CBSE Class 10 Science Life Processes Worksheet

Answer : C

Question. The xylem in plants are responsible for
(a) transport of water.
(b) transport of food.
(c) transport of amino acids.
(d) transport of oxygen.

Answer : A

Question. The autotrophic mode of nutrition requires
(a) carbon dioxide and water.
(b) chlorophyll.
(c) sunlight.
(d) all of the above.

Answer : D

Question. The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(a) cytoplasm.
(b) mitochondria.
(c) chloroplast.
(d) nucleus.

Answer : B

Question. Which is main form in which CO₂ is transported by blood ? 
(a) Carbonic acid
(b) Oxyhaemoglobin
(c) Carboxyhaemoglobin
(d) Bicarbonates

Answer: D

Question. In respiration, air passes through :- 
(a) Pharynx, nasal cavity, larynx, trachea, bronchi, bronchiole, lungs
(b) Nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, Alveoli
(c) Larynx, nasal cavity, pharynx, trachea, lungs
(d) Larynx, pharynx, trachea, lungs

Answer: B

Question. The exchange of gases in the alveoli of the lungs takes place by :- 
(a) Osmosis
(b) simple diffusion
(c) Passive transport
(d) Active transport

Answer: B

Question. Blood is red in :- 
(a) Cockroach
(b) Housefly
(c) Mosquito
(d) None of these

Answer: D

Question. During inspiration 
(a) the diaphragm is lowered
(b) the diaphragm is lowered and ribs are raised
(c) the diaphragm and ribs are lowered
(d) the ribs are lowered and diaphragm is raised.

Answer: B

Question. During digestion of food in the alimentary canal, protein is acted upon by enzymes in the following sequence: 
(a) pepsin, trypsin and peptidase
(b) peptidase, trypsin and pepsin
(c) ptyalin, trypsin and peptidase
(d) ptyalin, pepsin and trypsin.

Answer: A

Question. The blood vessel of frog which opens in its right auricle bringing oxygenated blood is :- 
(a) Pulmocutaneum artery
(b) Inferior vena cava
(c) Pulmocutaneum vein
(d) Superior vena cava

Answer: C

Question. The two places in the alimentary canal where carbohydrates are digested are 
(a) mouth and intestine
(b) stomach and duodenum
(c) large intestine and ileum
(d) mouth and stomach.

Answer: A

Question. The respiratory centres, which control inspiration and expiration, are located in :- 
(a) Cerebellum
(b) Diencephalon
(c) Medulla oblongata
(d) Spinal cord

Answer: C

Question. Which blood type is a universal donor ? 
(a) A
(b) B
(c) O
(d) AB

Answer: C

Question. The exchange of gases between the external air and the blood occurs in the: 
(a) bronchus
(b) bronchiole
(c) trachea
(d) alveoli.

Answer: D

Question. Blood from superior vena cavaflows into :- 
(a) Right atrium
(b) Right ventricle
(c) Left atrium
(d) Left ventricle

Answer: A

Question. Renal portal system is absent in :- 
(a) Birds
(b) Reptiles
(c) Amphibians
(d) Reptiles and amphibians

Answer: A

Question. Site of respiration in bacteria is :- 
(a) Episome
(b) Mesosome
(c) Ribosome
(d) Microsome

Answer: B

Question. Which of the following is helpful for erythropoeisis :- 
(a) Fe++
(b) Mg++
(c) Ca++
(d) Cu++

Answer: A

Question. In which of the three groups of the following mammals is uric acid also excreted out :- 
(a) Carnivora, insectivora and marsupials
(b) Elephants, chiroptera, primates
(c) Logomorpha, man, horse
(d) Man, apes, dalmatian dog

Answer: D

Question. Dialysis is carried out in case:- 
(a) both kidneys are damaged
(b) brain and spinal cord are damaged
(c) heart and lungs are damaged
(d) liver and spleen do not function

Answer: A

Question. On a slide a drop of anti B serum is placed and then a drop of blood of unknown type is added to it. The blood cells do not clump. The blood type is :- 
(a) A or O
(b) B or AB
(c) AB or A
(d) O or B

