Life processes class 10 ncert solutions(intext and Exercise)
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NCERT intext Solutions
Page 81 Question 1
Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans? Solution:
The body structure of multicellular organism such as humans is very complex design. They comprised of specialized cells and tissues for performing various important functions of the body. Unlike the unicellular organisms, multicellular organisms are not in the direct contact with surrounding environment. Therefore, simple diffusion will not meet the oxygen requirement of all the cells and tissues.
What criteria do you use to decide whether something is alive? Solution:
Movement of various type such as walking, breathing or growing which are visible to us can be taken as an indication of life. However a living organism can also have movements which are not visible to the naked eye. So, the presence of life process is the fundamental criteria that are used to decide whether something is alive or not.
What are outside raw materials used by an organism? Solution:
(i)food for providing energy
(ii)Oxygen for breakdown of food to obtain energy
(iii) Water for proper digestion of food and water functions inside the body.
What process would you consider essential for maintaining life? Solution:
Life process which are essential
Page 87 Question 5
What are the difference between autotrophic nutrition and heterotrophic nutrition? Solution:
Where do the plants get each of the raw materials required for photosynthesis? Solution:
Plants need the following things for photosynthesis:
(i) Plants get $CO_2$ from atmosphere through stomata
(ii)Plants absorbed water from soil through roots and transport to leaves.
(iii)Sunlight, which absorbed by the chlorophyll and other green parts of the plant.
What is role of acid in our stomach? Solution:
Roles of acid in our stomach are-
(i) It makes an acidic medium in our stomach which is necessary for activation of pepsin enzyme.
(ii) It kills germ present in the food.
What is function of digestive enzymes? Solution:
Digestive enzymes such as amylase, lipase, trypsin, etchelp to break the complex food particles into simple ones so that these simple particles can be easily absorbed by the blood and thus transported to all the cells of the body.
How is the small intestine designed to digested food? Solution:
The inner line of small intestine has millions of tiny finger-like projection called villi. These villi increase the surface area for absorption of food. These villi is richly supplied with food vessels which take the absorbed food to each and every cell of the body, where it is used for obtaining energy building up new tissues and repairing old tissues.
Page 91 Question 10
What advantage over an aquatic organism does a terrestrial organism have with regard to obtain oxygen for respiration? Solution:
Terrestrial like organisms take up oxygen from atmosphere whereas aquatic animals that live in water use oxygen dissolved in surrounding water. Since, air is dissolved in water has fairely low concentration of oxygen, the aquatic organisms has to breath faster to get more oxygen. Terrestrial organisms take oxygen from the oxygen rich atmosphere so, they much less breathing rate than aquatic organism.
What are different ways in which glucose is oxidized to provide energy in various organisms? Solution:
Glucose is broken down into three carbon molecule called pyruvate in the cell cytoplasm . Pyruvate is then further broken down by different ways to provide energy in various organism. Pyruvate is broken down in different ways on different organism is shown in the figure.
In yeast cells during fermentation pyruvate is converted into ethanol and carbon dioxide in the absence of oxygen.
In mitochondria, breakdown of pyruvate takes place in presence of oxygen to give rise 3 molecules of carbon dioxide and water.
Sometimes, when there is lack of oxygen, especially during vigorous activity, in our muscles, pyruvate is converted into lactic acid.
How are oxygen and carbon dioxide transported in human beings? Solution:
How are lungs designed in human beings to maximize area for exchange of gases? Solution:
In the lungs, the wind pipe branches into bronchi which in turn branches into bronchioles which finally terminate in balloon like structures called alveoli. Each lungs contains about 300-350 millions alveoli. The alveoli provides maximum surface for exchange of gases. The alveoli have very thin walls and are surrounded by an extensive network of blood vessels to facilitate exchange of gases.
Page 96 Question 14
What are the components of the transport system in human beings? Solution:
The components of the transport system in human beings are heart, blood, and blood vessels.
(i) Heart receives deoxygenate blood from various body parts of the body and sends this impure blood to the lungs for oxygenation. After receiving the oxygenated blood it pump oxygenated blood to all the parts of the body.
(ii) Blood helps in transport of oxygen, nutrients, Carbon dioxide, and nitrogenous wastes throughout the body. WBC helps in protects the body against the infection and disease.
