RBSE Class 10 Science Important Questions Chapter 6 Life Processes

Rajasthan Board RBSE Class 10 Science Important Questions Chapter 6 Life Processes Important Questions and Answers.

RBSE Class 10 Science Chapter 6 Important Questions Life Processes

Objective Type Questions

Question 1.
Ethyl alcohol is formed –
(a) In combustion
(b) In aerobic respiration
(c) In anaerobic respiration
(d) Not in any
Answer:
(c) In anaerobic respiration

Question 2.
The main objective of respiration is –
(a) Exchange of gases
(b) Produce energy by oxidation of glucose
(c) Digestion of food
(d) Pass out the excretory materials.
Answer:
(b) Produce energy by oxidation of glucose

Question 3.
Number of chamber in fish heart –
(a) Two
(b) Three
(c) Four
(d) One
Answer:
(a) Two

Question 4.
The cells which help is clotting of blood are –
(a) Red blood cells
(b) White blood cells
(c) Platelets cells
(d) Eosin
Answer:
(c) Platelets cells

Question 5.
The enzyme found in saliva of human is –
(a) Amylase
(b) Pepsin
(c) Trypsin
(d) Lipase
Answer:
(a) Amylase

Question 6.
In healthy adult, the initial filterate in the Kidney is about –
(a) 160 liters
(b) 170 liters
(c) 180 liters
(d) 190 liters
Answer:
(c) 180 liters

Question 7.
Haemoglobin is found –
(a) In white blood cells
(b) In red blood cells
(c) In platelets
(d) In lymphocytes
Answer:
(b) In red blood cells

Question 8.
In which chamber of heart the wall is thick and strong—
(a) Right atrium
(b) Left atrium
(c) Right ventricle
(d) Left ventricle
Answer:
(d) Left ventricle

Very Short Answer Type Questions

Question 1.
What is ‘Life processes’?
Answer:
The processes which together perform the maintenance job are life processes.

Question 2.
What do you mean by ‘food’ and ‘nutrition’?
Answer:
The source of energy for an organism is food and the process to take it inside the body is called nutrition.

Question 3.
What is ‘respiration’?
Answer:
The process of acquiring oxygen from outside the body, and to use it in the process of break-down of food sources for cellular needs, is called respiration.

Question 4.
What is obtained from the digestion of protein, carbohydrate and fats?
Answer:
Digestion of proteins give amino acids, carbohydrates give glucose and fats give fatty acids and glycerol.

Question 5.
How much energy is obtained during the break-down of one molecule of ATP ?
Answer:
When the terminal phosphate linkage in ATP is broken using water, the energy equivalent to 30.5 kJ/mol is released.

Question 6.
Why the presence of rings of cartilage in throat is important ?
Answer:
The presence of rings of cartilage in throat is important because they ensures that the air-passage does not callapse.

Question 7.
Write the chemical formula of photosynthesis reaction.
Answer:

Question 8.
What will be the effect on removal of xylem from plants?
Answer:
Xylem is a conducting tissue so on removal there will be no conduction of water and mineral salts in plants and plant become dry and destroyed.

Question 9.
What are ‘enzymes’?
Answer:
Enzymes are biological catalysts which increases the rate of bio-chemical reactions.

Question 10.
How do fungi obtain their nutrition ?
Answer:
Fungi like bread-moulds, yeast and mushrooms, breakdown the food material outside the body and then absorb it.

Question 11.
On what does the food to be taken in and its breakdown depends in an organism ?
Answer:
The food to be taken in and its breakdown depends on the body design and functioning.

Question 12.
What is the difference between the Amoeba and Paramecium in the mode of nutrition ?
Answer:
Amoeba takes in food using temporary finger-like extensions of the cell surface whereas Paramecium has a definite shape and food is taken in at a specific spot.

Question 13.
Which component of food is completely digested in the intestine?
Answer:
Protein, carbohydrate and fat.

Question 14.
In human kidney is a part of system, which is related to ….
Answer:
Excretory system.

Question 15.
Write the name of any two unicellular organisms.
Answer:
Amoeba and Paramaecium.

Question 16.
Write the name of two plants which get nutrition from them without killing the plant.
Answer:

• Cuscuta
• Orchid.

Question 17.
From which organ unicellular organisms gets food?
Answer:
In unicellular organism food is obtained from complete surface.

Question 18.
What we call the finger like projections on the inner layer of intestine?
Answer:
The finger like projections on the inner layer of intestine is called villi.

Question 19.
Which energy is called currency in most of the cellular processes?
Answer:
ATP is the currency in most of the cellular processes.

