Maharashtra Board Class 8 Science Chapter 1 Living World and Classification of Microbes Solutions

Living World And Classification Of Microbes Class 8 Science Chapter 1 Questions And Answers Maharashtra Board

Balbharti Maharashtra State Board Class 8 Science Solutions Chapter 1 Living World and Classification of Microbes Notes, Textbook Exercise Important Questions and Answers.

Std 8 Science Chapter 1 Living World And Classification Of Microbes Question Answer Maharashtra Board

Class 8 Science Chapter 1 Living World And Classification Of Microbes Question Answer Maharashtra Board

Question 1. Use Whittaker method to classify bacteria, protozoa, fungi, algae, prokaryotic, eukaryotic, microbes.
Answer:
• Bacteria: Kingdom Monera
• Protozoa: Kingdom Protista
• Fungi: Kingdom Fungi
• Algae: If unicellular, Kingdom Protista. If multicellular, Kingdom Plantae
• Prokaryotic: Kingdom Monera
• Eukaryotic: Any kingdom other than Monera.
• Microbes: Kingdom Monera or Protista.
In simple words: The Whittaker method classifies organisms based on cell structure, complexity, nutrition, and evolutionary relationships, placing different microbial groups into distinct kingdoms like Monera, Protista, and Fungi.

🎯 Exam Tip: Understanding the basis of Whittaker's classification for different microbe types is crucial for conceptual clarity and scoring well.

Question 2. Complete the five kingdom method of classification using-living organism, prokaryotes, eukaryotes, multicellular, unicellular, protista, animals, plants, fungi.
Answer:

ℹ️ चित्र व्याख्या (Diagram Explanation): यह आरेख एक प्रवाह चार्ट के रूप में सजीवों के पाँच-राज्य वर्गीकरण को दर्शाता है। यह लिविंग ऑर्गनिज़्म (सजीव) से शुरू होता है, फिर उन्हें प्रोकैरियोट्स और यूकेरियोट्स में विभाजित करता है, जो आगे मोनरा, प्रोटिस्टा, फंगी, प्लांटे और एनिमलिया जैसे विभिन्न राज्यों में वर्गीकृत होते हैं, और उनकी एककोशिकीय या बहुकोशिकीय प्रकृति को भी दर्शाता है।

ℹ️ चित्र व्याख्या (Diagram Explanation): यह आरेख सजीवों के पाँच-राज्य वर्गीकरण को दर्शाता है, जो लिविंग ऑर्गनिज़्म से शुरू होकर प्रोकैरियोट्स और यूकेरियोट्स में विभाजित होता है। यूकेरियोट्स को आगे एककोशिकीय (प्रोटिस्टा) और बहुकोशिकीय (फंगी, प्लांटे, एनिमलिया) में वर्गीकृत किया गया है, जबकि प्रोकैरियोट्स मोनरा को दर्शाते हैं।
In simple words: The five-kingdom classification starts with living organisms, dividing them into prokaryotes and eukaryotes, which are then further categorized into kingdoms like Monera, Protista, Fungi, Plantae, and Animalia based on characteristics like unicellularity or multicellularity.

🎯 Exam Tip: Mastering the flowchart of the five-kingdom classification is key for questions requiring structural understanding and diagram interpretation.

Question 3. Find out my partner

🎯 Exam Tip: Correctly pairing organisms with their examples or characteristics demonstrates strong recall and understanding of biological classifications.

Question a. Lactobacilli are harmful bacteria.
Answer: False.
Explanation Lactobacilli are useful bacteria. They are used for curdling the milk. They are also used for preparing variety of milk products.
In simple words: Lactobacilli are beneficial bacteria, not harmful, as they play a crucial role in making curd and other milk products.

🎯 Exam Tip: Knowing the beneficial roles of specific bacteria, like Lactobacilli, helps in differentiating between useful and harmful microorganisms.

Question b. Cell wall of fungi is made up of chitin.
Answer: True.
Explanation The cell wall of the plants is made up of cellulose while the cell wall of fungi is made up of complex sugar called chitin. Inside the fungal cell wall there is cytoplasm which contains many nuclei.
In simple words: Fungi have a cell wall made of chitin, a complex sugar, which is distinct from plant cell walls made of cellulose.

🎯 Exam Tip: Differentiating cell wall compositions, especially between plants and fungi (cellulose vs. chitin), is a common question and highlights key structural differences.

Question d. Organ of locomotion in amoeba is pseudopodia.
Answer: True.
Explanation Amoeba is a protozoan, primitive organism which possesses pseudopodia as the organ for locomotion.
In simple words: Amoebas use temporary, foot-like extensions called pseudopodia for movement.

🎯 Exam Tip: Identifying the specific locomotory structures of various microorganisms, like pseudopodia for amoeba, is important for descriptive questions.

