Lakhmir Singh Biology Class 10 Solutions Life Processes
Lakhmir Singh Biology Class 10 Solutions Page No:23
Which is the basic requirement of living organisms for obtaining energy ?
Food is the basic requirement of living organisms for obtaining energy.
Which of the following type of energy is used by living organisms to perform vital life processes ?
Kinetic energy, Chemical energy, Potential energy, Nuclear energy
Which of the following is an autotroph ? Green plant or Man
Name two inorganic substances which are used by autotrophs to make food.
Carbon dioxide and Water.
What is the mode of nutrition in fungi ?
Name one organism each having saprophytic, parasitic and holozoic modes of nutrition.
Saprophytic – Fungi.Parasitic – Plasmodium.Holozoic – Human Beings.
Name the process by which plants make food.
Lakhmir Singh Biology Class 10 Solutions Page No:24
In addition to carbon dioxide and water, state two other conditions necessary for the process of photosynthesis to take place.
Sunlight and chlorophyll.
Apart from sunlight and chlorophyll, what other things are required to make food by photosynthesis ?
Carbon dioxide and water.
(a) Name a gas used in photosynthesis.
(b) Name a gas produced in photosynthesis.
(a) Carbon dioxide.
The leaves of a plant first prepare food A by photosynthesis. Food A then gets converted into food What are A and B ?
A is glucose and B is starch.
Which substance is used to remove chlorophyll from a green leaf during photosynthesis experiments ?
Why do we boil the leaf in alcohol when we are testing it for starch ?
We boil the leaf in Alcohol to remove all its green pigment called chlorophyll.
(a) Name the pigment in leaves which absorbs sunlight energy.
(b) What is the colour of this pigment ?
(a) Chlorophyll. (b) Green.
Name the pigment which can absorb solar energy.
Name the organelle of plant cells in which photosynthesis occurs.
Apart from carbon dioxide and water, name four other raw materials which are needed by the plants.
Nitrogen, phosphorus, iron and magnesium.
Where is chlorophyll mainly present in a plant ?
What is the name of those cells in the leaf of a plant which control the opening and closing of stomata?
Name an animal whose process of obtaining food is called phagocytosis.
All the animals can be divided into three groups on the basis of their eating habits. Name the three groups.
(i) Herbivores.(ii) Carnivores.(iii) Omnivores.
What is the scientific name of the animals which are :
(i) only meat eaters ?
(ii) only plant eaters ?
(iii) both, plant and meat eaters ?
(i) Carnivores.(ii) Herbivores.(iii) Omnivores.
Name the green pigment present in the leaves of a plant.
Arrange the following processes involved in the nutrition in animals in the correct order (in which they take place):
Assimilation, Egestion, Ingestion, Absorption, Digestion
Ingestion, digestion, absorption, assimilation, egestion.
How does Amoeba engulf the food particle ?
Amoeba engulfs the food particles with the help of finger like projections called pseudopodia.
What substances enter into the food vacuole in Amoeba to break down the food ?
From which part of the body, undigested food is egested in Amoeba ?
Amoeba has no fixed place for egestion. The undigested food gets collected inside amoeba, then its cell membrane suddenly ruptures and the undigested food is thrown out of the body of amoeba.
Name a unicellular animal which uses cilia to move food particles into its mouth.
Name the enzyme present in human saliva. What type of food material is digested by this enzyme ?
Salivary amylase is present in human saliva. It digests starch.
Which of the organs perform the following functions in humans ?
(i) Absorption of food
(ii) Absorption of water
Which of the organs perform the following functions in humans ?
(i) Absorption of food
(ii) Absorption of water
(i) Small Intestine.
(ii) Large Intestine.
What moves the food in the digestive organs ?
What is the other name of food pipe ?
What substance is mixed with food in the mouth during chewing by the teeth ?
What is the name of tiny projections on the inner surface of small intestine which help in absorbing the digested food ?
In which part of the digestive system is water absorbed ?
What is the name of the opening in the human body through which undigested food is thrown out ?
Where is digested food absorbed into blood in human body ?
Name the biological catalysts which bring about chemical digestion of food.
Fill in the following blanks with suitable words :
(a) All green plants are…………..
(b) All non-green plants and animals are…………
(c) Heterotrophs depend on…….. and other……………… for food,
(d) Green plants use……… ,………… and………… to make food.
(e) Iodine turns blue-black on reacting with………………
(d) Carbon dioxide, water.
