CBSE Class 10 Biology Life Processes Worksheet Set G

Question. When air is blown from mouth into a test – tube containing lime water, the lime water turned milky due to presence of –
(a) Oxygen
(b) Nitrogen
(c) Water vapours
(d) Carbon dioxide

Answer: d

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. Amoeba shows thefollowing kind of nutrition –
(a) Autotrophic
(b) Holozoi
(c) Saprotrophic
(d) Parasitic 

Answer: b

Question. Which of the following organisms have parasitic mode of nutrition?
(a) Penicillium
(b) Plasmodium
(c) Paramecium
(d) Rhizobium 

Answer: b

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 kidneys in human beings are a part of the system for
(a) nutrition.
(b) respiration.
(c) excretion.
(d) transportation. 

Answer: c

Question. In Human beings the process of digestion of food begins in:
(a) Stomach
(b) Food Pipe
(c) Mouth
(d) Small Intestine 

Answer: b

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. The process by which blood is cleared of metabolic wastes in case of kidney failure is called
(a) Artificial kidney
(b) Dialysis
(c) Transplantation
(d) Filtration 

Answer: b

Question. ASSERTION (a):Energy is required to carry out different life processes.
REASON(R): Energy is obtained in the form of ATP in the mitochondria.
(a) Both A and R are true and R is the correct explanation for A
(b) Both A and R are true and R is not the correct explanation for A
(c) A is true but R is false
(d) A is false but R is true 

Answer: a

Question. ASSERTION (a): Aerobic respiration require less energy as compared to anaerobic respiration.
REASON(R): Mitochondria is the power house of the cell.
(a) Both A and R are true and R is the correct explanation for A
(b) Both A and R are true and R is not the correct explanation for A
(c) A is true but R is false
(d) A is false but R is true 

Answer: d

Question. Leaves of a healthy potted plant were coated with Vaseline to block the stomata. Will this plant remain healthy for long? Stage three reasons for your answer. 
Answer : No, the plant will not stay healthy for a long time.
The reasons are:
a. It will not be able to exchange O2 and CO2, hence respiration will be affected adversely.
b. Photosynthesis will also be affected as CO2 will not be available.
c. Transpiration will not take place hence there will be no ascent of sap, hence no water absorption from the soil.

Question. How is food transported in a plant?
Answer : The food prepared by plant may be sucrose, amino acids or other materials. It is done with the help of living cells- sieve tubes and companion cell of phloem tissue by utilizing energy of ATP. The movement occurs both upwards and down ward from the place of formation (leaves) to storage organ (roots or stems) from storage organ to organ of its utilization (growing buds) depending upon the situation. 
a. Translocation: Transport of organic food from the leaves to the other parts of the plants through the sieve tubes of phloem tissue is called translocation.
b. Importance: It is an essential process as every part of the plant requires food. For energy, building and maintenance.
c. Sugars are synthesized in the leaves whereas hormones are synthesized in the growing parts of roots and shoots.

Question. What are the main events occurring in the small intestine?
Answer : The main events occurring in the small intestine are as follows:
a. Bile emulsifies fat present in the food (emulsification means breaking of fat molecules into smaller globules).
b. Pancreatic juice containing trypsin for digesting proteins and pancreatic amylase for starch act upon the food.
c. Bicarbonate ions secreted by duodenal wall make the medium alkaline because it is required for the action of pancreatic enzynies.
d. Enzymes produced in intestinal juice complete the digestive process.
e. Digested food - amino acids, sugar are absorbed by the blood capillaries present in the villi of intestine.
f. Digested fats are absorbed by lymph vessels present in the villi of intestine.

Question. Explain how the air is inhaled during breathing in humans.
Answer : Mechanism of inhalation:
a. The diaphragm and rib muscles contract which make the throat move upwards and outwards.
b. The volume inside the thoracic cavity increases i.e., it expands.
c. Air pressure inside the thoracic cavity decreases.
Thus, air from outside rushes into the lungs / alveoli through nostrils, trachea and bronchi.

