Here are the NCERT Solutions of Chapter 6 Life Processes
Page No. 95
Q1.Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?
Ans.As in multicellular organisms, all the cells are not in direct contact with environment,
simple diffusion does not meet the requirement of all the body cells.
Q2.What criteria do we use to decide whether something is alive?
Ans.All the living organism must have movement at molecular levels along with
respiration and other life process like nutrition, respiration, transportation and
excretion to be called alive.
Q3. What are outside raw materials used for by an organism?
Ans.Food, Water, and Oxygen
Q4.What Processes would you consider essential for maintaining life
Ans.Nutrition, Respiration,Transportation,Excretion
Page No. 101
Q1.What are difference between autotrophic and heterotrophic nutrition?
Ans.
Q2. Where do plants get each of the raw materials required for photosynthesis?
Ans. 1. Light from Sun 2.Water from Soil 3.Carbon dioxide from air 4.Chlorophyl from chloroplast of green plants
Q3.What is the role of acids in our stomach
Ans. Our Gastric gland secrete HCl which makes the medium acidic to facilitate action of pepsin, and it also kills bacteria present in our food.Mucus protects the stomach lining under normal conditions from acid
Q4.What is the role of digestive enzymes
Ans. Enzymes are bio catalysts which help in breaking down complex food into simpler and soluble form so that they can be absorbed easily.
Q5.How is Small intestine designed to absorb food
Ans.The inner lining of small intestine has numerousfinger-like projections called villi which increase the surface area for absorption. The villi are richly supplied with blood vessels which transport the absorbed food to each and every cells of the body. Where, it is utilized to obtaining energy and repair of old tissues.
Page No. 105
Q1.What advantage over an aquatic organism does a terrestrial organism have with
regard to obtaining oxygen for respiration?
Ans.
The amount of dissolved oxygen is fairly low compared to the amount of oxygen in the air, the rate of breathing of aquatic animals is much faster than seen in terrestrial organism
Q2.What are different ways in which glucose is oxidized to provide energy in various organisms?
Ans.
Q3. How carbon dioxide and oxygen are transported in human beings
Ans.Carbon dioxide is more soluble in water, is mostly transported in dissolved form (by plasma)in our blood. and a pigment haemoglobin present in RBC has affinity to oxygen and it binds with oxygen to form oxyhaemoglobin and carry it to tissues
Q4.How are the lungs designed in human beings to maximize the area for exchange of
gases?
Ans. In lungs, the bronchioles terminate in balloon-like structures called alveoli. The
alveoli contains network of blood capillaries that increase the surface area for
exchange of gases.
(Page No. 110)
Q1.What are the components of the transport system in human beings? What are the functions of these components?
Ans.The components of human transport system include :
(a) Heart- receives and pumps the blood.
(b)Arteries- carry oxygenated blood away from the heart to various organs.
(c) Veins- Bring back blood to heart.
(d) Capillaries- exchange of various materials and gases between blood and tissues.
Q2.Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
Ans.The separation of the right and left side of hea rt is useful to prevent oxygenated blood and deoxygenated blood from mixing. Such sepa ration allows a highly efficient supply of oxygen to the body. This is useful in ani mals that have high energy needs, such as birds and mammals that constantly use the e nergy to maintain their body temperature.
Q3. What are the components of transport system in highly organized plants?
Ans. Vascular bundle helps in transport of material in highly organized plants.Vascular bundle consists of conductive tissues Xylem and phloem, xylem conducts water and minerals from roots to the other parts of the plants, where as phloem transports food from leaves to other parts of the plants
xylem consits of tracheids,vessels,xylem parenchyma and xylem fibres
Phloem consists of companion cells,sieve tubes,phloem parenchyma,phloem fibres
Q4.How are minerals transported in plants
Ans.Water and minerals are transported in plants thr ough xylem which consists of trachieds and vessels. Water and minerals absorbed by root hairs present in root by osmosis is passed to xylem tissues of root. From ro ot xylem it passes to stem xylem and thus water reaches to leaves.
Q5.,How is food transported in plants
Ans. Food is transported in plants through phloem wh ich consists of sieve tubes, sieve cells and companion cells. The food prepared in le aves in soluble form transported to leaves phloem. Active transport of food passes to all other parts of plants.
Page No. 112
Q1.Describe the structure and functioning of nephron.
Ans.
