Life Processes Class-10 Biology 3 Marks Previous Year Questions
Q.1) Complete the pathways given below, showing the breakdown of glucose.
Identify ‘A’, ‘B’, ‘C’, ‘D’, ‘E’ and ‘F’.
Q.2) (a) Draw a neat diagram of the human respiratory system and label its lungs, trachea, bronchi and alveoli.
(b) State the roles of the following in the process of respiration :
(i) Alveoli
(ii) Respiratory pigments
(a)
(b) (i) Alveoli - Exchange of gases
(ii) Respiratory pigment - Helps in the transportation of oxygen
Q.3) Observe the following diagrams :
(a) What change will be observed in Cases ‘P’, ‘Q’ and ‘R’ ? Give reasons.
(b) In which case :
(i) is aerobic respiration taking place ?
(ii) is fermentation taking place ?
(a) • Case P- Change occurs extremely slow / No change.
• Case Q- Limewater will turn milky because exhaled air contains high concentration of carbon dioxide.
• Case R- Fermentation occurs in sugar solution / limewater may turn milky.
(b) (i) Case Q (ii) Case R
Q.4) Give reasons for the following :
(a) Herbivores have a longer small intestine.
(b) Inner lining of small intestine has numerous finger-like projections.
(c) Rate of breathing in aquatic organisms is much faster than that in terrestrial organisms.
(a) Herbivores eat grass, need a longer small intestine to allow the cellulose to be digested.
(b) The finger like projections on the inner lining of small intestine, the villi, increase the surface area for absorption of digested food.
(c) Dissolved oxygen in water is much lower as compared to oxygen in air.
Q.5) Give reasons for the following :
(a) Plants do not have an excretory system so how they excrete their wastes ?
(b) Why do mammals and birds have double circulation ?
(a) Some waste is stored in leaves that fall off/wastes may be stored in cellular vacuoles/other wastes are stored as resins and gums in old xylem/may excrete some waste into soil via roots.
(b) Mammals and birds have high energy needs to maintain their body temperature. Therefore, mixing of blood is prevented by separation of right and left side of heart and thus they have double circulation.
Q.1) Name the blood vessel that brings (i) oxygenated blood (ii) deoxygenated blood, to the human heart. Also name that chamber of the heart which receives deoxygenated blood and state how deoxygenated blood from this chamber is sent to lungs for oxygenation.
(i) Pulmonary vein
(ii) Vena cava
• chamber of the heart which receives deoxygenated blood : Right atrium
• After receiving blood, the right atrium contracts
• As a result blood passes into the right ventricle
•Then the ventricle contracts and the deoxygenated blood flows into the lungs through pulmonary artery.
Q.2) List three raw materials required by terrestrial plants for photosynthesis. Explain how nature provides these raw material to the plants.
Raw material – CO2, water and light
CO2 – from the atmosphere/air through stomata
H2O – from soil through absorption by root
Light – from the sun
Q.3) Give reasons for the following :
(a) Rate of breathing in aquatic animals is much faster than terrestrial organisms.
(b) Rings of cartilage are present in throat of human being.
(c) During anaerobic respiration, a 3 carbon molecule (compound) is formed as an end product instead of CO2, in some cells of human beings.
(a) Amount of dissolved oxygen is fairly low in water as compared to the amount of oxygen in air.
(b) Rings of cartilage ensure that air passage does not collapse in absence of air
(c) Due to lack of oxygen in our muscle cells
Q.4) (a) Write the name and one function of respiratory pigment found in human beings.
(b) Why do lungs always contain a residual volume of air ?
(c) Why is ATP known as energy currency of the living beings ?
(a) •Haemoglobin
•To take up oxygen from lungs and carry it to tissues which are deficient in oxygen / Transports oxygen to various body parts.
(b) To provide sufficient time for oxygen to be absorbed and for carbon dioxide to be released.
(c) ATP provides energy for various cellular processes
Q.5) What is the first step in cellular respiration ? In which part of the cell does it occur ? Write the equation for the process of breakdown of glucose in a human cell :
(i) in presence of oxygen
(ii) due to lack of oxygen
• The breakdown of glucose to form pyruvate or pyruvic acid.
• Occurs in cytoplasm of the cell.
(i) In the presence of oxygen:
(ii) Due to lack of oxygen
Q.6) (i) Study the diagram and name the parts marked as A, B, C and D.
(ii) Write the function of A and C.
(i) A: pulmonary artery
B: pulmonary vein
C: aorta
D: vena cava
(ii)
• Function of A: Carries deoxygenated blood from heart to lungs.
