Life Processes: Class 10 Science Q&A · Page 4
107 free answers on Life Processes (Science) for Class 10 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- ScienceClass 10CBSE
Which of the following statement(s) is (are) true about respiration? (i) During inhalation, ribs move inward and diaphragm is raised (ii) In the alveoli, exchange of gases takes place i.e., oxygen from alveolar air diffuses into blood and carbon dioxide from blood into alveolar air (iii) Haemoglobin has greater affinity for carbon dioxide than oxygen (iv) Alveoli increase surface area for exchange of gases (a) (i) and (iv) (b) (ii) and (iii) (c) (i) and (iii) (ii) and (iv)
Answer is (d) (ii) and (iv) Explanation: Statement i) is wrong because ribs move outward and diaphragm is lowered during inhalation. Similarly Option iii) is wrong because Hemoglobin has greater a
- ScienceClass 10CBSE
Choose the function of the pancreatic juice from the following (a) trypsin digests proteins and lipase carbohydrates (b) trypsin digests emulsified fats and lipase proteins (c) trypsin and lipase digest fats trypsin digests proteins and lipase emulsified fats
Answer is (d) trypsin digests proteins and lipase emulsified fats Explanation: Trypsin breaks down proteins into polypeptides and Lipase digest emulsified fat molecules into fatty acids and glycerol.
- ScienceClass 10CBSE
1. In which part of the alimentary canal food is finally digested? (a) Stomach (b) Mouth cavity (c) Large intestine Small intestine
Answer is (d) Small intestine Explanation: Although primary digestion process is conducted in mouth and stomach most of the digestion process occur in small intestine and in large intestine digestion process will not take place.
- ScienceClass 10CBSE
A few drops of iodine solution were added to rice water. The solution turned blue-black in colour. This indicates that rice water contains (a) complex proteins (b) simple proteins (c) fats starch
Answer is (d) starch Explanation Starch is made up of two components Amylose and Amylo pectin. When we add iodine to starch containg waqter Amylose reacts with iodine to form a blue colour complex. Here solution gives blue-black colour on adding Iodine which confirms the presence of starch in the rice water.
- ScienceClass 10CBSE
Which part of alimentary canal receives bile from the liver? (a) Stomach (b) Small intestine (c) Large intestine Oesophagus
Answer is (b) Small intestine
- ScienceClass 10CBSE
The inner lining of stomach is protected by one of the following from hydrochloric acid. Choose the correct one (a) Pepsin (b) Mucus (c) Salivary amylase (d) Bile
Answer is (b) Mucus
- ScienceClass 10CBSE
If salivary amylase is lacking in the saliva, which of the following events in the mouth cavity will be affected? (a) Proteins breaking down into amino acids (b) Starch breaking down into sugars (c) Fats breaking down into fatty acids and glycerol Absorption of vitamin
Answer is (b) Starch breaking down into sugars Explanation: Salivary Amylase enzyme present in the saliva breaks down Starch into simpler sugar and helps in digesting them. Hence the breakdown of starch will be affected if salivary amylase is lacking in the saliva.
- ScienceClass 10CBSE
Which is the correct sequence of parts in human alimentary canal? (a) Mouth → stomach → small intestine → oesophagus → large intestine (b) Mouth →oesophagus → stomach → large intestine → small intestine (c) Mouth → stomach → oesophagus → small intestine → large intestine Mouth → oesophagus → stomach → small intestine → large intestine
Soln: Answer is (d) Mouth → oesophagus → stomach → small intestine → large intestine
- ScienceClass 10CBSE
Select the correct statement (a) Heterotrophs do not synthesise their own food (b) Heterotrophs utilise solar energy for photosynthesis (c) Heterotrophs synthesise their own food Heterotrophs are capable of converting carbon dioxide and water into carbohydrat
Answer is (a) Heterotrophs do not synthesise their own food Explanation: Heterotrophs either dependent on Phototrophs or other organisms for their food.
- ScienceClass 10CBSE
Which of the following statements about the autotrophs is incorrect? (a) They synthesise carbohydrates from carbon dioxide and water in the presence of sunlight and chlorophyll (b) They store carbohydrates in the form of starch (c) They convert carbon dioxide and water into carbohydrates in the absence of sunlight They constitute the first trophic level in food chains
<p>They convert carbon dioxide and water into carbohydrates in the absence of sunlight</p><p><strong>Explanation:</strong></p><p>They need sunlight to convert carbon dioxide and water into carbohydrates.</p>
- ScienceClass 10CBSE
Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.
Solution: Alveoli Nephrons Structure Structure (i) Alveoli are tiny balloon-like structures present inside the lungs. (i) Nephrons are tubular structures present inside the kidneys. (ii) The
- ScienceClass 10CBSE
What are the differences between the transport of materials in the xylem and phloem?
Solution: Transport of Materials in Xylem Transport of Materials in Phloem Xylem tissue helps in the transport of water and minerals. Phloem tissue helps in the transport of food. Water is transported upwards from roots to all other plant parts. Food is transported in both upward and downward direc
- ScienceClass 10CBSE
Describe the double circulation of blood in human beings. Why is it necessary?
Solution: Double circulation means, in a single cycle, blood goes twice in the heart. The process helps in separating oxygenated and deoxygenated blood to maintain a constant body temperature. The double circulatory system of blood includes Pulmonary circulation Systemic circulation. Pulmonary circulation The right ventricle pumps deoxygenated blood into the lungs, where it is oxygenated. The ox
- ScienceClass 10CBSE
What would be the consequences of a deficiency of haemoglobin in our bodies?
Solution: Haemoglobin is a protein responsible for the transportation of oxygen to the body cells for cellular respiration. A deficiency of Haemoglobin can affect the oxygen-carrying capacity of RBCs. This lead to a lack of oxygen in our body cells. Haemoglobin deficiency leads to a disease called anaemia.
- ScienceClass 10CBSE
How are the alveoli designed to maximise the exchange of gases?
Solution: The lung is an important part of the body. The passage inside the lungs divides into smaller and smaller tubes, which finally terminate in balloon-like structures called alveoli. The alveoli provide a surface where the exchange of gases can take place. The walls of the alveoli usually contain an extensive network of blood vessels. We know that when we breathe in, we lift our ribs, flatten our diaphragm and the chest cavity becomes larger.</l
- ScienceClass 10CBSE
What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.
Solution: Aerobic respiration The process takes place in the presence of free oxygen. The products of aerobic respiration are CO2, water and energy. The first step of aerobic respiration (glycolysis) takes place in the cytoplasm, while the next step takes place in mitochondria. The process of aerobic respiration takes place in all higher organisms. In this process, complete oxidation of
- ScienceClass 10CBSE
What are the necessary conditions for autotrophic nutrition, and what are its byproducts?
Solution: The energy and carbon requirements of the autotrophic organism are obtained by the process of photosynthesis. It is defined as the process by which autotrophs take in substances from the outside surroundings and convert them into stored forms of energy. This substance is taken in the form of carbon dioxide and water, which are converted into carbohydrates in the presence of sunlight and chlorophyll. The main purpose of ca
- ScienceClass 10CBSE
What is the role of saliva in the digestion of food?
Solution: The food we intake is complex in nature; if it is to be absorbed from the alimentary canal, then it has to be broken into smaller molecules. This process is mainly done with the help of biological catalysts called enzymes. The saliva contains an enzyme called salivary amylase that breaks down starch, which is a complex molecule to give sugar. The food is mixed thoroughly with saliva and moved around the mouth while chewing the muscular tongue. Hence, saliva
- ScienceClass 10CBSE
How are fats digested in our bodies? Where does this process take place?
Solution: The small intestine is the place for the complete digestion of carbohydrates, fats and proteins. It receives the secretions of the liver and pancreas for this purpose. The food coming from the stomach is usually acidic in nature, and it has to be made alkaline so that pancreatic enzymes can act on it. Bile juice produced in the liver accomplishes this process. Fats are usually present in the intestine in the form of larger globules
- ScienceClass 10CBSE
The breakdown of pyruvate to give carbon dioxide, water, and energy takes place in (a) cytoplasm. (b) mitochondria (c) chloroplast (d) nucleus
Solution: The breakdown of pyruvate to give carbon dioxide, water and energy take place in mitochondria. Hence, the answer is (b) mitochondria