Question e. Tomato wilt is a viral disease.
Answer: True.
Explanation: Tomato wilt is a viral disease. These viruses are able to infect only plant cells.
In simple words: Tomato wilt is indeed caused by a virus that specifically targets and infects plant cells.

🎯 Exam Tip: Recognizing specific plant diseases and their causative agents (e.g., viral, bacterial) demonstrates knowledge of microbiology and plant pathology.

Question a. State the merits of Whittaker's method of classification.
Answer: For the answer of Merits of Whittaker's method refer to point I of answer given on this Digest's page no. 11; under "Use your brain power!"
In simple words: The merits of Whittaker's classification are detailed on page 11 of the Digest, specifically under the "Use your brain power!" section, providing a comprehensive understanding of its advantages.

🎯 Exam Tip: When a question refers to another section, ensure you locate and review that content thoroughly as it's directly relevant to the current query.

Question b. Write the characteristics of viruses.
Answer:
1. Viruses are extremely minute of the size range of 10 nm to 100 nm. They are on the borderline of living and non-living. They are 10 to 100 times smaller than bacteria and are visible only through the electron microscope.
2. Though they are not considered as living, they can make replica of their own.
3. They exist in the form of independent particles. They are long molecules of DNA or RNA which are covered by a protein coat.
4. Their survival is possible only inside the living plant or animal cells. When they infect the host cells, they produce their own proteins with the machinery of the host cell. These proteins form many replicas of the infecting virus.
5. This infection destroys the host cell and the virus replicas are released. These free replicas re-infect the other adjoining cells of the host.
6. Most of the viruses are pathogenic, they cause diseases in plants and animals.
In simple words: Viruses are tiny, borderline living/non-living entities composed of DNA or RNA encased in protein, replicating only inside host cells and often causing diseases.

🎯 Exam Tip: Memorizing the unique characteristics of viruses, especially their size, replication mechanism, and pathogenic nature, is vital for questions on their biology.

Question c. Explain the nutrition in fungi.
Answer: Most of the fungi are saprophytic in their nutrition. They absorb the nourishment from dead and decaying matter. By taking the organic matter from dead bodies of plants and animals, fungi survive. In this process they degrade the organic matter completely.
In simple words: Fungi are saprophytic, meaning they obtain nutrients by absorbing organic matter from dead and decaying organisms, thus acting as decomposers.

🎯 Exam Tip: Understanding fungal nutrition as saprophytic, involving absorption from dead matter, is a key concept for explaining their ecological role.

Question d. Which living organisms are included in the kingdom Monera?
Answer:
1. All the living organisms belonging to Kingdom Monera are unicellular.
2. The mode of nutrition in them is either autotrophic or heterotrophic.
3. All of them are prokaryotic and thus they do not have well-formed nucleus. The nuclear membrane and the cell organelles are absent in them.
4. Kingdom Monera consists of different types of bacteria and blue-green algae.
E.g. Bacteria Clostridium titani, Vibrio choleri, Treponema pallidum, Streptococcus pneumoniae, Legionella pneumoniae, Salmonella typhi, Staphylococcus aureus, Clostridium botulinum.
In simple words: Kingdom Monera includes all unicellular, prokaryotic organisms like bacteria and blue-green algae, characterized by the absence of a true nucleus and membrane-bound organelles, with varied nutritional modes.

🎯 Exam Tip: Key features of Kingdom Monera - unicellular, prokaryotic, absence of true nucleus, and examples like bacteria and blue-green algae - are important for classification questions.

Question a. I don't have true nucleus, cell organelles or plasma membrane.
Answer: Microbe from Monera
In simple words: An organism lacking a true nucleus, cell organelles, or a plasma membrane is a microbe belonging to the Kingdom Monera.

🎯 Exam Tip: Associating the absence of a true nucleus and organelles with Monera is fundamental for "Who am I?" type questions.

Question b. I have nucleus and membrane bound cell organelles.
Answer: Protozoan from Protista/I am any one of Eukaryote
In simple words: An organism possessing a true nucleus and membrane-bound cell organelles is a eukaryote, such as a protozoan from Kingdom Protista.

🎯 Exam Tip: The presence of a nucleus and membrane-bound organelles is the defining characteristic of eukaryotes, including Protista.

Question c. I live on decaying organic matter.
Answer: Fungus
In simple words: An organism that thrives on decaying organic matter is a fungus, acting as a decomposer.

🎯 Exam Tip: Linking "decaying organic matter" to fungi highlights their saprophytic nature and ecological role as decomposers.

Question d. I reproduce mainly by cell division. (*Binary fission)
Answer: Bacteria and some Protozoa.
In simple words: Bacteria and some protozoa primarily reproduce through cell division, specifically binary fission.