• Function of C: Transports oxygenated blood from heart to all parts of the body.
Q.7) The digestion of food in human alimentary canal is a complex process. State the enzyme/salt present in the following and mention their function in the process of digestion:
(a) Saliva
(b) Bile juice
(c) Pancreatic juice
(i) Salivary amylase - converts Starch to sugar
(ii) Bile salts – changing the acidic food alkaline/ emulsifies fats.
(iii) Trypsin – Helps in digestion of proteins / Lipase – Breaking down emulsified fats
Q.8) Why is blood circulation in vertebrates known as ‘‘double circulation’’? Trace its path in the form of a flow chart.
• Blood flows twice in the heart before it completes one complete round of the body.
Q.9) (a) Enlist any two nitrogenous waste products removed from the blood of human kidney.
(b) Name the capillary cluster formed by the branch of renal artery in the Bowman’s capsule.
(c) Depict in the form of a flow chart the path of the urine formed in each kidney until it is finally passed out through the urethra.
(a) Urea, Uric acid
(b) Glomerulus
(c)(Kidney) → Ureter → Urinary bladder → (Urethra)
Q.10) On the basis of the characteristics of the processes given in the brackets in each case, differentiate between the following :
(a) Products of breakdown of pyruvate in aerobic and anaerobic respiration in human beings (product(s) of the processes)
(b) Respiration and photosynthesis in plants (gas released)
(c) Respiration in terrestrial animals and fishes (organs involved)
a) Aerobic – carbon dioxide+water
Anaerobic - Lactic Acid
(b) Respiration –carbon dioxide
Photosynthesis – oxygen
(c) Terrestrial Animals – lungs / skin
Fish– Gills
Q.11) (a) Write the end products of the breakdown of pyruvate in yeast cells and in our muscle cells under anaerobic conditions.
(b) In which part of the cell does the above process take place ?
(a) • Yeast cells
Ethanol , Carbon dioxide , Energy
• Muscle cells
Lactic acid , Energy
(b) Cytoplasm
Q.12) Explain how urine is produced in kidneys.
• Kidney has large number of filtration units called nephrons.
• Blood enters kidney and is filtered through a cluster of capillaries(glomerulus) and the filtrate is collected by a cup shaped structure (Bowman’s capsule)
• Some substances as glucose, amino acids, salt and a major amount of water are selectively re-absorbed as the urine flows along the tube of nephron.
Q.1) Write the main difference between aerobic and anaerobic respiration. State the pathway which is common for both. Write the overall chemical equation of aerobic respiration and mention the site where this process occurs inside the cells.
• Difference :
Common pathway for aerobic and anaerobic respiration
Glucose → Pyruvate
Site − in mitochondria
Q.2) We water the soil but it reaches the topmost leaves of the plants. Explain in brief the process involved.
When water is lost through stomata in the leaves by transpiration, it creates a suction force/transpiration pull, due to which water is pulled up through xylem of the roots to the leaves.
Q.3) Give reasons for the following :
(i) Alveoli in lungs are richly supplied with blood capillaries.
(ii) Respiratory pigment in the blood takes up oxygen and not carbon dioxide.
(iii) During anaerobic respiration, a 3-carbon molecule is formed as an end product instead of CO2 in human beings.
(i) To facilitate efficient exchange of gases.
(ii) It has high affinity for oxygen.
(iii) Lack of oxygen does not oxidise glucose completely and forms a 3-Carbon molecule or lactic acid.
Q.4) (i) Name the movements that occur all along the gut in human digestive system. How do they help in digestion ?
(ii) Where is bile juice stored in human body ? List two roles of bile juice.
(i) • Peristaltic movements
• Muscles contract rhythmically in order to push the food forward in a regulated manner to be digested properly.
(ii) • Gall bladder
• Two roles:
1. Emulsification of fats
2. Makes the acidic medium alkaline.
Q.5) (i) Why is respiratory pigment needed in multicellular organisms with large body size ? (ii) Give reasons for the following :
(a) Rings of cartilage are present in the throat.
(b) Lungs always contain a residual volume of air.
(c) The diaphragm flattens and ribs are lifted up when we breathe in.
(d) Walls of alveoli contain an extensive network of blood vessels.
(i) Diffusion /Diffusion pressure alone cannot take care of oxygen delivery to all parts of the body.
(ii) Reasons:
(a) To ensure that the air-passage does not collapse.
(b) There is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released.
(c) Chest cavity becomes larger.
(d) Because exchange of gases takes place in the alveoli.
