Chapter 6 : Life Processes

Class 10 Science Chapter 6 : Life Processes Internal Questions and Answers:

Internal Questions :

1. Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?

Answer : Diffusion is insufficient to meet the oxygen requirements of multicellular organisms like humans because it is a passive process that occurs over short distances. The larger the organism, the longer the diffusion pathway becomes, making it difficult for oxygen to reach all cells efficiently. Therefore, specialized respiratory systems, such as lungs in humans, are needed to facilitate a more efficient and rapid exchange of gases.

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

Answer : The criteria used to determine if something is alive typically include the presence of cellular organization, growth, reproduction, response to stimuli, metabolism, homeostasis, and the ability to adapt to the environment.

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

Answer : Organisms use outside raw materials for various purposes, including obtaining energy through metabolism, building and repairing cellular structures, synthesizing necessary molecules, and fulfilling nutritional requirements for growth, development, and maintenance of their biological processes.

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

Answer : Essential processes for maintaining life include metabolism (chemical reactions that sustain cellular activities), homeostasis (maintenance of internal stability), growth (increase in size or number of cells), reproduction (production of offspring), response to stimuli (ability to sense and react to the environment), and adaptation (adjustment to changing conditions for survival and success).    

Internal Questions :

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

Answer : Autotrophic nutrition involves organisms producing their own food using energy from sunlight or inorganic compounds, while heterotrophic nutrition involves organisms obtaining food by consuming other organisms or organic matter.

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

Answer : Plants obtain carbon dioxide ( ) from the atmosphere through stomata, water ( ) from the soil through their roots, and sunlight as the source of energy from sunlight-exposed parts such as leaves.

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

Answer : : The acid in our stomach, known as gastric acid or hydrochloric acid, plays a crucial role in the digestion process. It helps break down food, particularly proteins, sterilizes the stomach, and activates enzymes for further digestion in the small intestine.

4. What is the function of digestive enzymes?

Answer :  Digestive enzymes have the function of breaking down large complex molecules into smaller, simpler molecules during the process of digestion. They aid in the breakdown of carbohydrates, proteins, and fats into forms that can be absorbed and utilized by the body.

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

Answer: The small intestine is designed for efficient absorption of digested food through various adaptations. It has a large surface area due to the presence of villi and microvilli, which increase the absorptive area. Additionally, the intestinal walls are thin and permeable, allowing for the absorption of nutrients into the bloodstream for distribution throughout the body.

Internal Questions :

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

Answer : A terrestrial organism has the advantage of having easy access to atmospheric oxygen compared to aquatic organisms, which rely on dissolved oxygen in water. Terrestrial organisms can directly extract oxygen from the air, which is more abundant and readily available.

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

Answer : Glucose is oxidized to provide energy in organisms through different pathways. In aerobic respiration, glucose is completely oxidized in the presence of oxygen to produce carbon dioxide, water, and ATP. In anaerobic respiration, glucose is partially oxidized without oxygen, resulting in the production of lactic acid or ethanol and ATP. Additionally, in certain organisms like yeast, glucose can be fermented to produce ethanol and carbon dioxide, releasing energy in the process.

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

Answer : In human beings, oxygen and carbon dioxide are transported through the following mechanisms:

Oxygen Transport:

(i) The majority of oxygen is transported in the blood bound to hemoglobin, a protein found in red blood cells. This forms oxyhemoglobin.

(ii) Oxygen diffuses from areas of higher partial pressure (lungs) to areas of lower partial pressure (tissues) facilitated by the concentration gradient.

Carbon Dioxide Transport:

(i) Carbon dioxide is transported in the blood in three forms: dissolved in plasma, bound to hemoglobin (carbaminohemoglobin), and as bicarbonate ions (HCO3-) dissolved in plasma.

(ii) The majority of carbon dioxide is converted into bicarbonate ions in red blood cells and transported in the plasma.

(iii) Carbon dioxide can also directly dissolve in plasma or bind to hemoglobin.

Overall, oxygen is primarily carried by hemoglobin, while carbon dioxide is transported in various forms, including dissolved in plasma, as bicarbonate ions, and bound to hemoglobin.

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

Answer : The lungs in human beings are designed to maximize the area for gas exchange through the following features: the presence of numerous small air sacs called alveoli that provide a large surface area, thin and moist alveolar and capillary walls for efficient diffusion, a network of capillaries surrounding the alveoli for close proximity of blood, and a ventilation mechanism that ensures continuous fresh air supply.

Internal Questions :

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

Answer : The transport system in human beings consists of the following components:

Heart: The heart pumps blood and ensures its circulation throughout the body, delivering oxygen, nutrients, and hormones to tissues while removing waste products.

