Life Processes Chapter
NCERT INTEXT QUESTIONS:
I. Textbook Page No.81
- Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?
Answer:
In multicellular organisms all the body cells are not in direct contact with the surrounding environment. All cells of the body will not get oxygen by the process of diffusion. Hence it will not fulfil the oxygen requirement of all cells of the body as volume of human body and number of cells is high.
life processes class 10
2. What criteria do we use to decide whether something is alive?
Answer:
Movement like locomotion or growth-related movement, movement of body parts like breathing and life processes such as nutrition, excretion are the criteria that we use to decide whether something is alive.
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3. What are outside raw materials used for by an organism?
Answer:
Outside raw materials like food, water and oxygen are used by an organism for maintenance of life. Autotrophic organisms use carbon dioxide, minerals and water as raw materials.
4. What processes would you consider essential for maintaining life?
Answer:
All life processes like digestion, respiration, transportation and excretion are essential for maintaining life.
II. Textbook Page No.87
- What are the differences between autotrophic nutrition and heterotrophic nutrition?
Answer:
| No. | Autotrophic nutrition | Heterotrophic nutrition |
| 1. | Food is prepared from carbon dioxide and water. | Food is obtained from autotrophs directly or indirectly. |
| 2. | Photosynthesis or chemosynthesis occur in this type of nutrition. | Photosynthesis or chemosynthesis does not occur in this type of nutrition. |
| 3. | It is found in green plants and some bacteria | It is found in all animals. |
| 4. | It requires sunlight | It is not dependent on sunlight. |
2. Where do plants get each of the raw materials required for photosynthesis?
Answer:
Raw materials required for photosynthesis are as follows:
i. Water: Plants absorb water from soil through roots.
ii. Carbon dioxide: plants get carbon dioxide from the atmosphere through the stomata of leaves.
iii. Sunlight: It is obtained from the sun.
iv. Chlorophyll: It is present in the leaves and green parts of the plant.
3. What is the role of the acid in our stomach?
Answer: Role of acid in our stomach:
i. It creates acidic medium for the activation of enzyme pepsin.
ii. It kills germs ingested with food.
4. What is the function of digestive enzymes?
Answer: Digestive enzymes break down the complex substances into simple and soluble molecules in the process of digestion.
5. How is the small intestine designed to absorb digested food?
Answer: The small intestine has finger-like processes called villi in the inner lining. They increase surface area for absorption of food. Villi are richly supplied with blood capillaries which take absorbed food to each and every cell of the body.
III. Textbook Page No. 91
- What advantages over an aquatic Organism does a terrestrial Organism have with regard to obtaining oxygen for respiration?
Answer: Aquatic Organisms use oxygen dissolved in water. Terrestrial organisms obtain oxygen directly from air. Oxygen dissolved in water is less as compared to air. so in terrestrial organisms breathing rate is lower as compared to aquatic Organisms.
2. What are the different ways in which glucose is oxidised to provide energy in various organisms?
Answer:
3. How is oxygen and carbon dioxide transported in human beings?
Answer:
i. When we inhale air, oxygen reaches the alveoli in lungs. Oxygen diffuses from the walls of alveoli to the blood in Capillaries surrounding the alveoli.
ii. Oxygen is carried by haemoglobin present in RBCs of the blood. RBCs carry oxygen to the tissues.
iii. Carbon dioxide is soluble in water. Hence it is transported by blood in dissolved form.
iv. Blood carries Co2 back to the lungs, where it diffuses into the alveoli. From the alveoli, it is passed to the trachea, then to the nostrils and then out of the body into the air.
4. How are the lungs designed in human beings to maximise the area for exchange of gases?
Answer:
i. In human beings, the trachea divides into smaller tubes called bronchioles.
ii. Bronchioles further form a balloon- like structure called alveoli.
iii. The presence of alveoli provides a large surface area for exchange of gases.
iv. The alveoli have very thin walls and contains an extensive network of blood vessels which helps in exchange of gases.
IV. Textbook Page No. 96
- What are the components of transport system in human beings? What are the functions of those components?
Answer: In human beings, transport system consists of heart, blood and blood vessels.
i. Heart: it is a muscular blood pumping organ.
ii. Blood: It is a fluid connective tissue. It consists of plasma, RBCs, WBCs and Platelets. RBCs transport oxygen. Blood also transports many substances like Harmons, salts, carbon dioxide etc. WBCs protect the body from infections and platelets help in clotting of blood.
iii. Blood vessels:
- Veins: these bring de-oxygenated blood to the heart.
