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Hindi Question English Question Answers Marks Category Manage
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Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?
Our body is very huge and complex, each and every cell of the body requires oxygen. And the process of diffusion is very slow, will take so much time to reach each and every cell. Hence, diffusion is insufficient to meet the oxygen requirements of multicellular organisms like humans
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What criteria do we use to decide whether something is alive?
To consider something living or dead, we primarily focus on the events of Life processes. Fundamental life processes include nutrition, respiration, transportation, excretion, control and coordination, growth and reproduction. If these systems works normally we can declare the organisms living because none of the non-living things shows any of the life processes
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What are outside raw materials used for by an organism?
Outside raw materials used by an organism are food, water and oxygen. These are mainly used for some important functions in the body and the amounts, source and type vary from organisms to organisms.
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What processes would you consider essential for maintaining life?
Nutrition, respiration, transportation, excretion and control and coordination
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What are the differences between autotrophic nutrition and heterotrophic nutrition?
AUTOTROPHIC NUTRITION: [i] The organisms make their own food with the help of carbon dioxide and water in the presence of sunlight and chlorophyll [ii] Autotrophs use light as a source of energy to synthesise food. (III) All green plants, some bacteria, algae, seaweeds, etc.HETEROTROPHIC NUTRITION [i] The organisms obtain their nutrition from other living organisms like plants (autotrophs) [ii] Heterotrophs derive energy by digesting other organic substances that they consume as their food. (III) All animals, Humans, fungi such as mushrooms, yeast, etc.
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Where do plants get each of the raw materials required for photosynthesis?
These are the following raw materials required by plants for photosynthesis: carbon dioxide, water, sunlight, chlorophyll. • Plants obtain CO2, from the atmosphere and it is absorbed through the stomata. • Water is mainly available in the soil so it is absorbed from the soil by plant roots. • Sunlight is absorbed from the nature • Chlorophyll is present as the main component of the plant organelle chloroplast. (chlorophyll is present is all green parts of the plants).
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What is the role of the acid in our stomach?
Acid mainly dissolves chunks of food and creates an acidic medium. That acidic medium is required by enzyme pepsinogen to be converted to pepsin, which is a protein-digesting enzyme. Pepsin is activated in the presence of HCl. The acid is also responsible for killing microorganisms that enter the stomach along with food
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What is the function of digestive enzymes?
There are various digestive enzymes present in the body, such as amylase, lipase, pepsin, trypsin, etc. These enzymes help in the breaking down of complex food molecules into simpler molecules which can be easily absorbed by the cells of the body. These enzymes also act as a biocatalyst which accelerates the rate of breaking down of complex food.
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Write the role of villi in human digestive system
Throughout the internal surface of small intestine, there are finger like projections known as VILLI. They are primarily responsible for increasing the surface area of the small intestine which in turn increases surface area for absorption of the digested food. Villi are majorly supplied with blood vessels which help to absorb digested food into the bloodstream.
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What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Terrestrial organisms breathe oxygen which is freely available in the air of the atmosphere. While the aquatic organisms have to breathe air which is only dissolved in the water. The amount of oxygen in air is much more than the amount of oxygen present in the
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What are the different ways in which glucose is oxidized to provide energy in various organisms?

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In mammals and birds, why is it necessary to separate oxygenated and deoxygenated blood?
Mammals and birds are warm blooded animals. This means they can control their body temperature and do not have to depend on the environment for their body temperature regulation. Because of this, birds and mammals require optimum oxidation of glucose which would be possible with a good supply of oxygen. So it is important to have separate oxygenated and deoxygenated blood to supply the required amount of oxygen
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List three characteristics of lungs which make it an efficient respiratory surface
Features that make lungs an efficient respiratory surface: 1. Thin: Air sac walls are very thin so that gases can quickly diffuse through them. Oxygen is absorbed into the blood and carbon dioxide is given out into the lungs to be exhaled out. 2. Moist: Air sacs are moist with mucus so that gases can dissolve before diffusing. 3. Large surface area: The surface area for gases to diffuse through in human lungs is roughly the same as a tennis court. The alveoli help to increase the surface area for absorption of oxygen. 4. Good blood supply: The air sacs or alveoli have a large capillary network so that large volumes of gases can be exchanged. Greater the flow of blood, greater would be the exchange.
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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 transports it to the lungs for oxygenation. • Blood helps in the transport of oxygen, nutrients, carbon dioxide, nitrogenous wastes and hormones. Blood also is a main component in our immune system due to the presence and action of the WBCs. The presence of platelets causes clotting of blood which is essential for repairing damaged blood vessels. Additionally, the transport of blood helps in maintaining body temperature. • Blood vessels (arteries, veins, and capillaries) carry blood either away from the heart to various organs or from various organs back to the heart. Arteries carry blood away from the heart to other parts of the body. All arteries except pulmonary arteries carry oxygenated blood. Veins carry blood to the heart from various parts of the body. All veins except pulmonary veins carry deoxygenated blood. Capillaries are the site of exchange of materials between blood and tissues
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What are the components of the transport system in highly organised plants?
In highly organised 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
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How are water and minerals transported in plants?
