1. What are the functions of lymph in our body?
Ans. Functions of lymph are-
a) It returns tissue fluid from interstitial space into the blood.
b) It collects carbon dioxide, waste products and metabolites from tissues via tissue fluid.
c) Lymph has lymphocytes (WBC’S), the lymph provides in immunity to the body and fight against the invading organisms.
2. How is haemoglobin associated with respiration explained?
Ans. Transportation of oxygen and carbon – dioxide occurs with the help of respiratory pigment haemoglobin. Haemoglobin is a red pigment having very high affinity for oxygen. Oxygen is transported from the lungs to the body cells in the form of oxyhemoglobin. Carbon – dioxide is transported from the body cells to the lungs in the form of carbamino – haemoglobin
3. What are the modes of excretion in plants?
Ans. Modes of excretion in plants are –
a) The plants get rid of excess water by transpiration.
b) The only major gases excretory product of plants in oxygen. It is released from plants into the environment by diffusion.
c) Organic wastes of plants are stored within dead permanent tissues such as wood or within leaves or bark which are periodically removed.
d) The plants also excrete some wastes substances into the soil around them.
e) Many wastes products of plants are stored in cellular vacuoles.
4. Give an experiment to prove the essentiality of light for photosynthesis
Ans. a) Destarched the plant by leaving it in dart for 48 – 72 hours.
b) Now place strips of black paper or metal foil over destarched leaves and expose them to light for several hours.
5. What is “translocation”? Why it is essential for plants.
Ans. Transportation of organic solutes in the plants is called translocation. It is necessary, because all the cells need food to carry out their vital functions. It occurs in upward as well as downward direction or to the storage organs of roots, fruits, seeds and to growing organs.
6. How respiration does takes place in plants?
Ans. There are three modes for the exchange of gases in plants –
a) Some small plants can carry out gaseous exchange by simple diffusion over their whole surfaces.
b) Large flowering plants exchange gases through stomata on their leaves and green stem.
c) In woody stems, exchange occurs through cracks in the bark or lenticels.
7. How is transpiration pull responsible for upward movement of water?
Ans. The leaves loose water in the form of water vapours through stomata by a process known as transpiration. Continuous transpiration creates a s suction in the water column of the xylem elements and it reaches upto the roots. This pull is called transpiration pull. Due to transpiration, the water column of the plant is pulled up from below to the top of the plant.
8. Discuss the major steps involved in process of nutrition in human beings.
Ans. Major steps involved in human nutrition are –
a) Ingestion – Intake of food through mouth. Humans have holozoic mode of nutrition. They engulf solid particles.
b) Digestion – The break down complex food material into simpler one in alimentary canal with the help of mechanical as well as chemical process.
c) Absorption – Digested food is absorbed by the small finger like projections, villi present in the small intestine.
d) Assimilation – Absorbed food reaches to all cells via blood, and utilized for energy, growth and development.
e) Excretion – Undigested food from small intestine passed into large intestine, and then it is thrown out by Anus.
9. Discuss the mode of nutrition in amoeba.
Ans. Steps of Nutrition in amoeba –
a) Formation of pseudopodia – When Amoeba comes in contact with a food particle, it forms pseudopodia which envelops food particles.
b) Ingestion – The tips of pseudopodia fuse with each other, together with variable amount of food particles and water, forms food vacuole, this process is known as ingestion.
c) Digestion – The vacuoles are surrounded by lysosomes which fuses with vacuole and digest the food particles present in vacuole.
d) Exocytosis – The soluble products of digestion are passed out into due cytoplasm from the food vacuole. And the remaining undigested materials are passed out of the body with the help of a process called exocytosis.
10. With the help of labelled diagram, discuss the structure of cross – section of leaf.
Ans. Leaf has two parts:
(i) Epidermis – Outermost layer of cell is called epidermis. Lower epidermis has small pores in between cells called stomata.
ii) Mesophyll – Parenchymatons cells containing chloroplast is called mesophyll. It is two types – palisade and spongy parenchyma.
11. What do you mean by ‘lymph’. Mention its function.
Ans. Lymph- The fluid present in the spaces between the cells in the tissues is called tissue fluid or lymph.
Functions of lymph: (i) It returns tissue fluid from the interstitial spaces into the blood.
(ii) Lymph capillaries of intestinal villi called lacteals helps in absorption of fats.