Question 20.
If the alveolar surface were spread out then how much square meter area they would cover?
Answer:
If the alveolar surface were spread out then approximate 80 meter square area will cover.

Question 21.
Write the name of that organism in which only one time blood goes through heart in one cycle.
Answer:
In fish during one cycle, blood goes only once through the heart.

Question 22.
By which instrument blood pressure in measured?
Answer:
Sphygmomanometer instrument is used in measurement of blood pressure.

Question 23.
What is ‘excretion’?
Answer:
The process of removal of waste products from the body is called excretion.

Question 24.
Who performs the work of closing and opening of stomata ?
Answer:
Guard cells.

Question 25.
What is ‘pepsin’? What is its function ?
Answer:
‘Pepsin’ is a digesting enzyme which digest protein.

Question 26.
Why the muscular walls of ventricles are thicker then atria ?
Answer:
Since ventricles have to pump blood into various organs, they have thicker muscular walls than the atria.

Question 27.
Why valves are found in heart ?
Answer:
Valves ensure that blood does not flow backwards when the atria and ventricles contract.

Question 28.
Why plants need less energy in comparison to animals ?
Answer:
Plant bodies have a large proportion of dead cells in many tissues, therefore, plants have low energy needs.

Question 29.
In which organ urine is formed in human?
Answer:
Urine is formed in human kidney.

Question 30.
Write the name of any four materials found is initial filterate.
Answer:

1. Glucose
2. Amino acid
3. Salt
4. Water.

Question 31.
Write the name of any two plant waste products, where these products are stored?
Answer:
Resin and gum. These waste products are stored specially is old xylem tissues.

Question 32.
What is called the artificial method by which excretory materials are removed from the body of file patient?
Answer:
The artificial method by which excretory materials are removed from the body of patient is called Haemodialysis.

Question 33.
What is called the blood filterate? Write its one speciality.
Answer:
Filterate of blood is known as lymph. It does not consist red blood cells.

Question 34.
If a hole is developed in human diaphragm then what will be the effect on respiratory process?
Answer:
If hole is developed in human diaphragm then breathing process will stopped.

Question 35.
What is the residual volume?
Answer:
After forced expiration the remaining quantity of air in lungs is called residual volume.

Short Answer Type Questions

Question 1.
Describe and draw diagram of the nutrition method in Amoeba.
Answer:
Amoeba takes in food using temporary finger like extensions of the cell surface which fuse over the food particle forming a food-vacuole. Inside the food-vacuole, complex substances are broken down into simpler ones which then diffuse into the cytoplasm. The remaining undigested material is moved to the surface of the cell and thrown out.

Nutrition in Amoeba

Question 2.
What happens to the carbo-hydrates which are not used immediately after photosynthesis by plants? What similar situation is seen in our body?
Answer:
The carbohydrates which are not used immediately are stored in the form of starch, which serves as the internal energy reserve to be used as and when required by the plant. A somewhat similar situation is seen in us where some of the energy derived from the food we eat is stored in our body in the form of glycogen.

Question 3.
How does the process of photosynthesis in desert plants differ from other plants ?
Answer:
Desert plants take up carbon dioxide at night and prepare an intermediate which is acted upon by the energy absorbed by the chlorophyll during the day. Whereas the other normal plants the process of photosynthesis is completed in the day itself.

Question 4.
How nitrogen is important for plants ? How plants obtain them ?
Answer:
Nitrogen is an essential element used in the synthesis of proteins and other compounds. This is taken up in the form of inorganic nitrates or nitrites. Or it is taken up as organic compounds which have been prepared by bacteria from atmospheric nitrogen.

Question 5.
What is the difference in vein and artery?
Answer:
Differences in Vein and Artery –

Vein	Artery
1. Carry the blood from organs to heart or carry towards heart.	Carry away the blood from heart to organs.
2. Except lung veins, all veins contain de-oxyganated blood.	Except the lung arteries which goes to lungs, all contain oxygeneted blood.
3. It has low blood pressure.	It has high blood pressure.
4. Its wall is thin.	Wall is thick and elastic.
5. Its outer layer thick.	Its middle layer (Tunica media) is thick.
6. Due to thin wall the empty veins get shrink.	Due to thick wall the empty artries does not shrink.
7. Mostly veins present surface.	Mostly veins
8. Inside valves present	No
9. Colour of vein are dark red blue.	No

Question 6.
What is single circulatory system? Explain with example.
Answer:
Single circulatory system:
Blood goes only once through die heart in one complete cycle in the body, called single circulatory system. This type of circulation found in fishes. There are two chambers in the heart of a fish, to which call auricle and ventricle. The heart pumps this deoxygeneted blood to gills. Gills are the organ for respiratory exchange in fish, so blood gets oxygeneted in gills. This oxygeneted blood is then sent to different body parts directly. In this way blood goes only once through the heart in fish during one complete cycle.