Answer: A

Question. The major effect of hyperventilation is 
(a) increased oxygen in the blood
(b) decreased carbon dioxide in the blood
(c) increased carbon dioxide in the blood
(d) decreased oxygen in the blood

Answer: B

Question. Liver is an important gland of the body. In addition to its function in digestion and food storage, the liver participates in excretion. Which of the following function(s) :- 
(a) Deamination and urea formation
(b) Elimination of haemoglobin and bile salts
(c) Inactivation of chemicals after their role is over
(d) All the three mentioned above

Answer: D

Question. Heamoglobin is having maximum affinity with :- 
(a) NH₃
(b) O₂
(c) CO
(d) CO₂

Answer: C

Question. Which of the following characteristics are of the leucocytes (white blood cells) :- 
(a) They are nucleated and can move from place to place by amoeboid movements
(b) They (granulocytes) kill bacteria
(c) They (lymphocytes) produce antibodies
(d) All of the above

Answer: D

Question. Lymph is pushed along its path in lymph vessels :- 
(a) by pumps present in lymph nodes
(b) by valves present in lymph vessels
(c) by the contraction of voluntary muscles present on either side of lymphvessels
(d) by the involuntary muscles present along with lymph vessels

Answer: C

Question. In a 70 kg man, kidneys, liver, heart and brain weigh 3.5 kg and skin, muscles and remaining organs weight 66.5 kg. Out of the total cardiac output of 5.6 litres per minute, the first four organs, namely kidneys, liver, heart and brain, receive 3.6 litres while the remaining organs of the body receive 2.0 litres of blood. The reason for the kidneys, liver, heart and brain receiving more than half the total cardiac output can be that :- 
(a) they are big organs
(b) they are located in the centre of the body
(c) they are compact organs
(d) they are most active organs and majority of the cells work almost 24 hours

Answer: D

Question. The blood proteins involved in blood clotting are :- 
(a) gamma globulin and haemoglobin
(b) prothombin and fibrinogen
(c) albumin and prothrombin
(d) collagen and fibrinogen

Answer: B

Question. A blood vessel which has thick strong muscular wall is :- 
(a) artery
(b) vein
(c) capillary
(d) lacteal

Answer: A

Question. The backward flow of blood in the veins is prevented by the presence of :- 
(a) thin walls
(b) thick walls
(c) heart beat
(d) valves

Answer: D

Question. Which of the following colours of light in the visible spectrum is the most efferctive in photosynthesis ? 
(a) Red
(b) Green
(c) Violet
(d) Yellow

Answer: A

Question. The chlorophylls absorb mostly :- 
(a) Blue and green light
(b) Blue and red light
(c) Green and red light
(d) Green light

Answer: B

Question. Vitamin K is useful for :- 
(a) Converting prothrombin to thrombin
(b) Synthesis of prothrombin
(c) Calcium combination with prothrombin
(d) All of these

Answer: B

Question. The walls of right ventricle are less muscular as compared to the left ventricle because :- 
(a) the right ventricle receives blood from the body
(b) the right ventricle sends blood to the head
(c) the right ventricle pumps blood to the lungs
(d) the right ventricle pumps blood to the alimentary canal

Answer: C

Question. Entire haemoglobin of blood becomes oxidised while it goes out of lung and it relieves oxygen in body tissues, because :- 
(a) Of reduction of oxyhaemoglobin
(b) In comparison to lung, tissues have high conc. of CO₂
(c) Tissues can absorb oxygen from haemoglobin
(d) Tissues have high conc. of O₂ and low conc. of CO2

Answer: B

Question. The most stable product formed with haemoglobin is by :- 
(a) CO₂
(b) O₂
(c) CO
(d) SO₂

Answer: C

Question. Mountain sickness results due to 
(a) anaemic hypoxia
(b) arterial hypoxia
(c) lack of sufficient RBCs
(d) lack of sufficient WBCs

Answer: B

Question. As blood flows out of a damaged blood vessel, blood platelets release a substance called :- 
(a) Thrombin
(b) Prothrombin
(c) Thromboplastin
(d) Fibrin

Answer: C

Question. Conversion of fibrinogen to fibrin is catalysed by :- 
(a) Thrombin
(b) Prothrombin
(c) Thromboplastin
(d) All of these