🎯 Exam Tip: Binary fission is a key reproductive method for many single-celled organisms, particularly bacteria and some protozoa, demonstrating asexual reproduction.

Question e. I can produce my replica.
Answer: Virus
In simple words: Viruses are unique in their ability to produce replicas of themselves, but only by hijacking the machinery of host cells.

🎯 Exam Tip: The ability of viruses to self-replicate is a critical characteristic, even though it requires a host cell, and is often tested.

Question f. I am green, but don't have organs.
Answer: Algae
In simple words: Algae are typically green due to chlorophyll for photosynthesis, but they lack true organs like plants.

🎯 Exam Tip: Understanding that algae are photosynthetic and green but lack complex organ systems is important for their classification within Protista or Plantae.

Question a. Different types of bacteria:
Answer:

ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र विभिन्न प्रकार के जीवाणुओं के आकार और आकृति को दर्शाता है, जिनमें गोलाकार (कोकस), दंडाकार (बैसिलस), कोमा के आकार का (विब्रियो), और कुंडलित (स्पिरिलम) जीवाणु शामिल हैं। इसमें कोको-बैसिलस प्रकार भी दिखाया गया है, जो जीवाणुओं की रूपात्मक विविधता को स्पष्ट करता है।
In simple words: The diagram illustrates various bacterial shapes including Coccus (spherical), Bacillus (rod-shaped), Vibrio (comma-shaped), and Spirillum (spiral), along with Cocco-bacillus, showcasing the morphological diversity of bacteria.

🎯 Exam Tip: Being able to draw and label common bacterial shapes (coccus, bacillus, spirillum, vibrio) is a fundamental skill for understanding bacterial morphology.

Question b. Paramoecium:
Answer:

ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र एक पैरामीशियम को दर्शाता है, जो एककोशिकीय प्रोटिस्ट है, और इसके विशिष्ट स्लीपर-आकार के शरीर, सिलिया (गति के लिए), और स्पष्ट नाभिक जैसे आंतरिक संरचनाओं को प्रदर्शित करता है। यह एक जटिल सूक्ष्मजीव की संरचना को समझाता है।
In simple words: The diagram displays a Paramoecium, a single-celled protozoan, highlighting its characteristic slipper-like shape, cilia for movement, and internal structures like the prominent nucleus.

🎯 Exam Tip: Accurately drawing and labeling the Paramoecium, especially its cilia and distinct body shape, is essential for questions on protozoan structure.

Question c. Bacteriophage
Answer:

ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र एक बैक्टीरियोफेज वायरस की जटिल संरचना को दर्शाता है, जिसमें एक कैप्सिड हेड (DNA युक्त), एक कॉलर, एक शीथ, बेसप्लेट, पूंछ फाइबर और स्पाइक्स शामिल हैं। यह एक जीवाणु को संक्रमित करने वाले वायरस की यांत्रिक संरचना को स्पष्ट करता है।
In simple words: The diagram illustrates the intricate structure of a bacteriophage virus, showing its capsid head containing DNA, a collar, sheath, baseplate, tail fibres, and spikes, detailing its components for infecting bacteria.

🎯 Exam Tip: Knowing the key parts of a bacteriophage (capsid head, sheath, tail fibers) is crucial, as its structure is distinct and frequently examined in virology.

Question a. Arrange the following in ascending order of size Bacteria, Fungi, Viruses, Algae.
Answer: Viruses, Bacteria, Fungi, Algae.
In simple words: When arranged by size from smallest to largest, the order is Viruses, followed by Bacteria, then Fungi, and finally Algae.

🎯 Exam Tip: Remembering the relative sizes of different microbial groups is important for comparative analysis and classification questions.

Project:

Question 1. Prepare a chart showing infectious bacteria and the diseases caused by them.

Question 2. Visit a nearby pathology lab. Get the information about pathogenic microbes, methods to observe them, different microscopes from the technicians there.

Class 8 Science Chapter 1 Living World And Classification Of Microbes Additional Important Questions And Answers

Question 1. The process of dividing living organism into groups and subgroups is called ........................
Answer: Biological classification.
In simple words: The systematic process of organizing living organisms into distinct groups and subgroups is known as biological classification.

🎯 Exam Tip: Defining biological classification accurately is essential as it is a foundational concept in biology.

Question 2. Organisms with cell wall but not able to perform photosynthesis are called ........................
Answer: Fungi.
In simple words: Fungi are organisms characterized by having a cell wall but lacking the ability to perform photosynthesis.

🎯 Exam Tip: The combination of a cell wall and heterotrophic nutrition (no photosynthesis) is a defining feature of fungi.

Question 3. Most of the fungi are ........................
Answer: saprotrophic.
In simple words: Most fungi obtain their nutrition by being saprotrophic, meaning they feed on dead or decaying organic matter.

