RBSE Solutions Class 11 Biology Chapter 34 अमीबा

Rajasthan Board RBSE Class 11 Biology Chapter 34 अमीबा

RBSE Class 11 Biology Chapter 34 पाठ्यपुस्तक के प्रश्न

RBSE Class 11 Biology Chapter 34 वस्तुनिष्ठ प्रश्न

 

Question 1. शब्द एमोइब (Amoibe) का क्या अर्थ है
(अ) अत्यन्त सूक्ष्म प्राणी
(ब) सरलतम प्राणी
(स) परिवर्तनशील प्राणी
(द) कूटपादों की उपस्थिति
Answer: (स) परिवर्तनशील प्राणी
In simple words: Amoeba's name means "changeable creature" because it constantly changes its shape. Amoeba does not have a fixed shape like many other animals, allowing it to move and feed in unique ways.

🎯 Exam Tip: Remember that "amoibe" comes from the Greek word meaning "to change", directly relating to its shape-shifting nature.

 

Question 2. अमीबा में संकुचनशील रिक्तिका का कार्य होता है
(अ) पोषण
(ब) श्वसन
(स) लोबोपोडिया
(द) फिलोपोडिया
Answer: (स) लोबोपोडिया
In simple words: The contractile vacuole in amoeba primarily helps in maintaining water balance by expelling excess water from the cell. Amoeba moves by extending its temporary foot-like structures called pseudopods.

🎯 Exam Tip: The contractile vacuole is crucial for osmoregulation in freshwater amoeba, preventing it from bursting due to excess water intake.

 

Question 3. अमीबा में आहार रिक्तिका की प्रकृति होती है
(अ) केवल अम्लीय
(ब) केवल क्षारीय
(स) पहले क्षारीय बाद में अम्लीय
(द) पहले अम्लीय बाद में क्षारीय
Answer: (द) पहले अम्लीय बाद में क्षारीय
In simple words: The food vacuole in Amoeba first becomes acidic to break down food, and then becomes alkaline for further digestion. This change in pH helps different enzymes work at their best to fully digest the captured food.

🎯 Exam Tip: Note the two-phase pH change in the food vacuole: acidic initially for partial digestion, followed by alkaline for complete digestion.

 

Question 4. अमीबा में कूटपाद का प्रकार है
(अ) एक्टोपोडिया
(ब) रेटिकुलोपोडिया
(स) लोबोपोडिया
(द) फिलोपोडिया
Answer: (स) लोबोपोडिया
In simple words: Amoeba uses lobopodia as its type of pseudopod for movement and feeding. Lobopodia are broad and blunt, allowing the amoeba to move slowly but powerfully across surfaces.

🎯 Exam Tip: Remember that lobopodia are typically thick, blunt pseudopods, common in the genus Amoeba, used for crawling and engulfing food.

 

Question 5. अमीबा का उत्सर्जी पदार्थ होता है
(अ) अमोनिया
(ब) यूरिया
(स) गुआनिन
(द) यूरिक अम्ल
Answer: (अ) अमोनिया
In simple words: The main waste product Amoeba gets rid of is ammonia. Ammonia is highly soluble in water, making it easy for aquatic organisms like amoeba to excrete it directly into their surroundings.

🎯 Exam Tip: Aquatic organisms often excrete ammonia because its high solubility allows for quick diffusion into the water, preventing toxic buildup.

RBSE Class 11 Biology Chapter 34 अतिलघूत्तरात्मक प्रश्न

 

Question 1. अमीबा किस वर्ग का प्राणी है?
Answer: Amoeba is a creature that belongs to the Sarcodina/Rhizopoda class. This class includes many organisms that use pseudopods for movement and feeding.
In simple words: Amoeba belongs to a group of animals called Sarcodina or Rhizopoda.

🎯 Exam Tip: Mentioning both Sarcodina and Rhizopoda shows a complete understanding of its classification.

 

Question 3. अमीबीय गति का सॉल-जेल मत किस वैज्ञानिक ने सर्वप्रथम प्रस्तुत किया?
Answer: Hyman first put forward the sol-gel theory for how amoeba moves in the year 1917. This theory describes how the amoeba's cytoplasm changes between a fluid (sol) and a gel-like state to enable its movement.
In simple words: The idea of sol-gel movement in amoeba was first explained by a scientist named Hyman in 1917.

🎯 Exam Tip: Remember the scientist's name (Hyman) and the year (1917) associated with the sol-gel theory.