Blood Vessels: Arteries carry oxygenated blood away from the heart, veins return deoxygenated blood back to the heart, and capillaries enable the exchange of gases, nutrients, and waste products between blood and tissues.

Blood: Blood carries oxygen, nutrients, hormones, and waste products. It also helps regulate body temperature, pH balance, and defends against infections through its cellular and antibody components.

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

Answer :  Separation of oxygenated and deoxygenated blood is necessary in mammals and birds to ensure efficient delivery of oxygen to tissues. It allows for the maintenance of a high concentration gradient for oxygen uptake in the lungs, as well as the prevention of mixing with deoxygenated blood, which would reduce the efficiency of oxygen transport to the body.

3. What are the components of the transport system in highly organized plants?

Answer : The components of the transport system in highly organized plants include xylem and phloem. Xylem transports water and minerals from roots to leaves, while phloem transports organic molecules, such as sugars, from leaves to other parts of the plant.

4. How are water and minerals transported in plants?

Answer : Water and minerals are transported in plants through the xylem, a specialized vascular tissue. The movement of water and minerals occurs through a process called transpiration. Water is absorbed by the roots and transported upward through the xylem vessels, driven by transpiration and cohesion-tension mechanisms. This continuous upward flow of water is essential for the plant's hydration and the delivery of minerals to different parts of the plant.

5. How is food transported in plants?

Answer : Food is transported in plants through the phloem tissue. The process is known as translocation, where organic nutrients, such as sugars and amino acids, produced in photosynthetic tissues are transported to other parts of the plant for growth, storage, and energy utilization.

Internal Questions :

1. Describe the structure and functioning of nephrons.

Answer : Nephrons are the microscopic functional units of the kidneys responsible for the filtration and excretion of waste products. Each nephron consists of a renal corpuscle, composed of a glomerulus and Bowman's capsule, and a renal tubule. The glomerulus filters blood under high pressure, allowing water, ions, and small molecules to pass into the Bowman's capsule as filtrate. The filtrate then flows through the renal tubule, where selective reabsorption of water, ions, and nutrients occurs back into the bloodstream. Additionally, waste products and excess substances are actively secreted into the tubule. The remaining filtrate forms urine, which is eventually collected by the collecting ducts and excreted from the body.

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

Answer : Plants primarily get rid of excretory products through the process of transpiration, where water vapor containing dissolved waste substances is released through the stomata on the surface of leaves. Some plants also excrete waste substances through their roots into the soil.

3. How is the amount of urine produced regulated?

Answer : The amount of urine produced is regulated by a complex mechanism involving several factors. The main regulator is the antidiuretic hormone (ADH), which controls water reabsorption in the kidneys. When there is a need to conserve water, ADH levels increase, leading to increased water reabsorption and reduced urine production. Other factors like hydration levels, blood pressure, and electrolyte balance also influence urine production.

Class 10 Science Chapter 6 : Life Processes Exercises :

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

Answer : (c) excretion.

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

Answer : (d) all of the above.

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

Answer : (b) mitochondria.

5. How are fats digested in our bodies? Where does this process take place?

Answer: Fats are digested in our bodies through a process called lipolysis. It starts in the small intestine, where bile salts emulsify large fat droplets into smaller droplets, increasing the surface area. Pancreatic lipase then breaks down these smaller droplets into fatty acids and glycerol, which are absorbed by the intestinal cells and transported to the bloodstream for further utilization.
6. What is the role of saliva in the digestion of food?

Answer: Answer: Saliva plays a crucial role in the digestion of food by moistening and lubricating the food, making it easier to swallow. It contains enzymes, such as amylase, that initiate the breakdown of carbohydrates into simpler sugars, starting the process of digestion in the mouth.
7. What are the necessary conditions for autotrophic nutrition and what are its by-products?

Answer: The necessary conditions for autotrophic nutrition are sunlight, chlorophyll, carbon dioxide, and water. The by-products of autotrophic nutrition are oxygen, which is released as a result of photosynthesis, and glucose, which serves as a source of energy for the plant.
8. What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.

Answer:  The differences between aerobic and anaerobic respiration are as follows:

Aerobic Respiration:

(i) Oxygen Requirement: Aerobic respiration requires oxygen.

(ii) Efficiency: It is highly efficient and produces a large amount of ATP (energy).

(iii)  End Products: The end products of aerobic respiration are carbon dioxide and water.

(iv) Energy Yield: It yields a higher amount of energy (ATP) per glucose molecule.

(v) Organisms: Organisms such as humans, animals, and most aerobic bacteria undergo aerobic respiration.

Anaerobic Respiration:

(i) Oxygen Requirement: Anaerobic respiration does not require oxygen.

(ii) Efficiency: It is less efficient and produces a limited amount of ATP.

