BSEB Bihar Board Class 10 Science Solutions Chapter 6 Life Processes Textbook Questions and Answers.
Bihar Board Class 10 Science Solutions Chapter 6 Life Processes
Bihar Board Class 10 Science Chapter 6 Life Processes InText Questions and Answers
In-text Questions (Page 95)
Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?
In unicellular organisms, the cell is in direct contact with the environment, so there is no need for specific organs and gaseous exchange occurs by diffusion through the cell surface. But in multicellular organisms, all the cells are not in direct contact with the surrounding environment, so diffusion is not sufficient to quickly transport oxygen into all the cells. Hence, diffusion is insufficient to meet the oxygen requirements of multicellular organisms like humans.
What criteria do we use to decide whether something is alive?
Movement without any external help and cellular organisation are the criteria which help to decide whether an organism is alive or not. Besides this, the metabolic life processes like respiration, transportation, excretion, reproduction are only present in the living organisms.
What are outside raw materials used for by an organism?
Raw materials like nutrients, carbon dioxide, sunlight, water and oxygen are some of the raw materials used by the organisms for the various life processes.
What processes would you consider essential for maintaining life?
Nutrition, respiration, transportation and excretion are the essential processes for maintaining life.
In-text Questions (Page 101)
What are the differences between autotrophic nutrition and heterotrophic nutrition?
- Food is synthesised from simple inorganic raw materials. For example, CO2 and H2O.
- Presence of green pigment (chlorophyll) is necessary.
- Food is prepared in day time.
- All green plants and some bacteria have this type of nutrition.
- Food is obtained directly or indirectly from autotrophs. This food is broken down with the help of enzymes.
- No pigment is required in this type of nutrition.
- Food is prepared at all times.
- All animals and fungi have this type of nutrition.
Where do plants get each of the raw materials required for photosynthesis?
Raw materials required for photosynthesis and their sources are:
Sunlight: Received naturally from the sun.
Chlorophyll: It is present in the chloroplasts of aerial parts of the plant.
Water: Absorbed by roots from the soil.
Carbon dioxide: Comes from atmosphere for terrestrial plants and the water in aquatic plants.
What is the role of the acid in our stomach?
The hydrochloric acid secreted in our stomach plays two roles:
- Creates an acidic medium for the action of protein digesting enzyme called pepsin.
- Kills the harmful germs/bacteria present in the food.
What is the function of digestive enzymes?
The complex organic molecules are broken down by the enzymes into simple, absorbable inorganic molecules. Enzymes are also called as the bio-catalysts as they increase the rate of chemical reactions occurring in the body of an organism.
How is the small intestine designed to absorb digested food?
The small intestine has finger like projections which help to increase the surface area of absorption of nutrients from the digested food into the blood stream. They are supplied with a rich blood supply for the absorption.
In-text Questions (Page 105)
What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
The aquatic organisms utilise the oxygen dissolved in water for respiration. Since the amount of oxygen dissolved in water is low compared to the amount of oxygen in air, the aquatic organisms have to breathe at a faster rate. The terrestrial organism can obtain oxygen more easily than them and breathe at a slower rate.
What are the different ways in which glucose is oxidised to provide energy in various organisms?
Glucose is broken down into pyruvic acid in the cytoplasm by the process of glycolysis. The pyruvic acid is further metabolised on the basis of the following conditions:
- Under anaerobic conditions the pyruvic acid is either degraded into ethanol and carbon dioxide in yeast or into lactic acid in the muscle cells.
- Under aerobic conditions the pyruvic acid is degraded into carbon dioxide and water in mitochondria.
How is oxygen and carbon dioxide transported in human beings?
Oxygen is taken up at the lung surface by the respiratory pigment called haemoglobin present in the red blood corpuscles and transported to the tissue surface. The oxygen is exchanged for carbon dioxide at the tissue surface by haemoglobin and transported to lungs for elimination of carbon dioxide from the body. Haemoglobin has a very high affinity for oxygen.
How are the lungs designed in human beings to maximise the area for exchange of gases?
Lungs have the tube like structures called bronchioles which divide into balloon like structures called alveoli which help to provide a larger surface area for the exchange of gases between them and the blood capillaries. The thin, moist permeable walls of alveoli and the one-cell thick capillary walls help in easy diffusion of gases between them.
In-text Questions (Page 110)
What are the components of the transport system in human beings? What are the functions of these components?
The transport system in human beings comprises of the blood vascular system and the lymphatic system. The blood circulatory system in human beings consists of:
- A pumping organ—a muscular heart.
- Blood vessels—Arteries to carry blood away from heart to various organs of the body; veins to carry blood from various organs of the body towards heart and capillaries for the exchange of materials between blood and various tissues.