 

Question 4. अमीबा की खाद्यधानियों से कौनसी रचनाएँ जुड़कर एन्जाइम पहुँचाती हैं?
Answer: Lysosome structures connect with the food vacuoles in amoeba to bring enzymes for digestion. Lysosomes are known as the "suicide bags" of the cell because they contain digestive enzymes that break down waste materials and cellular debris.
In simple words: Lysosomes connect to the food vacuoles in amoeba. They bring enzymes to help digest the food.

🎯 Exam Tip: Always remember that lysosomes are the primary source of digestive enzymes within a cell, vital for breaking down engulfed food.

 

Question 5. अमीबा में उपस्थित उत्सर्जी रवों के नाम लिखिये।
Answer: The excretory crystals found inside amoeba are called biuret and triuret. These crystals are metabolic byproducts that the amoeba needs to eliminate to maintain its internal balance.
In simple words: Amoeba has waste crystals named biuret and triuret.

🎯 Exam Tip: Be precise with the names of the excretory crystals, biuret and triuret.

 

Question 6. अमीबा कहाँ पाया जाता है?
Answer: Amoeba lives in fresh water, which means it can be found in places like ponds, small pools, and lakes. These freshwater environments provide the necessary conditions for amoeba to thrive, including food sources and a stable temperature.
In simple words: Amoeba is found in fresh water, like in ponds and lakes.

🎯 Exam Tip: Focus on freshwater bodies as the primary habitat for amoeba, such as ponds, lakes, and puddles.

 

Question 7. अमीबा में अनुकूल परिस्थितियों में सम्पन्न होने वाली जनन विधि का नाम बताइये।।
Answer: When conditions are good, amoeba reproduces by a method called binary fission. In binary fission, one parent amoeba divides into two identical daughter amoebae, ensuring rapid population growth.
In simple words: When conditions are right, amoeba divides into two new amoebas. This is called binary fission.

🎯 Exam Tip: Binary fission is the most common asexual reproduction method in amoeba under favorable conditions.

 

Question 8. अमीबा में केन्द्रक को नष्ट करने पर क्या होगा?
Answer: If the nucleus of an amoeba is destroyed, the amoeba will also die. The nucleus contains the amoeba's genetic material and controls all its vital functions, so its removal is fatal.
In simple words: If the nucleus of an amoeba is broken, the amoeba will die.

🎯 Exam Tip: Emphasize that the nucleus is the control center of the cell; without it, essential life functions cannot be managed, leading to death.

 

Question 10. सॉल-जेल प्रावस्थाओं का विभेदात्मक आधार क्या है?
Answer: The main difference between sol and gel states is how protein molecules fold and unfold. This dynamic change in protein structure allows the cytoplasm to switch between a more fluid (sol) and a more viscous (gel) state, crucial for amoeboid movement.
In simple words: Sol-gel states are different because protein molecules can either fold up or open up.

🎯 Exam Tip: Understand that the folding and unfolding of proteins dictate the fluidity (sol) and rigidity (gel) of the cytoplasm, which is key to amoeboid movement.

 

Question 11. अमीबा पोषण की दृष्टि से किस प्रकार का प्राणी है?
Answer: From the perspective of how it eats, amoeba is an omnivore. This means it can consume both plant-like organisms (like algae) and small animal-like organisms (like bacteria), making it highly adaptable to its environment.
In simple words: Amoeba eats many kinds of food, so it is called an omnivore.

🎯 Exam Tip: An omnivore consumes both plant and animal matter, which perfectly describes the amoeba's diverse diet of small organisms.

 

Question 12. अमीबा में भोज्य पदाथों का पाचन कहाँ होता है?
Answer: Food digestion in amoeba takes place inside the food vacuole. The food vacuole acts like a temporary stomach, where enzymes break down the food into simpler forms that the amoeba can absorb.
In simple words: Amoeba digests its food inside a special sac called a food vacuole.

🎯 Exam Tip: The food vacuole functions as the primary site of intracellular digestion in amoeba, containing digestive enzymes.

 

Question 13. अमीबा में श्वसन विधि का नाम बताइये।
Answer: Amoeba breathes by a simple process called diffusion. In diffusion, oxygen from the surrounding water enters the amoeba's body, and carbon dioxide leaves, directly through its cell membrane.
In simple words: Amoeba breathes using a method called diffusion.