Question 7.
What are the autotrophic plants? Draw diagram of transverse section of leaf.
Answer:
Autotrophs:
Those plants which are able to synthesize their food in presence of sunlight with the help of chlorophyll by taking water and CO₂ called autotrophs.

Transverse section of a leaf

Question 8.
What is fluid connective tissue? Write its functions
Answer:
Blood is called fluid connective tissue. The blood has following functions—

1. Haemoglobin present in red blood cells of blood, transport the 02 and C02.
2. Blood transports digested and absorbed material to different cells.
3. Blood helps in maintaining the body temperature.
4. Blood clotting capacity, is present in blood, therefore, protect us from blood loss during an injury.
5. Transport of hormone.
6. Blood provide immunity.

Question 9.
Explain how Paramoecium obtain their nutrition ?
Answer:
In Paramoecium, which is also a unicellular organism, the cell has a definite shape and food is taken in at a specific spot. Food is moved to this spot by the movement of like which cover the entire surface of the cell.

Question 10.
On what does the length of the small intestine depends in different organisms ? Explain by giving example.
Answer:
The length of the small intestine differs in various animals depending on the food they eat. Herbivores eating grass need a longer small intestive to allow the cellulose to be digested. Meat is easier to digest, hence carnivores like tigers have a shorter small intestine.

Question 11.
What is Bile Juice ? Explain its role in digestion.
Answer:
The digestive juice secreated by liver is called bile juice. Its role in digestion is as follows –
1. The food coming from the stomach is acidic and has to be made alkaline for the pancreatic enzymes to act. This function is done by bile juice.

2. Fats are present in the intestive in the form of large globules which makes it difficult for enzymes to act on them. Bile salts break them down into smaller globules increasing the efficiency of enzyme action.

Question 12.
What are the two specility found in human blood circulatory system?
Answer:
The following two specialities are found in blood circulatory system of human –
1. Oxygeneted blood and deoxygeneted blood never found in heart and blood vessels that is it always remain separate.

2. To complete the one cycle of blood in body, blood passes twicely through the heart. First time all deoxygeneted blood of body comes to right atrium and ventrical and pass to lungs. Second time oxygeneted blood from lungs to lung veins comes to left atrium, then comes to left ventricle and then passes through aorta which goes to whole body.

Question 13.
Explain human heart with the help of a labelled diagram.
Answer:
The heart is a muscular organ which is as big as our first. Because both oxygen and carbon dioxide have to be transported by the blood, the heart has four different chambers to prevent the oxygen rich blood from mixing with the blood containing carbon dioxide.

Oxygen-rich blood from the lungs comes is the thin walled upper chamber of the heart on the left, the left atrium. The left atrium relaxes when it is collecting this blood. It them contracts, while the next chamber, the left ventricle, relaxes, so that the blood is transferred to it. When the muscular left ventricle contracts in its turn, the blood is pumped out to the body. Deoxygenated blood comes from the body to the upper chamber on the right, the right atrium, as it relaxes.

As the right atrium, contracts, the corresponding lower chamber, the right ventricle, dilates. This transfers blood to the right ventricle, which is turn pumps it is the lungs for oxygenation. Since ventricles have to pump blood into various organs, they have thicker muscular walls than the atria do. Values ensure that blood does not flow backwards when the atria or ventricls, contract.

Longitudinal section of human heart

Question 14.
Describe the blood vessels found in human.
Answer:
There are three types of blood vessels found in human –
1. Arteries: Arteries carry blood from heart to all parts of the body. The blood flows in with a high pressure so the wall of arteries are thick and elastic.

2. Veins: They carry blood from all body parts to the heart. Veins are thin walled vessels. Their lumen (cavity) is wider and blood does not flow with pressure. Veins have valves to prevent the back flow of blood or to allow the blood to flow in one direction only.

3. Capillaries: On reaching an organ or tissue, the artery divides into smaller and smaller vessels to bring the blood in contact with all the individual cells. The smallest vessels have walls which are one cell thick and are called capillaries. Exchange of material between the blood and surrounding cells take place across this thin wall. The capillartes then join together to form veins that convey the blood away from the organ or tissue.

