occurs throughout the day andnight.

4. It is carried out by all livingorganisms.

Aerobic respiration

1. It occurs in the presence ofoxygen.

2. It takes place in the cytoplasmand mitochondria.

3. The end products are carbondioxide and water.

4. Large amount of energy isreleased (38 ATP).

Anaerobic respiration

1. It occurs in the absence of oxygen.

2. It takes place in the cytoplasm.

3. The end products are ethyl alcoholor lactic acid.

4. Less amount of energy is released(2 ATP).

Arteries

1. Arteries carry blood away fromthe heart.

2. Arteries carry oxygenated bloodexcept pulmonary artery.

3. Deeply situated.4. Arteries are thick-walled.5. Arteries do not have valves.

Veins

1. Veins carry blood to the heart.

2. Veins carry deoxygenated bloodexcept pulmonary vein.

3. Superficially situated.4. Veins are thin-walled.5. Veins have valves.


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5. External respiration (Breathing) and Internal respiration (Cellularrespiration).

Ans.

6. Blood and Lymph.Ans.

Q.IV (B) Draw a neat and labelled diagram of the following :*1. Human excretory system.

Ans.

External respiration(Breathing)

1. It is a physical process.2. It takes place in the respiratory

system.3. During this process energy is not

released.4. In this process exchange of gases

takes place.

Internal respiration(Cellular respiration)

1. It is biochemical process.2. It takes place in the mitochondria

of the cells.3. During this process energy is

released.4. In this process glucose is oxidized

within the cells to release energy.

Blood

1. Blood is red in colour.2. Blood flows through blood

vessels.3. Blood has more amount of

proteins in it.4. Blood flows in two directions i.e.

from the heart to the tissues andfrom the tissues to the heart.

Lymph

1. Lymph is light yellow in colour.2. Lymph flows through lymph

vessels.3. Lymph has less amount of

proteins in it.4. Lymph flows only in one direction

i.e. from the tissues to the heart.

Renal artery

Kidney

Renal vein

Ureter

Urinarybladder

Urethra


SCHOOL SECTION234

*2. Vertical section of the human heart.Ans.

*3. Digestive glands.Ans.

4. Vertical section of a kidney.Ans.

Kidney

Renal artery

Renal vein

Ureter

Kidney medulla

From upper partof the body

To body To body From lungs

From lungsTo lungs

From lower part of the body

Superiorvenacava

Aorta

Rightatrium Left

ventricle

Rightventricle

Leftatrium

Interiorvenacava

Liver

Gall bladder

Common duct


SCHOOL SECTION 235

5. A Nephron.Ans.

6. Absorption by roots.Ans.

7. Human respiratory system (Breathing system).Ans.

Bronchioles

Pharynx

Larynx

Trachea

Bronchi

Lung

Diaphragm

Absorptionby roots

Soilparticles

Water

Roothair Cortex

Xylem vessel

Soil

Filteredblood out Glomerulus

Unfilteredblood in

Bowman’s capsuleTubule

Urine


SCHOOL SECTION236

8. Villi.Ans.

9. Pancreas with their associated structures.Ans.

10. Human digestive system.Ans.

Lacteal

Blood vessel

Oral cavity

Salivary glands

Liver

Gall bladder

Oesophagus

Stomach

Pancreas

Large intestine

Small intestine

Anus

Gall bladder

Bile duct

Common duct

Pancreatic duct

Pancreas


SCHOOL SECTION 237

11. Alveoli in the lungs.Ans.

Q.V Answer the following in detail :1. Describe the exchange of gases in plants.

Ans. 1. Plants are stationary so their energy requirement is less and theprocess of respiration is slower as compared to that of the animals. Theprocess involves exchange of carbon dioxide and oxygen.

2. Plants do not have a special respiratory organ and there is very littletransport of gases from one part of the plant to another.

3. They have the source of oxygen in their own body as oxygen is releasedduring the process of photosynthesis.

4. Large intercellular spaces ensure that all the cells are in contact withthe air that enters through the stomatal openings.

5. All parts of the plant like root, stem and leaf perform respiration. Thegases are exchanged by the process of diffusion.

6. During the day time, photosynthesis and respiration go onsimultaneously. The carbon dioxide released during respiration isutilised for photosynthesis and more oxygen is released. At night, whenthere is no photosynthesis, only respiration goes on and more carbondioxide is eliminated.

2. Describe the process of cellular or internal respiration.Ans. 1. Cellular respiration is a biochemical process in which the simple

nutrients like glucose are oxidized within the cells to release energy.2. This process takes place in the mitochondria of the cells and involves a

series of biochemical reactions.3. The process of cellular respiration varies greatly in different organisms

yet the first step is common in all. The six carbon molecule glucose(C6H12O6) is broken down in the cytoplasm into a three carbon moleculecalled pyruvate. This processs is anaerobic and is called glycolysis.

(Break down of glucose by various pathways)

Glucose(6 carbon

compound)

Pyruvate(a threecarbon

compound)

In lack of oxygenEg. in humanmuscle cells

In presence ofoxygen Eg. inmitochondria

In absence of oxygen(fermentation) Eg. in

yeast Ethanol + carbon dioxide + energy(2-Carbon (2ATP)compound)

Lactic acid + energy (2ATP)(3-Carbon compound)

Carbon dioxide + water + energy(1-Carbon compound) (38ATP)

Glycolysisin the

cytoplasm

(no oxygenis required)

Alveoli

Bronchus


SCHOOL SECTION238

4. The energy released during cellular respiration is used to synthesizeATP which is used to fuel all other activities in the cell.

5. The energy released during aerobic respiration is more than the energyreleased during anaerobic respiration.

3. Describe the structure of human heart.Ans. Structure of human heart :

1. The human heart isa muscular organwhich pumps blood.

2. The heart is coveredby the pericardialmembrane.

3. It is of the size of ahuman fist andweighs about 360gm.

4. As oxygen andcarbon dioxide bothhave to betransported by theblood, the heart hasdifferent chambers, the left and the right, to prevent oxygen rich bloodfrom mixing with the blood containing carbon dioxide.