🎯 Exam Tip: Diffusion is a passive process where gases move from an area of high concentration to an area of low concentration across the cell membrane.

 

Question 14. अमीबा में संचित भोजन किस रूप में पाया जाता है?
Answer: Amoeba stores its food mainly as glycogen. Glycogen serves as a readily available energy reserve, similar to how animals store glucose for later use.
In simple words: Amoeba stores its food as glycogen.

🎯 Exam Tip: Glycogen is a common storage polysaccharide in animals and fungi, providing an accessible source of glucose.

 

Question 15. अमीबा द्वारा ठोस पदार्थों के ग्रहण करने की क्रिया क्या, कहलाती है?
Answer: When an amoeba takes in solid food particles, this process is known as phagocytosis. Phagocytosis is a crucial feeding mechanism for many single-celled organisms, allowing them to engulf larger food items.
In simple words: Amoeba eats solid things by a process called phagocytosis.

🎯 Exam Tip: Phagocytosis involves the engulfment of solid particles by the cell membrane, forming a phagosome or food vacuole.

RBSE Class 11 Biology Chapter 34 लघूत्तरात्मक प्रश्न

 

Question 2. अमीबा में जीवद्रव्य कला के प्रमुख कार्य लिखिए।
Answer: The main functions of the plasma membrane in amoeba are:

• It forms the outer covering of the amoeba's body, which prevents the cytoplasm from flowing out.
• It helps in endo-osmosis, which is the movement of water into the cell.
• It has small finger-like projections called microvilli that help the amoeba stick to surfaces.
• It aids in regeneration, allowing the amoeba to regrow lost parts.
• It helps in forming pseudopods for movement and feeding.
• It helps in the continuous exchange of substances with the outside environment, such as through diffusion, phagocytosis, and pinocytosis.

This versatile membrane plays a vital role in maintaining the amoeba's shape, movement, and interaction with its surroundings.
In simple words: The plasma membrane keeps the amoeba's insides from spilling out. It also helps water move in and out, helps the amoeba stick to things, regrow lost parts, make its "false feet" for moving, and swap things with the outside world.

🎯 Exam Tip: When listing functions, remember key roles like protection, osmoregulation, adhesion, regeneration, and active transport/exchange with the environment.

 

Question 3. अमीबा समसूत्रण (Promitosis) क्या है?
Answer: Asexual reproduction in amoeba happens through binary fission. During this process, one amoeba divides into two daughter amoebae using mitosis. However, in this type of division, the nuclear membrane does not disappear. So, the division where the nuclear membrane remains visible is called promitosis. It is also known as cryptomitosis. This unique characteristic of promitosis distinguishes it from typical mitosis observed in higher eukaryotes, where the nuclear envelope breaks down.
In simple words: Amoeba reproduces by dividing into two. When it divides, the outer covering of its nucleus does not go away. This special kind of cell division is called promitosis, or cryptomitosis.

🎯 Exam Tip: The defining feature of promitosis is the persistence of the nuclear membrane throughout the entire process of nuclear division.

 

Question 4. पुटीभवन क्या है? इससे अमीबा को क्या लाभ है?
Answer: In harsh conditions, an amoeba forms a three-layered protective covering around itself. This covering is called a cyst. The process of forming this cyst is known as encystment. This helps the amoeba survive bad conditions. Encystment allows the amoeba to endure extreme temperatures, dryness, or lack of food until favorable environmental conditions return.
In simple words: When the environment is bad, amoeba makes a strong, three-layered cover around itself. This cover is called a cyst, and making it is called encystment. This helps the amoeba stay safe until things get better.

🎯 Exam Tip: Encystment is a survival mechanism, enabling amoeba to withstand adverse environmental conditions by becoming dormant within a protective shell.

 

Question 6. यदि स्वच्छ जल के अमीबा को समुद्री जल में रखेंगे तो संकुचनशील रसधानी के अस्तित्व पर क्या प्रभाव पड़ेगा?
Answer: If a freshwater amoeba is put into seawater, its contractile vacuole might disappear. This happens because seawater is saltier, causing water to move out of the amoeba by osmosis, reducing the need for the contractile vacuole to expel excess water.
In simple words: If a freshwater amoeba is put in seawater, its contractile vacuole might go away.

🎯 Exam Tip: Understand that the contractile vacuole is primarily for osmoregulation in hypotonic environments; in a hypertonic (saltier) environment, its function becomes unnecessary or even detrimental.