(iii) End Products: The end products of anaerobic respiration can vary depending on the organism. In some cases, the end products are ethanol (alcohol) and carbon dioxide, while in others, they are lactic acid or other organic compounds.

(iv) Energy Yield: It yields a lower amount of energy (ATP) per glucose molecule compared to aerobic respiration.

(v) Organisms: Organisms such as yeast, some bacteria, and certain muscle cells in animals (during intense exercise) use anaerobic respiration.

Name some organisms that use the anaerobic mode of respiration are : yeast , multicellular neried and protozoans bacteria .

9. How are the alveoli designed to maximise the exchange of gases?

Answer: : The alveoli are designed to maximize the exchange of gases through several features. They have a large surface area, thin walls (one cell thick), and are surrounded by a network of capillaries, allowing for efficient diffusion of oxygen and carbon dioxide between the alveoli and blood.
10. What would be the consequences of a deficiency of haemoglobin in our bodies?

Answer: A deficiency of hemoglobin in our bodies can lead to several consequences. It can result in reduced oxygen-carrying capacity, leading to symptoms like fatigue, weakness, and shortness of breath. It may also cause anemia, impaired tissue function, and inadequate oxygen supply to organs and tissues.
11. Describe double circulation in human beings. Why is it necessary?

Answer:  Double circulation in human beings refers to the circulation of blood through two separate pathways: pulmonary circulation and systemic circulation.

Pulmonary Circulation: Deoxygenated blood from the body is pumped by the right side of the heart to the lungs, where it picks up oxygen and releases carbon dioxide through the process of respiration. Oxygenated blood then returns to the left side of the heart.

Systemic Circulation: Oxygenated blood is pumped by the left side of the heart to supply oxygen and nutrients to all body tissues and organs. Deoxygenated blood, carrying waste products, returns to the right side of the heart.

The separation of the circulatory pathways allows for efficient oxygenation of blood in the lungs and the delivery of oxygenated blood to the body tissues. This ensures that oxygen-rich blood is supplied to the tissues for their metabolic needs, while deoxygenated blood is directed to the lungs for oxygenation. This separation of oxygenated and deoxygenated blood helps maintain a high concentration gradient for efficient gas exchange and ensures the delivery of oxygen and nutrients to body cells while removing waste products effectively.

12. What are the differences between the transport of materials in xylem and phloem?

Answer:  The differences between the transport of materials in xylem and phloem are as follows:

Xylem:

(i) Direction of Flow: Xylem transports water and minerals from the roots to the aerial parts of the plant, such as the leaves and stems.

(ii) Movement Mechanism: The movement in xylem occurs through passive processes, primarily driven by transpiration and the cohesive and adhesive properties of water.

(iii) Composition: Xylem consists of non-living cells called tracheids and vessel elements, which form long tubes for water transport.

(iv) Types of Materials: Xylem primarily transports water, dissolved minerals, and some hormones.

(v) Flow Rate: The flow rate in xylem is unidirectional and relatively slow.

Phloem:

(i) Direction of Flow: Phloem transports organic nutrients, such as sugars and amino acids, from the photosynthetic parts (source) to the non-photosynthetic parts (sink) of the plant.

(ii) Movement Mechanism: The movement in phloem occurs through active processes, primarily driven by energy-dependent mechanisms, including translocation.

(iii) Composition: Phloem consists of living cells called sieve elements (sieve tube elements and companion cells) connected end-to-end to form sieve tubes.

(iv) Types of Materials: Phloem transports organic nutrients, signaling molecules, and hormones.

(v) Flow Rate: The flow rate in phloem can be bidirectional, allowing for the movement of materials both upwards and downwards in the plant.

13. Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning .

Answer: The functioning of alveoli in the lungs and nephrons in the kidneys can be compared as follows:

Structure:

Alveoli: Alveoli are tiny air sacs located at the ends of the bronchioles in the lungs. They have thin walls and a large surface area for efficient gas exchange.

Nephrons: Nephrons are the functional units of the kidneys. They consist of a glomerulus, Bowman's capsule, and a renal tubule. The tubule is responsible for filtration, reabsorption, and secretion.

Functioning:

Alveoli: Alveoli are involved in the exchange of gases. Oxygen from inhaled air diffuses into the bloodstream through the thin alveolar walls, while carbon dioxide diffuses out of the blood into the alveoli to be exhaled.

Nephrons: Nephrons perform the vital function of filtration and formation of urine. Blood is filtered in the glomerulus, and the filtrate enters the renal tubule. As it moves along the tubule, reabsorption of water, ions, and nutrients occurs, while waste products and excess substances are secreted. The final urine is formed as the filtrate reaches the collecting duct.