5. The left half carries oxygenated blood whereas the right half carriesdeoxygenated blood. Such separation allows a highly efficient supply ofoxygen to the body.

6. This is very essential in animals that have high energy needs, such asbirds and mammals, which constantly use energy to maintain theirbody temperature.

7. Each half is further divided into two chambers. The upper one is calledatrium and the lower one is termed as the ventricle. Therefore thehuman heart has four chambers.

8. There are valves between the atria and ventricles which ensure thatthe blood does not flow backwards.

4. Describe the double circulation of blood.Ans. 1. The muscles of the atria are relaxed.

2. The right atrium receives deoxygenatedblood collected from different organs of thebody via large veins called venacava. Theleft atrium receives oxygen rich blood fromthe lungs simultaneously through the fourpulmonary veins.

3. The atria contract and pour the blood intorespective ventricles which expand toreceive the blood. Left ventricle gets filledwith oxygenated blood and right ventriclegets filled with deoxygenated blood.

4. Now both the thick walled ventriclescontract resulting in pumping out theoxygenated blood to all the parts of the bodythrough the aorta (the largest artery) andthe deoxygenated blood from the rightventricle enters the lungs through thepulmonary artery for oxygenation.

Lung capillaries

Pulmonaryvein fromlungs

Aortato body

Capillaries inthe body partfrom the lungs

From upper partof the body

To body To body From lungs

From lungsTo lungs

From lower part of the body

Superiorvenacava

Aorta

Rightatrium Left

ventricle

Rightventricle

Leftatrium

Interiorvenacava


SCHOOL SECTION 239

5. The valves between the atria and ventricles ensure that the blood doesnot flow backwards.

6. Thus the deoxygenated blood enters the right part of the heart andagain after oxygenation it enters the left part of the heart so the bloodgoes through the heart twice during each cycle. This is known as doublecirculation.

5. Describe the excretory system in human beings.Ans. 1. The excretory system in human beings

includes a pair of kidneys, a pair of ureters,urinary bladder and urethra. Kidneysremove the waste products from the bloodand form urine.

2. Kidneys are two bean shaped structureslocated at the back of the abdomen, oneon either side of the vertebral column. Theright kidney is placed slightly lower thanthe left kidney.

3. Though the kidneys are the major excretoryorgans in a human being, the skin andthe lungs also help in the process ofexcretion.

4. An average person has around 5 litres of blood which the kidneys filterabout 400 times in a day. Kidneys filter out about 190 litres of filtratedaily to produce 1-1.9 litres of urine, rest is reabsorbed.

*6. Explain the structure and function of a nephron.Ans. 1. The basic filtration unit in

the kidney is a cluster of thinwalled blood capillariescalled as a Nephron. Eachkidney has approximately amillion nephrons. Eachnephron has a cup shapedthin walled upper end calledBowman’s capsule whichcontains a bundle of bloodcapillaries called glomerulus.

2. Urea formed in the liverenters the blood. When bloodcontaining urea enters theglomerulus, it gets filtered through glomerular capillaries.

3. The selectively permeable wall of the Bowman’s capsule allows thewater molecules and small molecules of other substances to passthrough them and forms glomerular filtrate.

4. The glomerular filtrate collected in the Bowman’s capsule further passesthrough the nephron tubule where reabsorption of water and usefulmolecules takes place.

5. The remaining fluid containing the waste, forms the urine whicheventually enters long tube called the ureter. It is further stored inthe urinary bladder and from there it is thrown out through the urethra.

6. As the bladder is muscular, it is under the control of nerves. As aresult, we can usually control the urge to urinate.

7. An average person has around 5 litres of blood which the kidneys filterabout 400 times in a day. Kidneys filter out about 190 litres of filtratedaily to produce 1-1.9 litres of urine, rest is reabsorbed.

Filteredblood out Glomerulus

Unfilteredblood in

Bowman’scapsule

Tubule

Urine

Renal artery

Kidney

Renal vein

Ureter

Urinary bladder

Urethra


SCHOOL SECTION240

7. Describe the structure and function of the stomach.Ans. 1. The stomach is a ‘J’ shaped organ

placed on the left side of theabdomen.

2. The partly digested food goesdown through the oesophagusinto the stomach. The food ispushed forward in the canal dueto rhythmic contraction andrelaxation of the muscles of thecanal called as peristalticmovement.

3. The gastric glands present in thewall of the stomach release threegastric juices namelyhydrochloric acid, enzyme pepsinand mucus.

4. Hydrochloric acid creates acidicconditions which are necessary for the action of the enzyme pepsinwhich digests proteins. Mucus protects the inner lining of the stomachfrom the action of acids under normal conditions.

5. The muscular walls of the stomach churn the food and help in propermixing of the food with gastric juices.

6. The exit of the food from the stomach is regulated by the sphinctermuscle which releases small amount of partly digested food into thesmall intestine.

8. Describe the basic steps of nutrition in all animals.Ans. Basic steps of nutrition in animals :

1. Ingestion : The act of taking food inside.2. Digestion : The process of breaking down of complex organic food into

simpler soluble substances. This is done mechanically by teeth andchemically with the help of enzymes.

3. Absorption : After digestion is completed soluble digested food isabsorbed into the blood.

4. Assimilation : The absorbed food is transported into tissues and cellsof the body where they are used to produce energy or for growth anddevelopment or stored for future use.

