Amoeba is a simple, single-celled organism that belongs to the kingdom Protista. It is commonly studied in Class 7 biology because it helps students understand unicellular organisms, movement, nutrition, and reproduction. This topic provides important questions and answers on Amoeba to help students prepare for their exams.
What Is Amoeba?
Amoeba is a microscopic, unicellular organism that can change its shape. It is found in freshwater, soil, and moist environments. It moves using pseudopodia (false feet) and feeds by a process called phagocytosis.
Important Questions and Answers on Amoeba
1. Basic Questions on Amoeba
Q1: What is Amoeba?
A: Amoeba is a unicellular microorganism that belongs to the Protista kingdom. It has an irregular shape and moves using pseudopodia.
Q2: Where is Amoeba found?
A: Amoeba is commonly found in ponds, lakes, rivers, damp soil, and other moist environments.
Q3: How does Amoeba move?
A: Amoeba moves by extending pseudopodia, which are temporary projections of the cytoplasm.
Q4: What is the size of an Amoeba?
A: The size of an Amoeba varies but is usually between 0.1 mm and 0.3 mm in diameter.
Q5: Is Amoeba a plant or an animal?
A: Amoeba is neither a plant nor an animal. It belongs to the Protista kingdom, which includes unicellular organisms with characteristics of both plants and animals.
2. Structure of Amoeba
Q6: What are the main parts of an Amoeba?
A: The main parts of an Amoeba include:
-
Cell membrane – Outer covering of the cell.
-
Cytoplasm – Jelly-like fluid inside the cell.
-
Nucleus – Controls the activities of the Amoeba.
-
Contractile vacuole – Helps in excreting excess water.
-
Food vacuole – Stores and digests food.
Q7: What is the function of the nucleus in Amoeba?
A: The nucleus controls all the activities of the Amoeba, including growth, reproduction, and movement.
Q8: What is the function of the contractile vacuole?
A: The contractile vacuole helps in osmoregulation by removing excess water from the Amoeba’s body.
Q9: What is the difference between cytoplasm and nucleus?
A:
-
Cytoplasm is the jelly-like substance that fills the cell and contains organelles.
-
Nucleus is the control center of the cell and contains genetic material.
3. Nutrition in Amoeba
Q10: How does Amoeba obtain food?
A: Amoeba obtains food by phagocytosis, where it surrounds the food ptopic with pseudopodia, engulfs it, and forms a food vacuole for digestion.
Q11: What type of nutrition does Amoeba have?
A: Amoeba follows holozoic nutrition, where it ingests, digests, and absorbs food.
Q12: What does Amoeba eat?
A: Amoeba eats bacteria, algae, protozoa, and tiny organic ptopics found in water.
Q13: What happens after food is digested in Amoeba?
A: After digestion, the nutrients are absorbed into the cytoplasm, and the undigested waste is removed through the cell membrane.
4. Respiration in Amoeba
Q14: How does Amoeba breathe?
A: Amoeba breathes through diffusion, where oxygen enters and carbon dioxide exits through the cell membrane.
Q15: Does Amoeba have lungs or gills?
A: No, Amoeba does not have lungs or gills. It respires through simple diffusion.
5. Excretion in Amoeba
Q16: How does Amoeba remove waste?
A: Amoeba removes waste through the contractile vacuole and cell membrane.
Q17: What type of waste is excreted by Amoeba?
A: Amoeba excretes carbon dioxide, ammonia, and excess water.
6. Reproduction in Amoeba
Q18: How does Amoeba reproduce?
A: Amoeba reproduces asexually by binary fission, where the nucleus divides into two, and the cell splits into two daughter Amoebae.
Q19: What is binary fission?
A: Binary fission is a type of asexual reproduction where a single cell splits into two identical cells.
Q20: Does Amoeba reproduce sexually?
A: No, Amoeba does not reproduce sexually. It only reproduces by asexual methods like binary fission.
7. Adaptations of Amoeba
Q21: How does Amoeba survive in harsh conditions?
A: Amoeba forms a cyst around itself in unfavorable conditions. This process is called encystment, which helps it survive until conditions improve.
Q22: What happens when the environment becomes favorable again?
A: When conditions improve, the cyst breaks, and the Amoeba becomes active again.
8. Importance of Amoeba in Nature
Q23: Is Amoeba useful or harmful?
A: Amoeba is mostly harmless, but some species can cause diseases.
Q24: What is the role of Amoeba in the ecosystem?
A: Amoeba helps in decomposing organic matter and recycling nutrients in the ecosystem.
9. Diseases Caused by Amoeba
Q25: Can Amoeba cause diseases in humans?
A: Yes, some species like Entamoeba histolytica cause diseases in humans.
Q26: What disease is caused by Entamoeba histolytica?
A:Amoebiasis (or amoebic dysentery), which affects the human intestines.
Q27: What are the symptoms of amoebiasis?
A: Symptoms include diarrhea, stomach pain, weight loss, and fever.
Q28: How can amoebiasis be prevented?
A: By drinking clean water, maintaining hygiene, and avoiding contaminated food.
10. Fun Facts About Amoeba
Q29: Can Amoeba think or feel?
A: No, Amoeba does not have a brain or nervous system, but it responds to stimuli.
Q30: How long does an Amoeba live?
A: An Amoeba’s lifespan is not fixed, but it keeps reproducing continuously through binary fission.
Amoeba is a fascinating microorganism that helps us understand unicellular life, movement, reproduction, and nutrition. It plays a role in nature as both a decomposer and a disease-causing organism. By studying Amoeba, students can learn about basic biological functions that apply to all living organisms.