Lakhmir Singh Biology Class 10 Solutions Page No:25
(a) What is chlorophyll ? What part does chlorophyll play in photosynthesis ?
(b) (i) Which simple food is prepared first in the process of photosynthesis ?
(ii) Name the food which gets stored in plant leaves.
(a) Chlorophyll is a green coloured pigment present in the leaves of plants. It helps in absorbing energy from sunlight during the process of photosynthesis.(b) (i) Glucose(ii) Starch.
(a) What criteria can be used to decide whether something is alive ?
(b) What is meant by life processes ? Name the basic life processes common to all living organisms which are essential for maintaining life.
(a) The criteria to decide whether something is alive is the movement.
(b) The basic functions performed by living organisms to maintain their life on this earth are called life processes. The basic life processes common to all living organisms are ? Nutrition and Respiration; Transport and Excretion; Control and Coordination; Growth; Movement and Reproduction.
(a) What are autotrophs ? Give one example of autotrophs.
(b) What are the conditions necessary for autotrophic nutrition ?
(a) Autotrophs are those organisms which can make their own food from carbon dioxide and water. Example: Green Plants.(b) The conditions necessary for autotrophic nutrition are sunlight, chlorophyll, carbon dioxide and water.
(a) What are heterotrophs ? Give one example of heterotrophs.
(b) What is the difference between autotrophic nutrition and heterotrophic nutrition ?
(a) Those organisms which cannot make their own food from inorganic substances like carbon dioxide and water, and depend on other organisms for their food are called heterotrophs. Example: All Animals.
It is that mode of nutrition in which an organism makes its own food from the simple inorganic materials like carbon dioxide and water present in the surroundings (with the help of sunlight energy) Example: Green Plants
It is that mode of nutrition in which an organism cannot make its own food from simple inorganic materials like carbon dioxide and water, and depends on other organisms for its food.Example: Animals.
(a) Define a nutrient. Name four important nutrients present in our food.
(b) What are the various types of heterotrophic nutrition ?
(a) A nutrient can be defined as a substance which an organism obtains from its surroundings and uses it as a source of energy or for the biosynthesis of its body constituents (like tissues and organs). The four important nutrients present in our food are: carbohydrates, fats, proteins and mineral salts.
(b) The various types of Heterotrophic nutrition are:
(i) Saprotrophic nutrition.
(ii) Parasitic nutrition.
(iii) Holozoic nutrition.
(a) Photosynthesis converts energy X into energy Y. What are X and Y ?
(b) State the various steps involved in the process of photosynthesis.
(a) X is sunlight energy and Y is chemical energy.
(b) The photosynthesis takes place in the following three steps;
(i) Absorption of sunlight energy by chlorophyll.
(ii) Conversion of light energy into chemical energy and splitting of water into hydrogen and oxygen by light energy.
(iii) Reduction of carbon dioxide by hydrogen to form carbohydrates like glucose by utilising the chemical energy
(a) How do plants obtain food ?
(b) Why do plants need nitrogen ? How do plants obtain nitrogen ?
(a) Plants obtain food by a process called photosynthesis.
(b) Plants need nitrogen to make proteins and other compounds. They take up nitrogen from the soil in the form of inorganic salts called nitrates (or nitrites), or in the form of organic compounds which are produced by bacteria from the atmospheric nitrogen.
Define (i) saprophytic nutrition (ii) parasitic nutrition, and (iii) holozoic nutrition. Give one example of each type.
(i) Saprophytic nutrition: It is that nutrition in which an organism obtains its food from dead organic matter of dead plants, dead animals and rotten bread. Example: Fungi and many bacteria obtain food by saprophytic nutrition.
(ii) Parasitic nutrition: It is that nutrition in which an organism derives its food from the body of another living organism (called its host) without killing it.Example: Plasmodium and round worms obtain food by parasitic nutrition.
(iii) Holozoic nutrition: It is that nutrition in which an organism takes the complex organic food materials into its body by the process of ingestion; the ingested food is digested and then absorbed into the body cells of the organism.Example: Human beings obtain food by holozoic nutrition
Define (2) saprophyte, and (22) parasite. Name two saprophytes and two parasites.
(a) Saprophyte – Saprophytes are the organisms which obtain their food from dead plants (like rotten leaves), dead and decaying animal bodies, and other decaying organic matter (like rotten bread).Example: Fungi and some bacteria.
(b) Parasite: A parasite is an organism (plant or animal) which feeds on another living organism called its host.Example: Plasmodium and round worm.