(iii) It collects carbondioxide, waste products and metabolites form tissues via tissue fluid.
12. How are lungs designed in human beings to maximize the area of exchange of gases
Ans. Lungs have some adaptations in them so that efficient exchanges of gases take place.
The adaptations are –
a) Increased surface area
b) Very fine and delicate surface for easy exchange of oxygen and carbon dioxide
c) Mechanism for moving the air in and out of respiratory surface where the oxygen is absorbed.
16. What are the functions of human respiratory system?
Ans. (i) Gaseous exchange for the cellular respiratory process.
(ii) Sound production by vocal cords
(iii) Abdominal compression which helps in urination, passing of faces and childbirth.
(iv) Laughing and sneezing for self-cleaning the respiratory surface.
17. What is role of skin, lungs and intestine in the process of excretion in man?
Ans. Skin – Skin excrete excess salts and water in the form of sweat.
Lungs – Lungs expel carbon – dioxide during exhalation.
Intestine – Intestine throw out undigested food in the form of faeces through anus
19. Why and how does water enter continuously into the root xylem of plants?
Ans. Xylem transports water and minerals to the plant body. The roots of a plant have hair called root hairs. The root hairs are directly in contact with the film of water in between the soil particles. Water and minerals get into the root hair by the process of diffusion. The water and minerals absorbed by the root hair form the soil pass from cell to cell by osmosis through the epidermis root cortex, endodermis and reaches the root xylem. The xylem vessels of the root the plant are connected to the xylem vessels into stem. Therefore, the water containing dissolved minerals enter the root xylem vessels into stem xylem vessels. The xylem vessels of the stem branch into the leaves of the plants. So the water & minerals carried by the xylem vessels in the stem reach the leaves through the branched xylem vessels which enter from the petiole into the each part of the leaf. Thus the water and minerals form the soil reach through the root and stem to the leaves of the plants. Evaporation of water molecules from the cells of a leaf creates a suction which pulls water form the xylem cells of roots. The loss of water in the form of vapour from the aerial parts of the plants is known as transpiration.
20. What is the role of following in human digestive system –
a) mucous
b) Bicarbonate
c) Trypsin
Ans. a) Mucus – It protects the inner living of stomach from HCl.
b) Bricarbonate – It makes the acidic food alkaline so that pancreatic enzymes act on it.
c) Trypsin – It digest proteins into amino acids.
21. What are outside raw materials used for by an organism?
Ans. Outside raw materials used for by an organism includes:
a. Food
b. Water
c. Oxygen
22. What processes would you consider essential for maintaining life?
Ans. The processes essential for maintaining life are
a. Nutrition
b. Respiration
c. Transportation
d. Excretion
26. How is small intestine deigned to absorb digested
Ans. The inner lining of small intestine has numerous finger-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.
27. What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Ans. The rate of breathing is slower in terrestrial organisms as compared to aquatic organisms. This is due to the fact that in water, the amount of oxygen is less as compared to air while in aquatic organisms the rate of breathing is faster.
29. How is oxygen and carbon dioxide transported in human beings?
Ans. In human beings, a pigment hemoglobin is present in RBC which has high affinity for oxygen, takes up the oxygen from the air in the lungs and carry it to tissues which are deficient in oxygen. Some oxygen is carried in dissolved state in blood plasma. Carbon dioxide is more soluble in water than oxygen is mostly transported in the dissolved form in our blood.
30. 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.
31. Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
Ans. The separation of the right and left side of heart is useful to prevent oxygenated blood 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 that constantly use the energy to maintain their body temperature.
32. What are the components of transport system in highly organized plants?
Ans. The transport system of higher plants consists of xylem and phloem. Xylems have vessels and trachieds to transport water and minerals from root to other part of the plants. Phloem, which consists of sieve tubes and companion cells, transport food from leaves to storage organs and other parts of plant.
33. How are water and minerals transported in plants?
Ans. Water and minerals are transported in plants through 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 root xylem it passes to stem xylem and thus water reaches to leaves.
34. How is food transported in plants?
Ans. Food is transported in plants through phloem which consists of sieve tubes, sieve cells and companion cells. The food prepared in leaves in soluble form transported to leaves phloem. Active transport of food passes to all other parts of plants.