Question 15.
What are heterotrophs? What are the types? Give the description of each.
Answer:

1. Heterotrophs: Animals (including human) can not make their own food and depend directly or indirectly for food on others, called heterotrophs. They are of five types –
2. Herbivores: The animals which directly depend on plants are called herbivores. Example cow, goat etc.
3. Carnivores: They feed on other animals are called carnivores. Ex. Lion, tiger etc.
4. Saprophyte: Bacteria and fungi like organsims, obtain their food from decaying organic matter, called saprophytes.
5. Parasites: Some organisms obtain their nutrition without killing the plants and animals, called parasites. Ex. Cuscuta, lice, ticks, tapeworm, orchids etc.
6. Omnivores: Those organisms which eat both plants and animals, called omnivores. Ex. rat, pig, human etc.

Question 16.
What is ‘villi’ ? Write its importance.
Answer:
The inner living of the small intestive has numerous finger-like projec¬tions called villi which increae the surface area for absorption. The villi are richly supplied with blood vessels which take the absorbed food to each and every cell of the body, where it is utilised for obtaining energy, building up new tissues and the repair of old tissues. The unabsorbed food is sent into the large intestine where its wall absorb more water from this material.

Question 17.
Write difference in blood and lymph.
Answer:
Differences between blood and lymph –

Blood	Lymph
Usually red colou-red.	Colourless.
Contains red blood cells.	Contains white blood cells.
Consist high quantity of protein.	Comparatively have low quantity of protein.
Comparatively consist less amount of digested food.	Comparatively consist high amount of digested food.
More fibronogen is present.	Less quantity of fibronogen.
More oxygen.	Less oxygen.
Contain	Contain
Excess neutrophils.	Excess lymphocytes.
It is a common fluid connective.	It is filterate blood.

Question 18.
Explain the cause of cramps in muscle.
Answer:
Sometimes, when there is a lack of oxygen in our muscle cells, another pathway for the breakdown of pyruvate is taken. Here the pyruvate is converted into lactic acid which is also a three-carbon molecule. This build up of lactic acid in our muscles during sudden activity causes cromps.

Question 19.
Why the rate of breathing in aquatic organisms is much faster than terrestrial organisms ?
Answer:
Animals that live in water need to use the oxygen dissolved in water. Since the amount of dissolved oxygen is fairly low compared to the amount of oxygen in the air, the rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms.

Question 20.
What is ‘hypertension’ ? Write its causes and side effects.
Answer:
High blood pressure is also called hypertension and is caused by the constriction of arterioles, which results in increased resistance to blood flow. It can lead to the rupture of in artery and internal bleeding.

Question 21.
Write the functions of liver.
Answer:
Functions of liver –

1. It synthesize the bile juice.
2. Liver cells synthesise the urine.
3. Liver’ cells secretes the heparin protein which prevent to clot the blood in arteries.
4. Emulsification of fat.
5. Liver cells convert the excessive amount of glucose into glycogen and stored it. This process is known as glycogenesis.
6. Liver also detoxifying the toxic substances which develop in body.

Question 22.
Compare the open and closed circulatory system.
Answer:
Comparison in closed and open circulatory system –

Closed circulatory system	Open circulatory system
1. Such blood circulatory system in which blood flows in closed tubes,	That blood circulatory system in which blood does not flow totally in closed tubes called open circulatory system.
2. Blood does not contain to tissues.	Blood remain in contact to tissues.
3. Blood flow is fast.	Blood flow is sloe.
Example — Human, earthworm, rabbit.	Example—Insects,cockroach, spiders, unio etc.
Closed circulatory system	Open circulatory system

Question 23.
What is blood pressure? What is the value of normal blood pressure and by which instrument it is measured?
Answer:
Blood pressure: The force that , blood exerts against the wall of a vessel is called blood pressure. This pressure is much greater in arteries than in veins. The pressure of blood inside the artery during ventricular systole (contraction) is called systolic pressure and pressure in artery during ventricular diastole (relaxation) is called diastolic pressure. The normal systolic pressure is about 120 mm of Hg and diastolic pressure is 80 mm of Hg. Blood pressure is measured with an instrument called sphygmomanometer.

Question 24.
How is smoking injurious to health ? Explain.
Answer:
Lung cancer is one of common causes of death in the world. The upper part of respiratory tract is provided with small hair – like structures called cilia. These cilia help to remove germs, dust and other harmful particles from inhaled air. Smoking destroys these hair due to which germs, dust, smoke and other harmful chemicals enter lungs and cause infection, cough and even lung cancer.