(a) How does carbon dioxide from the air enter the leaves of a plant to be used in photosynthesis ?
(b) How does water from the soil reach the leaves of a plant to be used in photosynthesis ?
(a) The carbon dioxide gas enters the leaves of the plants through the stomata present on their surface.
(b) The water required by the plants for photosynthesis is absorbed by the roots of the plants from the soil through the process of osmosis. The absorbed water is then transported upward through the xylem vessels to the leaves where it reaches the photosynthetic cells and utilized in photosynthesis.
What substances are contained in gastric juice ? What are their functions ?
The gastric juice contains three substances; hydrochloric acid, the enzyme pepsin and mucus. Functions: (a) Hydrochloric acid: It makes the medium of gastric juice acidic so that the enzyme pepsin can digest the proteins properly and also kills any bacteria that might have entered the stomach with food.
(b) Pepsin: The enzyme pepsin digests the proteins present in the food and converts them into smaller molecules.
(c) Mucus: The mucus helps to protect the stomach wall from its own secretions of hydrochloric acid.
What substances are contained in pancreatic juice ? What are their functions ?
Pancreatic juice contains digestive enzymes ? Pancreatic Amylase, trypsin and lipase. Functions:
(a) Pancreatic amylase: The enzyme amylase breaks down the starch.
(b) Trypsin: trypsin digests the proteins.
(c) Lipase: Lipase breaks down the emulsified fats.
(a) What is the role of hydrochloric acid in our stomach ?
(b) What is the function of enzymes in the human digestive system ?
(a) Hydrochloric acid: It makes the medium of gastric juice acidic so that the enzyme pepsin can digest the proteins properly and also kills any bacteria that might have entered the stomach with food.
(b) Enzymes help in the breaking down of complex organic food materials into simpler forms.
(a) Which part of the body secretes bile ? Where is bile stored ? What is the function of bile ?
(b) What is trypsin ? What is its function ?
(a) Liver secretes bile which gets stored in the gall bladder. Bile performs two functions:
(i) Makes the acidic food coming from the stomach alkaline so that the pancreatic enzymes can act on it.
(ii) Bile salts breaks the fats present in the food into small globules making it easy for the enzymes to act and digest them.
(b) Trypsin: It is a pancreatic enzyme present in the pancreatic juice. Its function is to digest the proteins.
What are the functions of liver and pancreas in the human digestive system ?
Liver secretes bile which helps in the emulsification of fats. Pancreas secretes pancreatic juice which emulsifies starch, proteins and fats.
Match the organisms given in column I with the processes given in column II :
(i) – (c)
(ii) – (a)
(iii) – (d)
(iv) – (b)
Name the following :
(a) The process in plants which converts light energy into chemical energy.
(b) Organisms that cannot prepare their own food.
(c) Organisms that can prepare their own food.
(d) The cell organelle where photosynthesis occurs.
(e) The cells which surround a stomatal pore.
(f) An enzyme secreted by gastric glands in stomach which acts on proteins.
(e) Guard cells.
Match the terms in column I with those in column II :
(i) – (c)
(ii) – (d)
(iii) – (a)
(iv) – (b)
Lakhmir Singh Biology Class 10 Solutions Page No:26
(a) What is common for Cuscuta, ticks and leeches ?
(b) Name the substances on which the following enzymes act in the human digestive system :
(i) Trypsin (ii) Amylase (iii) Pepsin (iv) Lipase
(c) Why does absorption of digested food occur mainly in the small intestine ?
(a) Parasitic mode of nutrition.
(c) Absorption of digested foods occurs mainly in the small intestine due to the presence of a large number of finger like projections called villi.
(a) Why is small intestine in herbivores longer than in carnivores ?
(b) What will happen if mucus is not secreted by the gastric glands ?
(c) What causes movement of food inside the alimentary canal ?
(a) Herbivores eat only plants so they need a longer small intestine to allow the cellulose present in the plants to be digested completely.
(b) If mucus is not secreted, hydrochloric acid will cause the erosion of inner lining of stomach leading to the formation of ulcers in the stomach.
(c) The contraction and expansion movements of oesophagus also called peristaltic movements pushes the food down into the elementary canal.
(a) How do guard cells regulate opening and closing of stomatal pores ?
(b) Two similar green plants are kept separately in oxygen free containers, one in dark and the other in continuous light. Which one will live longer ? Give reasons.