Question. Which process in plants is responsible for clouds formation and precipitation? Define the process. How is this process important for the plants?
Answer : 
They are due to transpiration. Transpiration is evaporation of water from aerial parts, leaves of plant, through mainly stomata.
a. In plants, water rises because of transpiration and in nature water cycle operates because of it.
b. Transpiration is the process of cooling the parts of a plant.
c. Evaporation of water molecules from the cells of a leaf creates a suction force which pulls water from the xylem cells. This transpiration helps in upward movement of water from roots to leaves.

Question. If a plant is kept covered with a polythene sheet, we notice some water drops on the inner side of the sheet after some time. What are they due to? Name and define the process. What is the significance of this process in plants and in nature? How does
transpiration help in upward movement of water from roots to leaves? 
Answer : If a plant is kept covered with a polythene sheet, we notice some water drops on the inner side of the sheet after sometime due to transpiration. The loss of water in the form of vapour from the aerial parts of the plant is known as transpiration. This process helps in the absorption and upward movement of water and minerals dissolved in it from roots to the leaves. It also helps in temperature regulation.

Question. What is the function of digestive enzymes?
Answer. 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.

Question. What is the role of saliva in digestion of food?
Answer: Digests starch

Question. Which tissue transports soluble products of photosynthesis?
Answer: Phloem

Question. What is the role of the acid in our stomach?
Answer. 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. 

Question. Where do plants get each of the raw materials required for photosynthesis?
Answer. The following raw materials are required for photosynthesis:
1. The raw material CO₂ enters from the atmosphere through stomata.
2. Water is absorbed from the soil by the plant roots.
3. Sunlight, an important component to manufacture food, is absorbed by the chlorophyll and other green parts of the plants.

Question. What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Answer. Terrestrial organisms take up oxygen from the atmosphere whereas aquatic animals need to utilize oxygen present in the 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 have to show various adaptations for better gaseous exchange.

Question. What are outside raw materials used for by an organism?
Answer. An organism uses outside raw materials mostly in the form of food and oxygen. The raw materials required by an organism can be quite varied depending on the complexity of the organism and its environment. 

Question. Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
Answer. Warm-blooded animals such as birds and mammals maintain a constant body temperature by cooling themselves when they are in a hotter environment and by warming their bodies when they are in a cooler environment. Hence, these animals require more oxygen (O₂) for more cellular respiration so that they can produce more energy to maintain their body temperature. Thus, it is necessary for them to separate oxygenated and de-oxygenated blood, so that their circulatory system is more efficient and can maintain their constant body temperature.

Question. What are the methods used by plants to get rid of excretory products? 
Answer. Plants can get rid of excess of 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.

Question. How are fats digested in our bodies? Where does this process take place? 
Answer. 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 can easily act on them. This is referred to as emulsification of fats. It takes place in the small intestine.

Question. What are the components of the transport system in human beings? What are the functions of these components?
Answer. The main components of the transport system in human beings are the heart, blood, and blood vessels.
1. 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.
2. Being a fluid connective tissue, blood helps in the transport of oxygen, nutrients, CO₂, and nitrogenous wastes.
3· 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.

Question. What criteria do we use to decide whether something is alive?
Answer. 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. 

 Question. What would be the consequences of a deficiency of haemoglobin in our bodies? 
Answer. Haemoglobin is the respiratory pigment that transports oxygen to the body cells for cellular respiration. Therefore, deficiency of haemoglobin 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 anaemia.

Question. In order to prepare a temporary mount of a leaf peel to observe stomata, which chemicals used for staining and mounting? 
Answer :
The chemicals used for staining and mounting respectively are safranin and glycerine.

Question. What processes would you consider essential for maintaining life?
Answer. Life processes such as nutrition, respiration, transportation, excretion, etc. are essential for maintaining life.

Question. How is the amount of urine produced regulated? 
Answer. The amount of urine produced depends on the amount of excess water and dissolved wastes present in the body. Some other factors such as habitat of an organism and hormone such as Antidiureti chormone (ADH) also regulates the amount of urine produced. 

Question. What are the components of the transport system in highly organised plants?
Answer. 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. 

