A abampere (aA) The unit of electric current in the CGSeniu system, defined as that current that, if flowing through two parallel conductors of negligible cross section and infinite length, placed 1 cm apart in vacuo, would produce on each conductor a force of 1 dyne per centimeter of length. 1 abampere = 1 abcoulomb/s = r statampere (where c = speed of light in cm/s) = 10 ampere. aberration Imperfect image formation due to geometric imperfections in the optical elements of a system ablation 1 . The wasting of glacier ice by any process (calving, melting, evaporation, etc.). 2. The shedding of molten material from the outer sur- face of a meteorite or tektite during its flight through the atmosphere. absolute age The age of a natural substance, of a fossil or living organism, or of an artifact, obtained by means of an absolute dating method. See absolute dating method. absolute density Density in kg/m' or, more commonly, in g/cm\ both at STP. Cf. density, relative density abso
Life processes class 10 NCERT biology SAQ & MCQ
Life processes class 10 NCERT biology NCERT SOLUTION
1. Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?
Unlike the unicellular organisms, the multi-cellular organisms have complex body structures with specialized cells and tissues to perform various necessary functions of the body. Since these cells are not in direct contact with the surrounding environment, simple diffusion cannot meet the oxygen requirement of all these cells.
2. What criteria do we use to decide whether something is alive?
Any visible movement such as walking, breathing, or growing is generally used to decide whether something is alive or not. However, a living organism can also have movements, which are not visible to the naked eye. Therefore, the presence of life processes is a fundamental criterion that can be used to decide whether something is alive or not.
3. What are outside raw materials used for by an organism?
Various outside raw materials used by an organism are as follows:
→ Food as a source of supplying energy and materials.
→ Oxygen for breakdown of food to obtain energy.
→ Water for proper digestion of food and other functions inside the body.
The raw materials required by an organism will vary depending on the complexity of the organism and its environment.
4. What processes would you consider essential for maintaining life?
Life processes such as nutrition, respiration, transportation, excretion, etc. are essential for maintaining life.
1. What are the differences between autotrophic nutrition and heterotrophic nutrition?
2. Where do plants get each of the raw materials required for photosynthesis?
The following raw materials are required for photosynthesis:
→ Carbon Dioxide: Plants get CO2 from the atmosphere through stomata.
→ Water: Plants absorb water from soil through roots and transport to leaves.
→ Sunlight: Sunlight, which is absorbed by the chlorophyll and other green parts of the plant.
3. What is the role of the acid in our stomach?
Following are the roles of acid in our stomach:
→ The hydrochloric acid present in our stomach dissolves bits of food and creates an acidic medium. In this acidic medium, enzyme pepsinogen is converted to pepsin, which is a protein-digesting enzyme.
→ It also kills many bacteria and other microorganisms that enter along with the food.
4. What is the function of digestive enzymes?
digestive enzymes such as amylase, lipase, pepsin, trypsin, etc. help in the breaking down of complex food particles into simple ones. These simple particles can be easily absorbed by the blood and thus transported to all the cells of the body.
5. How is the small intestine designed to absorb digested food?
The small intestine has millions of tiny finger-like projections called villi. These villi increase the surface area for more efficient food absorption. Within these villi, many blood vessels are present that absorb the digested food and carry it to the bloodstream. From the bloodstream, the absorbed food is delivered to each and every cell of the body.
1. What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Terrestrial organisms take up oxygen from the atmosphere whereas aquatic animals obtain oxygen from water. Air contains more O2 as compared to water. Since the content of O2 in air is high, the terrestrial animals do not have to breathe faster to get more oxygen. Therefore, unlike aquatic animals, terrestrial animals do not need adaptations for gaseous exchange.
2. What are the different ways in which glucose is oxidized to provide energy in various organisms?
At first glucose (6 carbon molecules) is broken in the cytoplasm of cells of all organisms. This process yields a 3 carbon molecule compound called pyruvate.
Further breakdown of pyruvate takes place in different manners in different organisms.
→ Anaerobic Respiration: This process takes place in absence of oxygen, e.g. in yeast during fermentation. In this case, pyruvate is converted into ethanol and carbon dioxide.