🎯 Exam Tip: Knowing that fungi are predominantly saprotrophic is a key aspect of their ecological role and nutritional strategy.

Question 4. Viruses can be seen only with ........................
Answer: electron microscope.
In simple words: Due to their extremely small size, viruses can only be observed using an electron microscope, not a standard light microscope.

🎯 Exam Tip: Understanding the limitations of microscopes and the appropriate tool for observing viruses (electron microscope) is important.

Question 5. ........................ viruses attack bacteria.
Answer: Bacteriophage
In simple words: Bacteriophages are specific types of viruses that infect and replicate within bacteria.

🎯 Exam Tip: Knowing the term "bacteriophage" and its role as a bacterial virus is crucial for understanding specific viral interactions.

Question 6. In fungi the cell wall is made up of j tough and complex sugar called ........................
Answer: 'Chitin'.
In simple words: The rigid cell wall of fungi is composed of a tough and complex sugar polymer known as chitin.

🎯 Exam Tip: The composition of the fungal cell wall (chitin) is a distinguishing feature and a frequently tested detail in microbiology.

Question 1. Plasmodium causes dysentery.
Answer: False.
Explanation Plasmodium causes malaria. Entamoeba histolytica causes amoebic dysentery or amoebiasis.
In simple words: Plasmodium causes malaria, not dysentery; amoebic dysentery is caused by Entamoeba histolytica.

🎯 Exam Tip: Accurately associating specific pathogens with the diseases they cause, like Plasmodium with malaria, is critical for medical microbiology questions.

Question 1.

🎯 Exam Tip: Knowledge of the historical contributions of scientists to classification, including the number of kingdoms/groups they proposed, is important for evolutionary context.

Question 2.

🎯 Exam Tip: Accurately classifying organisms into their correct groups or kingdoms demonstrates a strong grasp of the principles of biological classification.

Question 3.

🎯 Exam Tip: Knowing the approximate size ranges for different types of microbes is essential for understanding their microscopic nature and the tools needed to observe them.

Question 1. Three organs of locomotion in Protista
Answer:
1. Pseudopodia
2. Cilia
3. Flagella
In simple words: Protists use various structures for movement, primarily pseudopodia, cilia, and flagella.

🎯 Exam Tip: Listing the main locomotory organs of Protista is a direct recall question, highlighting key structural adaptations for movement.

Question 2. Two autotrophic Protista
Answer:
1. Euglena
2. Volvox
In simple words: Euglena and Volvox are examples of autotrophic protists, capable of producing their own food through photosynthesis.

🎯 Exam Tip: Identifying specific examples of autotrophic protists like Euglena and Volvox is important for illustrating nutritional diversity within the kingdom Protista.

Question 3. Institute in India which is involved in research on viruses
Answer: National Institute of Virology, Pune
In simple words: The National Institute of Virology located in Pune, India, is a leading research center dedicated to the study of viruses.

🎯 Exam Tip: Knowing prominent research institutions, like the National Institute of Virology, shows an awareness of scientific infrastructure related to microbiology.

Question 4. Two methods of asexual reproduction in Fungi
Answer:
1. Binary fission
2. Budding
In simple words: Fungi can reproduce asexually through methods such as binary fission and budding.

🎯 Exam Tip: Understanding the asexual reproduction methods in fungi, like binary fission and budding, is key for questions on fungal life cycles.

Question 5. Two pathogenic protozoans and the diseases caused by them
Answer:
1. Entamoeba histolytica causes amoebiasis
2. Plasmodium vivax causes malaria.
In simple words: Entamoeba histolytica causes amoebiasis, and Plasmodium vivax is responsible for malaria, both being pathogenic protozoans.

🎯 Exam Tip: Linking specific pathogenic protozoans to the diseases they cause is essential for understanding human health and microbial impact.

Question 1. What are the types of living organisms according to their lifestyle?
Answer: Producers, consumers and decomposers are the types of living organisms according to their lifestyle.
In simple words: Living organisms are categorized by lifestyle into producers (making their own food), consumers (eating other organisms), and decomposers (breaking down dead matter).

🎯 Exam Tip: Classifying organisms by their ecological roles (producers, consumers, decomposers) is fundamental to understanding ecosystem dynamics.

Question 2. What are the characteristics of prokaryotic cells?
Answer: Absence of nuclear membrane, well- formed nucleus and lack of cell organelles are the characteristics of the prokaryotic cells.
In simple words: Prokaryotic cells are defined by the absence of a nuclear membrane, a well-formed nucleus, and membrane-bound cell organelles.

🎯 Exam Tip: The key defining features of prokaryotic cells (no true nucleus, no membrane-bound organelles) are critical for distinguishing them from eukaryotes.