Question. How are the lungs designed in human beings to maximize the area for exchange of gases?
Answer. The exchange of gases takes place between the blood of the capillaries that surround the alveoli and the gases present in the alveoli. Thus, alveoli are the site for exchange of gases. The lungs get filled up with air during the process of inhalation as ribs are lifted up and diaphragm is flattened. The air that is rushed inside the lungs fills the numerous alveoli present in the lungs. Each lung contains 300-350 million alveoli. These numerous alveoli increase the surface area for gaseous exchange making the process of respiration more efficient.

Question. What is the role of saliva in the digestion of food? 
Answer. Saliva is secreted by the salivary glands, located under the tongue. It moistens the food for easy swallowing. It contains a digestive enzyme called salivary amylase, which breaks down starch into sugar. 

Question. Usman collected her saliva and mixed it with liquid A in the test tube. In another test tube she took only liquid A after about 10 minutes, she added a few drops of iodine solution to the mixture in the first test tube. It did not show any colour but when she treated the other test tube with iodine, a blue black colour appeared. Now answer the following questions:
a. What is the aim of this activity?
b. What is liquid A?
c. Why did the first test tube not show any colour change with iodine while the second one did?
d. Which enzyme is responsible for such a result?
e. Why does a piece of bread chewed for a long time tastes sweet?
Answer : 
a. To show the action of salivary amylase on starch.
b. Liquid A is starch.
c. The first test tube did not show any colour
change with iodine because starch was not present anymore in it. It was already digested by salivary amylase present in saliva. The colour of liquid in the second one changed to blue black as the starch was still unchanged due to absence of the enzyme.
d. Salivary amylase enzyme is responsible for such a result.
e. A piece of bread chewed for a long time tastes sweet because the starch is broken down by salivary amylase to maltose sugar.

Question. Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
Answer. Multicellular organisms such as humans possess complex body designs. They have specialised cells and tissues for performing various necessary functions of the body such as intake of food and oxygen. Unlike unicellular organisms, multicellular cells are not in direct contact with the outside environment. Therefore, diffusion cannot meet their oxygen requirements.

Question. (i) Explain the importance of the following:
(a) salivary amylase
(b) villi
(c) pepsin
(ii) Explain how oxygenated blood from this chamber
is sent to all parts of the body.
Answer : 
(i) (a) Salivary amylase: It’s an enzyme present in the saliva, secreted by salivary glands. It digests starch into maltose there by starting the digestion of carbohydrate in the buccal
cavity.
(b) Villi: They increase the surface area for absorption of digested food into the blood.
(c) Pepsin: It is a digestive enzyme secreted by gastric glands. It is responsible for the digestion of proteins in stomach.
(ii) When the left atrium contracts, the oxygenated blood is poured into the left ventricle. When the left ventricle contracts the blood is pumped into the aorta, the largest artery which distributes it to all the parts of the body through arteries.

Question. How are oxygen and CO₂ transported in human beings? How are lungs designed to maximise the area for exchange of gases?
Answer :
Exchange of gases in tissues occurs through diffusion.
Oxygen is carried as oxyhaemoglobin from lungs to tissues. It dissociates and carbon dioxide diffuses out into blood from tissues. It is transported in dissolved form and reaches lungs where again it diffuses to alveoli. Lungs have a tree like branching pattern of bronchi and bronchioles. The terminal part of bronchiole ends into sac like structures called alveoli
which are present in groups. Alveoli have curved wall to increase surface area for exchange of gases. The wall of alveoli is extremely thin and is lined by blood capillaries.

Question. Write the difference between aerobic and anaerobic respiration? 
Answer: 

Aerobic respiration Anaerobic respiration
1. Takes place in presence of Oxygen. 1. Takes place in absence of Oxygen.
2. End products-Carbon dioxide &Water 2. End products –Ethanol&Carbon dioxide
3. Moreenergyis released.(38ATP) 3. Lessenergyisreleased.(2ATP)
4. Takes placeinCytoplasm &Mitochondria 4. Takes placeinonlyinCytoplasm.
5. Complete oxidation ofglucosetakes place. 5. Incomplete oxidation ofglucosetakes place.