→ Aerobic Respiration: In aerobic respiration, the breakdown of pyruvate takes place in presence of oxygen to give rise to 3 molecules of carbon dioxide and water. The release of energy in aerobic respiration is much more than anaerobic respiration.
→ Lack of Oxygen: Sometimes, when there is lack of oxygen, especially during vigorous activity, in our muscles, pyruvate is converted into lactic acid (3 carbon molecule compounds). Formation of lactic acid in muscles causes cramp.
3. How is oxygen and carbon dioxide transported in human beings?
Transport of Oxygen: The respiratory pigments (hemoglobin) present in red blood cells takes up the oxygen from the air to the lungs. They carry the oxygen to tissues which are deficient in oxygen.
→ Transport of carbon dioxide: Carbon Dioxide is more soluble in water. Hence, it is mostly transported from body tissues in the dissolved form in our blood plasma to lungs where it diffuses from blood to air in the lungs and then expelled out through nostrils.
4. How are the lungs designed in human beings to maximize the area for exchange of gasses?
Lungs contain millions of alveoli which provide a surface for the exchange of gasses. An extensive network of blood vessels is present in the wall of the alveoli. By lifting our ribs and flatten the diaphragm, the chest cavity becomes spacious. Air is sucked into the lungs and alveoli. The oxygen from the breath, diffuses into the blood and CO2 from the blood brought from the body, diffuses out into the air.
1. What are the components of the transport system in human beings? What are the functions of these components?
The main components of the transport system in human beings are the heart, blood, and blood vessels.
→ Heart pumps oxygenated blood throughout the body. It receives deoxygenated blood from the various body parts and sends this impure blood to the lungs for oxygenation.
→ Blood helps in the transport of oxygen, nutrients, CO2, and nitrogenous wastes.
→ The blood vessels (arteries, veins, and capillaries) carry blood either away from the heart to various organs or from various organs back to the heart.
2. Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
It is necessary to separate oxygenated and deoxygenated blood to maintain efficient supply of oxygen into the body. This system is essential in animals that have high energy needs. For example, animals like mammals and birds which constantly use this energy to maintain their body temperature.
3. What are the components of the transport system in highly organized plants?
In highly organized plants, there are two different types of conducting tissues - xylem and phloem. Xylem conducts water and minerals obtained from the soil (via roots) to the rest of the plant. Phloem transports food materials from the leaves to different parts of the plant body.
4. How are water and minerals transported in plants?
Water and minerals are transported through xylem cells from soil to the leaves. The xylem cells of roots stem and leaves are interconnected to form a conducting channel that reaches all parts of the plant. The root cells take ions from the soil. This creates a difference between the concentration of ions of roots and soil. Therefore, there is a steady movement of water into the xylem. An osmotic pressure is formed and water and minerals are transported from one cell to the other cell due to osmosis. The continuous loss of water takes place due to transpiration. Because of transpiration, a suction pressure is created as a result of which water is forced into the xylem cells of roots. The effect of root pressure for transportation in plants is more important at night while during day time transpiration pull becomes the major driving force.
5. How is food transported in plants?
Phloem transports food materials from the leaves to different parts of the plant. The transportation of food in phloem is achieved by utilizing energy from ATP which helps in creating osmotic pressure that transport food from the area of high concentration to low concentration.
1. Describe the structure and functioning of nephrons.
Nephrons are the basic filtering units of kidneys. Each kidney possesses a large number of nephrons, approximately 1-1.5 million. The main components of the nephron are glomerulus, Bowman's capsule, and a long renal tubule.
Functioning of a nephron:
→ The blood enters the kidney through the renal artery, which branches into many capillaries associated with glomerulus.
→ The water and solute are transferred to the nephron at Bowman's capsule.
→ In the proximal tubule, some substances such as amino acids, glucose, and salts are selectively reabsorbed and unwanted molecules are added in the urine.
→ The filtrate then moves down into the loop of Henle, where more water is absorbed.
→ From here, the filtrate moves upwards into the distal tubule and finally to the collecting duct. Collecting duct collects urine from many nephrons.
→ The urine formed in each kidney enters a long tube called a ureter. From the ureter, it gets transported to the urinary bladder and then into the urethra.