5. Egestion : The undigested and unabsorbed residues of food are thrownout of the body.

9. Describe the transport of water in plants.Ans. The transport of water in plants takes place because of :

1. Root pressure 2. Transpiration pull.1. Root pressure :

Food

Oesophagus

Musclescontract

Previous mouthfulof food swallowed

Musclesrelax

Sphinctermuscles

Stomach

Absorptionby roots

Soilparticles

Water

Roothair Cortex

Xylem vessel

Soil


SCHOOL SECTION 241

(a) Root cells are in contact with water and minerals present in thesoil. Due to the difference in concentration, water molecules andminerals enter the cells of roots.

(b) The cells at the surface become turgid and exert pressure onneighbouring cells called as root pressure.

(c) The minerals and water reach the root xylem and is pushed furtherand further to eliminate this difference.

(d) This steady movement creates a column of water that is steadilypushed upwards.

(e) However, this pressure is not enough to move the water up in talltrees, though it is adequate in small plants like herbs or shrubs oreven small trees.

2. Transpiration pull :(a) The loss of water in the form

of water vapour from theaerial parts of the plants, likestomata of leaves, is knownas transpiration.

(b) Evaporation of water from theleaves to the atmosphereresults in a decrease in thewater potential of the cells.

(c) The water which is lost isreplaced by the water fromthe xylem vessels in the leaf.Gradually it creates suctionwhich pulls water fromxylem cells of roots which inturn absorb more water.

(d) Thus the pull due totranspiration helps in absorption and movement of water anddissolved minerals in tall plants during the day when stomata areopen, while effect of root pressure is important during night.

10. Explain how food is digested in the small intestine.Ans. 1. The small intestine is the longest part (about 5 to 6 m) of the alimentary

canal fitted into a compact space in the belly by extensive coiling.2. The length of the small intestine differs in various animals depending

on the food they eat. Carbohydrates, fats and proteins are fully digestedin the small intestine.

3. Since this action takes place only in alkaline conditions, the acidicfood received from the stomach has to be first made alkaline.

4. Liver, the largest gland in the body secretes bile juice which is storedin the gall bladder.

5. Whenever food enters the small intestine the gall bladder releasesbile into it through a duct. Bile makes the food alkaline and breaks thelarge fat globules into smaller ones, this increases the enzyme action.

6. Pancreas secretes pancreatic juice. It has digestive enzymes like trypsin(to digest proteins), lipase (to break down fats) and pancreatic amylase(to digest carbohydrates). The bile and the pancreatic juice enter thesmall intestine through a common duct.

7. Various intestinal juices are also secreted by the walls of the smallintestine to complete the digestion process of converting proteins toamino acids, complex carbohydrates to glucose, and fats into fatty acids.

Water evaporatesfrom leaf surface

Water travelsthrough plant

Waterabsorbedby roots

Sun


SCHOOL SECTION242

8. The digested food is absorbed by the walls of the small intestine havingnumerous finger like projections called villi which are richly suppliedby blood capillaries.

9. The absorbed food is taken to each and every cell of the body where itis utilized for obtaining energy.

10. Unused glucose is stored in the liver in the form of glycogen. Theunabsorbed food is sent to the large intestine.

11. Describe nutrition is plants. ORDescribe the process of photosynthesis in plants.

Ans. 1. Plants need food for growth and energy.2. Green plants synthesize their food during the process of photosynthesis.3. They take in carbon dioxide and water and convert them into

carbohydrates (glucose) in the presence of chlorophyll and sunlight.Reaction for photosynthesis :

6CO2 + 12H2O Chlorophyll

Sunlight C6H12O6+ 6H2O + 6O2

Glucose

Process of photosynthesis :1. Carbon dioxide

enters into theleaves through tinypores present on thesurface of the leafcalled stomata.

2. Water is taken upfrom the soil.

3. Chlorophyll presentin the chloroplastsabsorb the radiantenergy from thesunlight. It createssuch conditions that light energy splits up the water molecules intohydrogen and oxygen, releasing energy in the form of Adenosine TriPhosphate (ATP).

4. The energy produced is used to reduce carbon dioxide to carbohydrates.5. The above steps may or may not take place one after another

inmediately. Eg. desert plants take up carbon dioxide at night andprepare an intermediate product which is acted upon during the day bythe energy absorbed by chlorophyll.

Site of photosynthesis :The process ofphotosynthesis takes placeonly in green plants,mostly in the leaves andto a lesser extent in greenstems and floral parts.

WaxycuticleChloroplast

Mesophyll

Guard cells

WaxycuticleStoma

Lowerepidemis

Upperepidemis

Given offinto air

Light

Waterabsorbedfrom the roots

Converted

Starchstored food in otherparts of the plant

Carbon dioxideenters through thestomata of the leaves


SCHOOL SECTION 243

Raw materials for photosynthesis :1. Raw materials of photosynthesis are carbon dioxide and water.2. With the help of sunlight, chlorophyll, water and carbon dioxide autotrophs

synthesize carbohydrates and meet their energy requirements.3. Along with this they also need body building and regulating nutrients

like nitrogen, phosphorus, iron, magnesium etc. which are taken upfrom the soil.

4. Nitrogen is essential for synthesis of proteins. it is taken up in theirorganic form or in the form of an organic compound.

*12. Explain the process of translocation in plants.Ans. 1. Food manufactured in the cells of the leaves is transported to each cell

of the plant.2. Besides amino acids, excess food is taken to the storage organs like

roots, fruits and seeds.3. This process is called translocation and it takes place through phloem

in upward as well as downward direction.4. Translocation is not a simple process but needs energy in the form of ATP.5. When food material like sucrose is transferred to phloem tissue, using

ATP, the concentration of water molecules decreases in that area.This results into the movement of water into the cells due to osmosis.

6. The increased contents within the cells exert a high amount of pressureon their wall. This pressure moves the food materials to adjacent cellswith low pressure.

7. This allows the phloem to move material according to the plant’s needs.8. In the flowering season, sugar stored in the roots or stem is translocated

to the buds for growing them into flowers.13. Describe the respiratory system in human beings.