(a) The opening and closing of stomatal pores is controlled by the guard cells, when water flows into the guard cells, they swell, become curved and cause the pore to open whereas when the guard cells lose water, they shrink, become straight and close the stomatal pore. (b) Plant kept in continuous light will live longer because it will be able to produce oxygen required for its respiration by the process of photosynthesis.
(a) What would happen if all the green plants disappear from the earth ?
(b) If a plant is releasing carbon dioxide and taking in oxygen during the day, does it mean that there is no photosynthesis occurring ? Justify your answer.
(a) If all the green plants disappear from the earth, then all the organisms (herbivores, carnivores and omnivores) will die due to starvation as green plants are the source of food for all organisms.
(b) When photosynthesis occurs during the day, the carbon dioxide released by plants by respiration is all used up and not released. Similarly, some of the oxygen produced during photosynthesis is used up in respiration. Since the plant is releasing carbon dioxide and taking in oxygen even during the day, it means that no photosynthesis is taking place.
(a) Leaves of a healthy potted plant were coated with vaseline. Will this plant remain healthy for long ? Give reason for your answer.
(b) What will happen to the rate of photosynthesis in a plant under the following circumstances ?
- cloudy day in morning but bright sunshine in the afternoon
- no rainfall in the area for a considerable time.
- gathering of dust on the leaves
(a) This plant will not remain healthy for long because vaseline coating closes the stomatal pores on the leaves due to which
(i) plant will not get oxygen for respiration
(ii) plant will not get carbon dioxide for photosynthesis, and
(iii) plant will not get water (and minerals) due to stoppage of transpiration.
(b) (i) Decreases in morning but increases in the afternoon
(a) What is photosynthesis ?
(b) Write a chemical equation to show the process of photosynthesis in plants.
(c) Explain the mechanism of photosynthesis.
(a) The process by which green plants make their own food (like glucose) from carbon dioxide and water by using sunlight energy in the presence of chlorophyll is called photosynthesis.
(c) The process of photosynthesis takes place in the green leaves of a plant. The carbon dioxide gas required for making food is taken by the plant leaves from the air which enters the leaves through tiny pores called stomata. Water required for making food is taken from the soil which is transported to the leaves from the soil through the roots and the stem. The sunlight provides energy required to carry out the chemical reactions involved in the preparation of food. The green pigment called chlorophyll absorbs sunlight energy. The photosynthesis takes place in three steps:
(i) Absorption of sunlight energy by chlorophyll.
(ii) Conversion of light energy into chemical energy and splitting of water into hydrogen and oxygen by light energy.
(iii) Reduction of carbon dioxide by hydrogen to form carbohydrates like glucose by utilising the chemical energy.
(a) Name the raw materials required for photosynthesis. How do plants obtain these raw materials ?
(b) What are the various conditions necessary for photosynthesis ?
(c) Name the various factors which affect the rate of photosynthesis in plants.
(a) The raw materials for photosynthesis are carbon dioxide and water. The green plants take carbon dioxide from air for photosynthesis. The carbon dioxide gas enters the leaves of the plants through the stomata present on their surface. The water required by the plants for photosynthesis is absorbed by the roots of the plants from the soil through the process of osmosis. The water absorbed by the roots is transported upwards through the xylem vessels to the leaves where it reaches the photosynthetic cells and utilized in photosynthesis.
(b) The conditions for photosynthesis are sunlight, chlorophyll, carbon dioxide and water.
(c) Factors affecting the rate of photosynthesis are
(ii) Carbon dioxide
(v) Mineral elements.
(a) Define nutrition. Why is nutrition necessary for an organism ?
(b) What are the different modes of nutrition ? Explain with one example of each mode of nutrition.
(c) Name the mode of nutrition in (i) roundworm, and (ii) Plasmodium.
(a) Nutrition is defined as a process of intake of nutrients (like carbohydrates, fats, proteins, minerals, vitamins and water) by an organism as well as the utilisation of these nutrients by the organism. Nutrition is necessary for an organism as it provides energy to them from the food they eat. (b) There are mainly two modes of nutrition:
(i) Autotrophic – Autotrophic nutrition is that mode of nutrition in which an organism makes its own food from the simple inorganic materials like carbon dioxide and water present in the surroundings (with the help of sunlight energy). Example: Green plants obtain food by autotrophic nutrition.
(ii) Heterotrophic – Heterotrophic nutrition is that mode of nutrition in which an organism cannot make its own food from simple inorganic materials like carbon dioxide and water, and depends on other organisms for its food. Example: All animals obtain food by heterotrophic nutrition.