- Arteries: These carry oxygenated blood from the heart to the body.
2. Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
Answer: Mammals and birds are warm Blooded animals. They need energy to maintain their body temperature. This energy is created by breakdown of food with the help of oxygen. To meet the high demand of oxygen, it is necessary to separate oxygenated and deoxygenated blood in mammals and birds.
3. What are the components of the transport system in highly organized plants?
Answer:
i. The components of transport system in highly organised plants are xylem and phloem.
ii. Xylem consists of vessels, tracheids and other xylem tissues.
iii. Phloem consists of sieve tubes, companion cells, phloem fibres and phloem parenchyma.
4. How are water and minerals transported in plants?
Answer:
i. Water and dissolved minerals are transported through xylem tissues.
ii. Root cells in contact with soil actively take up ions from the soil. This process is called diffusion. It creates difference in the concentration of ions between root and soil. water enters the roots due to difference in concentration of ions and creates a column of water that is steadily pushed upward into vessels and tracheids of roots.
iii. Besides this, water is lost from aerial parts or leaves of the plants by the process of transpiration. This water loss from a leaf creates suction pressure which pulls water from the xylem cells of the roots.
5. How is food transported in plants?
Answer:
i. Plants transport soluble products of Photosynthesis through the phloem to storage organs like roots, fruits and seeds and also to growing organs. This type of transportation is called translocation.
ii. The translocation of food material is carried out in the phloem by sieve tubes with the help of components cells.
iii. Sucrose like materials are transported using energy from ATP and osmotic pressure, which is called due to water. This osmotic pressure transport the dissolved material in the phloem to tissues which have less pressure. This allows the phloem to move food material according to the need of the plant. For example, during Spring, Sugar stored in the root or stem would be translocated to the growing bud which needs energy.
V. Textbook Page No. 98
- Describe the structure and functioning of nephrons?
Answer: Structure of nephrons:
i. Nephron is the structural and functional unit of kidney. It consists of Bowman’s capsule and long coiled tubule.
ii. Each Bowman’s capsule contains a cluster of capillaries, called glomerulus. The blood enters the glomerulus through the afferent arteriole and leaves it through the efferent arteriole.
Functioning of nephron:
i. Filtration: Filtration of blood takes place in the Bowman’s capsule from the capillaries of glomerulus. Afferent artery is wider and it becomes narrow in the glomerulus and it leads to the efferent arteriole. This filtrate contains glucose, amino acids, urea, uric acid, Salt and water.
ii. Reabsorption: As the filtrate flows along the tubule, useful substances such as glucose, amino acids, Salt and water are selectively reabsorbed into the blood by the capillaries surrounding the tubule.
iii. Urine formation: Water and dissolved nitrogenous wastes remain in the urine. Urine is sent to the collecting duct and from there it is sent to the ureter.
2. What are the methods used by plants to get rid of excretory products? OR List any four strategies used by plants for excretion?
Answer:
i. Plants get rid of gaseous Waste products through stomata on leaves.
ii. Some waste products such as resigns and gem are stored in the bark.
iii. Some plants also excrete waste through roots into the soil.
iv. Plants get rid of stored waste products in leaves by shedding of leaves.
v. Excess water or liquid wastes are removed through leaves by the process of transpiration.
3. How is the amount of urine Produced regulated?
Answer.
i. The amount of urine produced depends on factors such as excess water and nitrogenous waste in the body.
ii. When water is abundant, dilute urine is excreted out. But when water is less in quantity, concentrated and less urine is excreted.
iii. When nitrogenous wastes are more, large amount of water is required to eliminate them and more amount of urine is produced.
NCERT EXERCISE QUESTIONS
1.The kidneys in human beings are a part of the system for ______
(a)Nutrition
(b) respiration
(c)excretion
(d) transportation
Answer C: excretion
2. The xylem in plants are responsible for ______
(a)Transport of water
(b)Transport of food
(c)Transport of amino acids
(d)Transport of oxygen
Answer A: Transport of water
3. The autotropic mode of nutrition requires ______
(a)Carbon dioxide and water
(b)Chlorophyll
(c)Sunlight
(d)All of the above
Answer D: all of the above
4. The breakdown of pyruvate to give carbon dioxide, water and energy takes place in _____
(a)Cytoplasm
(b)Mitochondria
(c)Chloroplast
(d)Nucleus
Answer B: Mitochondria
5. How are fats digested in our bodies? Where Does this process take place?
Answer:
¡. The process of fat digestion takes place in small intestine.