35. What are the methods used by plants to get rid of excretory products?
Ans. (i) Plant produces carbon dioxide as wastes during respiration and oxygen as waste during photosynthesis.
(ii) Excess of water is removed through transpiration.
(iii) Some waste products like gums and resins are stored in older xylem tissue.
36. How is amount of urine produced regulated?
Ans. The amount of urine depends on how much excess of water is in the body and how much a water soluble waste is to be excreted. If the 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.
37. 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 these large globules into smaller globules. Afterwards fat digesting enzyme lipase present in pancreatic juice and intestinal juice converts it into fatty acids and glycerol
41. What would be the consequence of a deficiency of 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 deficient 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.
44. Leaves of a healthy potted plant were coated with petroleum jelly. How will it affect the plant? State two reasons.
Ans. The plant will not remain healthy for long due to the following reasons:
1. There will be no transpiration.
2. There will be no exchange of gases which will affect the rate of photosynthesis.
45. How does respiration in plants differ from that in animals?
Ans. In plants, all parts like the root, stem, leaves, etc., perform respiration individually., while in animals, either the general body surface or specific organs like the skin, gills, lungs, etc., are involved in respiration. The rate of respiration is much slower in plants than in animals. Unlike animals, there is little transport of gases from one part of the plant to another.
46. How does respiration in plants differ from that in animals?
Ans. The acid is formed in the mouth after a sugary food (chocolates and sweet) has been taken. This acid lowers the pH in the mouth. Tooth decay starts when the pH of acid formed in the mouth falls below 5.5. This is because then the acid becomes strong enough to attack the enamel of our teeth and corrode it.
47. Name the cartilaginous flap which closes the glottis to check the entry of food into it during swallowing.
Ans. The tissue that got blocked may be xylem. It is through the xylem that water and minerals absorbed by roots from the soil are transported to the leaves and other parts of the plant. So, if xylem is blocked, the leaves will not get the nourishment and will get wilted.
48. How does respiration in plants differ from that in animals?
Ans. In plants, all parts like the root, stem, leaves, etc., perform respiration individually., while in animals, either the general body surface or specific organs like the skin, gills, lungs, etc., are involved in respiration. The rate of respiration is much slower in plants than in animals. Unlike animals, there is little transport of gases from one part of the plant to another.
49. Write one feature which is common to each of the following pairs of the term/organs.
i) glycogen and starch
ii) chlorophyll and haemoglobin
iii) gills and lungs
iv) arteries and veins.
Ans. i) Carbohydrate (food)
ii) Pigments.
iii) Respiratory organs.
iv) Blood vessels.
50. A certain tissue in a green plant somehow get blocked and the leaves wilted. What was the tissue that got blocked?
Ans. The tissue that got blocked may be xylem. It is through the xylem that water and minerals absorbed by roots from the soil are transported to the leaves and other parts of the plant. So, if xylem is blocked, the leaves will not get the nourishment and will get wilted.
51. Write the functions of the following in the digestive process:
i. Bile
ii. Bicarbonate secreted by the duodenal wall.
iii. Pancreatic amylase.
Ans. i. Bile: It is secreted by the gall bladder and it emulsifies & it into the smaller droplets for their easy digestion.
ii. It provides alkaline medium in the duodenum which is needed for the action of pancreatic enzymes of different food components for their digestion.
iii. Pancreatic amylase enzyme digests starch and changes it into maltose.
52. The two openings of the pharynx, one leading to trachea and the other leading to oesophagus, lie very close to each other. Yet food we swallow normally does not enter into our trachea. Why?
Ans. The food does not enter into trachea because during swallowing, the aperture leading to trachea (glottis) gets covered by a cartilaginous flap called epiglottis and the food has no other passage except going into the oesophagus.
53. How would it affect the digestion of proteins and carbohydrates if the duodenum of man if there is a blockade in the pancreatic duct?
Ans. Duodenum is the region where the pancreatic juice secreted by the pancreas enters. The enzymes pancreatic amylase and trwsin helps in the digestion of carbohydrates and proteins. Thus, if there is a blockade, the digestion of carbohydrates and proteins gets affected
54.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.
55.Describe double circulation in human beings. Why 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 then it enters the right ventricle from where it is pumped to lungs for oxygenation. From lungs after oxygenation it comes to left auricle and then enters left ventricle 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.
56.How is amount of urine produced regulated?