Ans. The human respiratory system is made up of respiratory tract (Breathingtract) and respiratory organs (Breathing organs).Respiratory tract (Breathing tract) :1. The human

respiratory tractstarts withnostrils.

2. The air passingthrough thenostrils isfiltered by thefine hair thatlines thepassage. It alsobecomes moistand warm. Thedust particlesare trapped inthe mucus.

3. The respiratorytract includesexternal nostrils,pharynx, larynx and trachea. The trachea or the wind pipe is divided intotwo bronchi. One enters the right lung and the other the left lung.

4. Though conventionally called as respiratory tract, this tract carries outonly breathing (part of respiration). So we can also call it as breathingtract.

Human respiratory system(Breathing system)

Bronchioles

Pharynx

Larynx

Trachea

Bronchi

Lung

Diaphragm


SCHOOL SECTION244

Respiratory organs (Breathing organs) :1. The respiratory organs are

the lungs which lie in thethoracic cavity on bothsides of the heart.

2. Within each lung the majorbronchus divides into twobronchi and further intosmaller and smallerbronchioles which finallyterminate into balloon likestructures called alveoli(Singular-alveolus, meanscavity in Latin). Alveoli provide the surface for exchange of gases.

3. The thin walls of the alveoli are closely surrounded by a network of bloodcapillaries. The haemoglobin present in the RBCs of the blood absorbs theoxygen from the air present in the alveoli through the thin walls of thecapillaries. At the same time carbon dioxide from the blood is released intothe alveoli by diffusion, which goes out of the body when we breathe out air.

4. The oxygen is carried to all the tissues of the body which are deficientin oxygen.

14. Describe the network of tubes (blood vessels) in human body.Ans. 1. Arteries carry blood away from the heart and have to tolerate the force

exerted by the blood which is under high presssure exerted by theheart. The walls of the arteries are thick and elastic.

2. The veins collect the blood from different parts of the body and bring it backto the heart. They do not need thick walls as blood is no longer under highpressure; instead they have valves to prevent the backward flow of blood.

3. On reaching the tissues arteries divide and redivide into smaller and smallervessels called capillaries to bring the blood in contact with individual cells.

4. Exchange of material between the blood and the surrounding cellstakes place across the thin walls of the capillaries.

5. The capillaries join together to form veins which take the blood awayfrom the organ but towards the heart.

Q.VI Answer the following questions in one sentence each :1. How many kilometres of blood vessels are there in the human body ?

Ans. There are 97000 kilometres of blood vessels in the human body.2. How much water does an oak tree transpire from its leaves per year ?

Ans. An oak tree may transpire from its leaves 1,51,000 litres of water per year.3. How much water does an acre of corn crop give off each day ?

Ans. An acre of corn crop gives off 11,400-15,100 litres of water each day.4. Name some plant wastes that are useful to human beings.

Ans. Some of the plant wastes that are very useful to human beings are rubberlatex, gum, resins and essential oils like eucalyptus or sandalwood oil.

5. What is the normal blood pressure in human beings ?Ans. In human beings, the normal systolic pressure is 120 mm of Hg and diastolic

pressure is 80 mm of Hg.6. How is blood pressure measured ?

Ans. Blood pressure is measured by an instrument called as sphygmomanometer.7. What is glycolysis ?

Ans. During cellular respiration, the six carbon molecule glucose (C6H12O6) isbroken down into the cytoplasm into a three carbon molecule called pyruvate.This process is anaerobic and is called as glycolysis.

Network of capillaries


SCHOOL SECTION 245

8. Name the air passage that takes air up to the respiratory organs inhuman beings.

Ans. The air passage that takes air upto the respiratory organs in human beingsincludes external nostrils, pharynx, larynx, trachea and bronchi.

9. What is alimentary canal ?Ans. Alimentary canal is a long and muscular tube of varying diameter which

extends from the mouth to the anus.10. Name the digestive glands associated with the alimentary canal.

Ans. The salivary glands, liver, the pancreas and the gastric glands are thedigestive glands associated with the alimentary canal.

11. Which organs of the body are involved in breaking the large food particlesinto smaller ones ?

Ans. The teeth and the tongue present in the mouth are involved in breakingthe large food particles into smaller ones.

12. Name the three gastric juices released by the gastric glands in the stomach.Ans. The gastric glands present in the wall of the stomach release three gastric

juices namely hydrochloric acid, enzyme pepsin and mucus.13. What is the function of mucus secreted by the gastric glands ?

Ans. Mucus protects the inner lining of the stomach from the action of acidsunder normal conditions.

14. Name the digestive enzymes present in pancreatic juice.Ans. Pancreatic juice has digestive enzymes like trypsin (to digest proteins),

lipase (to break down fats) and pancreatic amylase (to digest carbohydrates).15. What is the significance of waxy cuticle on the upper and lower surface

of a leaf ?Ans. The waxy cuticle on the upper and lower surface of a leaf prevents the

excess loss of water from the plants.16. How much area will be covered if the alveolar surface of the lungs in

spread out ?Ans. If the alveolar surface of lungs is spread out, it will cover about l80 m2 area.17. Why do certain cells such as mammalian RBCs carry out only anaerobic

respiration ?Ans. Certain cells, such as mammalian RBCs carry out only anaerobic respiration

because mitochondria are absent in them.18. What is the function of the valves present in the heart ?

Ans. The valves present between the atria and ventricles ensure that the blooddoes not flow backwards.

19. Name the tissue that transports water and minerals in a plant.Ans. Xylem is the tissue which transports water and minerals in a plant.20. Name the tissue that transports food in a plant.

Ans. Phloem is the tissue that transports food in a plant.21. What is lymph ?

Ans. Lymph is a light-yellow coloured tissue fluid which flows only in onedirection i.e., from the tissues to the heart.