 

Question 7. वलन-अवलन सिद्धान्त के अनुसार अमीबीय गति को समझाइए।
Answer: The molecular folding and unfolding theory was presented by Goldacre and Lorch in 1950. According to this theory, the sol and gel states of cytoplasm are a result of proteins folding and unfolding. When polypeptide chains in the uroid part (rear) fold and contract, the plasmagel changes into plasmasol. In the front part, when the polypeptide chains start to straighten, plasmasol changes back into plasmagel. So, the plasmasol state occurs due to folding, and the plasmagel state occurs due to unfolding. This continuous interconversion between sol and gel states provides the driving force for the flowing movement of cytoplasm within the amoeba, pushing out pseudopods.
In simple words: Goldacre and Lorch gave a theory in 1950. They said amoeba moves because proteins in its body fold and unfold. When proteins fold, one part of the body becomes soft (sol). When they unfold, another part becomes firm (gel). This change helps the amoeba push itself forward.

🎯 Exam Tip: Key terms are 'Goldacre and Lorch', 'folding and unfolding of protein chains', and the 'interconversion between plasmasol and plasmagel' driving movement.

 

Question 8. सोल और जेल अवस्था में विभेद कीजिए।
Answer:

The dynamic interconversion between these two states is crucial for amoeboid movement, allowing for fluidity and rigidity as needed.
In simple words: Sol is the soft, inner part of the amoeba's body, while gel is the firm, outer part.

🎯 Exam Tip: Clearly differentiate sol as the more fluid, inner part (endoplasm) and gel as the more viscous, outer part (ectoplasm) of the cytoplasm.

 

Question 9. सारकोडिना वर्ग के क्या लक्षण है?
Answer: The characteristics of the Sarcodina class are:

• They move using pseudopods, which are temporary false feet.
• Most of these organisms live freely, but some are parasites.
• They get nutrition through holozoic (animal-like feeding), saprophytic (feeding on dead matter), or parasitic (living off another organism) methods.
• They do not have a fixed mouth opening.
• Their body is either naked (without a covering) or has some type of outer skeleton in certain animals.

This diverse group is primarily characterized by its ability to form temporary cytoplasmic extensions for locomotion and feeding.
In simple words: Sarcodina animals move with false feet. Many live free, some are parasites. They eat in different ways, don't have a fixed mouth, and their bodies are either bare or have a simple outer shell.

🎯 Exam Tip: Focus on pseudopods as the key characteristic for movement and feeding, and highlight the varied nutritional modes within this class.

 

Question 10. अमीबा के कूटपाद को कूटपाद क्यों कहा जाता है?
Answer: The pseudopods of amoeba are called pseudopods because they constantly form and disappear. They do not have a fixed shape. Therefore, they are referred to as pseudopods (meaning "false feet"). This temporary and changeable nature of pseudopods is essential for the amoeba's flexible movement and engulfing food.
In simple words: Amoeba's "false feet" are called pseudopods because they keep forming and then going away. They don't have a fixed shape, so they are not real, permanent feet.

🎯 Exam Tip: The term "pseudopod" itself means "false foot," which perfectly describes their temporary and dynamic nature, used for both locomotion and phagocytosis.

 

Question 11. अमीबा में बहिक्षेपण क्रिया को समझाइए।
Answer: After food is digested, the remaining undigested waste material is pushed out of the body. This process is called egestion (or ejection). During egestion, the food vacuole usually moves to the rear end of the amoeba and touches the plasma membrane. The plasma membrane then breaks open, allowing the food waste to be released outside. Egestion is a crucial step in maintaining cellular health, preventing the accumulation of indigestible substances within the amoeba.
In simple words: After amoeba digests its food, it pushes out the leftover waste. This process is called egestion. The food sac goes to the back, touches the body wall, and the waste comes out.

🎯 Exam Tip: Clearly distinguish egestion (removal of undigested waste) from excretion (removal of metabolic waste). Egestion occurs at the posterior end (uroid) in amoeba.

 

Question 12. अमीबा को अकोशिकीय कहना अधिक है, क्यों?
Answer: It is more fitting to call Amoeba acellular (not made of cells) because its single cell can perform all the functions of a complex body, just like multicellular organisms. Thus, it is more appropriate to call amoeba acellular. The term "acellular" emphasizes that despite being a single unit, it carries out all life processes, unlike specialized cells in multicellular organisms.
In simple words: It is better to call amoeba acellular because its single body can do all the life work, just like animals with many cells.