Answer: A

Question. The pH value of blood varies between :- 
(a) 6.00–7.00
(b) 7.00–8.00
(c) 7.30–7.45
(d) 7.50–8.00

Answer: C

Question. Body tissues obtain oxygen from haemoglobin because of its dissociation in tissues caused by 
(a) low oxygen concentration and high carbon dioxide concentration
(b) low oxygen concentration
(c) low carbon dioxide concentration
(d) high carbon dioxide concentration

Answer: B

Question. Which of the following enzyme acts efficiently at pH two? 
(a) Trypsin
(b) Pepsin
(c) Ptyalin
(d) All of the above

Answer: B

Question. If a cell membrane shrinks after being placed in a solution, it is :- 
(a) hypotonic
(b) hypertonic
(c) isotonic
(d) normal

Question. Name the first digestive organ that is associated with the breakdown of proteins in humans. What are its three releases?
Answer : The first digestive organ in humans is the stomach. It releases proteolytic enzymes, HCl and mucus.

Question. Name the component of blood that helps in the formation of blood clot in the event of a cut.
Answer : Platelets help in clotting of blood in the event of a cut.

Question. Give one reason why multicellular organisms require special organs for exchange of gases between their body and their environment. :
Answer : In unicellular organisms the entire body of the organism is in contact with the environment hence exchange of materials can take place but, in multicellular organisms the entire body of the organism is not in contact with the environment and hence simple diffusion is not helpful.

Question. What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Answer : The amount of oxygen dissolved in water is very low, as compared to amount of oxygen in air. Thus, terrestrial organism has to make less efforts to obtain oxygen than an aquatic organism to obtain oxygen for respiration.

Question. How is carbon dioxide obtained by (a) aquatic plants and (b) terrestrial plants ?
Answer : (a) Aquatic plants take up carbon dioxide dissolved in water.
(b) Terrestrial plants use carbon dioxide present in air.

Question. What is‘translocation’in plants?
Answer : Translocation is the movement of soluble materials, products of photosynthesis from leaves to other tissues throughout the plant.

Question. Name the two ways in which glucose is oxidised to provide energy in various organisms.
Answer : The two ways in which glucose is oxidised to provide energy in various organisms are aerobic respiration pathway which uses oxygen to break-down glucose completely into carbon dioxide and water and some use other pathways that do not involve oxygen which is called anaerobic respiration pathway.

Question. Specify two conditions in which photo-respiration may take place in green plants.
Answer : Two conditions in which photorespiration may take place in green plants are: (i) High concentration of oxygen and (ii) High temperature

Question. Describe the mechanism of blood clotting.
Answer : Blood Clotting: It is the mechanism that prevents the loss of blood at the site of an injury or wound by forming a ‘blood clot’. The blood has platelet cells which circulate around the body and plug these leaks by helping to clot the blood at these points of injury to prevent it from excessive bleeding.

Question. Which part of the human heart is considered as pace-maker? Why is it so called?
Answer : Sino-atrial node of the human heart is considered as pacemaker. Sino-atrial node is also called as pacemaker because it determines the rate of heartbeat by determining the rate of discharge of cardiac impulse.

Question. Which enzyme initiates the digestion of proteins ? Name the other enzyme produced by the same gland.
Answer : The enzyme gastric pepsin initiates the digestion of proteins. The other enzyme produced by the stomach is gastric lipase.

Question. Where does digestion of fat take place in our body?
Answer : Digestion of fat takes place in the small intestine of our body.

Question. State any one difference between autotrophic and heterotrophic modes of nutrition.
Answer : In autotrophic nutrition, organisms obtain their food from inorganic substances. In heterotrophic nutrition, organisms derive their food from organic substances.

Question. Why do the walls of the trachea not collapse’when there is less air in it?
Answer : Rings of cartilages are present in trachea. These rings support the trachea and do not allow the trachea to collapse when there is less air in it.

Question. How would digestion of food be affected if the bile duct is completely blocked? Explain.
Answer : If the bile duct is completely blocked, bile juice will not reach the small intestine and the digestion of fats will be affected.