Question 3. When do virus destroy the host cells?
Answer: After synthesising their own proteins and creating numerous replica of their own type, then the virus destroys the host cells.
In simple words: Viruses destroy host cells after they have successfully used the host's machinery to synthesize their own proteins and produce many new viral replicas.

🎯 Exam Tip: Understanding the lytic cycle of viral replication, where host cell destruction occurs after progeny virus production, is important for virology.

Give Answers

Question 1. Which criteria were considered for classification method of Whittaker?
Answer: The criteria considered for classification by Whittaker are as follows:
1. Complexity of cell structure: Whether the cells of the organisms are prokaryotic or eukaryotic.
2. Complexity of organisms Whether the organisms are unicellular or multicellular is considered.
3. Mode of nutrition Whether the organism is autotrophic and is performing photosynthesis on its own or it is heterotrophic is considered. Plants are autotrophic, fungi are saprotrophic while animals use food from plants and other animals and hence they are heterotrophic.
4. Lifestyle According to nutrition, every living organism is at certain trophic level. This is called lifestyle. Plants are producers, animals are consumers while fungi are decomposers.
5. Phylogenetic relationship When the evolution proceeded gradually, there was transition from prokaryotes to eukaryotes, unicellular to multicellular. In this order the different groups of living organisms were evolved. This is known as phylogenetic relationship.
In simple words: Whittaker's classification considers five main criteria: cell structure complexity (prokaryotic vs. eukaryotic), organism complexity (unicellular vs. multicellular), mode of nutrition (autotrophic vs. heterotrophic), lifestyle (producer, consumer, decomposer), and phylogenetic relationships based on evolutionary development.

🎯 Exam Tip: Understanding these five criteria is crucial for explaining Whittaker's system and comparing it with other classification methods. Focus on the distinct aspects of each criterion.

Use Your Brain Power!

Question 1. Explain merits and demerits of Whittaker's classification.
Answer: I. Merits of Whittaker's classification:
1. The classification system that Whittaker has adapted is totally based on scientific foundation.
2. Prokaryotes are placed separately in a different kingdom. The prokaryotic organisms are different from other organisms, thus placing them separately is justified.
3. All unicellular eukaryotic organisms are clubbed together in one kingdom named, Protista. This has helped to solve the placement of Euglena.
4. Euglena has chloroplasts like plants but as animals it has flagella and thus there was conflict about such species during previous classification systems. It was placed in protozoa previously.
5. Fungi are saprophytic and hence they are placed separately in a unique kingdom.
6. According to five kingdom classification, the cell structure, organization of cell, mode of nutrition, lifestyle and phylogenetic relationship are taken into consideration.
7. Therefore the system of 5 kingdom classification becomes most authentic system of biological classification.
II. Demerits of Whittaker's method of classification:
1. Some organisms belonging to Monera and Protista have ability to perform photosynthesis. Thus they show mode of nutrition as autotrophic, while others are heterotrophic. Similarly some monerans have cell wall and some Protists also have cell wall. This becomes confusing during their placement.
2. In kingdom Protista, organisms show varied characteristics. In spite of this they are placed together.
3. In kingdoms, Plantae, Animalia and Fungi the organisms having primitive characters and were initial examples during evolution are not included. E.g. In Kingdom Animalia, amoeba is not included though it is said to be unicellular animal. This creates confusion.
4. Similarly if algae are unicellular, they are placed in kingdom Protista and if they are multicellular they are placed in kingdom Plantae. In reality, unicellular and multicellular algae both show much similarity. But due to Whittaker's classification system they are placed away from each other.
5. Species of algae such as Chlorella, Chlamydomonas are not included in Kingdom Protista.
6. Viruses are not included in any of the kingdoms by Whittaker. Their classification has become a point of debate among the biologists.
In simple words: Whittaker's classification is scientifically sound, correctly separates prokaryotes and fungi, and groups unicellular eukaryotes into Protista. However, it faces criticism for the diverse characteristics within Monera and Protista, and for excluding viruses and some algal species from specific kingdoms despite their similarities or evolutionary significance.

🎯 Exam Tip: When discussing merits and demerits, ensure you provide clear, concise points for each. Highlighting specific examples like Euglena or viruses strengthens your answer. This is a common comparative question.

Write Short Notes:

Question 1. Characteristics of Fungi.
Answer: 1. The organisms which are placed in kingdom Fungi are multicellular, heterotrophic, non-green, and eukaryotic in nature.
2. Most of the fungi are saprophytic and they sustain on the dead and decaying organic matter.
3. The cell wall of the fungal cells is made up of chitin. Chitin is the tough and complex sugar.
4. Fungi have thread like body. The cytoplasm of the fungal cells contain many nuclei.
5. The reproduction in Fungi is either sexual or asexual. Asexual reproduction is by fission or by budding.
6. Examples Baker's yeast, Candida, Mushroom, Aspergillus (Fungus on corn), Penicillium
In simple words: Fungi are multicellular, eukaryotic, heterotrophic organisms, often saprophytic, with cell walls made of chitin. They have thread-like bodies with multiple nuclei and reproduce both sexually and asexually, including by fission or budding.