🎯 Exam Tip: Emphasize that "acellular" acknowledges the complete functional autonomy of the single amoeba cell, performing all biological activities typical of an organism.

 

Question 14. अमीबा के अन्तर्द्रव्य में उपस्थित धानियों (Vacuoles) का विवरण दीजिए।
Answer: The amoeba's endoplasm contains various types of vacuoles that perform different roles:

• संकुचनशील रिक्तिका (Contractile vacuole): Amoeba has one contractile vacuole. It is a clear, round structure filled with watery fluid, surrounded by a single membrane. Around it, there are many small water vacuoles and mitochondria. It is usually found at the rear of the organism. This vacuole changes size as it fills and empties. Its main job is to control the amount of water in the body (osmoregulation).
• खाद्य रिक्तिकाएँ (Food vacuoles): Many non-contractile food-filled vacuoles are found in the endoplasm. Food digestion happens in these vacuoles, and they are surrounded by lysosomes. After all the food is digested and absorbed, these vacuoles move to the surface and burst to release waste.
• जलधानियाँ (Water vacuole): Many small, round, clear water vacuoles are present in the endoplasm. They are filled with water and do not contract.

These different types of vacuoles collectively ensure the amoeba's survival by managing water balance, nutrition, and waste removal.
In simple words: Amoeba has different kinds of vacuoles inside its body. The contractile vacuole helps push out extra water. Food vacuoles digest the food it eats. Water vacuoles just store water.

🎯 Exam Tip: For each vacuole type, clearly state its structure (e.g., single membrane, transparent) and its primary function (e.g., osmoregulation for contractile, digestion for food).

 

Question 15. अमीबा में खाद्यधानियों का क्या कार्य होता है?
Answer: The food vacuoles in amoeba digest food. After digestion and absorption, the undigested waste materials are pushed out when the vacuoles burst at the outer surface. Food vacuoles also help in the distribution of digested food within the endoplasm through a process called cyclosis. These dynamic organelles are essential for the amoeba's heterotrophic nutrition, breaking down complex molecules into usable nutrients.
In simple words: Food vacuoles in amoeba digest food. After digestion, they throw out the waste. They also help spread the digested food inside the amoeba.

🎯 Exam Tip: The two main roles of food vacuoles are digestion and elimination of undigested waste, sometimes also aiding in nutrient distribution.

RBSE Class 11 Biology Chapter 34 निबन्धात्मक प्रश्न

 

Question 1. अमीबा की सूक्ष्मदर्शीय संरचना का सचित्र वर्णन कीजिए।
Answer:Amoeba can be considered acellular or unicellular. It is more accurate to call it acellular because its single cell can perform all life functions, similar to multicellular organisms.
(1) Size, Shape, and Color: Amoeba varies in size (0-600 μm). It has an irregular shape, is transparent, and colorless. It does not have a pellicle (outer covering).
(3) Plasma Membrane (जीवद्रव्य कला): Amoeba does not have a cell wall or pellicle. It is covered by a thin, soft membrane, about 1-2 µm thick, called the plasma membrane or plasmalemma. This membrane is strong and flexible, stopping cytoplasm from leaking out but allowing body growth and pseudopod formation. It is selectively permeable and helps in osmosis. It is made of a double layer of proteins and lipids, and has microvilli that help it stick to surfaces. It also has a high ability to regenerate.
Internal Structure (आन्तीरक संरचना):
Cytoplasm (कोशिकाद्रव्य): The cytoplasm is enclosed by the plasma membrane. It is a fundamental fluid that also contains various structures. It is divided into ectoplasm (outer) and endoplasm (inner).

• Ectoplasm (एक्टोप्लाज्म): This is the outer, thin, peripheral layer. It is clear, transparent, and fluid. It forms a hyaline cap at the tip of the pseudopods.
• Endoplasm (अन्तःप्रदव्य): This is granular, semi-transparent, and more fluid, surrounding the ectoplasm. Clear movements of fluid, called cyclosis, can be seen in it. According to Mast (1926), endoplasm exists in two colloidal states: plasmasol (fluid central part) and plasmagel (jelly-like outer part). These two states can change into each other. Plasmagel becomes plasmasol by protein unfolding and contraction, while plasmasol becomes plasmagel by protein folding. This change is called solation and gelation, respectively.