Question. Name one accessory pigment and one essential pigment in photosynthetic plants.
Answer : Accessory pigment – Carotene/Xanthophyll
Essential pigment – Chlorophyll

(ii)Oxygen gas is evolved during photosynthesis. Oxygen gas is evolved by splitting of water
2H₂O → 2H₂ + O₂
(iii)They take take up CO₂ at night through stomata, which open during night and produce an intermediate organic acid which is acted upon by the energy absorbed by chlorophyll during the day and breaks up to release of CO₂ .The CO₂ so produced internally is used in photosynthesis during day when stomata are closed. Example-desert pant 

Question. Draw a diagram of human respiratory system and label on it :
(i) Diaphragm (ii) Larynx
Answer :

Question. (a) Name the site of exchange of material between the blood and surrounding cells. (b) Draw a schematic representation of transport and exchange of oxygen and carbon dioxide in human body.
Answer :
(a) Capillaries
(b)

Question. List three characteristics of lungs which make it an efficient respiratory surface.
Answer : These features which particularly make our lungs efficient for gas exchange.
1.Thin: the air sac walls are very thin so that gases can quickly diffuse through them. Oxygen is absorbed in to the blood and carbon dioxide is given out in to the lungs to be exhaled out.
2.Moist: the 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 the alveoli have a large capillary network so that large volumes of gases can be exchanged. More the flow of blood more exchange.

Question. (a) What is the role of HCl in our stomach ?
(b) What is emulsification of fats ?
(c) Which protein digesting enzyme is present in pancreatic juice ?
Answer : (a)(i) It sterilises food by killing pathogens and other microbes.
(ii) It has a pH of 2, which is perfect for entyaus such as pepsin to break down proteins as effectively as possible.
(iii) Helps emulsify food (digestion of protein and stimulates the pancreas to produce digestive enzymes and bile) and protects against harmful ‘ bacteria
(b) Breakdown of large gloubule fats into smaller fats droplets is known as emulsification.
(c) Trypsin is the enzyme secreted by the pancreas which aids in digestion of proteins.

Question. List in tabular form three differences between arteries and veins.
Answer :

Long Answer Type Questions

Question. (a) Draw a diagram of human respiratory system and label the following:
(i) part where air is filtered by fine hair and mucus
(ii) part which terminates in balloon – like structures
(iii) balloon – like structures where exchange of gases takes place.
(iv) part which separates chest cavity from abdominal cavity.
(b) Why is the rate of breathing in aquatic organisms much faster than in terrestrial organisms?
Answer : (a)

(b) Quantity of dissolved oxygen is fairly low in water as compared to the amount of oxygen in air. Aquatic organisms therefore have to breath faster than terrestrial organisms to absorb the required amount of oxygen from the water.

Question. (a) Draw a schematic representation of transport and exchange of oxygen and carbon dioxide during transportation of blood in human beings and label on it: Lung capillaries, Pulmonary artery to lungs, Aorta to body, Pulmonary veins from lungs.
(b) What is the advantage of separate channels in mammals and birds for oxygenated and deoxygenated blood?
Answer : (a) A schematic representation of transportation and exchange of oxygen and carbon dioxide during transportation of blood in human beings

(b) It is necessary to separate oxygenated and deoxygenated blood in mammals and birds because they need high energy and large amount of oxygen. The separation of oxygenated and deoxygenated blood provides high oxygen supply to the organs.

Question. (a) Draw a diagram depicting Human Alimentary Canal and label on it: Gall bladder, Liver and Pancreas.
(b) State the roles of Liver and Pancreas.
(c) Name the organ which performs the following functions in humans:
(i) Absorption of digested food
(ii) Absorption of water.
Answer : (a)

(b) Liver: It synthesize and store bile juice secreted by gall bladder which breaks down fats into fat globules. Pancreas: It secretes pancreatic juice which contains protein-digesting and starchdigesting enzymes.
(c) The organ which performs the following functions in humans are as follows:
(i) Absorption of digested food – Small intestine.
(ii) Absorption of water – Large intestine.