🎯 Exam Tip: Remember to include the key features like chitin cell walls, saprophytic nutrition, and methods of reproduction. Providing examples is essential for full marks.

Question 2. Characteristics of Bacteria.
Answer: 1. Bacteria are microscopic, unicellular, prokaryotic organisms belonging to the kingdom Monera.
2. Some bacteria are solitary with independent existence. Some are colonial forms.
3. The bacterial cell lacks well-formed nucleus with nuclear membrane and cell organelles.
4. Reproduction is by binary fission.
5. In favourable conditions, bacteria duplicate with a great speed. Within 20 minutes they can double in number.
6. Bacteria may be round as in Cocci, elongated as in Bacillus, comma shaped as in Vibrio and spiral shaped as in Spirillum.
In simple words: Bacteria are microscopic, unicellular prokaryotes from Kingdom Monera, lacking a true nucleus and organelles. They reproduce rapidly via binary fission and come in various shapes like cocci, bacilli, vibrios, and spirilla.

🎯 Exam Tip: Focus on prokaryotic nature, unicellularity, lack of true nucleus/organelles, and binary fission as key distinguishing features of bacteria. Mentioning common shapes is a good addition.

Question 3. Characteristics of Protozoa.
Answer: 1. Protozoa are unicellular, eukaryotic organisms belonging to kingdom, Protista.
2. They are microscopic of the size of about 200 pm.
3. They have different organs of locomotion such as pseudopodia, cilia and flagella.?
4. Reproduction is by asexual method, usually by binary fission..
5. Protozoa are seen in varied habitats such as soil, fresh water and marine water.
6. Some protozoans are parasitic and cause various types of illness in hosts. E.g. Entamoeba histolytica is a species of amoeba that causes amoebiasis. Malaria is caused by Plasmodium vivax.
7. Protozoa show different modes of nutrition. E.g. Euglena is autotrophic as it does photosynthesis with the help of 5 chloroplasts present in its body. Amoeba and Paramoecium are heterotrophic and free living seen in contaminated water.
In simple words: Protozoa are microscopic, unicellular eukaryotes belonging to Kingdom Protista, characterized by various locomotion organs like pseudopodia, cilia, or flagella. They reproduce asexually, inhabit diverse aquatic and soil environments, and exhibit different nutritional modes, with some being parasitic.

🎯 Exam Tip: Highlight their eukaryotic, unicellular nature and diverse modes of locomotion and nutrition. Mentioning examples of parasitic protozoans and their diseases is good for practical application.

Complete The Paragraph Using The Words Given In The Brackets

[Monera, Euglena, autotrophic, cell organelles, chitin, nuclear, prokaryotic, viruses, replicas, saprotrophic, viral particles]
In Kingdom .......... bacteria were included but not .......... Viruses are on the border line of living and non-living. Do we really call them living? If they are making .......... of their own type, are they not considered as living? Throughout the world they spread hazardous epidemics. Antibiotics do not act on ........ However, bacteria can be controlled by antibiotics. All the living organisms belonging to Monera are with .......... cell. They do not have .......... membrane and neither they have .......... But a nice nucleus is seen in .........., Euglena is .......... protist. The fungi with cell wall of .......... are .......... in their mode of nutrition.
Answer: In Kingdom Monera bacteria were included but not viruses. Viruses are on the border line of living and non-living. Do we really call them living? If they are making replicas of their own type, are they not considered as living? Throughout the world they spread hazardous epidemics. Antibiotics do not act on viral particles. However, bacteria can be controlled by antibiotics. All the living organisms belonging to Monera are with prokaryotic cell. They do not have nuclear membrane and neither they have cell organelles. But a nice nucleus is seen in Euglena. Euglena is autotrophic protist. The fungi with cell wall of chitin are saprotrophic in their mode of nutrition.
In simple words: This paragraph fills in key terms about classification, noting that viruses are on the borderline of living and non-living, bacteria are prokaryotic lacking a true nucleus and cell organelles, and fungi are saprotrophic with chitin cell walls.

🎯 Exam Tip: Pay close attention to keywords related to each kingdom (Monera, Fungi, Protista) and viral characteristics. Understanding the distinctions between prokaryotic and eukaryotic cells is critical for such fill-in-the-blanks.