Ans. The amount of urine depends on how much excess of water is in the body and how much a water soluble waste is to be excreted. If the 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
57.Explain the process of nutrition in Amoeba.
Ans.Ingestion: Amoeba makes finger-like projections outside its body. These projections are called pseudopodia. Amoeba traps food particle with pseudopodia. After that, amoeba takes in the food particle; along with water.
Digestion: Amoeba makes food vacuole after ingesting the food particle. Enzymes are released in the food vacuole for digestion.
Absorption: After digestion, nutrients enter the cytoplasm through osmosis.
Assimilation: Nutrients are utilized by the cell for various purposes.
Egestion: Food vacuole goes near the cell membrane to empty its contents outside the cell. This results in expulsion of waste materials from the cell.
58. Explain the mechanism of photosynthesis.
Ans. Photosynthesis is the process by which green plants prepare their food in the presence of sunlight. Green plants utilize carbon dioxide and water to make carbohydrate. The reaction of photosynthesis can be shown by following equation:
The whole process of Photosynthesis is composed of following steps:
(a) Absorption of light energy by chlorophyll
(b) Conversion of light energy into chemical energy
(c) splitting of water molecules into hydrogen and oxygen.
(d) Reduction of carbon dioxide to form carbohydrate
These steps need not take place one after another immediately. For example; desert plants take up carbon dioxide at night to make an intermediate. During daytime, they make carbohydrate. After photosynthesis, carbohydrate is converted into starch and starch is stored in different plant organs.
59.. Describe the process of urine formation in kidneys.
Ans.
The functional unit of kidney is called nephron.
A nephron is composed of a tuft of blood capillaries and highly coiled ducts. The tuft of blood capillaries is surrounded by a cup-shaped structure; called Bowman’s capsule. Waste material from blood are filtered out of the capillaries and they go through the wall of Bowman’s capsule. After that, the waste material and water pass through the ducts. When the mixture of water and other materials move through the duct, some materials and water are reabsorbed. This depends on excess amount of water present in the body. After reabsorption of water and other material, urine becomes concentrated. This then goes to the collecting duct. Urine from collecting ducts moves through ureter into the urinary bladder. From the urinary bladder, urine is expelled from the body as and when required.
Ans. Functions of lymph are-
a) It returns tissue fluid from interstitial space into the blood.
b) It collects carbon dioxide, waste products and metabolites from tissues via tissue fluid.
c) Lymph has lymphocytes (WBC’S), the lymph provides in immunity to the body and fight against the invading organisms.
2. How is haemoglobin associated with respiration explained?
Ans. Transportation of oxygen and carbon – dioxide occurs with the help of respiratory pigment haemoglobin. Haemoglobin is a red pigment having very high affinity for oxygen. Oxygen is transported from the lungs to the body cells in the form of oxyhemoglobin. Carbon – dioxide is transported from the body cells to the lungs in the form of carbamino – haemoglobin
3. What are the modes of excretion in plants?
Ans. Modes of excretion in plants are –
a) The plants get rid of excess water by transpiration.
b) The only major gases excretory product of plants in oxygen. It is released from plants into the environment by diffusion.
c) Organic wastes of plants are stored within dead permanent tissues such as wood or within leaves or bark which are periodically removed.
d) The plants also excrete some wastes substances into the soil around them.
e) Many wastes products of plants are stored in cellular vacuoles.
4. Give an experiment to prove the essentiality of light for photosynthesis
Ans. a) Destarched the plant by leaving it in dart for 48 – 72 hours.
b) Now place strips of black paper or metal foil over destarched leaves and expose them to light for several hours.
5. What is “translocation”? Why it is essential for plants.
Ans. Transportation of organic solutes in the plants is called translocation. It is necessary, because all the cells need food to carry out their vital functions. It occurs in upward as well as downward direction or to the storage organs of roots, fruits, seeds and to growing organs.
6. How respiration does takes place in plants?
Ans. There are three modes for the exchange of gases in plants –
a) Some small plants can carry out gaseous exchange by simple diffusion over their whole surfaces.
b) Large flowering plants exchange gases through stomata on their leaves and green stem.
c) In woody stems, exchange occurs through cracks in the bark or lenticels.