Q.1) (a) Name the glands present in the walls of the stomach and write the secretions which are released by them.
(b) Although the liver does not contain any enzyme yet it plays an important role in digestion. Comment.
(a)
Gastric glands
Pepsin, Mucus, HCI
(b)
-- Emulsification of fats / Bile juice breaks fats into small globules
-- It makes the food coming from the stomach alkaline for the pancreatic enzymes to act.
Q.2) Write any two ways by which plants obtain carbon dioxide. What causes the opening and closing of the stomata ?
-- Exchange of gases through stomata.
-- By the process of respiration.
-- The guard cells absorb water and swell causing the stomatal pore to open.
-- The guard cells lose water and shrink and hence the pore closes.
Q.3) (a) Give the structure and function of alveoli in human respiratory system.
(b) What is meant by residual volume of air in the lungs ?
(a) Within the lungs when the air passage divides into smaller and smaller tubes which finally terminate into balloon- like structures, these are called alveoli. /
Function — It provides a surface where the exchange of gases takes place.
(b) It is the volume of air left in the lungs after exhalation.
Q.4) What is photosynthesis ? Name the organelle and the organs in which photosynthesis takes place. Where does the oxygen liberated come from during this process ? What happens to the carbohydrates which are not immediately used by the plant ?
• The process in which plants/autotrophs take in substances from outside and convert them into stored form of energy. / The process in which CO2 and water is converted into carbohydrates in the presence of sunlight and chlorophyll. /
• Chloroplast
• leaves/ green part of the plant.
• water
• stored as starch
Q.5) (i) In the human respiratory system, name the following :
(I) Part where air is filtered by fine hairs and mucus lining
(II) Part which separates chest cavity from abdominal cavity
(III) Balloon like structures where exchange of gases takes place (IV) The two large air passages that lead from trachea to the lungs
(ii) List any two characteristics of lungs which make it an efficient respiratory surface.
(i) (I) Nasal passage / Nasal Cavity
(II) Diaphragm
(III) Alveoli
(IV) Bronchi
(ii) -- Large surface area
-- Extensive network of blood vessels
-- Thin, delicate and fine surface
(Any two)
Q.6) (i) What is meant by excretion ?
(ii) Name the organ that connects the kidneys with the urinary bladder. State its function.
(iii) List two factors on which the amount of water reabsorbed depends.
(i) The biological process involved in the removal of harmful nitrogenous metabolic wastes from the body is called excretion.
(ii) Ureter: it serves as a passage for the urine to move from kidneys to the urinary bladder.
(iii) Two factors :
(I) amount of excess water in the body
(II) amount of dissolved waste that is there to be excreted
Q.7) (a) With the help of an activity, explain the action of saliva on the food we eat.
(b) Why is bile juice important in the process of digestion ?
(a) • Take 1 ml 1% starch solution in two test tubes A and B.
• Add 1 ml saliva in test tube A and leave both test tubes undisturbed for 20 – 30 minutes. Now add a few drops of iodine to both the test tubes.
• The colour of iodine does not change in the test tube A as starch is converted to sugar by enzymes present in saliva.
• The colour of iodine changes to blue-black in test tube B because it contains only starch solution.
(b) (1) Bile changes the acidic medium of food to alkaline medium so that the pancreatic enzymes can act on it.
(2) It also emulsifies fats. / Breaks down the large fat globules into smaller particles.
(any one)
Q.8) (i) How does Paramecium obtain its food ?
(ii) List the role of each of the following in our digestive system :
(a) Hydrochloric acid
(b) Trypsin
(c) Muscular walls of stomach
(d) Salivary amylase
(i) Food enters through a specific spot with the help of movement of cilia.
(ii) (a) Creates an acidic medium which facilitates the action of enzyme / kills microorganisms ingested with the food.
(b) Digestion of proteins
(c) Mixing the food thoroughly with digestive juices. / pushes food forward by peristalsis.
(d) Conversion of starch into sugar.
Q.9) (i) What is double circulation ?
(ii) Why is the separation of the right side and the left side of the heart useful ? How does it help birds and mammals ?
(i) Blood goes through the heart twice during each cycle.
(ii) • To prevent oxygenated and deoxygenated blood from mixing for efficient supply of oxygen to the body.
• It helps birds and mammals who have high energy needs and constantly use energy to maintain their body temperature.
Q.10) (i) What is the first step in the breakdown of glucose during aerobic and anaerobic respiration ? Where does it take place ?
(ii) ATP is called the energy currency of the cell. Why ?
(iii) What is meant by residual volume of air in a breathing cycle ?