Complete The Chart:

Question 1. Draw a chart showing different types of Microorganisms.
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): यह एक प्रवाह-चार्ट है जो सूक्ष्मजीवों के वर्गीकरण को दर्शाता है। इसे दो मुख्य श्रेणियों में बांटा गया है: प्रोकैरियोट्स और यूकैरियोट्स। प्रोकैरियोट्स में बैक्टीरिया शामिल हैं, जबकि यूकैरियोट्स को प्रोटिस्टा, कवक (फंगी) और शैवाल (एल्गी) में विभाजित किया गया है। यह चार्ट सूक्ष्मजीवों के मुख्य समूहों का एक संरचित अवलोकन प्रदान करता है।
In simple words: This chart illustrates the classification of microorganisms, dividing them into prokaryotes (bacteria) and eukaryotes (protista, fungi, algae). It provides a structural overview of the main groups of microorganisms.

🎯 Exam Tip: When asked to draw a chart, ensure clear labels and logical flow. For classification, practice remembering the hierarchical structure and main examples for each group.

Draw Neat And Labelled Diagrams:

Question 1. Fungi:
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र कवक (फंगी) की संरचना को दर्शाता है, जिसमें स्पोरेंजियम (बीजाणुधानी), अपोफिसिस, कोल्यूमेला, हाइफा और राइजॉइड्स जैसे महत्वपूर्ण भाग शामिल हैं। स्पोरेंजियोफोर वह डंठल है जिस पर स्पोरेंजियम विकसित होता है, जबकि राइजॉइड्स वे संरचनाएं हैं जो आधार से जुड़ती हैं और पोषक तत्वों को अवशोषित करती हैं।
In simple words: This diagram illustrates the structure of a fungus, showing key parts like the sporangium, apophysis, columella, hypha, sporangiophore, and rhizoids, which are involved in reproduction and nutrient absorption.

🎯 Exam Tip: For diagrams of fungi, clearly label the sporangium (spore-producing part), hyphae (thread-like structures), and rhizoids (anchoring/absorbing parts). Precision in labeling is key.

Question 2. Euglena:
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र यूग्लीना नामक एककोशिकीय यूकेरियोटिक जीव को दर्शाता है। इसमें एक लम्बा कशाभिका (फ्लैगेलम) होता है जिसका उपयोग गति के लिए किया जाता है, साथ ही एक स्पष्ट केंद्रक (न्यूक्लियस) और कई क्लोरोप्लास्ट भी दिखाई देते हैं जो प्रकाश संश्लेषण में मदद करते हैं। यह एक अंडाकार शरीर वाला जीव है।
In simple words: This diagram shows Euglena, a single-celled eukaryotic organism with a long flagellum for movement, a nucleus, and chloroplasts for photosynthesis, depicted with an oval body shape.

🎯 Exam Tip: When drawing Euglena, ensure the flagellum, nucleus, and chloroplasts are visible and correctly labeled. The distinct shape and presence of a flagellum are important characteristics.

Question 3. Amoeba:
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र अमीबा नामक एक एककोशिकीय जीव को दर्शाता है, जिसमें कोई निश्चित आकार नहीं होता। यह अपने नकली पैरों, जिन्हें स्यूडोपोडिया (pseudopodia) कहते हैं, का उपयोग गति और भोजन पकड़ने के लिए करता है। चित्र में कोशिकाद्रव्य (cytoplasm), केंद्रक (nucleus) और रिक्तिकाएं (vacuoles) भी स्पष्ट रूप से दिखाई गई हैं।
In simple words: This diagram depicts Amoeba, a single-celled organism with an irregular shape, using pseudopodia for movement and feeding. The cytoplasm, nucleus, and vacuoles are clearly visible within its body.

🎯 Exam Tip: For Amoeba, the key features to draw and label are its irregular shape, pseudopodia (false feet), nucleus, and vacuoles. Emphasize its dynamic and changing form.

Question 4. Correctly label the various organisms shown in the Kingdom Monera:
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र किंगडम मोनेरा के तहत आने वाले विभिन्न प्रकार के बैक्टीरिया को दर्शाता है, जिसमें उनके विशिष्ट आकार और रूप जैसे कोकस (गोलाकार), बैसिलस (छड़ के आकार का), स्पिरिलम (सर्पिल) और विब्रियो (अल्पविराम के आकार का) शामिल हैं। प्रत्येक प्रकार को एक अलग आकृति द्वारा दर्शाया गया है जो उनकी रूपात्मक विविधता को उजागर करता है।
1. Streptococcus pneumoniae
2. Clostridium titani
3. Vibrio choleri
4. Treponema pallidum
5. Staphylococcus aureus
6. Legionella pneumoniae
7. Salmonella typhi
8. Clostridium botulinum
In simple words: This image displays various types of bacteria from Kingdom Monera, showcasing their distinct shapes and forms such as coccus, bacillus, spirillum, and vibrio. The answer then lists specific examples of these bacteria.