¡¡. Large fat globules are broken down into smaller globules by bile salts for increasing the efficiency of enzyme action on them, by a process known as Emulsification.
¡¡¡. The bile also makes the medium alkaline which help in activating the enzyme lipase.
iv. Lipase breaks down fats into fatty acids.
6. What is the role of saliva in the digestion of food?
Answer:
Saliva lubricates the food bolus and the enzyme salivary amylase or ptyalin present in saliva helps to break down starch into maltose.
7. What are the necessary conditions for autotrophic nutrition and water are its by products?
Answer:
i. The conditions necessary for autotrophic nutrition are sunlight, chlorophyll, carbon dioxide and water.
ii. The by-products of autotrophic nutrition are water and oxygen. Oxygen is released through stomata.
8. What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration?
Answer :
| No | Aerobic respiration | Anaerobic respiration |
| 1. | Aerobic respiration takes place in presence of oxygen. | Anaerobic respiration takes place in absence of oxygen. |
| 2. | End products are carbon dioxide and water. | End products can be ethyl alcohol and carbon dioxide or lactic acid. |
| 3. | Complete oxidation of glucose takes place. | Incomplete oxidation of glucose takes place. |
| 4. | More energy is released in this process. | Comparatively less energy is released in this process. |
Organisms that use the anaerobic mode of respiration or Yeast, some bacteria and some parasites.
9. How are the alveoli designed to maximise the exchange of gases?
Answer.
i. Alveoli are small balloon-like structures.
ii. They help to increase surface area for exchange of gases.
iii. Millions of alveoli present in the lungs provide large surface area.
iv. These are richly supplied with blood vessels to take oxygen to different cells.
10. What would be the consequence of deficiency of haemoglobin in our body?
Answer:
i. Haemoglobin present in RBCs Is important for transport of oxygen in our body.
ii. If haemoglobin deficiency occurs, oxygen reaching our body cells will decrease.
iii. The deficiency of haemoglobin in the body is called anaemia. In this disease, due to less haemoglobin and oxygen, less energy would be available to the body. Thus, a person experience weakness and gets tired easily.
11. Describe double circulation of blood in human beings. Why is it necessary?
Answer:
i. The blood passes through the heart twice, via. two separate pathways for Completion of one cycle. This type of circulation is called double circulation.
ii. Human heart is divided into four chambers- right atrium, right ventricle, Left Atrium and left ventricle.
iii. Right atrium of the Heart receives de-oxygenated blood from various body organs through vena cava. From right atrium, blood is passed to right ventricle and from there it is sent further for purification to lungs. Through Pulmonary artery.
iv. Left atrium of the heart receives oxygenated blood from lungs which is pumped to left ventricle. From there it is sent to all parts of the body through aorta. In this way, blood passes through the heart twice during one cycle.
v. Search Separation of blood allows highly efficient supply of oxygen to the blood cells which is necessary for energy production. It is useful in human beings because the constantly require energy to maintain their body temperature.
12. What are the differences between the transport of materials in xylem and phloem?
Answer:
| No | Transport in xylem | Transport in phloem |
| ¡ | Xylem helps in the transport of water and minerals. | Phloem helps in the transport of food. |
| ¡¡. | Water is transported only in one direction, i.e. from roots to leaves and other parts of the plant. | Food is transported in both upward and downward directions. |
| ¡¡¡. | Transport in xylem occurs with the help of force such as diffusion and transpiration pull. | Transport in phloem requires energy in the form of ATP. |
| ¡ν. | It is carried out by xylem vessels and tracheid. | It is carried out by sieve tubes with the help of adjacent companion cells. |
13. Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning?
Answer:
| No. | Alveoli | Nephron |
| ¡. | It is the structural and functional unit of lungs. | It is the structural and functional unit of kidney. |
| ¡¡. | It removes carbon dioxide from the blood. | It removes nitrogenous wastes from the blood. |
| ¡¡¡. | Alveoli are the sites of exchange of gases. | Nephron is the basic filtration unit of the kidney. |
| ¡ν. | Alveoli increase surface area for diffusion of CO2 and O2 | Nephron increase surface area for filtration of blood and reabsorption of useful substances. |