(c) The mode of nutrition in
(i) round worm and
(ii) plasmodium is parasitic nutrition.
(a) What are herbivores, carnivores and omnivores ? Give two examples of each.
(b) Classify the following into herbivores, carnivores and omnivores :
Lion, Man, Dog, Goat, Crow, Elephant, Snake, Hawk, Rabbit, Deer
(c) Name the five steps which occur in the process of nutrition in animals.
(a) (i) Herbivores – Those animals which eat only plants are called herbivores. Example: Goat and cow.
(ii) Carnivores – Those animals which eat only other animals as food are called carnivores. Example: Tiger and Lion.
(iii) Omnivores – Those animals which eat both plants and animals are called omnivores. Example: Human Being and dog.
(c) The five steps involved in the process of nutrition in animals are
(a) Describe the process of nutrition in Draw labelled diagrams to show the various steps in the nutrition in Amoeba.
(b) What is the mode of nutrition in Amoeba known as ?
(c) What is the process of obtaining food by Amoeba called ? What does it mean ?
(a) Nutrition in amoeba: Nutrition in amoeba involves the following steps
(i) Ingestion ? Amoeba has no mouth for ingestion of food. It ingests the food by using its pseudopodia. The food is engulfed with little water to form a food vacuole.
(ii) Digestion ? The food is digested by digestive enzymes present in the cytoplasm which breaks the food into small soluble molecules by chemical reactions.
(iii) Absorption ? The digested food is absorbed directly into the cytoplasm by diffusion. The digested food spreads out from the food vacuole into the whole cell and after absorption the food vacuole disappears.
(iv) Assimilation ? Food is used to obtain energy through respiration and the remaining part of the food is used for growth.
(v) Egestion ? The undigested food collects inside the cell and the cell membrane ruptures. Through this, the undigested food is thrown out of the body.
(b) The mode of nutrition in amoeba is holozoic.
(c) The process of obtaining food is called phagocytosis, which means cell feeding.
(a) Draw a labelled diagram of the human digestive system. With the help of this diagram, describe the process of digestion of food in man (humans).
(b) Describe one way in which the small intestine is adapted for the absorption of digested food.
(c) What is the special name of the contraction and expansion movement which pushes the food further in our digestive tract (or alimentary canal) ?
(a) Digestion of food in human beings: Digestion of food begins in the mouth. The mouth cavity contains teeth, tongue and salivary glands. The teeth cut the food into small pieces, chew and grind it. This is called physical digestion. Salivary glands produce saliva which mixes with the food. This involves chemical digestion of food. The saliva contains an enzyme called salivary amylase which digests the starch and converts it into maltose sugar. Mouth opens into a small funnel shaped area called pharynx which leads to a long tube called oesophagus. It carries the food down into the stomach. The wall of oesophagus is muscular. When the slightly digested food enters the food pipe, the walls of the oesophagus starts contraction and expansion movements called peristaltic movements which push the food into the stomach. Digestion does not take place in the oesophagus. The glands present on the walls of the stomach secrete gastric juice that contains hydrochloric acid, the enzyme pepsin and mucus. A small amount of gastric lipase is also present that breaks down the fats present in the food. Gastric juice is acidic due to the presence of HCl which is necessary for the pepsin to become active and converts the proteins into peptones. The mucus protects the stomach walls from HCl. From the stomach, the partially digested food goes into the small intestine through sphincter muscle. Small intestine is divided into two parts: Duodenum and Ileum. Duodenum receives the secretions of two glands, liver and pancreas through a common duct. Liver secretes bile which is alkaline and contains salts to emulsify the fats (or lipids). The bile secreted by the liver is stored in the gall bladder. Pancreas secretes pancreatic juice which contains trypsin, lipase and pancreatic amylase. Trypsin digests the proteins, lipase emulsifies the fats and pancreatic amylase breaks down the starch. Thus, small intestine is the site of complete digestion of carbohydrates, proteins and fats. The walls of ileum secrete succus entericus which completes the digestion process.
(b) The walls of small intestine has finger like projections like villi which increases the surface area for absorption.
(c) Peristaltic movements.
(a) Describe the parts of our tooth with the help of a labelled diagram.
(b) What is meant by dental caries ? How are they caused ?
(c) What is dental plaque ? What harm can it do ? How can the formation of plaque be prevented ?