🎯 Exam Tip: When identifying different bacteria, focus on their characteristic shapes (cocci are spherical, bacilli are rod-shaped, spirilla are spiral, vibrio are comma-shaped). Memorize common examples for each shape.

Activity-Based Questions

1. Try This:

Question. Activity Take a small drop of curd or buttermilk on a clean glass slide. Dilute it with a little water. Carefully keep a coverslip. Observe it under high power of compound microscope. What did you see?
Answer: In the slide we can see Lactobacilli \ bacteria.
In simple words: When observing curd or buttermilk under a microscope, you will see Lactobacilli bacteria, which are responsible for the curdling process.

🎯 Exam Tip: For observation-based questions, accurately describe what is seen and relate it to the biological concept, in this case, the presence of Lactobacilli in curd.

2. Try This:

Question. Activity Prepare a temporary mount of one drop of pond water on a glass slide. Observe it under low power and high power microscope.
Answer: The drop on the slide shows motile microscopic organisms which have irregular shape. They are amoeba.
In simple words: Observing pond water reveals motile, irregularly shaped microscopic organisms known as amoeba.

🎯 Exam Tip: When describing pond water observations, mention key characteristics like motility and irregular shape, which are indicative of protozoans like amoeba.

3. Try This:

Question. Activity Take a moist piece of bread or bhakri and keep it in a container with lid for 2-3 days. After 2-3 days a fine cotton thread like tuft is found growing on the surface of the bread. Prepare a temporary mount of few threads from this culture and observe it under the microscope.
Answer: Upon observation of thread like structures the fungal hyphae (fibre like body) are seen.
In simple words: When mold grows on bread, microscopic observation shows thread-like structures called fungal hyphae, which constitute the main body of the fungus.

🎯 Exam Tip: For questions about fungal growth on bread, identify the visible thread-like structures as fungal hyphae, which are characteristic of molds.

MCQs Based On Experiments:

Choose The Appropriate Alternative Of The Following:

Experiment 1: To Observe Lactobacilli In Curd/Buttermilk.

Question 1. Which of the following bacterium is used to make curds from milk?
(a) Streptococcus
(b) Lactobacillus
(c) Staphylococcus
(d) Clostridium
Answer: (b) Lactobacillus
In simple words: Lactobacillus is the specific bacterium responsible for fermenting milk into curd.

🎯 Exam Tip: Remember the specific bacteria associated with common processes, such as Lactobacillus for curdling milk, as this is a frequently asked factual question.

Question 2. In which kingdom is Lactobacillus included?
(a) Monera
(b) Protista
(c) Fungi
(d) Plantae
Answer: (a) Monera
In simple words: Lactobacillus, being a bacterium, is classified under the Kingdom Monera.

🎯 Exam Tip: Understand the basic classification of organisms into kingdoms. All bacteria belong to Kingdom Monera.

Question 3. Which is the other organism that has been added in kingdom Monera in addition to bacteria?
(a) Virus
(b) Blue-green algae
(c) Fungi
(d) Protozoa
Answer: (b) Blue-green algae
In simple words: Besides bacteria, blue-green algae (cyanobacteria) are also classified within the Kingdom Monera due to their prokaryotic cell structure.

🎯 Exam Tip: Recall that Kingdom Monera includes both bacteria and cyanobacteria (blue-green algae) because they are both prokaryotic organisms.

Experiment 2: To Observe Fungus On The Bread

Question 1. In which kingdom is fungus growing on the bread included?
(a) Fungi
(b) Protozoa
(c) Monera
(d) Protista
Answer: (a) Fungi
In simple words: The fungus observed growing on bread is classified under the Kingdom Fungi.

🎯 Exam Tip: Recognize that molds and yeasts, commonly found on food, are types of fungi and belong to the Kingdom Fungi.

Question 2. What are dark coloured particles which are seen when the fungus is growing on the bread?
(a) Sporangiophore
(b) Rhizoids
(c) spores
(d) Columella
Answer: (c) spores
In simple words: The dark-colored particles observed on bread mold are spores, which are reproductive structures that allow the fungus to spread.

🎯 Exam Tip: Understand that the visible dark "dust" on molds consists of spores, which are how fungi reproduce and disseminate.

Question 3. Why is there growth of fungus on all the stale food?
(a) Fungus has affinity for food.
(b) Fungus grows on decaying organic matter.
(c) As food is open, the fungus drops on it and starts growing.
(d) None of the alternative is correct.
Answer: (b) Fungus grows on decaying organic matter.
In simple words: Fungi thrive on stale food because they are saprophytic, meaning they obtain nutrients from dead or decaying organic matter.

🎯 Exam Tip: Emphasize the saprophytic nature of fungi, which explains their growth on decaying or stale organic matter, like food.

Class 8 Questions And Answers

8th Std Science Questions And Answers: