6. Life Processes-Text-book Questions Science Class 10 In English

Text-book Questions

Page no. 95

Q1. Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?

Ans: In multicellular organisms sufficient amount of oxygen cannot be carried to every part of the body by diffusion. Oxygen is very essential in multicellular organisms. The structure of multicellular organisms is very complex. So every organ needs oxygen. which cannot complete the diffusion process.

Q2. What criteria do we use to decide whether something is alive?

Ans: Living things move continuously. Even if they are in a dormant state. Outwardly they appear unconscious. Their molecules remain in motion. This gives proof of their existence.

Q3. What are outside raw materials used for by an organism?

Ans: Organisms require additional raw material from outside for physical growth. Life on Earth is based on carbon molecules. Therefore, this food item is dependent on carbon. These organic compounds are another form of food. In these the exchange of oxygen and carbon-dioxide is prominent. Apart from this, there are other water and mineral salts. Starch is formed in the presence of sunlight along with these raw materials.

Q4. What processes would you consider essential for maintaining life?

Ans: Many biological activities are necessary for the maintenance of life such as: nutrition, movement, respiration, growth and excretion.

Page no. 101

Q1. What are the differences between autotrophic nutrition and heterotrophic nutrition?

Ans :

Autotrophic nutrition: - When green plants make their own food in the presence of chlorophyll and sunlight, using CO₂ and water. This process is called photosynthesis.

Heterotrophic Nutrition:- When organisms do not make their own food but depend on others for their food, then they are called heterotrophs. For example fungus, human.

Q2. Where do plants get each of the raw materials required for photosynthesis?

Ans:

Water - The roots of the plant get water from the ground.

Carbon dioxide - Plants get it from the atmosphere through stomata.

Chlorophyll - Green leaves have chloroplasts, in which chlorophyll is present.

Sunlight - received by the Sun.

Q3. What is the role of the acid in our stomach?

Ans: Hydrochloric acid is present in our stomach. This acid forms acidic medium in the stomach. With the help of this, the enzyme performs its function. HCl acid destroys the microbes present in our food. HCl acid helps in digestion of food in the stomach.

Q4. What is the function of digestive enzymes?

Ans: Digestive enzymes convert complex food into simple, subtle and beneficial substances. In this way simple substances are absorbed by the small intestine.

Q5. How is the small intestine designed to absorb digested food? 

Ans: The digested food is absorbed in the small intestine. There are thousands of microscopic, angular-like villous in the small intestine, due to which their internal area increases. Absorption also increases as the area increases. This absorbed food reaches the blood.

Page no. 105 

Q1. What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?

Ans: Adequate amount of oxygen is found in the atmosphere which is easily taken up by the terrestrial organisms but there is a small amount of oxygen in the water and it is mixed in the water, so the aquatic organisms are able to take this found oxygen at great speed. Breathe and fight

Q2. What are the different ways in which glucose is oxidised to provide energy in various organisms?

Ans: Glucose is oxidised in sufficient amount of oxygen in muscles and provides energy and when there is less amount of oxygen, it gets synthesized and forms lactic acid. Oxidation pathway is following in the cells of organisms.

(i) Aerobic Respiration : In this process Oxygen breaks down glucose into water and CO₂ breaks into Glucose is synthesized in sufficient amount of oxygen to form two molecules of 3 carbon atom pyruvate.

(ii) Anaerobic Respiration: In the absence of oxygen, fermentation takes place in yeast and pyruvate, ethanol andCO₂  are formed.

(iii) Lack of oxygen leads to the formation of lecitic acid, which causes camps in the muscles.

Q3. How is oxygen and carbon dioxide transported in human beings?

Ans: The transport of oxygen and carbon dioxide in humans is called respiration. This process is carried out by the lungs. Hemoglobin (red blood particles) from the air reached through the lungs, takes up oxygen and reaches all the cells of the body. In this way oxygen reaches every part of the body. Similarly, CO2 which is formed in our body when glucose is broken down and converted into energy. This CO2 dissolves in its plasma when it comes in contact with blood. This CO2 is carried from the whole body through the plasma again from the blood to the air and hence is expelled from the nasopharynx.

Q4. How are the lungs designed in human beings to maximise the area for exchange of gases?

Ans: Human lungs are divided into small tubes. Bronchus After the bronchioles, there are alveoli, whose structure is similar to that of a balloon. The alveoli itself facilitates the transport of gases and covers a large area.

Page no. 110

Q1. What are the components of the transport system in human beings? What are the functions of these components?

Ans: The major components of the carriage system in humans are: heart, blood and blood vessels.

(i) Heart : The heart like a pump exchanges blood with different parts of the body.

(ii) Blood : Contains three blood cells. Their liquid medium is plasma. Blood is present in the body.

Carries CO₂, food, water, oxygen, and other materials. RBC cells carry CO₂ and oxygen gases and other substances. WBC makes the body disease free by fighting the bacteria from outside in the body. Platelets prevent blood from flowing through an injury.

Q2. Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?

Ans: Mammals and birds require more energy, which is obtained when glucose is broken down. Oxygen is required for the breakdown of glucose. Only by separating oxygenated and deoxygenated blood can the body provide such a large amount of energy.

Q3. What are the components of the transport system in highly organised plants?

Ans: The major components of the carriage system in highly organized plants are:

  (i) Xylem Tissue

(ii) Phloem tissue

Q4. How are water and minerals transported in plants?

Ans: Xylem tissue carries water and minerals in plants. Root cells are inside the soil and they exchange ions. This creates a difference between the root and the root ion in the soil. To bridge this gap, water moves into the root xylem and forms a column of water, which is continuously pushed upwards. This pressure cannot reach the water upwards. There is a loss of water by the leaves through transpiration, which draws water through the cells present in the roots. Therefore, transpiration traction is the important force for the movement of water.

Q5. How is food transported in plants? 

Ans: Leaves prepare food. Phloem vessels carry food from the leaves throughout the plant.

Page no. 112

Q1. Describe the structure and functioning of nephrons.

Ans:

Q2. What are the methods used by plants to get rid of excretory products?

Ans: Following are the methods to get exemption from Utji product:

(i) Plants produce oxygen in photosynthesis and use carbon dioxide through stomata for respiration.

(II) Plants can reduce the water present in large numbers by the process of transpiration.

(III) Plants excrete some waste material to the soil around them.

Q3. How is the amount of urine produced regulated?

Ans: The amount of urine depends on the water consumed by the human being and the absorption by the body. When drinking less water, the amount of urine is less, some hormones keep it under control. The amount of water also increases for the excretion of urea and uric acid. Hence more urine is excreted.