Question 25.
Why do animals need respiratory pigments to transport oxygen?
Answer:
When the body size of animals is large, the diffusion pressure alone cannot take care of oxygen delivery to all parts of the body. Instead, respiratory pigments take up oxygen from the air in the lungs and carry it to tissues which are deficient in oxygen before releasing it. In human beings, the respiratory pigment is haemoglobin which has a very high affinity for oxygen.

Question 26.
Explain anaerobic respiration by means of chemical equation.
Answer:
Anaerobic respiration: This respiration takes place in absence of oxygen. This type of respiration takes place in yeast, bacteria, parasites and some lower level animals, which does not get free oxygen of atmosphere. Due to absence or deficiency of oxygen glucose convert in ethyl alcohol or lactic acid. It results in formation of less amount of energy. This process is also called sugar fermentation.

Question 27.
What is transpiration? Write its imporatnce.
Answer:
Transpiration: The loss of water in the form of vapour from the aerial parts of the plant is known as transpiration.
Importance of transpiration:

1. Transpiration helps to keep the turgidity of cells.
2. By transpiration water and mineral salts moves in plant.
3. Even in high temperature the transpiration keeps the plant and leaves cool.
4. Excess water can be rid of.

Question 28.
Write the differences in respiration and photosynthesis.
Answer:
Differences in respiration and photosynthesis –

Respiration	Photosynthesis
Sugar is broken down.	Sugar
It occurs in	Only takes place in light (day).
O2 is utilized	In this process CO2 and H2O utilized and O2 is produced.
H2O and CO2 produced.	It takes place only in chlorophyll containing cells.
It takes place in all living cells.	It takes place only in chloroplast of the cell.

Question 29.
What is lymph? Write functions of lymph.
Answer:
Through the pores present in the walls of capillaries some amount of plasma, proteins and blood cells escape into intercellular spaces in the tissues to form the tissue fluid or lymph. It is similar to the plasma of blood but colourless and contain less protein.
Functions of Lymph –

• Lymph carries digested and absorbed fat from intestine.
• Lymph drains excess fluid from extra cellular space back into the blood.

Question 30.
Why do plants have slow transport system ?
Or
Why pumping system as in animals (like heart) is not found in plants ?
Answer:
Energy needs differ between different body designs. Plants do not move, and plant bodies have a large proportions of dead cells in many tissues. As a result, plants have low energy needs, and can use relatively show transport systems.

Question 31.
Usually what types of respiration is found in animals? Explain the energy production by chemical equations.
Answer:
Usually aerobic respiration is found in animals. This respiration takes place in presence of oxygen. In this type of respiration glucose is broken down in presence of atmospheric oxygen, in the result carbon dioxide, water and more quantity of energy is produced.
C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O + energy
Thus, in the respiration animal takes oxygen from atmosphere and release carbon dioxide.

Question 32.
What is dental caries? Explain.
Answer:
Dental caries:
Dental caries or tooth decay causes gradual softening of enamel and dentine. It begins when bacteria acting on sugars produce acids that softens or demineralises the enamel. Masses of bacterial cells together with food particles stick to the teeth to form dental plaque. Saliva cannot reach the tooth surface to neutralise the acid as plaque covers the teeth. Brushing the teeth after eating removes the plaque before the bacteria produce acids. If untreated, microorganisms may invade the pulp, causing inflammation and infection.

Question 33.
Why is there a difference in the number of chambers in different animals ? Explain.
Answer:
The separation of the right side and the left side of the heart is useful to keep oxygenated and deoxygenated blood from mixing. Such separation allows a highly efficient supply of oxygen to the body. This is useful in animals that have high energy needs, such as birds and mammals, which constantly use energy to maintain their body temperature. In animals that do not use energy for this purpose, the body temperature depends on the temperature in the environment. Such animals, like amphibians or many reptiles have three chambered hearts, and tolerate some mixing of the oxygenated and de-oxygenated blood streams. Fishes, on the other hand, have only two chambers to their hearts.

Question 34.
What is plasma ? How it works?
Answer:
Blood consists of a fluid medium called plasma in which the cells are suspended.
Work of Plasma: Plasma transports food, carbon dioxide and nitrogenous wastes in dissolved form.

Question 35.
How ATP is formed ?
Answer:
ATP is the energy currency for most cellular processes. The energy released during the process of respiration is used to make an ATP molecule from ADP and inorganic phosphate.

Endothermic processes in the cell then use this ATP to drive the reactions.

Question 36.
What is the role of mucus in the stomach of human?
Answer:
Role of mucus in stomach: The secreted digestive juice by digestive glands of stomach contain HCl acid and enzymes as well as mucilage. In normal condition the mucus protects the inner lining of the stomach from the action of acid. Due to this the tissues of alimentary canal can’t be digested.