Water and minerals are transported within the plant by the xylem vessels (mainly in an upward direction); these are part of the vascular system which also includes phloem vessels. Phloem transports the products of photosynthesis within the plant, to all parts like the stem, roots, fruits, etc. in all directions.
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How is food transported in plants?
Phloem transports food materials from the leaves to different parts of the plant body. The transportation of food in phloem is achieved by utilizing energy from ATP. As a result of this, the osmotic pressure in the tissue increases causing water to move into it. This pressure moves the material in the phloem to the tissues which have less pressure. This is helpful in moving materials according to the needs of the plant. For example, the food material, such as sucrose, is transported into the phloem tissue using ATP.
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Describe the structure and function of the nephron in the human body.
Nephrons are the functional units of the kidney (filtration units). Each kidney has a large number of nephrons. Nephron consists of a renal corpuscle and renal tubule. The renal corpuscle includes a cup-shaped structure called Bowman’s capsule which encloses a cluster of capillaries. This part collects filtered urine. As the urine flows through the tubular part of nephron, its composition is altered because of reabsorption of glucose, amino acids, salts and water. The amount of water and other substances reabsorbed depends on their excess present in the body. The urine formed now enters into a long tube called the ureter through the collecting ducts of the kidney. Then urine is collected in the urinary bladder.
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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 vessels. It is also stored in the lea ves that later fall off. Waste products obtained at the end of photosynthesis (oxygen) and respiration (carbon dioxide) are released by diffusion through stomata.
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How is the amount of urine produced regulated?
The amount of urine produced in the body depends on the amount of excess water and dissolved wastes present in the body. If there is excess water present in the body then less water is reabsorbed and more water is lost from the body and so on. Some other factors such as habitat of an organism and hormone such as Antidiuretic hormone (ADH) regulates the amount of urine produced.
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The kidneys in human beings are a part of the system for (a) nutrition. (b) respiration. (c) excretion. (d) transportation.
(c) In human beings, the kidneys are a part of the system for excretion.
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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) In a plant, the xylem is responsible for transport of water.
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The autotrophic mode of nutrition requires (a) carbon dioxide and water. (b) chlorophyll. (c) sunlight. (d) all of the above.
(d) The autotrophic mode of nutrition requires carbon dioxide, water, chlorophyll and sunlight.
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The breakdown of pyruvate to give carbon dioxide, water and energy takes place in (a) cytoplasm. (b) mitochondria. (c) chloroplast. (d) nucleus.
The breakdown of pyruvate to give carbon dioxide, water and energy takes place in mitochondria.
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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 gets the secretions in the form of bile juice and pancreatic juice respectively 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 enzymes (lipases) can easily act on them. Break down of large globule fats into smaller fat droplets is known as emulsification.
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What is the role of saliva in the digestion of food?
Saliva is a watery fluid secreted by the salivary glands in the mouth. The digestive functions of saliva include moistening of food, and helping to create a food bolus, so it can be swallowed easily. Saliva contains the enzyme amylase that breaks down starch into maltose and dextrin.
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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 and sunlight are the necessary conditions required for autotrophic nutrition. Carbohydrates (food) and O2 are the by-products of photosynthesis.
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What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.
Aerobic respiration: 1) It takes place in the presence of oxygen. 2) In aerobic respiration, complete breakdown (oxidation) of glucose takes place. 3) End products are carbon dioxide, water and energy. 4) Occurs in plant and animal cells. Anaerobic respiration: 1) It takes place in the absence of oxygen. 2) In anaerobic respiration, the glucose molecule is incompletely broken down. 3) End products are either ethyl alcohol or lactic acid, carbon dioxide and energy. 4) Occurs in many anaerobic bacteria, yeast and human muscle cells.
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How are the alveoli designed to maximise the exchange of gases?
Alveoli are tiny pouches or sac-like structures. They are surrounded by blood capillaries. Thus, a large amount of air is brought in contact with the air in the lungs. More than millions of alveoli are present in the lungs, providing a very large surface area for the exchange of gases. This maximises the exchange of gases. Alveoli and capillaries
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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 anaemia, an iron-deficiency condition.
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Describe double circulation in human beings. Why is it necessary?
Double circulation is a process in which blood flows twice through the heart. It includes two steps: 1. Pulmonary circulation. 2. Systemic circulation. Pulmonary circulation begins from right ventricle, after oxygenation from the lungs it ends in left atrium. Systemic circulation begins from left ventricle, after exchange of materials from throughout the body, it ends in the right atrium. Importance of double circulation: The separation of oxygenated and deoxygenated blood allows a more efficient supply of oxygen to the body cells. This efficient system of oxygen supply is very useful in human beings.
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What are the differences between the transport of materials in xylem and phloem?
Transport of materials in xylem: (i) Transports water (ii) Consists vessels and tracheids (iii) Begins from roots (iv) Supplies water and minerals to all parts of the plant. Transport of materials in Phloem: (i) Transports water and minerals (ii) Consists sieve tubes and companion cells (iii) Begins from leaves (iv) Supplies nutrients to all parts of the plant.
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Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.

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