- Blood which has red blood cells have respiratory pigment to transport oxygen to various parts of body and remove carbon dioxide.
White blood cells help to provide immunity from diseases. Blood platelets help in clotting of blood on injury. The lymphatic system comprises of lymph, lymph vessel and lymph nodes which help to carry digested and absorbed fat from intestine, drain excess interstitial fluid to the bloodstream. Lymph may pick up bacteria and bring them to lymph nodes where they are destroyed.
Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
The separation of oxygenated and deoxygenated blood prevents their mixing in order to efficiently supply oxygen to the body. It is more important for the mammals and birds as it helps to provide the higher amount of energy required by these animals to maintain a constant body temperature.
What are the components of the transport system in highly organised plants?
The components of transport system in the plants are:
- Xylem composed of tracheids, vessels, xylem parenchyma and xylem fibres which help in the transport of water and minerals in the plants.
- Phloem composed of sieve tubes, companion cells, phloem parenchyma and phloem fibres which help in the transport of the food to various parts of the plant.
How are water and minerals transported in plants?
Transport of Water and Minerals
(i) By root pressure: The cells of root in contact with soil actively take up ions which creates a difference in ion concentration between the root and the soil. Water moves into the root from the soil to eliminate this difference, creating a column of water that is steadily pushed upwards.
(ii) By transpiration pull: Loss of water from stomata by transpiration gets replaced by the xylem vessels in the leaf which creates a suction to pull water from the xylem cells of the roots. This strategy is used during day time and helps to transport water to the highest points of the plant body.
How is food transported in plants?
Transport of food and other substances: Translocation is the transportation of soluble products of photosynthesis through phloem. Sucrose is transferred into sieve tubes of phloem via the companion cells using energy from ATP. This increases the osmotic pressure inside the sieve tubes which causes movement of water into the sieve tubes from the adjacent xylem. This pressure helps in translocation of material in the phloem to tissues which have less pressure.
In-text Questions (Page 112)
Describe the structure and functioning of nephrons.
The structural and functional unit of a kidney is called the nephron which has two parts—Malpighian body (renal corpuscle) and the renal tubule.
The Malpighian body has a cup shaped structure called as the Bowman’s capsule which encloses a tuft of capillaries called as the Glomerulus. It helps in the filtration of the wastes from the blood.
The renal tubule has convoluted tubules which open into the collecting duct. The useful substances like the glucose, amino acids, minerals, etc. are reabsorbed from the filtrate in the tubular portions and the nitrogenous wastes are poured by the tubules of the nephrons into the collecting duct.
What are the methods used by plants to get rid of excretory products?
The various ways by which plants get rid of excretory waste are:
- Excess oxygen and carbon dioxide removed through stomata,
- Excess water removed by transpiration through stomata.
Plant waste products are also removed by:
- Storage in cellular vacuoles
- Storage in leaves that fall off
- Storing as resins and gums in old xylem
- By excreting into the soil around them.
How is the amount of urine produced regulated?
The amount of urine produced is regulated by the amount of excess water and dissolved wastes present in the body of an organism. If their amount is more, the amount of urine produced will be more. But if their amount is lower in the body then lesser amount of urine will be produced.
Bihar Board Class 10 Science Chapter 6 Life Processes Textbook Questions and Answers
The kidneys in human beings are a part of the system for
The xylem in plants are responsible for
(a) transport of water.
(b) transport of food.
(c) transport of amino acids.
(d) transport of oxygen.
(a) transport of water.
The autotrophic mode of nutrition requires
(a) carbon dioxide and water.
(d) all of the above.
(d) all of the above.
The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
How are fats digested in our bodies? Where does this process take place?
Bile juice secreted by the liver into the small intestine helps to break the large fat globules into small, fine globules by the process called emulsification. These small globules are acted upon by the enzyme lipase present in pancreatic juice and the intestinal juice secreted by walls of the small intestine to convert them into fatty acids and glycerol. These are absorbed by villi and passed on to lacteals which later on drain them into the blood stream.
What is the role of saliva in the digestion of food?
Saliva contains an enzyme called as salivary amylase which helps to break down the starch into maltose.
What are the necessary conditions for autotrophic nutrition and what are its by-products?
Necessary conditions for the autotrophic nutrition (photosynthesis) are the presence of raw materials- carbon dioxide, water, sunlight and chlorophyll. The by-products of this process are oxygen and water.
What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.
The differences between aerobic respiration and anaerobic respiration are:
- It takes place in the presence of air (oxygen).
- It occurs in mitochondria.
- The end products are CO2 and H2O.
- More amount of energy is released.
- It takes place in the absence of air (oxygen).
- It occurs in cytoplasm.
- The end product is either alcohol or lactic acid.
- Lesser amount of energy is released.