Each nephron is a cluster of very thin-
walled
blood
capillaries.
Each
capillary cluster in the kidney called
glomerulus is associated with the cup
shaped
Bowman’s
capsule
that
collects the filtered urine. Nephron
filters the blood in order to remove
nitrogenous waste. They also absorb
some
useful
substance
such
as
glucose, amino acids, minerals and
major amount of water from filtrate.
Q2.hat are the methods used by plants to get rid o f excretory products?
Ans.(i) Plant produces carbon dioxide as wastes duri ng respiration and oxygen as waste during photosynthesis.
(ii) Excess of water is removed through transpirat ion.
(iii) Some waste products like gums and resins are stored in older xylem tissue.
Q3. How is amount of urine produced regulated?
Ans.The amount of urine depends on how much excess o f water is in the body and how much a water soluble waste is to be excreted. If th e amount of water and dissolved wastes in boy are more than amount of urine will be more and if amount of wastes is less the amount of urine produced will be less.
Life Processes) (TEXTBOOK EXERCISE)
1. (c) excretion Page No. 95
Q1.Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?
Ans.As in multicellular organisms, all the cells are not in direct contact with environment,
simple diffusion does not meet the requirement of all the body cells.
Q2.What criteria do we use to decide whether something is alive?
Ans.All the living organism must have movement at molecular levels along with
respiration and other life process like nutrition, respiration, transportation and
excretion to be called alive.
Q3. What are outside raw materials used for by an organism?
Ans.Food, Water, and Oxygen
Q4.What Processes would you consider essential for maintaining life
Ans.Nutrition, Respiration,Transportation,Excretion
Page No. 101
Q1.What are difference between autotrophic and heterotrophic nutrition?
Ans.
Q2. Where do plants get each of the raw materials required for photosynthesis?
Ans. 1. Light from Sun 2.Water from Soil 3.Carbon dioxide from air 4.Chlorophyl from chloroplast of green plants
Q3.What is the role of acids in our stomach
Ans. Our Gastric gland secrete HCl which makes the medium acidic to facilitate action of pepsin, and it also kills bacteria present in our food.Mucus protects the stomach lining under normal conditions from acid
Q4.What is the role of digestive enzymes
Ans. Enzymes are bio catalysts which help in breaking down complex food into simpler and soluble form so that they can be absorbed easily.
Q5.How is Small intestine designed to absorb food
Ans.The inner lining of small intestine has numerousfinger-like projections called villi which increase the surface area for absorption. The villi are richly supplied with blood vessels which transport the absorbed food to each and every cells of the body. Where, it is utilized to obtaining energy and repair of old tissues.
Page No. 105
Q1.What advantage over an aquatic organism does a terrestrial organism have with
regard to obtaining oxygen for respiration?
Ans.
The amount of dissolved oxygen is fairly low compared to the amount of oxygen in the air, the rate of breathing of aquatic animals is much faster than seen in terrestrial organism
Q2.What are different ways in which glucose is oxidized to provide energy in various organisms?
Ans.
Ans.Carbon dioxide is more soluble in water, is mostly transported in dissolved form (by plasma)in our blood. and a pigment haemoglobin present in RBC has affinity to oxygen and it binds with oxygen to form oxyhaemoglobin and carry it to tissues
Q4.How are the lungs designed in human beings to maximize the area for exchange of
gases?
Ans. In lungs, the bronchioles terminate in balloon-like structures called alveoli. The
alveoli contains network of blood capillaries that increase the surface area for
exchange of gases.
(Page No. 110)
Q1.What are the components of the transport system in human beings? What are the functions of these components?
Ans.The components of human transport system include :
(a) Heart- receives and pumps the blood.
(b)Arteries- carry oxygenated blood away from the heart to various organs.
(c) Veins- Bring back blood to heart.
(d) Capillaries- exchange of various materials and gases between blood and tissues.
Q2.Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
Ans.The separation of the right and left side of hea rt is useful to prevent oxygenated blood and deoxygenated blood from mixing. Such sepa ration allows a highly efficient supply of oxygen to the body. This is useful in ani mals that have high energy needs, such as birds and mammals that constantly use the e nergy to maintain their body temperature.
Q3. What are the components of transport system in highly organized plants?