2. What are the methods used by plants to get rid of excretory products?
Plants can get rid of excess water by transpiration. Waste materials may be stored in the cell vacuoles or as gum and resin, especially in old xylem. It is also stored in the leaves that later fall off.
3. How is the amount of urine produced regulated?
The amount of urine produced depends on the amount of excess water and dissolved wastes present in the body. Some other factors such as the habitat of an organism and hormones such as Antidiuretic hormone (ADH) also regulate the amount of urine produced.
1. The kidneys in human beings are a part of the system for
(a) nutrition.
(b) respiration.
(c) excretion.
(d) transportation.
► (c) excretion.
2. The xylem in plants are responsible for
(a) transport of water.
(b) transport of food.
(c) transport of amino acids.
(d) transport of oxygen.
► (a) transport of water.
3. The autotrophic mode of nutrition requires
(a) carbon dioxide and water.
(b) chlorophyll.
(c) sunlight.
(d) all of the above.
► (d) all of the above.
4. The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(a) cytoplasm.
(b) mitochondria.
(c) chloroplast.
(d) nucleus.
► (b) mitochondria.
5. How are fats digested in our bodies? Where does this process take place?
Fats are present in the form of large globules in the small intestine. The small intestine receives the secretions from the liver and the pancreas. The bile salts (from the liver) break down the large fat globules into smaller globules so that the pancreatic enzyme lipase can easily act on them. This is referred to as emulsification of fats. This process takes place in the small intestine.
6. What is the role of saliva in the digestion of food?
The role of saliva in the digestion of food:
→ It moistens the food for easy swallowing.
→ It contains a digestive enzyme called salivary amylase, which breaks down starch into sugar.
7. What are the necessary conditions for autotrophic nutrition and what are its by-products?
Autotrophic nutrition takes place through the process of photosynthesis. Carbon dioxide, water, chlorophyll pigment, and sunlight are the necessary conditions required for autotrophic nutrition. Carbohydrates (food) and O2 are the by-products of photosynthesis.
8. What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.
Answer
The organisms that use anaerobic mode of respiration include some bacteria and microorganisms such as yeast.
9. How are the alveoli designed to maximize the exchange of gasses?
Alveoli provide a surface for the exchange of gasses. An extensive network of blood vessels is present in the wall of the alveoli. By lifting our ribs and flatten the diaphragm, the chest cavity becomes spacious. Air is sucked into the lungs and alveoli. The oxygen from the breath, diffuses into the blood and CO2 from the blood brought from the body, diffuses out into the air.
10. What would be the consequences of a deficiency of hemoglobin in our bodies?
Hemoglobin is the respiratory pigment that transports oxygen to the body cells for cellular respiration. Therefore, deficiency of hemoglobin in blood can affect the oxygen supplying capacity of blood. This can lead to deficiency of oxygen in the body cells. It can also lead to a disease called anemia.
11. Describe double circulation in human beings. Why is it necessary?
During a single cycle blood goes twice in the heart which is known as double circulation. It is necessary in human beings to separate oxygenated and deoxygenated blood because this makes their circulatory system more efficient and helps in maintaining constant body temperature.
12. What are the differences between the transport of materials in xylem and phloem?
13. Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.
Life processes class 10 NCERT biology MCQ:
Question : In Photosynthetic process, atmospheric carbon dioxide is _______ to carbohydrates
a) oxidized b) Reduced c) Neutralized d) Burnt
Answer : B
Question : When water enters the guard cells the stomata
a) Opens b) Closes c) Open or closes d) No effect
Answer : A
Question : On seeing good food our mouth waters. This fluid is actually
a) Water b) Hormone c) Enzyme d) None of the above
Answer : C
Question : The enzyme Pepsin is inactive in stomach without the presence of
a) Nitric Acid b) Hydrochloric acid c) Acetic acid d) Butyric acid
Answer : B
Question : Villi present on the inner lining of the intestinal wall
a) Secretes enzymes for digestion
b) Secretes hormones
c) Decreases the surface area for absorption
d) Increases the surface area for absorption
Answer : D
Question : During cellular respiration one molecule of glucose is first broken down into two molecules of ________
a) Acetic acid b) Pyruvic acid c) Lactic acid d) None of the above
Answer : B
Question : Rajib was absent in the class because of muscle pain which he claims to be due to excess physical exercise he had done yesterday. This pain is due to
a) Formation of lactic acid b) Formation of acetic acid c) Formation of Pyruvic acid d) Formation of Hydrochloric acid
Answer : A
Question : Right part of the human heart contains
a) Oxygenated blood b) Mixed blood c) Deoxygenated blood d) No blood
Answer : C
Question : The transport of soluble products of photosynthesis is called translocation and it occurs in the part of the vascular tissue called