Anaerobic respiration occurs in the roots of some waterlogged plants, some parasitic worms, animal muscles and some microorganisms, such as yeast.
How are the alveoli designed to maximise the exchange of gases?
The alveoli are richly supplied with blood vessels and are highly folded balloon like structures which helps to provide a larger surface area for the exchange of gases.
What would be the consequences of a deficiency of haemoglobin in our bodies?
Haemoglobin is the respiratory pigment which has high affinity for oxygen and helps in the transport of oxygen from lungs to the various tissues of the body. If there is deficiency of haemoglobin in the body, then lesser amount of oxygen will reach the tissues and the person will appear pale and will get tired soon.
Describe double circulation in human beings. Why is it necessary?
Birds and mammals have four chambered heart. Blood goes through the heart twice during each cycle in them. This is known as double circulation.
The deoxygenated blood from the various parts of the body is transported to the right atrium by the vena cava. From the right atrium, the blood moves into the right ventricle to be pumped towards lungs by pulmonary artery for oxygenation. The oxygenated blood from lungs returns to the left atrium of the heart by the pulmonary vein. Left atrium sends the blood to left ventricle which pumps the oxygenated blood to the various parts of the body through aorta.
What are the differences between the transport of materials in xylem and phloem?
The differences between the transport of materials in xylem and phloem are:
- Carries water and minerals from the roots to other parts of the plant.
- The elements of xylem are tracheids, vessels, xylem fibres and xylem parenchyma.
- It has dead tissues except the xylem parenchyma.
- The flow is unidirectional.
- No energy is used in transport.
- Carries products of photosynthesis from leaves to other parts of the plant.
- The elements of phloem are sieve tube, companion cells, phloem fibres and phloem parenchyma.
- It has living tissues except the phloem fibres.
- The flow is bidirectional.
- Energy in the form of ATP is used.
Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.
The functioning of alveoli in the lungs and nephrons in the kidneys are as follows:
Bihar Board Class 10 Science Chapter 6 Life Processes Textbook Activities
Activity 6.1 (Textbook Page 96)
The leaf gets decolourised on boiling in alcohol. The colour of the solution becomes green as the chlorophyll gets dissolved in alcohol. On comparing the colour of the leaf, we find that the colour of leaf changes to bluish-black at the regions where chlorophyll was present whereas the regions which did not have chlorophyll remain pale/yellow coloured in iodine solution. So, we can conclude that chlorophyll is necessary for photosynthesis because only the regions where chlorophyll is present are able to photosynthesise and produce starch.
Activity 6.2 (Textbook Page 97)
The leaves of the plant in the bellijar in which potassium hydroxide was present are not able to perform photosynthesis and produce starch whereas the leaves of the plant in the other belljar is able to perform photosynthesis and produce starch. We can conclude from this activity that carbon dioxide is necessary for photosynthesis as the plants which are devoid of carbon dioxide do not contain starch as they are not able to perform photosynthesis.
Activity 6.3 (Textbook Page 99)
No colour change occurs in the test-tube A on addition of iodine as starch is degraded by saliva. The colour changes to bluish-black in test-tube B on addition of iodine as starch is not degraded in it. This activity shows that saliva has a enzyme called salivary amylase which breaks down starch into simpler carbohydrates.
Activity 6.4 (Textbook Page 101)
Lime water turns milky faster in the test tube where air is blown through the mouth. This is because the air we breathe out contains higher levels of carbon dioxide than that present in the air.
Activity 6.5 (Textbook Page 101)
The lime water turns milky after sometime. This shows that Yeast produces carbon dioxide during the process of alcoholic fermentation. The carbon dioxide produced during the process turns the lime water milky.
Activity 6.6 (Textbook Page 103)
This activity shows that the rate of breathing is higher in the aquatic animals as they have to take in the oxygen dissolved in water. Their rate of breathing is higher and faster as compared to human beings.
Activity 6.7 (Textbook Page 105)
Normal results for adults vary, but in general are: Male: 13.8 to 17.2 grams per decilitre (g/dL)
Female: 12.1 to 15.1 g/dL
The range is not same for children and adults. Normal results for children vary, but in general are:
Newborn: 14 to 24 g/dL; Infant: 9.5 to 13 g/dL
Yes, this range is different in calves, male and female animals. The average range of haemoglobin content of cattle is as follows:
Cows: 10 to 15 gm/dL; Bulls: 8 to 12 gm/dL
The differences can be due to the hormonal and physiological differences in males and females.
Activity 6.8 (Textbook Page 108)
The soil in pot with the plant in it will lose its moisture due to which the plastic sheet covering it will have moisture on it. The soil of the pot without the plant will retain its moisture so no moisture will be there on the plastic sheet. This activity shows that the water absorbed by the plants from the soil is transpired by its leaves in the form of water vapour.