Ans. Vascular bundle helps in transport of material in highly organized plants.Vascular bundle consists of conductive tissues Xylem and phloem, xylem conducts water and minerals from roots to the other parts of the plants, where as phloem transports food from leaves to other parts of the plants
xylem consits of tracheids,vessels,xylem parenchyma and xylem fibres
Phloem consists of companion cells,sieve tubes,phloem parenchyma,phloem fibres
Q4.How are minerals transported in plants
Ans.Water and minerals are transported in plants thr ough xylem which consists of trachieds and vessels. Water and minerals absorbed by root hairs present in root by osmosis is passed to xylem tissues of root. From ro ot xylem it passes to stem xylem and thus water reaches to leaves.
Q5.,How is food transported in plants
Ans. Food is transported in plants through phloem wh ich consists of sieve tubes, sieve cells and companion cells. The food prepared in le aves in soluble form transported to leaves phloem. Active transport of food passes to all other parts of plants.
Page No. 112
Q1.Describe the structure and functioning of nephron.
Ans.
Q2.hat are the methods used by plants to get rid o f excretory products?
Ans.(i) Plant produces carbon dioxide as wastes duri ng respiration and oxygen as waste during photosynthesis.
(ii) Excess of water is removed through transpirat ion.
(iii) Some waste products like gums and resins are stored in older xylem tissue.
Q3. How is amount of urine produced regulated?
Ans.The amount of urine depends on how much excess o f water is in the body and how much a water soluble waste is to be excreted. If th e amount of water and dissolved wastes in boy are more than amount of urine will be more and if amount of wastes is less the amount of urine produced will be less.
Life Processes) (TEXTBOOK EXERCISE)
2. (a) transport of water
3. (d) all of the above
4. (b) mitochondria
Q5.How are fats digested in our bodies? Where does this process take place?
Ans. Digestion of fats takes place in small intestine . Fats entering in intestine are in the form of large globules. Bile juice breaks down thes e large globules into smaller globules. Afterwards fat digesting enzyme lipase pr esent in pancreatic juice and intestinal juice converts it into fatty acids and g lycerol.
Q6.What is the role of saliva in the digestion of f ood?
Ans.The saliva contains an enzyme called salivary am ylase that breaks down starch which is complex molecule into sugar.
Q7.What are the necessary conditions for autotrophi c nutrition and what are its by- products.
Ans.Conditions necessary for autotrophic nutrition a re:
(i) Light
(ii) Chlorophyll
(iii) Water and
(iv) Carbon dioxide
By-products are:
(i) Oxygen and
(ii) Water
Q8.What are differences between aerobic and anaerob ic respiration? Name some organisms that use anaerobic mode of respiration.
Ans.
Aerobic respiration
1.It takes place in the presence of oxygen
2.Complete oxidation of glucose occurs
3.more energy is produced
4.By products are carbon dioxide, energy and water
5.Pyruvate is broken down in mitochondria
Anaerobic respiration
1,It takes place in absence of oxygen
2.Incomplete oxidation of glucose occurs
3.less energy is produced
4.By products are ethanol,carbon dioxide,energy
5.Pyruvate is broken down in cytoplasm
Q9.How are the alveoli designed to maximize the ex change of gases?
Ans. The walls of the alveoli is folded and has large surface areas. It contain an extensive network of blood vessels which provide a surface wh ere the exchange of gases can take place.
Q10. What would be the consequence of a deficiency o f hemoglobin in our bodies?
Ans. Haemoglobin is a pigment present in RBC. It has a high affinity for oxygen. It carries oxygen from lungs to various tissues which are defi cient in oxygen. Presence of less hemoglobin will result in less supply of oxygen to tissues. A person having less hemoglobin will get tired soon and will have a pale look.
Q11.Describe double circulation in human beings. Wh y is it necessary?
Ans. In mammals and birds the blood goes through the heart twice during each cycle. This is known as double circulation. Deoxygenated blood which enters right auricle and t hen it enters the right ventricle from where it is pumped to lungs for oxygenation. F rom lungs after oxygenation it comes to left auricle and then enters left ventricl e from where it is pumped to various parts of body. Such system of circulation does not allow mixing of oxygenated and deoxygenated blood which allows efficient supply of oxygen to the body.
Q12.What are differences between the transport of m aterials in xylem and phloem?
Ans.
Q12. Compare the functioning of alveoli in the lungs and nephron in the kidneys with respect to their structure and functioning.
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