Question 37.
Why leaves are called photosynthetic organ?
Answer:
Because the process of photosynthesis from begining to end takes place in chloroplast and chloroplasts are packed in pallisade and spongy parenchyme of leaves, so leaves are called photosynthetic organs.

Question 38.
What is blood and its which component help in gaseous transport?
Answer:
Blood is a fluid connective tissue. It consist a liquid medium in which cells are suspended, called plasma. By means of blood materials are transported inside the body from one place to another. The haemoglobin present in red blood cells transport the respiratory gases (O₂ and CO₂) inside the body.

Question 39.
What will happen if the blood vessels starts flowing blood ? How it can be stopped ?
Or
Explain the maintenance process by platelets ?
Answer:
If bleeding from the blood vessel starts, then there will be deficiency of blood in the body, which would reduce the carrying of oxygen and other substances. In addition, leakage would lead to a loss of pressure which would reduce the efficiency of the pumping system. To avoid this, the blood has platelet cells which circulate around the body and plug these leaks by helping to clot the blood at these points of injury.

Question 40.
What is the photosynthesis? Describe the various events occur during this process.
Answer:
Photosynthesis: By taking water and carbon dioxide in chlorophyll containing plant cell in presence of sunlight the formation of simple carbonic material is known as photosynthesis. In the process oxygen and water form as a by-product.

During this process the following events occur –

1. Light energy is absorbed by chlorophyll.
2. Conversion of light energy into chemical energy and reduction of water molecules into hydrogen and oxygen.
3. Reduction of carbon dioxide into carbohydrate.

Essay Type Questions

Question 1.
What is stomata? Describe the mechanism of its opening and closing.
Answer:
Stomata: There are numerous small pores are found on the epidermis of the leaf, called stomata. Most of the gaseous exchange for photosynthesis takes place by these pores. There is sufficient amount of water loss by these pores. Thus, when carbon dioxide is not required for photosynthesis then plant closes these pores. The opening and closing of stomata depend on guard cells. The outer wall of guard cells is thin and inner wall is thick.

(a) Open and (b) closed stomatal pore
The guard cells swell when water flows into them causing the stomata pore to open. Similarly the pore closes if the guard cells shrink.

Question 2.
Describe and draw labelled diagram of respiratory system of human.
Answer:
In human beings, air is taken into the body through the nostrils. The air passing through the nostrils is filtered by fine hairs that line the passage. The passage is also lined with mucus which helps in this process. From here, the air passes through the throat and into the lungs. Rings of cartilage are present in the throat. These ensure that the air – passage does not collapse.

Within the lungs, the passage divides into smaller and smaller tubes which finally terminate in balloon – like structures which are called alveoli (singular-alveolus). The alveoli provide a surface where the exchange of gases can take place. The walls of the alveoli contain an extensive network of blood-vessels.

Human respiratory system

Question 3.
Describe the working mechanism of human respiratory system.
Answer:
Within the lungs, the passage divides into smaller and smaller tubes which finally terminate in balloon-like structures which are called alveoli. The alveoli provide a surface where the exchange of gases can take place. The walls of the alveoli contain an extensive network of blood-vessels. When we breathe in, we lift our ribs and flatten our diaphragm, and the chest cavity becomes larger as a result. Because of this, air is sucked into the lungs and fills the expanded alveoli. The blood brings carbon dioxide from the rest of the body for release into the alveoli, and the oxygen in the alveolar air is taken up by blood in the alveolar blood vessels to be transported to all the cells in the body. During the breathing cycle, when air is taken in and let out, the lungs always contain a residual volume of air so that there is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released.

Question 4.
The amount of carbon dioxide released during expiration is more than the amount of carbon dioxide present in atmosphere. Explain.
Answer:
Experiment: Take freshly prepared lime water in a test tube. Blow exhaled air from mouth into the lime water with the help of a glass tube as shown in figure. We observe that lime water turns milky within short period of time.
We take another test-tube. Take same amount of freshly prepared lime water in the test-tube.
We observe that lime water take more time to turns milk.
By this it is proved that the amount of exhaled carbon dioxide is more than the amount of carbon dioxide present in air. Due to this reason in test tube (a) lime water turns milky within short period of time.
So we’can say that CO₂, gas comes out during respiration.

(a) Air being passed into lime water with a pichkari/syringe.
(b) air being exhaled into lime water

Question 5.
How the heart is pump the blood, explain with the help of a labelled diagram.
Answer:
Human heart working is like a pump because both lateral part (right part and left part) are not in contact, so heart is working like two pumps together. Both parts are independent but work together.
Oxygen-rich blood from the lungs comes to the thin-walled upper chamber of the heart on the left. The left atrium. The left atrium relaxes when it is collecting this blood. It then contracts, while the next chamber the left ventricle, expands, so that the blood is transferred to it. When the muscular left ventricle contracts in its turn, the blood is pumped out to the body.