7. How is transpiration pull responsible for upward movement of water?
Ans. The leaves loose water in the form of water vapours through stomata by a process known as transpiration. Continuous transpiration creates a s suction in the water column of the xylem elements and it reaches upto the roots. This pull is called transpiration pull. Due to transpiration, the water column of the plant is pulled up from below to the top of the plant.
8. Discuss the major steps involved in process of nutrition in human beings.
Ans. Major steps involved in human nutrition are –
a) Ingestion – Intake of food through mouth. Humans have holozoic mode of nutrition. They engulf solid particles.
b) Digestion – The break down complex food material into simpler one in alimentary canal with the help of mechanical as well as chemical process.
c) Absorption – Digested food is absorbed by the small finger like projections, villi present in the small intestine.
d) Assimilation – Absorbed food reaches to all cells via blood, and utilized for energy, growth and development.
e) Excretion – Undigested food from small intestine passed into large intestine, and then it is thrown out by Anus.
9. Discuss the mode of nutrition in amoeba.
Ans. Steps of Nutrition in amoeba –
a) Formation of pseudopodia – When Amoeba comes in contact with a food particle, it forms pseudopodia which envelops food particles.
b) Ingestion – The tips of pseudopodia fuse with each other, together with variable amount of food particles and water, forms food vacuole, this process is known as ingestion.
c) Digestion – The vacuoles are surrounded by lysosomes which fuses with vacuole and digest the food particles present in vacuole.
d) Exocytosis – The soluble products of digestion are passed out into due cytoplasm from the food vacuole. And the remaining undigested materials are passed out of the body with the help of a process called exocytosis.
10. With the help of labelled diagram, discuss the structure of cross – section of leaf.
Ans. Leaf has two parts:
(i) Epidermis – Outermost layer of cell is called epidermis. Lower epidermis has small pores in between cells called stomata.
ii) Mesophyll – Parenchymatons cells containing chloroplast is called mesophyll. It is two types – palisade and spongy parenchyma.
11. What do you mean by ‘lymph’. Mention its function.
Ans. Lymph- The fluid present in the spaces between the cells in the tissues is called tissue fluid or lymph.
Functions of lymph: (i) It returns tissue fluid from the interstitial spaces into the blood.
(ii) Lymph capillaries of intestinal villi called lacteals helps in absorption of fats.
(iii) It collects carbondioxide, waste products and metabolites form tissues via tissue fluid.
12. How are lungs designed in human beings to maximize the area of exchange of gases
Ans. Lungs have some adaptations in them so that efficient exchanges of gases take place.
The adaptations are –
a) Increased surface area
b) Very fine and delicate surface for easy exchange of oxygen and carbon dioxide
c) Mechanism for moving the air in and out of respiratory surface where the oxygen is absorbed.
16. What are the functions of human respiratory system?
Ans. (i) Gaseous exchange for the cellular respiratory process.
(ii) Sound production by vocal cords
(iii) Abdominal compression which helps in urination, passing of faces and childbirth.
(iv) Laughing and sneezing for self-cleaning the respiratory surface.
17. What is role of skin, lungs and intestine in the process of excretion in man?
Ans. Skin – Skin excrete excess salts and water in the form of sweat.
Lungs – Lungs expel carbon – dioxide during exhalation.
Intestine – Intestine throw out undigested food in the form of faeces through anus
19. Why and how does water enter continuously into the root xylem of plants?
Ans. Xylem transports water and minerals to the plant body. The roots of a plant have hair called root hairs. The root hairs are directly in contact with the film of water in between the soil particles. Water and minerals get into the root hair by the process of diffusion. The water and minerals absorbed by the root hair form the soil pass from cell to cell by osmosis through the epidermis root cortex, endodermis and reaches the root xylem. The xylem vessels of the root the plant are connected to the xylem vessels into stem. Therefore, the water containing dissolved minerals enter the root xylem vessels into stem xylem vessels. The xylem vessels of the stem branch into the leaves of the plants. So the water & minerals carried by the xylem vessels in the stem reach the leaves through the branched xylem vessels which enter from the petiole into the each part of the leaf. Thus the water and minerals form the soil reach through the root and stem to the leaves of the plants. Evaporation of water molecules from the cells of a leaf creates a suction which pulls water form the xylem cells of roots. The loss of water in the form of vapour from the aerial parts of the plants is known as transpiration.