(iii) The blood vessels (arteries, veins, and capillaries) help in circulating blood all throughout the body.
Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds? Solution:
Warm- blooded animals such as birds and mammals maintain constant body temperature by cooling themselves when they are in a hotter environment and by warming their bodies when they are in a cooler environment. It is therefore necessary to separate oxygenated and deoxygenated blood to maintain efficient supply of oxygen into the body. Hence, these animals require more oxygen for more cellular respiration so that they can produce more energy to maintain their body temperature
What are components of the transport system in highly organized plants? Solution:
The components are
(i) Xylem:helps to conduct water and minerals obtained from the soil to the rest of the plant.
(ii) Phloem:transports the food materials from the leaves to different parts of the plant body.
How water and minerals care transported in plants? Solution:
Water and minerals transported through xylem cells from soil to the leaves. The xylem cells of the roots stem and leaves are interconnected to form a conducting channel that reaches all parts of plant. Because of transpiration, a suction pressure is created as a result of which water is forced into the xylem cells of roots. From xylem cells of the roots a steady movement of water takes place through the interconnected water- conducting channels.The effect of root pressure for transportation in plants is more important in night while during day time transpiration pull becomes the major driving force.
How is the food transported in plants? Solution:
Phloem transported food materials from leaves to different parts of the plant body. Food is transported in dissolved form. This is called translocation. The transportation of food in phloem is achieved by utilizing energy from ATP. This energy increases the osmotic pressure, as a result, water from outside moves into the phloem. This pressure maintains the movement of food through all the parts of plants.
Page 968 Question 19
Describe the structure and functioning of nephron. Solution:
Nephrons are the basic filtering units of kidneys. Each kidney processes large number of nephron, approximately 1-1.5 million. The components of the nephron are
Long renal tubule.
Functioning of a nephron:
(i) The blood enters the kidney through the renal artery, which braches into many capillaries associated with glomerulus.
(ii) The water and solute are transported to the nephron at Bowman’s capsule.
(iii) In the proximal tubule, some substances such as amino acids, glucose, and salts are selectively reabsorbed and unwanted molecules are added in the urine.
(iv) The filtrate then moves down into the loop of Henle, where more water is absorbed.
(v) From here, the filtrate moves upwards into the distal tubule and finally to the collecting duct. Collecting duct collect urine from many nephrons.
What are methods used by the plants to get rid of excretory product? Solution:
Plants used the below ways to get rid of excretory products
Many waste products are stored in vacuoles of the cells.
Some waste products are stored in the leaves and they are removed as the leaves fall off.
Some waste products such as resins, tannins and gums are stored in non-functional old xylem or bark.
Plants also excrete some waste products through roots into the soil around them
Plants get rid of excess water through transportations
How amount of urine is produced regulated? Solution:
The amount of urine produced depends on the amount of excess water and dissolved wastes present in the body. Some other factors such as habitat of an organism and hormone such as Anti-diuretic hormone (ADH) also regulates the amount of urine produced.
NCERT Exercise Solutions
The kidney in human beings is a part of the system for
(d) Transportation. Solution:
(c) Question 23
The xylem in plants is responsible for
(a) Transport of water.
(b) Transport of food.
(c) Transport of amino acids.
(d) Transport of oxygen. Solution:
(a) Question 24
The autotrophic mode of nutrition requires
(a) Carbon dioxide and water.
(c ) sunlight.
(d) all of the above. Solution:
(d) Question 25
The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(d) Nucleus. Solution:
(b) Question 26
How are fats digested in our body? Where this process does takes place? Answer:
Fats are present in form of large globules in the small intestine.
The small intestine gets the secretions in the form of bile juice and pancreatic juice respectively from the liver and pancreas
The bile salts (from the liver) break down the large fat globules into smaller globules so that the pancreatic enzymes can easily act on them.
Lipase enzyme present in the pancreatic juice causes breakdown of emulsified fats.
Glands present in the wall of small intestine secret intestinal juice which contains lipase enzyme that convers fats into fatty acids and glycerol. This is referred to as emulsification of fats. It takes place in the small intestine.
What is the role of saliva in the digestion of food?
Role of Saliva in Digestion
(i)Lubrication: Saliva helps in moistening the food, making it easier to chew and swallow. The mucus in saliva provides lubrication, facilitating the smooth passage of food through the esophagus.