De-oxygenated blood comes from the body to the upper chamber on the right, the right atrium, as it expands. As the right atrium contracts, the corresponding lower chamber, the right ventricle, dilates. This transfers blood to the right ventricle, which in turn pumps it to the lungs for oxygenation. Since ventricles have to pump blood into various organs, they have thicker muscular walls than the atria do. Valves ensure that blood does not flow backwards when the atria or ventricles contract.

Question 6.
What is digestion? Describe the digestion process in human.
Answer:
Digestion: The process of conversion of complex nutrient material by hydrolysis into simple nutrient material is called digestion.
(1) Mouth:
Naturally the food has to be processed to- generate particles which are small and of the same texture. This is achieved by crushing the food with our teeth. Since the lining of the canal is soft, the food is also wetted to make its passage smooth. This work is done by a fluid called saliva secreted by the salivary glands. The saliva contains an enzyme called salivary amylase that breaks down starch which is a complex molecules to give simple sugar. The good is mixed thoroughly with saliva and moved around the mouth while chewing by the muscular tongue.

(2) Oesophagus:
It is necessary to move the food in a regulated manner along the digestive tube so that it can be processed properly in each part. The lining of canal has muscles that contract rhythmically in order to push the food forward. These peristaltic movements occur all along the gut. From the mouth, the food is taken to the stomach through the food-pipe or oesophagus.

(3) Stomach:
The stomach is a large organ which expands when food enters it. The muscular walls of the stomach help in mixing the food thoroughly with more digestive juices. The digestion in stomach is taken care of by the gastric glands present in the wall of the stomach. These release hydrochloric acid, a protein digesting enzyme called pepsin, and mucus. The hydrochloric acid creates an acidic medium which facilitates the action of the enzyme pepsin.

(4) Small Intestine:
The exit of food from the stomach is regulated by a sphincter muscle which releases it in small amounts into the small intestine. From the stomach, the food now enters the small intestine. This is the longest part of the alimentary canal which is filted into a compact space because of extensive coiling. The length of the small intestine differs in various animals depending on the food they eat.

The small intestine is the site of the complete digestion of carbohydrates, proteins and fats. It receives the secretions of the liver and pancreas for this purpose. The food coming from the stomach is acidic and has to be made alkaline for the pancreatic enzymes to act. Bile juice from the liver accomplishes this in addition to acting on fats. Fats are present in the intestine in the form of large globules which makes it difficult for enzyme to act on them. Bile salts break them down into smaller globules increasing the efficiency of enzyme action.

The pancreas secretes pancreatic juice which contains enzymes like trypsin for digesting proteins and lipase for breaking down emulsified fats. The walls of the small intestine contain glands which secrete intestinal juice. The enzyme present in it finally convert the proteins to amino acids, complex carbohydrates into glucose and fats into fatty acids and glycerol. Digested food is taken up by the walls of the intestine. The inner living of the small intestine has numerous finger-like projections called villi which increase the surface area for absorption.

(5) Large Intestine: The unabsorbed food is sent into the large intestine where its wall absorb more water from this material. The rest of the material is removed from the body via the amus.

Question 7.
Draw labelled diagram of human digestive system and explain the digestion process in stomach.
Answer:
Figure of digestive system in human –

Human digestive system

Question 8.
Draw labelled diagram of human excretory system. Explain the mechanism of expelling the nitrogenous excretory material from blood.
Or
With the help of a labelled diagram of human excretory system explain the process of urine formation.

Answer:
The purpose of making urine is to filter out waste products from the blood. Just as CO₂is removed from the blood in the lungs, nitrogenous waste such as urea or uric acid are removed from blood in the kidneys. It is then no surprise that the basic filtration unit in the kidneys, like in the lungs, is a cluster of very thin-walled blood capillaries. Each capillary cluster in the kidney is associated with the cup-shaped end of a coiled tube called Bowman’s capsule that collects the filtrate. Each kidney has large numbers of these filtration units called nephrons packed close together.

Some substances in the initial filtrate, such as glucose, amino acids, salts and a major amount of water, are selectively reabsorbed as the urine flows along the tube. The amount of water reabsorbed depends on how much excess water there is in the body, and on how much of dissolved waste there is to be excreted. The urine formation in each kidney eventually enters a long tube, the ureter, which connects the kidneys with the urinary’ bladder. Urine is stored in the urinary’ bladder until the pressure of the expanded bladder leads to the urge to pass it out through the urethra.