(a) The tooth has hard outer covering called enamel. The part of tooth below enamel is called dentine inside which is the pulp cavity. The pulp cavity contains nerves and blood vessels.
(b) The formation of small cavities (or holes) in the teeth due to the action of acid forming bacteria and improper dental care is called dental caries. This happens as follows: When we eat sugary food, the bacteria in our mouth act on sugar to produce acids. These acids dissolve the calcium salts from the tooth enamel and then from dentine forming small cavities in the tooth over a period of time in our mouth act on sugar to produce acids. These acids dissolve the calcium salts from the tooth enamel and then from dentine forming small cavities in the tooth over a period of time.
(c) If the teeth are not cleaned regularly, they become covered with the sticky, yellowish layer of food particles and bacteria cells called dental plaque. It causes tooth decay. It can be prevented by brushing the teeth regularly as it neutralises the acids.
(a) Name the main organs of the human digestive system. Also name the associated glands.
(b) How do carbohydrates, fats and proteins get digested in human beings ?
(a) The various organs of the human digestive system are mouth, oesophagus, stomach, small intestine and large intestine. The glands associated with the human digestive system are salivary glands, liver and pancreas.
(b) (i) Carbohydrates – The digestion of carbohydrates begins in the mouth. The human saliva contains an enzyme called salivary amylase which digests the starch present in the food into maltose sugar. The slightly digested carbohydrates when reaches the small intestine, pancreatic amylase present in the pancreatic juice breaks down the starch. The intestinal juice of the small intestine completes the digestion of carbohydrates and finally coverts it into glucose.
(ii) Fats – The process of digestion of fats begins in the stomach. The glands of stomach secrete a small amount of gastric lipase that breaks down the fats present in the food. From the stomach the partially digested food goes into small intestine where the pancreatic lipase breaks down the emulsified fats. The walls of small intestine secrete intestinal juice which converts the fats into fatty acids and glycerol.
(iii) Proteins – The digestion of proteins begins in the stomach. The glands of the stomach secrete gastric juice which contains an enzyme called pepsin. Pepsin converts the proteins into peptones. Pancreatic juice contains trypsin which digests the proteins into peptides and the intestinal juice completes the process of digestion of proteins thus converting it into amino acids.
Lakhmir Singh Biology Class 10 Solutions Page No:46
Do all cells use oxygen to produce energy ?
Name one substance which is produced in anaerobic respiration by an organism but not in aerobic respiration.
Name one organism which can live without oxygen.
Yeast can live without oxygen.
In which type of respiration, aerobic or anaerobic, more energy is released ?
Name the substance whose build up in the muscles during vigorous physical exercise may cause cramps.
Which part of roots is involved in the exchange of respiratory gases ?
Lakhmir Singh Biology Class 10 Solutions Page No:47
Name the process by which plant parts like roots, stems, and leaves get oxygen required for respiration.
Name the pores in a leaf through which respiratory exchange of gases takes place.
Name the areas in a woody stem through which respiratory exchange of gases takes place.
What is the name of the extensions of the epidermal cells of a root which help in respiration ?
Out of photosynthesis and respiration in plants, which process occurs :
(a) all the time ?
(b) only at daytime ?
Name the organs of breathing in fish.
Name an animal which absorbs oxygen through its moist skin.
Name an animal which depends on simple diffusion of gases for breathing.
Name two animals which breathe through gills.
Prawns and mussels.
The trachea divides into two tubes at its lower end. What is the name of these tubes ?
Where does the blood absorb oxygen in the human body ?
Name the red pigment which carries oxygen in blood.
Which gases are exchanged in your lungs ?
Oxygen and carbon dioxide.
Where in the lungs does gas exchange take place ?
What is the name of tiny air-sacs at the end of smallest bronchioles in the lungs ?
What is the other name of wind-pipe ?
What organs are attached to the two bronchi ?
In the lungs :
(a) what substance is taken into the body ?
(b) what substance is removed from the body ?
(b) Carbon dioxide.
State whether the following statements are true or false :
(a) During respiration, the plants take C02 and release 02.
(b) Energy can be produced in cells without oxygen.
(c) Fish and earthworm exchange gases during respiration in the same way.
Fill in the following blanks with suitable words :
(a) The organs of respiration in man are the…………..
(b) The actual exchange of gases takes place in the………… of the lungs.
(c) ………………in the lungs provide a very large surface area for gaseous exchange.
(d) Yeast undergoes……….. respiration whereas Amoeba undergoes………….. respiration.
(e) Gills are the breathing organs in…………..