20. What is the role of following in human digestive system –
a) mucous
b) Bicarbonate
c) Trypsin
Ans. a) Mucus – It protects the inner living of stomach from HCl.
b) Bricarbonate – It makes the acidic food alkaline so that pancreatic enzymes act on it.
c) Trypsin – It digest proteins into amino acids.
21. What are outside raw materials used for by an organism?
Ans. Outside raw materials used for by an organism includes:
a. Food
b. Water
c. Oxygen
22. What processes would you consider essential for maintaining life?
Ans. The processes essential for maintaining life are
a. Nutrition
b. Respiration
c. Transportation
d. Excretion
26. How is small intestine deigned to absorb digested
Ans. The inner lining of small intestine has numerous finger-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.
27. What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Ans. The rate of breathing is slower in terrestrial organisms as compared to aquatic organisms. This is due to the fact that in water, the amount of oxygen is less as compared to air while in aquatic organisms the rate of breathing is faster.
29. How is oxygen and carbon dioxide transported in human beings?
Ans. In human beings, a pigment hemoglobin is present in RBC which has high affinity for oxygen, takes up the oxygen from the air in the lungs and carry it to tissues which are deficient in oxygen. Some oxygen is carried in dissolved state in blood plasma. Carbon dioxide is more soluble in water than oxygen is mostly transported in the dissolved form in our blood.
30. 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.
31. Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
Ans. The separation of the right and left side of heart is useful to prevent oxygenated blood 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 that constantly use the energy to maintain their body temperature.
32. What are the components of transport system in highly organized plants?
Ans. The transport system of higher plants consists of xylem and phloem. Xylems have vessels and trachieds to transport water and minerals from root to other part of the plants. Phloem, which consists of sieve tubes and companion cells, transport food from leaves to storage organs and other parts of plant.
33. How are water and minerals transported in plants?
Ans. Water and minerals are transported in plants through 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 root xylem it passes to stem xylem and thus water reaches to leaves.
34. How is food transported in plants?
Ans. Food is transported in plants through phloem which consists of sieve tubes, sieve cells and companion cells. The food prepared in leaves in soluble form transported to leaves phloem. Active transport of food passes to all other parts of plants.
35. What are the methods used by plants to get rid of excretory products?
Ans. (i) Plant produces carbon dioxide as wastes during respiration and oxygen as waste during photosynthesis.
(ii) Excess of water is removed through transpiration.
(iii) Some waste products like gums and resins are stored in older xylem tissue.
36. How is amount of urine produced regulated?
Ans. The amount of urine depends on how much excess of water is in the body and how much a water soluble waste is to be excreted. If the 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.
37. 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 these large globules into smaller globules. Afterwards fat digesting enzyme lipase present in pancreatic juice and intestinal juice converts it into fatty acids and glycerol
41. What would be the consequence of a deficiency of 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 deficient 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.
44. Leaves of a healthy potted plant were coated with petroleum jelly. How will it affect the plant? State two reasons.
Ans. The plant will not remain healthy for long due to the following reasons:
1. There will be no transpiration.
2. There will be no exchange of gases which will affect the rate of photosynthesis.
45. How does respiration in plants differ from that in animals?
Ans. In plants, all parts like the root, stem, leaves, etc., perform respiration individually., while in animals, either the general body surface or specific organs like the skin, gills, lungs, etc., are involved in respiration. The rate of respiration is much slower in plants than in animals. Unlike animals, there is little transport of gases from one part of the plant to another.
46. How does respiration in plants differ from that in animals?
Ans. The acid is formed in the mouth after a sugary food (chocolates and sweet) has been taken. This acid lowers the pH in the mouth. Tooth decay starts when the pH of acid formed in the mouth falls below 5.5. This is because then the acid becomes strong enough to attack the enamel of our teeth and corrode it.
47. Name the cartilaginous flap which closes the glottis to check the entry of food into it during swallowing.
Ans. The tissue that got blocked may be xylem. It is through the xylem that water and minerals absorbed by roots from the soil are transported to the leaves and other parts of the plant. So, if xylem is blocked, the leaves will not get the nourishment and will get wilted.
48. How does respiration in plants differ from that in animals?
Ans. In plants, all parts like the root, stem, leaves, etc., perform respiration individually., while in animals, either the general body surface or specific organs like the skin, gills, lungs, etc., are involved in respiration. The rate of respiration is much slower in plants than in animals. Unlike animals, there is little transport of gases from one part of the plant to another.