a) Xylem b) Sclerenchyma c) Phloem d) Collenchyma
Answer : C
Question : In human each kidney has large numbers of filtration units called ___
a) Neutrons b) Neurons c) Neptune d) Nephrons
Answer : D
1. Which among the following is the major excretory organ in humans?
(a) Kidney
(b) Small Intestine
(c) Large Intestine
(d) Heart
► (a) Kidney
2. It is necessary to separate oxygenated blood from the deoxygenated blood in mammals
(a) To maintain the body temperature
(b) To provide more oxygen to cells
(c) Both (a) and (b)
(d) None of the above
► (c) Both (a) and (b)
3. "Homeostasis" term was proposed by
(a) Claude Bernard
(b) Walter Cannon
(c) Marcello Malpighi
(d) Henle
► (b) Walter Cannon
4. Minerals absorbed by roots move to the leaf through
(a) Xylem
(b) Phloem
(c) Sieve tube
(d) None of the above
► (a) Xylem
5. Main function of kidney is
(a) Passive absorption
(b) Ultrafiltration
(c) Selective reabsorption
(d) All of the above
► (d) All of the above
6. The chlorophyll in photosynthesis is used for
(a) Absorbing light
(b) Breaking down water molecule
(c) No function
(d) Reduction of CO2
► (a) Absorbing light
7. What will happen if one kidney is removed from the body of a human being ?
(a) Death due to poisoning
(b) Uremia and death
(c) Stoppage of urination
(d) Nothing, the person will survive and remain normal kidney will become hypertrophied
► (d) Nothing, the person will survive and remain normal kidney will become hypertrophied
8. Which of the following are respiratory organs of a scorpion?
(a) Lungs
(b) Book-lungs
(c) Gills
(d) Ctenidia
► (b) Book-lungs
9. Which of the following sequences is truly a systemic circulation pathway?
(a) Left auricle → Left ventricle → Pulmonary aorta → Tissues → Right auricle
(b) Left auricle → Left ventricle → Aorta →Arteries →Tissues → Veins → Right atrium
(c) Right ventricle → Pulmonary aorta →Tissues → Pulmonary veins → Left auricle
(d) Right auricle → Left ventricle → Aorta →Tissues → Veins → Right auricle
► (b) Left auricle → Left ventricle → Aorta →Arteries →Tissues → Veins → Right atrium
10. The diffusion of CO2 across the alveolar membrane is 20 times faster than that of O2 because :-
(a) CO2 is actively transferred
(b) The alveolar area available for CO2 diffusion is larger
(c) CO2 is more soluble in H2O than O2, which enables it to pass the membrane more readily
(d) The CO2 pressure gradient in larger
► (d) The CO2 pressure gradient in larger
11. Reabsorption of useful substances from glomerular filtrate occurs in
(a) Collecting tube
(b) Loop of Henle
(c) Proximal convoluted tubule
(d) Distal convoluted tubule
► (c) Proximal convoluted tubule
12. Which one is uricotelic?
(a) Frog and toads
(b) Lizards and birds
(c) Cattle, monkey and man
(d) Molluscs
► (c) Lizards and birds
13. In insects, there is no structural or functional relationship between excretory or digestive system except in
(a) Earthworm
(b) Cockroach
(c) Lizards
(d) Ants
► (c) Cockroach
14. Autotrophs and heterotrophs differ in
(a) How they obtain their carbon.
(b) Whether they are prokaryotic or eukaryotic.
(c) How they reproduce, sexually or asexually.
(d) Whether they use chemicals or light as a source of energy.
► (a) How they obtain their carbon.
15. Most of the carbon dioxide in the blood is carried in the form of
(a) Carbonic acid
(b) Bicarbonates.
(c) Carbaminohaemoglobin.