22. What are alveoli ? What is their function ?Ans. Alveoli are balloon like structures present within the lungs. They provide

the surface for exchange of gases.23. Why do few intestinal parasites like liverfluke, tapeworm and roundworm

respire anaerobically?Ans. Few intestinal parasites like liverfluke, tapeworm and roundworm respire

anaerobically because they live in environments which have less amountof oxygen.


SCHOOL SECTION246

ACTIVITY BASED QUESTIONS

Complete the table by putting or in front of the activities that theitems are able to carry out.

Q. What can you conclude ?Ans. A table and a stone are non-living and are unable to carry out the activities

which are carried out by the living things mentioned in the table.

ACTIVITY : 10.1

Suggest one word for each of the activities mentioned in the above table.1. Able to move - movement.2. Produce offsprings - reproduction.3. Respond and react - sensitivity.4. Take food to stay alive - nutrition.5. Get rid of waste matter - excretion.6. Turn food to energy - respiration.7. Grow to adult size - growth.

ACTIVITY : 10.2

Q. A car moves, during the process of crystallization the crystals grow insize but a car and the crystals both are non-living. What is the reason?

Ans. 1. A car moves, due to the force exerted by the engine and the energyprovided by the fuel inside. The crystals grow due to the deposition ofmaterial from outside. The growth is not internal.

2. In both the cases, there are no life processes taking place. Thereforethe car and the crystals, both are non-living.

Q. Is the presence of only one life process sufficient to decide whether anobject is living or non- living?

Ans. Only one life process is not sufficient to decide whether an object is livingor non-living. Various life processes work in co-ordination to maintain life.

ACTIVITY : 10.3

Using the hint guess who we are :Q. We prepare our own food by using simple inorganic substances.

SNALPTAns. PLANTS.

Sr. Items A A mimosa A A A ANo. table plant mouse stone dog human

Activities being

1. Able to move.

2. Produce offsprings.

3. Respond and react.

4. Take food to stay alive.

5. Get rid of waste matter.

6. Turn food to energy.

7. Grow to adult size.


SCHOOL SECTION 247

Q. We use complex substances, break them into simple ones and use themfor upkeep and growth.NALSMIA

Ans. ANIMALS.

ACTIVITY : 10.4

• Take 1 ml of starch solution (1%) in two test tubes (A and B).• Add 1 ml of saliva to test tube A.• Leave both the test tubes undisturbed for 20-30 minutes.• Now add a few drops of dilute iodine solution to the test tubes.

Q. What is the colour change in test tube A and test tube B ?Ans. In test tube A, the solution is colourless whereas in test tube B, the solution

turns bluish black.Q. What conclusion can you draw about the presence of starch ?

Ans. In test tube A, starch is not present whereas in test tube B, starch is present.Q. What does this tell us about the action of saliva on starch ?

Ans. Saliva contains an enzyme called salivary amylase which breaks downstarch into maltose in test tube A.

ACTIVITY : 10.5

Q. Can you think of any other function served by hydrochloric acid ?Ans. Hydrochloric acid being acidic kills the microbes that enter our body through

food and water.Q. You must have heard people complaining of acidity. Is it related to the

hydrochloric acid present in the stomach ?Ans. Yes. When the level of hydrochloric acid in the stomach increases, that

condition called acidity.

ACTIVITY : 10.6

Q. Complete the photosynthesis reaction.

6CO2 + 12H2O Chlorophyll

Sunlight C6H12O6 + 6H2O + 6O2

Glucose

ACTIVITY : 10.7

Observe the given diagram of cross section of a leaf as seen under themicroscope.

WaxycuticleChloroplast

Mesophyll

Guard cells

WaxycuticleStoma

Lowerepidemis

Upperepidemis


SCHOOL SECTION248

Q. In which layer must the process of photosynthesis be taking place to agreater extent and why ?

Ans. The process of photosynthesis takes place to a greater extent in the mesophylllayer because mesophyll layer contains more number of chloroplasts.Chloroplasts are responsible for trapping light energy required for photosynthesis.

ACTIVITY : 10.8

• Take a potted croton plant.• Keep the plant in a darkroom for three days so that all the starch gets used up.• Now keep the plant in sunlight for about six hours.• Pluck a leaf of the plant and mark the green areas on it.• Dip the leaf in boiling water for a few minutes.• Now immerse the leaf in a beaker containing alcohol.• Carefully place the above beaker in a water bath and heat the alcohol, till

it begins to boil.Q. What happens to the colour of the leaf ? What is the colour of the

solution ?Ans. The leaf becomes colourless as the green pigment chlorophyll dissolves in

alcohol and the solution becomes green in colour.

• Now immerse the leaf in a dilute solution of iodine for a few minutes.• Take out the leaf and rinse off the iodine solution.• Observe the colour of the leaf specially the marked regions.

The marked regions on the leaf turn bluish black in colour.Q. What do you conclude ?

Ans. Photosynthesis takes place only in the presence of chlorophyll. There is anabsence of starch in the parts of the leaf which are devoid of chlorophyll.

ACTIVITY : 10.9

• Take two healthy potted plants which are nearly of the same size.• Keep the plants in dark for three days to de-starch them.

(Before starch test) (After starch test)

Watch-glasscontainingpotassiumhydroxide

Bell jar

Experimental set up to show CO2 is necessary for photysynthesis.A B


SCHOOL SECTION 249

• Now place each plant on a separate glass plate and place a watch glasscontaining potassium hydroxide by the side of one of the plants. Potassiumhydroxide is used to absorb the carbon dioxide.

• Cover both the plants with separate bell jars. Use vaseline to seal thebottom of the jars to make the set up air tight.

• Keep the plants in sunlight for two hours.• Pluck a leaf from each plant and check for presence of starch.

Q. What can you conclude ?Ans. Without carbon dioxide photosynthesis cannot take place. There is absence

of starch, in the leaves, where the air from the jar did not contain anycarbon dioxide.

ACTIVITY : 10.10

Q. Based on the above two activities suggest an experimental activity todemonstrate that sunlight is essential for photosynthesis.