(i) Glucose → Pyruvic acid /Pyruvate
In the cytoplasm
(ii) It is used as fuel for all activities in a cell / ATP is broken down giving rise to a fixed amount of energy which drive endothermic reactions in the cell.
(iii) When air is taken in and let out, the lungs always contain a residual volume of air so that there is sufficient time for the oxygen to be absorbed and for the carbon dioxide to be released / volume of air present in lung after exhalation.
Q.11) Write in sequence the steps for experimental verification of the fact that sunlight is essential for photosynthesis .
• A potted plant is taken and kept in dark for 24 hrs to destarch it.
• Cover a part of a leaf of the plant with black paper to prevent that area from getting sunlight.
• Keep the plant in sunlight for 24 hours.
• Pluck the leaf, remove the black paper, boil it in alcohol and dip the leaf in iodine solution for starch test.
• The covered part showed no change in colour indicating that starch has not been produced due to the absence of sunlight.
• The rest of the leaf turned blue black proving that starch is produced during photosynthesis and sunlight is essential for that.
Q.12) (i) State the role of ATP in cellular respiration.
(ii) What ensures sufficient exchange of gases in plants ?
(iii) State the conditions on which the direction of diffusion of gases in plant depend upon.
(i) Energy currency for cellular processes / ATP breaks down to give a fixed amount of energy which can drive the endothermic reactions taking place in the cell.
(ii) Stomata and surface of leaves, stems and roots.
(iii) Environmental conditions Requirements of the plant.
Q.13) (i) What is the internal energy reserve in plants and animals ?
(ii) How desert plants perform photosynthesis if their stomata remain closed during the day ?
(i) Plants -Starch
Animals- Glycogen
(ii) Desert plants take up carbon dioxide at night and prepare an intermediate compound which is acted upon by the energy absorbed by the chlorophyll during the day.
Q.14) Explain the process of transport of oxygenated and deoxygenated blood in a human body.
• Oxygen rich blood from the lungs comes to the left atrium of heart.
• It then contracts and the blood is transferred to left ventricle.
• Left ventricle in turn contracts and the blood is pumped out to the body.
• Deoxygenated blood from the body enters the right atrium.
• On its contraction, blood enters into right ventricle
• Right ventricle pumps it to the lungs for oxygenation
Q.1) (a) Explain the surgical method of contraception used by (i) males, and (ii) females to prevent fertilisation.
(b) Write the role of oral pills taken by women as a contraceptive.
(a) (i) males – vas deferens in the male is blocked, sperm transfer will be prevented.
(ii) females – the fallopian tube is blocked and the egg will not be able to reach the uterus / fertilisation does not take place.
(b) Oral pills change the hormonal balance in females / eggs are not released / fertilisation does not take place.
Q.2) What is vegetative propagation ? Name two methods in which this process is used to grow many plants. List any two advantages of vegetative propagation.
• Vegetative Propagation : Is a method in which parts of plants like root, stem or leaves develop into new plants.
• Layering, grafting (Or any other)
• Advantages:
- Plants raised can bear flowers and fruits earlier than those produced from seeds.
- Plants that have lost the capacity to produce seeds can grow into new plants.
- Plants produced are genetically similar to the parent plant. (Any two)
Q.3) In flowering plants, the pollen grains are transferred to stigma by pollination but the female germ cells are present in the ovary. Explain with the help of a labelled diagram (only concerned parts), how the male germ cell reaches the ovary.
After the pollen lands on a suitable stigma, it has to reach the female germ cells which is located in the ovary. For this a tube grows out of the pollen grain and travels through the style to reach the ovary.
Q.4) (a) Name the two types of gametes produced by men.
(b) Does a male child inherit X chromosome from his father ? Justify.
(c) How many types of gametes are produced by a human female ?
(a) Sperm having X chromosome and sperm having Y chromosome
(b) No. As male child gets only Y chromosome from his father and X chromosome from mother to have XY chromosome.
(c) One type / only ovum / egg
Q.5) (a) Mention one function each of the following organs in human male reproductive system : (i) Testis (ii) Scrotum (iii) Vas deferens (iv) Prostate gland
(b) Name the type of germ cell which (i) is motile, and (ii) stores food
(a) (i) Testis—To produce male gametes or sperms / To produce testosterone or male sex hormone
(ii) To provide lower temperature for sperm formation
(iii) Vas deferens—Transport of sperms
(iv) Prostate gland— Secretion of fluid for easier transport and nutrition of sperms
(b) (i) Sperm
(ii) Egg / Ovum
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