(d) Dissolved CO2.
► (b) Bicarbonates.
16. Sometimes we get painful cramps in our leg muscles after running for a long time due to the accumulation of:
(a) Hydrochloric acid
(b) Fat
(c) Carbon dioxide
(d) Lactic acid
► (d) Lactic acid
17. Epiglottis guards the opening of
(a) Esophagus
(b) Eustachian tubes
(c) Larynx
(d) Internal nares
► (c) Larynx
18. Correct order of excretory organs in cockroach, earthworm and rabbit respectively:
(a) Skin, malpighian tubules, kidney
(b) Malpighi tubules, nephridia, kidney
(c) Nephridia, malpighian tubules, kidney
(d) Nephridia, kidney, green gland
► (b) Malpighi tubules, nephridia, kidney
19. The process of taking in CO2 by plants and releasing O2 is component of
(a) Transpiration
(b) Respiration
(c) Endosmosis
(d) Photosynthesis
► (d) Photosynthesis
20. Doctors measure the blood pressure with the instrument known as__________.
(a) Sphygmomanometer
(b) Stethoscope
(c) Thermometer
(d) Manometer
► (a) Sphygmomanometer
21. Which part of the plant helps to absorb water and minerals from the soil?
(a) Root hairs
(b) Roots
(c) Root cap
(d) Tap root
► (a) Root hairs
22. The manufactured food in a green plant moves from the leaves to other parts through________.
(a) Xylem
(b) Phloem
(c) Cortex
(d) Pith
► (b) Phloem
23. The enzymes pepsin and trypsin are secreted respectively by
(a) Stomach and pancreas
(b) Salivary gland and stomach
(c) Liver and pancreas
(d) Liver and salivary gland
► (a) Stomach and pancreas
24. Ornithine cycle performs
(a) ATP synthesis
(b) Urea formation in spleen
(c) Urea formation in liver
(d) Urine formation in liver
► (c) Urea formation in liver
25. Oxygen is carried by:
(a) Leucocytes
(b) Erythrocytes
(c) Platelets
(d) None of the above
► (b) Erythrocytes
26. Which of the following help in protecting the inner lining of the stomach from the harmful effect of hydrochloric acid?
(a) Mucus
(b) Pepsin
(c) Trypsin
(d) Bile
► (a) Mucus
27. Breathing is controlled by a center in the
(a) Lungs
(b) Heart
(c) Cerebellum
(d) Medulla oblongata
► (d) Medulla oblongata
Life processes class 10 NCERT biology SAQ
Q.1. Write three types of blood vessels. Give one important feature of each. [Delhi 2019]
Ans. Three types of blood vessels in the human circulatory system: Arteries, Veins and Capillaries.Their functions are tabulated below:
Q.2. How does blood clotting occur?
Ans. Blood clotting is a phenomenon brought about by blood platelets that prevent excessive loss of blood at the time of injury or leakage from a blood vessel.
Platelets rupture to release a substance called thromboplastin
Q.3. Enumerate the events that occur during the process of photosynthesis.[CBSE 2017-18 C]
Ans. Photosynthesis is the formation of organic food from carbon dioxide and water with the help of sunlight inside chlorophyll-containing cells.
The various events that occur during this process are as follows:
Absorption of light energy by chlorophyll.
(a) Photolysis of water - Light energy splits water molecules into hydrogen and oxygen.
(b) Conversion of light energy into chemical energy i.e., synthesis of ATP from ADP (adenosine diphosphate) and inorganic phosphate takes place.Reduction of carbon dioxide into carbohydrates takes place. This process is a light independent reaction which can occur in day time as well as night.
Q.4. Name the components of blood which transport: [CBSE 2016]
(i) Food, carbon dioxide and nitrogenous wastes
(ii) Oxygen
Ans. (i) Blood plasma
(ii) EBC
Q.5. Kings of cartilage are present in the trachea. Why? [CBSE 2016]
Ans. From the nostril, the air passes through the pharynx into the lungs via the trachea. Incomplete C-shaped rings of cartilage are present in the trachea which ensure that the air passage does not collapse when there is no air in it.