Ans.

1. Take a destarched potted plant.2. Fix Ganong's light screen to one of its leaves and keep the plant in

sunlight for 6-8 hours.3. Detach the leaf, and take away Ganong's light screen.4. The leaf is immersed in boiling alcohol for few minutes to dissolve the

chlorophyll pigments.5. The leaf is tested for starch with iodine solution.6. Part of the leaf exposed under the star- shaped hole turns bluish -

black and the remaining portion does not turn bluish black.7. This shows that the part of the leaf which was exposed to sunlight

synthesizes starch whereas the remaining part which was not exposedto sunlight did not produce starch.

8. This proves that sunlight is essential for photosynthesis.

ACTIVITY : 10.11

Ganong’slight screen

UnexposedportionBluish

black

Experimental set up to show light is necessary for photysynthesis.

Tube

Pichkari

Rubber tube

Lime water

Test tubeTest tube

Lime water

A B


SCHOOL SECTION250

• Take two test tubes and fill half of each test tube with freshly preparedlime water.

• In the first test tube, marked as A, blow air repeatedly from your mouth tilla colour change is observed.

• In the second test tube, labelled as B, release air through a syringe orpichkari.

• Note down how long it takes for lime water in each test tube to turn milky.Q. What does it tell us about the amount of carbon dioxide in the air that

we breathe out ?Ans. The lime water in test tube B turns milky showing that we exhale carbon

dioxide during respiration. On the other hand the lime water in test tubeA takes a long time to turn milky. This shows that the air in test tube Aalso contains carbon dioxide but in a smaller amount.

ACTIVITY : 10.12

• Observe the movement of mouth of fish in an aquarium.• Observe the gill slits too.

Q. Are the timings of the opening and closing of the mouth and gill-slitscoordinated?

Ans. The fish breathes by taking in water through its mouth and then passing itout through gill-slits. Therefore, the opening and closing of the mouth andgill-slits is coordinated.

Q. Count the number of times the fish opens and closes its mouth in aminute.

Ans. A fish opens and closes its mouth approximately 100-150 times in a minute.Q. Compare this to the number of times you breathe in and out in a minute.

Ans. We (human beings) breathe about 12 to 20 times in a minute.

ACTIVITY : 10.13

Observe the experimental set up.

Q. What will happen when the elastic diaphragm is pulled down?Ans. When the elastic diaphragm is pulled down, the balloons swell up.

Q. Why do the balloons swell?Ans. When the elastic diaphragm is pulled down, the pressure inside the bell

jar decreases. This causes the air from outside to rush into the balloons.Therefore, the balloons swell up.

Mechanism of breathing

Expiration Inspiration‘Y’ Tube

(Trachea andbronchi

Bell jar(Chest cavity)

Balloon(Lung)

Sheath (diaphragm)


SCHOOL SECTION 251

Q. Why do they flatten when we release the diaphragm back?Ans. When we release the diaphragm back, the pressure inside the bell jar

increases. This forces the air out of the balloons. Therefore, they flatten.

ACTIVITY : 10.14

• Take some fruit juice or sugar solution in a test tube.• Add some yeast to it.• Fit the test tube with a one holed cork having a bent glass tube.• Dip the free end of the glass tube into a test tube containing freshly prepared

lime water.Q. What is the change observed in lime water? How long does it take for

this change to occur?Ans. The lime water turns milky.

Q. What does it tell us about the products of fermentation?Ans. The products of fermentation are ethyl alcohol (C2H5OH) and carbon dioxide

(CO2). The carbon dioxide released during fermentation turns lime watermilky.

ACTIVITY : 10.15

Q. Which electrical instrument is used to raise water from the groundlevel to the higher level?

Ans. An electric motor is used to raise the water from the ground level to thehigher level.

Q. When a person is in the pose of ‘Shirshasan’ of yoga how does the bloodreach the feet?

Ans. During the pose of ‘Shirshasan’ of yoga, the blood reaches the feet becausethe heart pumps the blood under high pressure against the force of gravity.

ACTIVITY : 10.16

Q. Observe the inner delicate region of the fore hand just below the palm.Observe the veins. What do you notice?

Ans. The veins look like bluish green lines just below the skin. The veins aredividing and re-dividing to form capillaries.

ACTIVITY : 10.17

Q. Why does a blue-black patch appear on a bruised skin?Ans. During a bruise, the blood vessels under the skin get damaged and the

blood gets collected near the skin surface. This appears like a blue-blackpatch on the skin.

Fruit juice + yeast

Lime water


SCHOOL SECTION252

Q. When there is a cut on your finger, does it keep on bleeding? Why?Ans. When there is a cut on the finger, it does not keep on bleeding because

the platelets present in the blood do the work of plugging these leaks byclotting the blood at the point of injury.

ACTIVITY : 10.18

Q. Why do we eat fruits and leafy vegetables?Ans. 1. Fruits provide us with sugars which give us energy.

2. Fruits and leafy vegetables provide us many vitamins and mineralswhich are necessary for growth and maintenance of our body.

3. Fruits and vegetables also provide us with soluble and insoluble fibres.Soluble fibres help to lower the cholesterol level and insoluble fibresspeed up the elimination of faeces thus preventing constipation.

Q. Do you think plants also need minerals?Ans. Yes. Plants also need minerals.

Q. From where do plants get the inorganic material other than carbondioxide and oxygen?

Ans. Plants gets inorganic materials from the soil.

ACTIVITY : 10.19

• Take a herbaceous plant like balsam or tuberose along with its roots. Washits roots thoroughly.

• Place it in a flask containing water with a dissolved red dye such as safraninor eosin.

• Observe the stem of the plant and the veins of the leaf after few hours.Ans. The stem of the plant and the veins of the leaves become reddish. This

indicates that coloured solution has risen in the stem through the xylem.

• Take a thin section of the stem of the plant and observe the stained xylemunder the microscope.