(d) Anaerobic, aerobic.
Explain why, a land plant may die if its roots remain water logged for a long time.
A land plant may die if its roots remain water logged for a long time because too much water expels all the air from in-between the soil particles. Due to this, oxygen is not available to the roots for aerobic respiration. Under these conditions the roots will respire anaerobically producing alcohol which may kill the plant.
What are the differences between aerobic and anaerobic respiration ? Name some organisms that use anaerobic mode of respiration.
(i) Aerobic respiration takes place in the presence of oxygen.
(ii) Complete breakdown of food occurs in aerobic respiration.
(iii) The end products in aerobic respiratin are carbon dioxide and water.
(iv) Aerobic respiration produces a considerable amount of energy.
(i) Anaerobic respiration takes place in the absence of oxygen.
(ii) Partial break down of food occurs in anaerobic respiration.
(iii) The end products in anaerobic respiration are ethanol and carbon dioxide (in yeast) and lactic and (in animal muscles).
(iv) Much less energy is produced in anaerobic respiration.
(b) Yeast and some bacteria.
Name the final product/products obtained in the anaerobic respiration, if it takes place :
(a) in a plant (like yeast).
(b) in an animal tissue (like muscles).
(a) Ethanol and carbon dioxide.(b) Lactic acid.
What type of respiration takes place in human muscles during vigorous physical exercise ? Give reason for your answer.
Anaerobic respiration takes place in human muscles during vigorous physical exercise because oxygen gets used up faster in the muscle cells than can be supplied by the blood.
Name the type of respiration in which the end products are :
(a) C2H,OH and C02
(b) C02 and H20
(c) Lactic acid
Give one example of each case where such a respiration can occur.
(a) Anaerobic respiration in yeast.
(b) Aerobic respiration in humans.
(c) Anaerobic respiration in muscle tissue of animals.
Define breathing. State the differences between breathing and respiration.
The mechanism by which an organism obtains oxygen from the air and releases carbon dioxide is called breathing.Difference between breathing and respiration:-
(i) Breathing is a simple process.
(ii) Breathing involves taking in oxygen from the air and releasing carbon dioxide into the air.
(iii) Breathing is a physical process.
(i) Respiration is a complex process.
(ii) Respiration includes breathing as well as the oxidation of food in the cells of the organism to release energy.
(iii) Respiration is a bio-chemical process.
What are the different ways in which glucose is oxidised to provide energy in various organisms ? Give one example of each.
There are two ways in which glucose is oxidized to provide energy in various organisms:
(i) Anaerobic respiration ? The respiration which takes place without oxygen is called anaerobic respiration.Example: Yeast and some bacteria break down glucose into ethanol and carbon dioxide.
(ii) Aerobic respiration ? The respiration which uses oxygen is called aerobic respiration.Example: Plants and animals break down glucose completely into carbon dioxide and water to release energy.
Lakhmir Singh Biology Class 10 Solutions Page No:48
Explain why, when air is taken in and let out during breathing, the lungs always contain a residual volume of air.
During the breathing cycle, when air is taken in and let out, the lungs always contain a certain residual volume of air so that there is sufficient time ‘for the oxygen absorbed’ into the blood and ‘for the carbon dioxide to be released’ from the blood.
Explain why, it is dangerous to inhale air containing carbon monoxide.
It is dangerous to inhale air containing carbon monoxide as it binds very strongly with haemoglobin in the blood and prevents it from carrying oxygen to the brain and other parts of the body. Due to lack of oxygen, the person cannot breathe properly and may become unconscious or may even die.
Describe the process of respiration in State whether it is anaerobic respiration or aerobic respiration.
(a) Respiration in amoeba: Amoeba depends on simple diffusion of gases for breathing. The diffusion of gases takes place through the thin cell membrane of amoeba. Amoeba lives in water which contains dissolved oxygen. The oxygen from water diffuses into the body of amoeba through its cell membrane. The oxygen spreads quickly into the whole body and is used for respiration inside the amoeba cell. The process of respiration produces carbon dioxide which diffuses out through its cell membrane into the surrounding water.
(b) It is aerobic respiration.
State the three common features of all the respiratory organs like skin, gills and lungs.
The common features of all respiratory organs ? skin, gills and lungs are: (i) All the respiratory organs have a large surface area to get enough oxygen.(ii) All the respiratory organs have thin walls for easy diffusion and exchange of respiratory gases.(iii) All the respiratory organs like skin, gills and lungs have a rich blood supply for transporting respiratory gases.