Q.6. When a sportsman runs, he gets muscle cramps. Why? [CBSE 2016]
Ans. During running, the sportsman requires a large amount of energy instantly. In order to release more energy, pyruvate is converted into lactic acid in the absence of oxygen. Accumulation of lactic acid in the muscles causes cramps.
Q.7. (i) Name the respiratory pigment found in human beings.
(ii) How is carbon dioxide transported in our body? [CBSE 2016]
Ans. (i) Hemoglobin
(ii) Generally diffused in blood plasma, as carbonate ions and as carbaminohemoglobin.
Q.8. (i) Name two organisms that obtain food through parasitic nutritive strategy.
(ii) How do fungi obtain their food? [CBSE 2016]
Ans. (i) Cuscuta, tapeworm obtain food through parasitic nutritive strategy.
(ii) Fungi are saprophytic and obtain food through dead and decaying matter.
Q.9. (a) Name the following :
(i) The three-carbon molecule that is formed due to the breakdown of glucose during respiration.
(ii) The nitrogenous waste that is removed from the blood in our kidneys.
(b) How do unicellular organisms generally remove waste? [CBSE 2016]
Ans. (a) (i) Pyruvic Acid/Pyruvate (ii) Urea
(b) The undigested food material in the vacuole reaches the rear end of the organism and is thrown out by the process of exocytosis. The membrane of the vesicle fuses with the surface membrane.
Q.10. Differentiate between aerobic and anaerobic respiration. [CBSE 2016]
Ans.
Q.11. Explain how the fats are digested in our bodies? Where does this process take place? [CBSE 2011,2016]
Ans. Fats are digested in the small intestine. When food enters the small intestine bile juice secreted by the liver emulsifies fat and then the enzyme lipase which is secreted by the pancreas converts fat into fatty acid and glycerol.
Q.12. Explain why transportation of materials is necessary in animals? [CBSE 2016]
Ans.
The transport of substances like oxygen, food, water, enzymes, hormones inside the body of organisms is called internal transport. Blood transports many substances like salts, vitamins, hormones, and waste products. We thus need a pumping organ to push blood around the body. The transport system in human beings consists of the heart, blood vessels (arteries, veins and capillaries) and circulatory fluid (blood and lymph).
Kidneys perform two main vital functions:
(i) filtering the nitrogenous waste from the blood,
(ii) osmoregulation i.e., maintaining the right amount of water and ionic balance in the body.All these substances are either required by various body cells or should be removed from body cells. Hence, transportation of materials is necessary.
Q.13. Mention the three kinds of cells present in the blood. Write one function of each. [CBSE 2016]
Ans. Blood is made up of plasma and corpuscles.
Three kinds of cells are: WBC, RBC and Blood platelets.
Red Blood cells (RBC) are small, biconvex cells that contain hemoglobin to transport O2 from the lungs to the body cells and CO2 from body cells to the lungs.
White blood cells (WBC) main function is defense of the body against diseases and other infections. Blood platelets are responsible for the clotting of blood during injuries.
Q.14. Write one function of each of the following components of the transport system in human beings: [CBSE 2016]
(a) Blood vessels
(b) Lymph
(c) Heart
Ans. The function of the following components of the transport system in human beings are as follows:
(a) Blood vessels: There are three types of blood vessels of different sizes involved in blood circulation viz. arteries, veins and capillaries, which are all connected to form a continuous closed system.
(b) Lymph: It carries digested and absorbed fat from the intestine and drains excess fluid from extracellular space back into the blood.
(c) Heart: It is a pumping organ that receives blood from the veins and pumps it into the arteries.
Q.15. Give reason:
(l) Fine hair and mucus are present in the nasal passage.
(ii) Rings of cartilage are present in the throat. [CBSE 2015]
Ans. (i) Fine hair and mucus are present in the nasal passage so that any dust particles, pathogens etc., can be trapped in here and only clean air will enter the lungs. This is one of the defense mechanisms of our body.
(ii) Rings of cartilage are present in the throat so that the trachea does not collapse on respiration.
Q.16. Define the term parasite. Name one plant parasite and one animal parasite. Some organisms break down the food material outside the body and then absorb it. Give two examples. [CBSE 2015]
Ans. Parasites are organisms that obtain nutrients from the body of other living organisms and harm them as a result.