Endoplasmic Organelles (अन्तर्द्रव्यी कोशिकांग): The endoplasm contains the following organelles:

• Nucleus (केन्द्रक): Amoeba has one biconvex, disc-shaped nucleus. It is surrounded by a fine, double-layered, porous nuclear membrane (karyotheca). It is usually centrally located and contains a honey-comb-like network. The nuclear fluid has many nucleoli and 500-600 chromatin particles (chromidia). The nucleus controls all biological activities of the amoeba.
• Food Vacuoles (खाद्य रसधानियाँ): Many non-contractile food vacuoles are found in the endoplasm. They are temporary structures formed during food intake. They move around by cyclosis. Food digestion occurs in them. After digestion and absorption, undigested waste is released when they burst at the outer surface. They are surrounded by lysosomes.
• Contractile Vacuole (संकुचनशील रिक्तिका): Amoeba proteus has one large, spherical, pulsating contractile vacuole in its posterior part. It looks like a clear, transparent water bubble. It is surrounded by a single membrane.
• Mitochondria (माइटोकॉन्ड्रिया): They are oval or rod-shaped and very numerous, containing cristae.
• Golgi Bodies (गॉल्जीकॉय): They are tubular structures found in 2-3 groups.
• Endoplasmic Reticulum (अन्तःद्रव्यी जालिका): This is also a network of tubules with ribosomes attached. It has vesicles but lacks cisternae.
• Lysosomes (लाइसोसोम्स): They are found abundantly around food vacuoles and contain digestive enzymes.
• Crystals in Endoplasm (एण्डोप्लाज्म में क्रिस्टल्स): Many scattered crystal-like substances are found in the endoplasm. They are bipyramidal and made of carbonyl diurea.
• Microtubules (सूक्ष्म नलिकाएँ): They are scattered in the cytoplasm and are proteinaceous.
• Stored Food (संचित भोजन): Amoeba lacks a centrosome. Its stored food is in the form of glycogen and fat.

The amoeba's simple yet highly adaptable structure allows it to survive and thrive in diverse aquatic environments.
In simple words: Amoeba is a single-celled creature that can do all life's work. It is irregular in shape, clear, and has no color. Its outer covering, the plasma membrane, is thin and flexible, controlling what goes in and out. Inside, it has cytoplasm, which has a firm outer part and a fluid inner part. It also has a nucleus that controls everything. Food vacuoles help digest food, and a special vacuole pumps out extra water. Many tiny powerhouses (mitochondria) give energy, and small tubes (endoplasmic reticulum) help make things. Lysosomes break down food, and special crystals are also present. Amoeba stores food as glycogen and fat.

🎯 Exam Tip: For descriptive questions, organize your answer with clear headings and bullet points. Focus on key structures like the plasma membrane, cytoplasm (ectoplasm/endoplasm, sol/gel), nucleus, and different types of vacuoles, explaining their functions clearly.

 

Question 2. अमीबा का आहार क्या होता है? भोजन के अन्तर्ग्रहण की विभिन्न विधियों का सचित्र वणन कीजिये
Answer:Introduction: Amoeba is a holozoic animal and an omnivore. It eats food by a process called phagocytosis. Its diet mainly includes algae, bacteria, diatoms, and small protozoa.
Methods of Food Ingestion: Amoeba takes in food in several ways:

• Import (Passive Intake): In this method, the amoeba takes in food without much effort. The food slowly sinks into the cell once it touches the amoeba.
  (Diagram 'चित्र 34.8 : अमीबा में आयातित विधि द्वारा भोजन का अन्तर्ग्रहण' shows this method.)
• Circumvallation (Engulfing): Here, the amoeba forms two false feet (pseudopods) like a cup around the food. These false feet then close around the food, bringing it inside along with some water. A food vacuole is formed.
  (Diagrams 'चित्र 34.9 : अन्तर्वलन' and 'चित्र 34.10 : सरकमवेलेशन' show this method.)
• Circumfluence (Flowing Around): In this method, when food touches the amoeba's false feet, the false feet spread over the food and then quickly pull it inside. This process usually takes about 1-2 minutes.
  (Diagram 'चित्र 34.11 : अमीबा में परिप्रवाह द्वारा भोजन का अन्तर्ग्रहण' shows this method.)