Describe the process of respiration in fish.
Respiration and fish: The fish has special organ of breathing called gills on both the sides of its head. The gills are covered by gill covers. The fish lives in water which contains dissolved oxygen. The fish breathes by taking in water through its mouth and sending it over the gills. When water passes over the gills, the gills extract dissolved oxygen from the water. The extracted oxygen is absorbed by the blood and carried to all the parts of the fish. The carbon dioxide produced by respiration is brought back by the blood into the gills for expelling into the surrounding water.
What would be the consequences of deficiency of haemoglobin in our bodies ?
The deficiency of haemoglobin in the blood of a person reduces the oxygen carrying capacity of blood resulting in breathing problems, tiredness and lack of energy.
Describe the process of respiration in the following parts of a plant :
(a) Root (b) Stem (c) Leaves
(a) Respiration in roots: The roots of a plant take the oxygen required for respiration from the air present in-between the soil particles by the process of diffusion. The roots have extensions of epidermal cells of a root called root hair which are in contact with the air in the soil. Oxygen diffuses from root hairs and reaches all the other cells of the root for respiration. Carbon dioxide gas produced in the cells of the root during respiration moves out through the root hairs by the process of diffusion. Thus, the respiration in roots occurs by diffusion of respiratory gases through the root hairs.
(b) Respiration in stems: The stems of herbaceous plants takes place through stomata. The oxygen from the air diffuses into the stem of a herbaceous plant through stomata and reaches all the cells for respiration. The carbon dioxide produced diffuses out through stomata. In woody stems, the bark has lenticels for the exchange of gases.
(c) Respiration in leaves: The leaves of a plant has tiny pores called stomata through which the exchange of respiratory gases takes place by diffusion. Oxygen from air diffuses into a leaf through stomata and reaches all the cells, where it is used for respiration and the carbon dioxide produced diffuses out from the leaf into the air through stomata.
(a) What is meant by aquatic animals and terrestrial animals ?
(b) From where do the aquatic animals and terrestrial animals obtain oxygen for breathing and respiration ?
(a) Aquatic animals are the animals which live in water and the terrestrial animals are the animals which live on land.
(b) The aquatic animals use the oxygen dissolved in water to carry out respiration. The terrestrial animals obtain oxygen from air.
Why do fishes die when taken out of water ?
Fishes die when taken out of water because they do not have lungs to utilize the oxygen of air for breathing and respiration. They have gills which can extract only dissolved oxygen from water.
Why is the rate of breathing in aquatic organisms much faster than in terrestrial organisms ?
The rate of breathing in aquatic animals is much faster than terrestrial animals because the amount of oxygen dissolved in water is low as compared to the amount of oxygen dissolved in air.
Name the energy currency in the living organisms. When and where is it produced ?
The energy currency of the cell is ‘ATP’. It is produced in cytoplasm in lower organisms which respire anaerobically. In higher organisms, ‘ATP’ is produced in mitochondria when they respire aerobically.
Explain why, plants have low energy needs as compared to animals.
Plants do not move. In a large plant body there are many dead cells like sclerenchyma as a result it requires less energy as compared to animals.
Explain how, it would benefit deep sea divers if humans also had gills.
If humans also had gills then the deep sea divers could remain under sea water even without carrying oxygen cylinders for breathing as they would be able to extract the dissolved oxygen from water for breathing purpose just like a fish does.
(a) What is the function of the respiratory system ?
(b) What are the major organs of respiratory system in man (or humans) ?
(c) Draw a labelled diagram of the human respiratory system.
(a) The function of respiratory system is to breathe in oxygen for respiration (producing energy from food), and to breathe out carbon dioxide produced by respiration.
(b) The major organs of respiratory system in human beings are:
(ii) Nasal Passage
(v) Lungs and
(a) Explain how, the air we breathe in gets cleaned while passing through the nasal passage.
(b) Why do the walls of trachea not collapse when there is less air in it ?
(c) How are oxygen and carbon dioxide exchanged in our body during respiration ?
(d) How are lungs designed in human beings to maximise the exchange of gases ?
(a) When air passes through the nasal passage, the dust particles and other impurities present in it are trapped by nasal hair and mucus so that clean air goes into the lungs.
(b) Trachea does not collapse even when there is no air in it because it is supported by rings of soft bones called cartilage.
(c) During the process of ‘breathing in’ the air sacs or alveoli of the lungs get filled with air contain.