Question. (a) Draw a sectional view of the human heart and label on it – Aorta, Right ventricle and Pulmonary veins.
(b) State the functions of the following components of transport system:
(i) Blood (ii) Lymph
Answer : (a) 

(b) The functions of blood and lymph are as follows:
(i) Blood
• Oxygen is transported by the blood to the tissues of the body for the breakdown of digested food.
• Carbon dioxide is transported to the lungs by the blood plasma.
• The digested and absorbed nutrients are transported by blood to the tissues. Nitrogenous wastes are transported to the kidneys.
• It regulates the body temperature and maintains the pH of the body tissues.
• It transports various hormones from one region to another and bring about the coordination.
• It maintains water balance to constant level.
• The lymphocytes produce antibodies against the invading antigens and protect from diseases.
• It helps in rapid healing of wounds by forming a clot at the site of injury.
(ii) Lymph
• It cleans the cellular environment.
• It returns proteins and tissue fluids to the blood (drainage)
• It provides a pathway for the absorption of fats and fat-soluble vitamins into the bloodstream.
• It defends the body against disease.

Question. (a) Draw a labelled diagram of the respiratory system of human beings with diaphragm at the end of expiration.
(b) List four conditions required for efficient gas exchange in an organism.
Answer : (a)

(b) (i) A large surface area over which exchange can take place.
(ii) A concentration gradient without which nothing will diffuse.
(iii) A thin surface across which gases diffuse.
(iv) Warm conditions.

Question. (a) What is meant by breathing? What happens to the rate of breathing during vigorous exercise and why?
(b) Define translocation with respect to transport in plants. Why is it essential for plants? Where in plants are the following synthesised
(i) Sugar (iii) Hormone
Answer : (a) The process of taking in of oxygen from air in to the lungs and expulsion of carbon dioxide out of the lungs is called breathing. The rate of breathing during vigorous exercise increases by about 20 to 25 times per minute. It is because, during vigorous exercise the demand for oxygen increases. Breathing occurs involuntarily but its rate is controlled by the respiratory center of the brain.
(b) Translocation is the transport of food from the leaves to other parts of the plant and occurs in the part of the vascular tissue known as phloem.
It is essential for plants because every part of the plant needs food for obtaining energy for building its parts and maintaining its life.
(i) Sugar is synthesised in the leaves of the plant.
(ii) Hormones are synthesised at the tips of roots and stems of a plant.

Question. (a) Explain how does the exchange of gases occur in plants across the surface of stems, roots and leaves.
(b) How are water and minerals transported in plants?
Answer : (a) In plants, there are tiny pores called stomata on leaves and lenticels in stem which facilitate the exchange of gases. CO2 is taken in and O2 given out (during photosynthesis) and vice-versa during respiration.
(b) Mechanism of Transport of Water and Minerals in a Plant
• The vessels and tracheids of roots, stems and leaves in xylem tissue are interconnected to form a continuous system of water-conducting channels reaching all parts of the plant.
• The cells of the roots in contact with the soil actively take up ions which creates a difference in the ion concentration between the root and the soil.
• Thus, there is steady movement of water into root xylem from the soil, creating a column of water that is pushed upwards.
• Plant uses another strategy to move water in the xylem upwards to the highest points of the plant body.
• The water which is lost through the stomata is replaced by water from the xylem vessels in the leaf.
• Evaporation of water molecules from the cells of a leaf creates a suction which pulls water from the xylem cells of roots.
• This loss of water is transpiration which helps in the absorption and upward movement of water and minerals dissolved in it from roots to the leaves.
• Transpiration becomes the major driving force in movement of water in the xylem during the day when the stomata are open.
• This mechanism is also known as cohesion of water theory or transpiration pull.

Question. (a) Complete the glucose breakdown pathway in case of aerobic respiration by filling the blanks.

(b) Name the molecule in the cell which stores the energy produced at the end of the pathway.
(c) Why do we get cramps during vigorous muscular activity?
Answer : (a) (1) Pyruvate (3 carbon molecules) (2) Energy (3) Presence of oxygen (4) In Mitochondria (5) Carbon dioxide (6) Water
(b) ATP
(c) Lactic acid accumulation, in the absence of oxygen (anaerobic respiration)cause cramps.