Ans. The section of the plants steam under the microscope shows xylem stainedred. The red colouration is due to transport of stained water from the rootsof the plant to the stem through the conducting tissue xylem.

ACTIVITY : 10.20

• Take a potted plant and cover one branch with a plasticbag, tie the bag properly to the branch.

• Now place the plant in sunlight, water it and observethe bag after a few hours.

Leaves

Red colour veins

Stand

Beaker

Eosin solution


SCHOOL SECTION 253

Q. What do you observe on the inner walls of the plastic bag?Ans. Small drops of water start appearing on the inner side of the plastic bag.

This shows that the leaves lose water in the form of vapours which getcondensed on the inner surface of the plastic bag.

ACTIVITY : 10.21

Some amount of waste is generated in every house daily.Q. What would happen if you keep the waste day after day in your house

itself?Ans. House waste consists of peels of fruits and vegetables, left over food items,

animal waste etc. If these wastes are kept in the house itself, they willattract harmful micro-organisms causing decay and rotting of the waste.This will result in release of foul odours and also affect the health of thefamily members.

ACTIVITY : 10.22

• Observe your mother cutting elephant yam or corm (suran) and colocacialeaves. You can try and help her in this.

Q. Do your hands start itching while you are cutting it?Ans. Yes. The hands start itching while cutting elephant yam or corm (Suran)

and colocasia leaves. This is because elephant yam and colocasia leavescontain calcium oxalate crystals called as raphides. These are needleshaped and therefore hurt and cause itching.

Q. Ask your mother about the way to avoid the itching.Ans. The itching can be avoided by applying some sour substance like tamarind

juice.Q. Find out the reason behind it.

Ans. This is because calcium oxalate crystals (raphides) are soluble in acidspresent in the tamarind juice.


SCHOOL SECTION254

HOTS QUESTIONS & ANSWERS

1. Dialysis is carried out on those patients whose .................... does notfunction properly.(a) heart (b) digestive system(c) kidney (d) brain

Ans. Kidney.

2. A girl in my school met with an accident. There were bruises along withblue-black patches on the parts of her body which were affected. Whatwas the reason for the blue-black patches ?

Ans. In an accident, the body organs get hurt. A cut damages the network ofblood vessels. In the view of controlling the loss of blood, the blood plateletsdo the work of plugging these leaks by clotting the blood at the point ofinjury. That is the reason for the blue-black patches on the body of thegirl.

3. On her holiday Richa was sitting on the river bank in the evening, shesaw many small tadpoles swimming in the shallow part of the river. Shewas wondering about the continuous movement of their mouth andgills and asked her father the reason for the same. What explanationmust have been given by her father ?

Ans. The tadpole uses oxygen dissolved in water during respiration. The solubilityof oxygen in water is very lower. Hence the rate of breathing is very fasterin aquatic animals. A tadpole takes water through mouth and releases itover the gills. The oxygen dissolved in water is absorbed in blood by diffusion.Therefore, the tadpole is seen to be continuously opening and closing itsmouth as well as gills simultaneously.

4. State how the components in the pair are related to each other.(a) Carbon dioxide and photosynthesis.(b) Respiration and stomata.(c) Breaking of Glucose and mitochondria.(d) Haemoglobin and human beings.(e) Raphides and tamarind paste.

Ans. (a) The plants produce their own food through the process ofphotosynthesis. The food is prepared with the help of chlorophyll, carbondioxide, water and sunlight. CO2 is an essential component of theprocess.

(b) The leaves have stomata on their surfaces. The exchange of gases inthe process of respiration takes place through stomata.

(c) Cellular respiration is a biochemical process in which the glucose isoxidized to release energy.

(d) In human beings, the haemoglobin present in the RBCs of the blood isresponsible for absorbing the oxygen from the air present in the alveolithrough the thin walls of the capillaries.

(e) Raphides are crystals of calcium oxalate present in some of the plants.These are needle-shaped and therefore hurt and cause itching whensubji prepared from the leaves, stems or roots of the plant is eaten.Therefore, while cooking, people mix paste of tamarind in the subjimade up of these plant parts. Tamarind has tartaric acid in it, whichdissolves these raphides.


SCHOOL SECTION 255

5. Compare the speed of respiration in aquatic and terrestrial animals andexplain the cause.

Ans. The speed of respiration in aquatic is faster than that in terrestrial animals.This is because the amount of oxygen is lower in water that in air and therefore,aquatic animals have to breath faster in order to get the required oxygen.

6. Name the process :(a) Glucose gets converted into ethanol, carbon dioxide and energy.(b) Glucose gets converted into carbon dioxide, water and energy.

Ans. (a) Anaerobic respiration.(b) Aerobic respiration.

7. A tall plant absorbs water and minerals from the soil and transports toall the parts of the plant. Is the root only organ responsible for thisprocess ? How ?

Ans. Only roots are not responsible for this process. The absorption andtransportation of water and mineral from the soil takes place due to(a) root pressure and (b) transpiration pull.Root pressure is created to move water and mineral from one place toanother by difference in the level of concentration in cells.Transpiration pull is exerted in the epidermal cells in the leaves by creatinga suction for water from xylem vessels. This happens on account of loss ofwater from stomata due to evaporation.

8. Correct the following statements :(a) Photosynthesis happens at night.(b) Autotrophic mode of nutrition is observed in mushrooms.(c) Small intestine is the smallest part of alimentary canal.(d) The finger like projections of small intestine called Villi are

responsible for digestion of food.(e) The fish has three chambered heart.

Ans. (a) Photosynthesis happens during the day.(b) Heterotrophic mode of nutrition is observed in mushrooms.(c) Small intestine is the largest part of alimentary canal.(d) The finger like projections of small intestine called Villi are responsible

for absorption of the food.(e) The fish has two chambered heart.