These diverse feeding strategies allow the amoeba to efficiently capture and consume a wide range of food particles in its aquatic habitat.
Food Digestion: Amoeba digests food inside its body, within special sacs called food vacuoles. These vacuoles are also known as gastric vacuoles.
The environment inside the food vacuole first becomes acidic, which helps kill and break down the food. Then, it turns alkaline, and lysosomes release enzymes like trypsin, peptidase, and proteinase to digest proteins, and lipase to digest fats. Water leaves the vacuole, making it smaller. Full digestion of food takes about one day.
This sequential change in pH within the food vacuole optimizes the activity of different digestive enzymes, ensuring efficient breakdown of nutrients.
Absorption and Assimilation: During digestion, the food vacuoles move around in a circular motion (cyclosis). The digested food then spreads into the cytoplasm. This absorbed food is used for different life processes and to build new parts of the amoeba. This entire process is called assimilation. Assimilation is vital for growth and energy production, converting absorbed nutrients into the amoeba's own cellular components.
Egestion: Undigested food waste is removed from the amoeba's body. This act of removing waste is called egestion. It usually happens from the back part of the amoeba, called the uroid.
(Diagram 'चित्र 34.12 : बहिश्लेपण' shows this process.)
Egestion prevents the accumulation of waste, maintaining a clean internal environment for cellular functions.
In simple words: Amoeba is an omnivore, eating different small living things like algae and bacteria. It takes in food in a few ways: sometimes food just slowly goes into it (import), other times it makes a cup with its false feet to pull food in (circumvallation), or its false feet spread over the food to take it inside (circumfluence). Amoeba digests food inside its food sacs. First, it becomes sour to kill food, then basic, and enzymes break down proteins and fats. As food digests, it spreads into the amoeba's body for energy and growth (assimilation). Amoeba removes undigested food from its back part (egestion).

🎯 Exam Tip: When describing food intake, clearly explain each method with its distinct characteristics (e.g., passive for import, cup-like formation for circumvallation, spreading for circumfluence). For digestion, highlight the pH changes and the roles of lysosomes and various enzymes.

 

प्रश्न 8. सोल और जेल अवस्था में विभेद कीजिए।
Answer: अमीबा में, प्लाज्मा सोल और प्लाज्मा जेल दो अलग-अलग अवस्थाएँ होती हैं जिनके बीच मुख्य अंतर नीचे दी गई तालिका में स्पष्ट किया गया है। ये दोनों अवस्थाएँ मिलकर अमीबा को गति करने और अपना आकार बदलने में मदद करती हैं, जिससे वह विभिन्न जैविक कार्य कर पाता है।

In simple words: सोल अमीबा का पतला, अंदरूनी हिस्सा है, जबकि जेल गाढ़ा, बाहरी हिस्सा। ये दोनों एक-दूसरे में बदलकर अमीबा को चलने में मदद करते हैं।

🎯 Exam Tip: जब भी दो चीजों के बीच अंतर पूछा जाए, तो एक तालिका (table) बनाकर स्पष्ट और संक्षिप्त बिंदुओं में अंतर स्पष्ट करें। यह उत्तर को प्रभावशाली बनाता है और पूरे अंक दिलाता है।

 

प्रश्न 4. परासरण नियमन क्या है? अमीबा में परासरण नियमन क्रिया को समझाइए।
Answer: परासरण नियमन (Osmoregulation) एक ऐसी प्रक्रिया है जिसमें अमीबा अपने शरीर के अंदर पानी की मात्रा को नियंत्रित करता है। अमीबा प्रोटियस जैसे जीव के अंदर का जीवद्रव्य बाहरी जलीय माध्यम से अधिक गाढ़ा होता है, जिसके कारण पानी परासरण (osmosis) के माध्यम से लगातार शरीर के अंदर आता रहता है। इस अतिरिक्त और अनावश्यक पानी को संकुचनशील रिक्तिका (contractile vacuole) द्वारा शरीर से बाहर निकाला जाता है। इस तरह, अमीबा अपने शरीर में पानी का एक निश्चित स्तर बनाए रखता है और अतिरिक्त जल को बाहर निकालता है, जिससे वह अपने आंतरिक संतुलन को बनाए रख पाता है।
In simple words: परासरण नियमन का मतलब है कि अमीबा अपने शरीर में पानी की सही मात्रा बनाए रखता है। यह शरीर में आने वाले फालतू पानी को एक खास थैली (रिक्तिका) से बाहर निकाल देता है ताकि वह ठीक से काम कर सके।