Excretory system in human beings

Question 9.
What is hemodialysis? Explain its mechanism.
Answer:
Dialysis (Hemodialysis): Some-times infection or restricted blood flow or other reasons the kidney damaged and stop the working. In such situation the amount of nitrogenous waste products (urea) increases in the blood. An artificial kidney is a device to remove nitrogenous waste products from the blood is called dialysis.

Mechanism of dialysis: Artificial kideny contains a number of tube with a semi- permeable lining, suspended in a tank filled with dialysing fluid. This fluid has the same osmotic pressure as blood, except that it is devoid of nitrogenous wastes. The patient’s blood is passed through these tubes. During this passage, the waste products from the blood pass into dialysing fluid by diffusion. The purified blood is pumped back into the patient. This is similar to the function of the kidney, but it is different since there is no reabsorpfion involved.
Normally, in a healthy adult, the initial filtrate in the kidneys in about 180L daily. However, the volume actually excreted in only a litre or two a day, because the remaining filterate is reabsorbed in the kidney tubules.

Question 10.
Organ donation is a generous act. Explain.
Answer:
Organ donation is a generous act of donating an organ to a person who suffers from non-function of organ(s). Donation of an organ may be done by the consent of the donor and his/her family. Anyone regardless of age or gender can become an organ or tissue donor. Organ transplants can save or transform the life of a person. Transplantation is required because recipient’s organ has been damaged or has failed by disease or injury. In organ transplantation the organ is surgically removed from one person (organ donor) and transplanted to another person (the recipient). Common transplantations include corneas, kidneys, heart, liver, pancreas, lungs, intestine and bone marrow. Most organ and tissue donations occur just after the donor has died or when the doctor declares a person brain dead. But some organs such a kidney, part of a liver, lung, etc., and tissues can be donated while the donor is alive.

Question 11.
What is life process? Describe the important essential process of maintenance of life.
Answer:
Life process: The processes which together perform the maintenance job are called life processes. Description of essential processes of maintenance of life is as follows –
(1) Nutrition:
Maintenance processes are needed to prevent damage and breakdown, energy is needed for them. This energy comes from outside the body of the individual organism. So there must be a process to transfer a source of energy from outside the body of the organism, which we call food, to the inside, a process we commonly call nutrition. If the body size of the organisms is to grow, additional raw material will also be needed from outside. Since life on earth depends on carbon-based molecules, most of these food sources arealso carbon-based. Depending on the complexity of these carbon sources, different organisms can then use different kinds of nutritional processes.

(2) Respiration:
The sources of energy, therefore, need to be broken down or built up in the body, and must be finally converted to a uniform source of energy that can be used for the various molecular movements needed for maintaining living structures, as well as to the kind of molecules the body needs to grow. For this, a series of chemical reactions in the body are necessary. Oxidising-reducing reactions are some of the most common chemical means to break-down molecules. For this, many organisms use oxygen sourced from outside the body. The process of acquiring oxygen from outside the body, and to use it in the process of break-down of food sources for cellular needs, is what we call respiration.

(3) Transportation: Food and oxygen takenup by some special organs but all parts of the body need them. This situation creats a need for a transportation system for carrying food and oxygen from one place to another in the body.

(4) Excretion: When chemical reactions use the carbon source and the oxygen for energy generation, they create by-products that are not only useless for the cells of the body, but could even be harmful. These waste by-products are therefore needed to be removed from the body and discarded outside by a process called excretion.

Question 12.
With the help of experiment prove that the presence of chlorophyll is essential for the process of photosynthesis.
Answer:
Experiment –

VarIegated leaf (a) before and (b) after starch test

Firstly we take a variegates leaf from croton plant, with the help of pensil mark the green and white areas of the leaf. Now boil this leaf in water for some time. Dip this boiled leaf in a alcohol containing petridish. The chlorophyll present in leaf dissolved in alcohol and leaf become colourless. Now take out two leaf from alochol and rinse off by water. Keep this leaf on glass plate and cover by iodine solution. After some time take out the leaf and rins off with water and observe, the green areas of leaf turns into blue colour, but white areas not turned into blue colour.

The reason is this that in green part chlorophyll is present and in this starch is formed, so this part turns blue due to iodine solution because this is the property of iodine solution that it turns blue to starch particles. The absence of chlorophyll in white part does not form starch so they did not turn blue by iodine solution. So it is proved that presence of chlorophyll is essential for the photosynthesis process.