49. Write one feature which is common to each of the following pairs of the term/organs.
i) glycogen and starch
ii) chlorophyll and haemoglobin
iii) gills and lungs
iv) arteries and veins.
Ans. i) Carbohydrate (food)
ii) Pigments.
iii) Respiratory organs.
iv) Blood vessels.
50. A certain tissue in a green plant somehow get blocked and the leaves wilted. What was the tissue that got blocked?
Ans. The tissue that got blocked may be xylem. It is through the xylem that water and minerals absorbed by roots from the soil are transported to the leaves and other parts of the plant. So, if xylem is blocked, the leaves will not get the nourishment and will get wilted.
51. Write the functions of the following in the digestive process:
i. Bile
ii. Bicarbonate secreted by the duodenal wall.
iii. Pancreatic amylase.
Ans. i. Bile: It is secreted by the gall bladder and it emulsifies & it into the smaller droplets for their easy digestion.
ii. It provides alkaline medium in the duodenum which is needed for the action of pancreatic enzymes of different food components for their digestion.
iii. Pancreatic amylase enzyme digests starch and changes it into maltose.
52. The two openings of the pharynx, one leading to trachea and the other leading to oesophagus, lie very close to each other. Yet food we swallow normally does not enter into our trachea. Why?
Ans. The food does not enter into trachea because during swallowing, the aperture leading to trachea (glottis) gets covered by a cartilaginous flap called epiglottis and the food has no other passage except going into the oesophagus.
53. How would it affect the digestion of proteins and carbohydrates if the duodenum of man if there is a blockade in the pancreatic duct?
Ans. Duodenum is the region where the pancreatic juice secreted by the pancreas enters. The enzymes pancreatic amylase and trwsin helps in the digestion of carbohydrates and proteins. Thus, if there is a blockade, the digestion of carbohydrates and proteins gets affected
54.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.
55.Describe double circulation in human beings. Why 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 then it enters the right ventricle from where it is pumped to lungs for oxygenation. From lungs after oxygenation it comes to left auricle and then enters left ventricle 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.
56.How is amount of urine produced regulated?
Ans. The amount of urine depends on how much excess of water is in the body and how much a water soluble waste is to be excreted. If the 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
57.Explain the process of nutrition in Amoeba.
Ans.Ingestion: Amoeba makes finger-like projections outside its body. These projections are called pseudopodia. Amoeba traps food particle with pseudopodia. After that, amoeba takes in the food particle; along with water.
Digestion: Amoeba makes food vacuole after ingesting the food particle. Enzymes are released in the food vacuole for digestion.
Absorption: After digestion, nutrients enter the cytoplasm through osmosis.
Assimilation: Nutrients are utilized by the cell for various purposes.
Egestion: Food vacuole goes near the cell membrane to empty its contents outside the cell. This results in expulsion of waste materials from the cell.
58. Explain the mechanism of photosynthesis.
Ans. Photosynthesis is the process by which green plants prepare their food in the presence of sunlight. Green plants utilize carbon dioxide and water to make carbohydrate. The reaction of photosynthesis can be shown by following equation:
The whole process of Photosynthesis is composed of following steps:
(a) Absorption of light energy by chlorophyll
(b) Conversion of light energy into chemical energy
(c) splitting of water molecules into hydrogen and oxygen.
(d) Reduction of carbon dioxide to form carbohydrate
These steps need not take place one after another immediately. For example; desert plants take up carbon dioxide at night to make an intermediate. During daytime, they make carbohydrate. After photosynthesis, carbohydrate is converted into starch and starch is stored in different plant organs.
59.. Describe the process of urine formation in kidneys.
Ans.
The functional unit of kidney is called nephron.
A nephron is composed of a tuft of blood capillaries and highly coiled ducts. The tuft of blood capillaries is surrounded by a cup-shaped structure; called Bowman’s capsule. Waste material from blood are filtered out of the capillaries and they go through the wall of Bowman’s capsule. After that, the waste material and water pass through the ducts. When the mixture of water and other materials move through the duct, some materials and water are reabsorbed. This depends on excess amount of water present in the body. After reabsorption of water and other material, urine becomes concentrated. This then goes to the collecting duct. Urine from collecting ducts moves through ureter into the urinary bladder. From the urinary bladder, urine is expelled from the body as and when required.
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