🎯 Exam Tip: परासरण नियमन की परिभाषा स्पष्ट करें और संकुचनशील रिक्तिका की भूमिका को विशेष रूप से बताएं, क्योंकि यह अमीबा में जल संतुलन का मुख्य अंग है।

 

प्रश्न 5. अमीबा में प्रजनन की विभिन्न विधियों का सचित्र वर्णन कीजिए।
Answer: अमीबा में प्रजनन मुख्य रूप से अलैंगिक (asexual) विधि से होता है। इसमें कई तरीके शामिल हैं, जैसे द्विविभाजन, बहुविभाजन, बीजाणुजनन और पुनरुद्भवन। अमीबा इन विधियों का उपयोग करके अपनी संख्या बढ़ाता है।

• द्विविभाजन (Binary Fission): यह अमीबा में प्रजनन का सबसे आम और सरल तरीका है, जो अनुकूल परिस्थितियों में होता है। इस विधि में, एक अमीबा से दो नए अमीबा बनते हैं। इस प्रक्रिया में केंद्रक का समसूत्री विभाजन (mitotic division) होता है, लेकिन केंद्रक झिल्ली (nuclear membrane) गायब नहीं होती। इसे प्रोमाइटोसिस या क्रिप्टोमाइटोसिस कहते हैं। यह प्रक्रिया लगभग आधे घंटे में पूरी हो जाती है, और नए अमीबा 48 घंटे के बाद फिर से प्रजनन कर सकते हैं।
• बहुविभाजन (Multiple Fission): यह प्रतिकूल परिस्थितियों में होता है। सबसे पहले, अमीबा सिकुड़ जाता है और अपने चारों ओर तीन परतों वाली एक सुरक्षात्मक पुटी (cyst) बना लेता है। इस पुटी के अंदर, केंद्रक कई बार समसूत्री विभाजन से विभाजित होकर लगभग 500-600 छोटे-छोटे संतति केंद्रक बनाता है। ये केंद्रक कोशिका द्रव्य की थोड़ी मात्रा से घिर जाते हैं और अमीब्यूली या स्यूडोपोडियोस्पोर्स (pseudopodiospores) कहलाते हैं। अनुकूल परिस्थितियाँ लौटने पर पुटी फट जाती है और ये स्यूडोपोडियोस्पोर्स बाहर निकलकर नए, छोटे अमीबा में विकसित हो जाते हैं। यह विधि प्रतिकूल वातावरण में जीवित रहने में मदद करती है।
• बीजाणुजनन (Sporulation): प्रतिकूल परिस्थितियों में अमीबा अपने कूटपादों को सिकुड़ कर गोल हो जाता है और एक सुरक्षात्मक पुटी बना लेता है। इसके अंदर, केंद्रक कई बार विभाजित होकर छोटे केंद्रक बनाता है। प्रत्येक केंद्रक थोड़ी मात्रा के कोशिका द्रव्य से घिर कर बीजाणु (spores) बनाता है, जो पुटी के अंदर रहते हैं। जब अनुकूल परिस्थितियाँ आती हैं, तो पुटी टूट जाती है और बीजाणु बाहर निकलकर नए अमीबा में विकसित हो जाते हैं।
• पुनरुद्भवन (Regeneration): अमीबा में पुनरुद्भवन की अद्भुत क्षमता होती है। यदि अमीबा का शरीर कई टुकड़ों में टूट जाए, और हर टुकड़े में कम से कम केंद्रक का एक हिस्सा मौजूद हो, तो प्रत्येक टुकड़ा एक पूर्ण अमीबा में विकसित हो सकता है। यह क्षमता उसे क्षतिग्रस्त होने पर भी जीवित रहने में मदद करती है।

In simple words: अमीबा कई तरीकों से बच्चे पैदा करता है। अच्छे मौसम में वह दो भागों में बंट जाता है (द्विविभाजन)। खराब मौसम में वह खुद को एक खोल (पुटी) में बंद करके कई छोटे बच्चे बनाता है (बहुविभाजन और बीजाणुजनन)। अगर उसका शरीर टूट जाए, तो भी हर टुकड़े से नया अमीबा बन सकता है (पुनरुद्भवन)।

🎯 Exam Tip: अमीबा में प्रजनन की सभी विधियों को स्पष्ट रूप से परिभाषित करें और प्रत्येक विधि के होने की परिस्थितियों (अनुकूल या प्रतिकूल) का उल्लेख करना न भूलें। प्रत्येक विधि के मुख्य चरण को भी संक्षेप में बताएं।