9. Rearrange the steps in the following process :Glucose Glycolysis Carbon dioxide + Water + Energy Pyruvate.

Ans. Glucose Glycolysis Pyruvate Carbon dioxide + Water + Energy.

10. Why do Yoga exercises (breathing exercises) help human beings to resorehealth ?

Ans. The carbon dioxide created in the body, which is not good for health, ispassed into alveoli through thin walls of capillaries. Yoga is related tobreathing exercises in which the carbon dioxide is thrown out and oxygenis taken in rigorously. This helps the human beings to restore their health.


SCHOOL SECTION256

11. Write down three pairs of processes and body organs of plants or animalswhich are related to each other.

Ans. (a) Leaf and respiration.(b) Alveoli and exchange of gases.(c) Blood platelets and plugging of damaged blood artilleries.

12. Derive a concept map (flow chart) out of following :Heterotrophic, algae, animals, aerobic, plants, fungi, anaerobic, yeast,aerobic, animals, autotrophic.

Ans.

13. The digested food is absorbed by the walls of the small intestine havingnumerous finger-like projections called villi. Villi which absorb the foodare richly supplied with blood vessels. The absorbed food is taken to eachand every cell of the body where it is utilized for obtaining energy. Unusedglucose is stored in the liver in the form of glycogen. The unabsorbed foodis sent to the large intestine.Questions :(a) Where is the digested food absorbed ?(b) What are villi ?(c) In what form is unused glucose stored ? Where is it stored ?(d) What happens to the unabsorbed food ?(e) Which structures are richly supplied with blood vessels in the small

intestine ?Ans. (a) The digested food is absorbed by the walls of the small intestine.

(b) Villi are finger-like projections in the walls of the small intestine.(c) The unused glucose is stored in the form of glycogen. It is stored in

the liver.(d) The unabsorbed food is sent to the large intestine.(e) Villi are the structures which are richly supplied with blood vessels in

the small intestine.

14. After a vigorous exercise, you may experience cramps in your muscles.Why does this happen ?

Ans. During heavy exercise, there is lack of oxygen in our muscle cells. So, themuscle cells switch over to the anaerobic mode of respiration. Wherepyruvate is broken down to lactic acid in the absence of oxygen. Lactic acidcauses fatigue of muscle cells. Therefore, after a vigorous exercise, youmay experience cramps in your muscles.

Living things

AnimalsPlants

Nutrition

Respiration Anaerobic

Aerobic

Heterotrophic

Autotrophic

Fungi

Algae


SCHOOL SECTION 257

15. The following flowchart describes the breakdown of glucose by variouspathways.

(a) What product will be formed at the place marked (1) ?(b) What product will be formed at the place marked (2) ?(c) What will be the product formed at the place marked (3) ?

Ans. (a) Ethanol + Carbon dioxide + Energy (2 ATP).(b) Lactic acid + Energy (2ATP).(c) Carbon dioxide + Water + Energy (38 ATP).

Lack of oxygen(in muscle cells)

Absence of oxygen(in yeast)

Incytoplasm

1

Pyruvate(3 C molecule)

Glucose(6 C molecule) Presence of

oxygen (inmitochondria)

Glycolysis2

3


SCHOOL SECTION258

CONCEPT MAP

Animals eg. human being

Living beings

Heterotrophic

Plants

Life processes

1. Nutrition

some are

Alimentary canal

Liver, pancreas

glands are

Alcohol + CO2 + energy

Anaerobic

products are

Energy +CO2 + H2O Aerobic

productsare

Lungs

throughAlveoli

have

typesare

Heterotrophic

Autotrophic

modes are

by

raw materialsare

CO2 + H2O

productsare

O2 + carbohydratesused

in

productsareStomata

through

Lymph

Bloodby pressure of

Bodyto

Heartby

Circulationcalled as

Root pressure

Transpirationpull

by Xylemand

Phloem

through

through

Leaves

Flowers,Fruits

Bark

Blood cells

Air

Soilaround

the roots

ofShedding

inStorage

Diffusionin

byKidneys

by

Nephrons

Blood

throughrenal vein

have

filter

used in

organ ismode is

through

2. Respiration

3. Transportation

Photosynthesis

CO2 +H2O +

energy

4. Excretion

Q.I [A] Fill in the blanks : 2

1. ....................... artery takes the blood to the lungs for oxygenation.

2. The digested food is absorbed by the ....................... in the small

intestine.

3. ....................... is the largest gland in the body.

4. Lymph flows in ....................... direction.

Q.I [B] Match the columns : 2

Column A Column B

1. Pepsin (a) Creates alkaline conditions

2. Pancreatic amylase (b) Digests proteins

3. HCl (c) Digests carbohydrates

4. Bile (d) Creates acidic conditions

(e) Protects the stomach

Q.I [C] State whether True or False : 3

1. Aquatic animals breathe at a slower rate than the terrestrial

animals.

2. Plasma is called as the tissue fluid.

3. Calcium oxalate crystals present in the cells of some plants are

called as resins.

Q.II Give scientific reasons : (Any Two) 4

1. It is necessary to separate oxygenated blood from the deoxygenated

blood in mammals.

2. Translocation is needed in all higher plants.

3. Breathing rate increases during vigorous exercising.

4. The plants are kept in dark before determining the factors essential

for photosynthesis.

CHAPTER 10 : LIFE’S INTERNAL SECRETS

S.S.C.

SCIENCE

Marks : 20

Duration : 1 hr.

... 2 ...

Best Of Luck

Q.III Answer the following questions : (Any Two) 4

1. How are fats digested in the human body ?

2. How do plants get rid of their excretory products ?

3. Write a note on Blood pressure.

4. Write a note on Lymph.

Q.IV Answer the following : (Any One) 5

1. Explain the structure and function of a nephron.

2. Describe the structure of human heart.

3. Describe the double circulation of blood.

10. life’s internal secrets - mt-iconnect.commt-iconnect.com/mte_content/mte/notes_question...

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