(i) Plant parasite - cuscuta
(ii) Animal parasite - Tapeworm
Organisms that break down food outside the body and then absorb it are saprophytes.
Example: fungi, bacteria.
Q.17. What is the following transport? [CBSE 2015]
(i) Xylem
(ii) Phloem
(iii) Pulmonary vein
(iv) Vena Cava
(v) Pulmonary artery
(vi) Aorta.
Ans.
Material transported by:
(i) Xylem: Water and minerals.
(ii) Phloem: Organic molecules like sucrose.
(iii) Pulmonary vein: Oxygenated blood from lungs to heart.
(iv) Venacava: Impure and deoxygenated blood from body to heart.
(v) Pulmonary artery: Deoxygenated blood from the heart to lungs.
(vi) Aorta: Oxygenated blood from the heart to body parts.
\
Q.18. In single-celled organisms, diffusion is sufficient to meet all their requirements of food, exchange of gasses or removal of wastes but it is not in the case of multicellular organisms. Explain the reason for this difference. [CBSE 2015]
Ans. In the case of a single celled organism, the entire surface of the organism is in contact with the environment and hence no specific organ for taking in food, exchange of gasses or removal of waste may be needed. In multicellular organisms, only the cells of the skin are in direct contact with the environment. Diffusion is a very slow process and it will take a very long time to reach all the cells of the body parts. Diffusion is insufficient to melt oxygen requirements.
Q.19. State the role of the following in the human digestive system: [CBSE 2015]
(a) Digestive enzymes
(b) Hydrochloric acid
(c) Villi
Ans. (a) Digestive enzymes digest the food we eat.
(b) Hydrochloric acid creates an acidic medium to facilitate the action of enzyme pepsin.
(c) Villi increases the surface area inside the small intestine to facilitate absorption of food.
Life processes class 10 NCERT biology LONG QUESTION
Q.1. (a) Write the reaction that occurs when glucose breaks down anaerobically in yeast.
(b) Write the mechanism by which fishes breathe in water.
(c) Name the balloon-like structures present in the lungs. List its two functions.
(d) Name the respiratory pigment and write its role in human beings. [CBSE 2017-18 C]
Ans. (a) Glucose breaks down anaerobically i.e., in absence o f O2; in yeast in the following manner:
(b) Since fishes are aquatic, they take in O2 dissolved in water. They take water through their mouth which goes to their gills where the dissolved oxygen is taken up by the blood and transported. The CO2 is given out through the same passage.
(c) The balloon-like structures in our lungs are the alveoli.
Their functions are:
They are very thin-walled and hence help in gaseous exchange.
They contain an extensive network of blood vessels which help in transport of respiratory gasses.
They increase the surface area for absorption of gasses.
(d) The respiratory pigment is Hemoglobin.
Its role is:
It has an affinity for oxygen and hence helps in the transport of oxygen from alveoli to body tissues.
It also has an affinity for CO2 and hence helps in the transport of CO2 from body tissues to alveoli.
Q.2. (a) Name the process and explain the type of nutrition found in green plants. List the raw materials required for this process. Give the chemical equation for the mentioned process.
(b) Write three events that occur during this process. [CBSE 2017-18 C]
Ans. (a) The process of nutrition in green plants is Photosynthesis. The type of nutrition is autotrophic nutrition. Autotrophic nutrition requires sunlight, chlorophyll, water and carbon dioxide.
Plants prepare their own food in the form of glucose which gets converted to starch. This is done using CO2 and H2O which gets fixed using energy from sunlight by the chlorophyll molecule present in green plants.
Equation -
(b) The three events involved are:
Absorption of sunlight by chlorophyll.
Conversion of this light energy into chemical energy and splitting of water into H+ and OH- using this energy.
Reduction of CO2 to carbohydrate by using H+ produced due to splitting of water.
Q.3. (a) Write the name of different components of the transport system in human beings and state their functions in brief.
(b) How is a blood clot formed if a leak develops in the system of blood vessels? [CBSE 2017-18 C]
Ans. (a) Various components of the transport system and their functions:
(b) If there is a leak in the blood vessels due to injury, then the blood platelets help plug these leaks. The platelets make the clot by forming a mesh-like structure over the leak in which other blood cells get entangled, ultimately plugging the leak.