(ii)Enzymatic Action: Saliva contains an enzyme called salivary amylase (or ptyalin), which plays a vital role in the digestion of carbohydrates. This enzyme breaks down complex carbohydrates like starch into simpler sugars like maltose.
(iii)Initiation of Digestion: The enzymatic action of salivary amylase starts the digestion process right in the mouth, even before the food reaches the stomach. This is unique as most of the digestion occurs in the stomach and intestines.
(iv)pH Regulation: Saliva helps in maintaining a neutral pH in the mouth, which is essential for the enzyme's activity and also protects the teeth and oral tissues from acidic or alkaline substances.
(v) Antibacterial Action: Saliva contains lysozymes, which have antibacterial properties, helping in keeping the oral cavity free from infections.
What are the necessary conditions for autotrophic nutrition and what are its byproducts? Question 29
What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration. Answer:
Aerobic Respiration: It occurs in the presence of oxygen and produces carbon dioxide, water, and energy.
Anaerobic Respiration: It occurs without oxygen and produces lactic acid (in muscles) or ethanol and carbon dioxide (in yeast).
The Organism that use the anaerobic mode of respiration
(i)Clostridium Species: These bacteria are known to thrive in oxygen-deprived environments and utilize anaerobic respiration. Clostridium botulinum, for instance, causes botulism.
(ii)Lactic Acid Bacteria: These bacteria, such as Lactobacillus, ferment sugars into lactic acid without the use of oxygen.
How are the alveoli designed to maximise the exchange of gases? Answer:
The alveoli are specialized structures found in the lungs that play a crucial role in the exchange of gases between the air we breathe and the blood. Their design is highly optimized to maximize this exchange, ensuring efficient uptake of oxygen and removal of carbon dioxide. Here's how the alveoli are designed to achieve this
(i)The lungs contain millions of tiny alveoli, creating a vast surface area for gas exchange.A larger surface area allows more oxygen and carbon dioxide to be exchanged at any given time, enhancing the efficiency of the process.
(ii)The walls of the alveoli are extremely thin and The thin walls minimize the distance that gases must travel between the air in the alveoli and the blood in the surrounding capillaries, speeding up the diffusion process.
(iii)The alveoli are surrounded by a dense network of capillaries, which are tiny blood vessels. A rich blood supply ensures that blood is constantly flowing past the alveoli, maintaining a concentration gradient that favors the diffusion of oxygen into the blood and carbon dioxide out of the blood.
What would be the consequences of a deficiency of haemoglobin in our bodies? Answer
The deficiency of hemoglobin makes an individual anemic which means fewer red blood cells.It will decrease the oxygen-carrying capacity of the blood. The decrease in hemoglobin in blood will lead to slow functioning of body parts and weakness due to the less supply of oxygen.
Describe double circulation of blood in human beings. Why is it necessary? Answer Systemic Circulation (Oxygenated Circuit)
This circuit carries oxygenated blood from the heart(left ventricle) to various parts of the body and returns deoxygenated blood to the heart(right atrium).Aorta Carries oxygenated blood from the left ventricle to the body and Vena Cava Returns deoxygenated blood from the body to the right atrium. Pulmonary Circulation (Deoxygenated Circuit)
This circuit carries deoxygenated blood from the heart(Right Ventricle) to the lungs for oxygenation and returns oxygenated blood to the heart(Left Atrium).Pulmonary Artery Carries deoxygenated blood from the right ventricle to the lung and Pulmonary Veins Return oxygenated blood from the lungs to the left atrium.
Why is Double Circulation Necessary?
Separation of Oxygenated and Deoxygenated Blood: Double circulation ensures that oxygen-rich and oxygen-poor blood are kept separate. This allows for efficient oxygen delivery to the tissues and effective removal of carbon dioxide.
Higher Blood Pressure: By separating the pulmonary and systemic circuits, the heart can generate higher pressure for the systemic circulation, ensuring that oxygen and nutrients are delivered effectively to all parts of the body.
Improved Oxygenation: The separation allows the blood to pass through the lungs to become fully oxygenated before being pumped to the rest of the body, enhancing the oxygen-carrying capacity.
What are the differences between the transport of materials in xylem and phloem? Answer
Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.