Q.4. (a) Name the process and explain the type of nutrition found in green plants. List the raw materials required for this process. Give a Chemical equation for the mentioned process.
(b) Write three events that occur during this process. [CBSE 2018C]
Ans. (a) Photosynthesis is the process where green plants show autotrophic nutrition. The raw materials required for photosynthesis are carbon dioxide and water and energy in the form of sunlight.
The equation is as follows:
(b) The three events in photosynthesis are:
Absorption of light energy by chlorophyll.
Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen.
Reduction of carbon dioxide to carbohydrates.
Q.5. (a) Write the reaction that occurs when glucose breaks down anaerobically in yeast.
(b) Write the mechanism by which fishes breathe in water.
(c) Name the balloon-like structures present in the lungs. List its two functions.
(d) Name the respiratory pigment and write its role in human beings. [CBSE 2018C]
Ans. (a)
(b) Fishes breathe with the gills by diffusion.
(c) Alveoli are the balloon-like structures:
They provide a surface for exchange of gasses.
They contain a residual volume of air so that there is sufficient time for exchange of gasses.
(d) Hemoglobin is the respiratory pigment in humans. It transports a major part of oxygen and some amount of carbon dioxide through blood.
Q.6. (a) Mention any two components of blood.
(b) Trace the movement of oxygenated blood in the body.
(c) Write the function of valves present in between atria and ventricles.
(d) Write one structural difference between the composition of arteries and veins. [CBSE 2018]
Ans. (а) Blood is composed of plasma and three types of cells-Red blood cells, white blood cells and platelets.
(b)
Oxygenated blood from the lungs is brought to the left atrium by pulmonary veins.
When the atrium contracts, blood is transferred to the left ventricle.
When the ventricle contracts, blood is pushed into the aorta and through arteries to all parts of the body.
(c) The valves prevent the backflow of blood from ventricles into the atria.
(d)
Q.7. (а) Define excretion.
(b) Name the basic filtration unit present in the kidney.
(c) Draw excretory system in human beings and label the following organs of the excretory system which perform the following functions:
(i) form urine.
(ii) is a long tube which collects urine from the kidney.
(iii) store urine until it is passed out. [CBSE 2018]
Ans. (a) Excretion is the biological process of removal of harmful metabolic wastes from the body.
(b) Nephrons
(c) (i) Kidney, (ii) Ureter, (iii) Urinary bladder.
Excretory System of Human Beings
Q.8. Draw diagram of human alimentary canal and label the following:
(i) Part in which starch digestion is initiated.
(ii) Organ in which bile is stored.
(iii) The gland that secretes digestive enzymes as well as hormones.
(iv) Part of the alimentary canal where water is reabsorbed.
(v) Part of the gut where finger-like projections are present to facilitate absorption of digested food. [CBSE 2016]
Ans. (i) Mouth, (ii) Gallbladder, (iii) Pancreas, (iv) Large Intestine, (v) Small intestine.
Q.9. (a) State the form in which the following are stored :
(i) Unused carbohydrates in plants.
(ii) Energy derived from food in humans.
(b) Describe the process of nutrition in the amoeba with the help of a diagram. [CBSE 2016]
Ans. (a) (i) As starch in fruits/storage roots, tubers etc. (ii) As glycogen.
(b) Amoeba is a unicellular eukaryotic organism that exhibits a holozoic mode of nutrition. Five steps are involved in this mode of nutrition:
Ingestion: Amoeba feeds on microscopic organisms. It takes in food using finger-like projections called pseudopodia. It encircles the food and engulfs or ingests it by a process called phagocytosis. The food comes to lie in a vesicle called phagosome or food vacuole.
Digestion: A lysosome fuses with phagosomes and complex substances are broken down into simpler ones. Such a type of digestion that occurs within a cell is referred to as Intracellular digestion. The digested food then diffuses into the cytoplasm.
Absorption and Assimilation: The digested food which has diffused into the cytoplasm is quickly absorbed by the organism and converted into various constituents of protoplasm.
Egestion: The undigested food material reaches the rear end of the organism and is thrown out by the process of exocytosis. The membrane of the vesicle fuses with the surface membrane.
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