Students can practice the best Class 8 Science MCQ and The Invisible Living World Beyond Our Naked Eye Class 8 Science Curiosity Chapter 2 MCQ Online Test with Answers for exam preparation.
Class 8 Science Chapter 2 The Invisible Living World Beyond Our Naked Eye MCQ
The Invisible Living World Beyond Our Naked Eye MCQ
Class 8 Science Chapter 2 MCQ Online Test
Question 1.
Within a plant cell, which structure confers a rigid and definitive form and is situated at the cell’s outermost boundary?
(a) Cell membrane
(b) Cytoplasm
(c) Cell wall
(d) Nucleus
Answer:
(c) Cell wall
Question 2.
Which part inside the cell is responsible for controlling all its activities, much like a manager in an office?
(a) Cytoplasm
(b) Cell wall
(c) Nucleus
(d) Vacuole
Answer:
(c) Nucleus
Question 3.
Identify the cellular component that comprises a viscous, jelly-like substance providing a medium in which the organelles are suspended and supported:
(a) Nucleus
(b) Cell wall
(c) Chloroplast
(d) Cytoplasm
Answer:
(d) Cytoplasm
Question 4.
Among the following cellular constituents, which one is uniquely present in plant cells but absent in animal cells?
(a) Cytoplasm
(b) Nucleus
(c) Cell membrane
(d) Chloroplast
Answer:
(d) Chloroplast
Question 5.
The image below shows a labelled diagram of a plant cell. One of the parts is marked as X, which is a large sac-like structure typically filled with fluid and helps maintain shape and store materials. (Competency Based Que.)
Which organelle does X represent?
(a) Cytoplasm
(b) Nucleus
(c) Vacuole
(d) Chloroplast
Answer:
(c) Vacuole
Question 6.
Which of the following is a correct order of organization in a living organism? (competency Based Que.)
(a) Tissue → Organ → Cell → Organ System
(b) Organism → Organ → Tissue → Cell
(c) Cell → Tissue → Organ → Organ System → Organism
(d) Organ System → Cell → Tissue → Organ
Answer:
(c) Cell → Tissue → Organ → Organ System → Organism
Question 7.
Which of the following is not a type of microorganism?
(a) Algae
(b) Fungi
(c) Bacteria
(d) Insects
Answer:
(d) Insects
Question 8.
Microorganisms that can survive in extreme conditions like hot springs or salty lakes are called
(a) Fungi
(b) Algae
(c) Protozoa
(d) Bacteria
Answer:
(d) Bacteria
Question 9.
What happens to organic waste when it is left in moist soil for a few weeks?
(a) It evaporates
(b) It turns into compost
(c) It becomes poisonous
(d) It freezes
Answer:
(b) It turns into compost
Question 10.
The gas released by microorganisms during anaerobic decomposition is
(a) Oxygen
(b) Carbon monoxide
(c) Methane
(d) Nitrogen
Answer:
(c) Methane
Question 11.
Which of the following microorganisms helps in the formation of curd?
(a) Yeast
(b) Lactobacillus
(c) Amoeba
(d) Algae
Answer:
(b) Lactobacillus
Question 12.
Which gas is released when yeast ferments sugar in dough?
(a) Oxygen
(b) Nitrogen
(c) Carbon dioxide
(d) Hydrogen
Answer:
(c) Carbon dioxide
Question 13.
Which one of these is used in baking and alcohol production due to its fermentation ability?
(a) Bacteria
(b) Algae
(c) Yeast
(d) Protozoa
Answer:
(c) Yeast
Question 14.
Which microorganism fixes nitrogen in the root nodules of legumes?
(a) Lactobacillus
(b) Penicillium
(c) Rhizobium
(d) Plasmodium
Answer:
(c) Rhizobium
Question 15.
Why is growing legumes in crop rotation beneficial?
(a) They produce more seeds
(b) They help control pests
(c) They enrich the soil with nitrogen
(d) They require less water
Answer:
(c) They enrich the soil with nitrogen
Question 16.
Which of the following is not a characteristic of microalgae?
(a) They can make their own food
(b) They are found only in salty water
(c) They produce oxygen
(d) Some are used as health supplements
Answer:
(b) They are found only in salty water
Question 17.
What would most likely happen if all microalgae disappeared from Earth? (Competency Based Que.)
(a) More rainfall
(b) Increase in oxygen
(c) Loss of aquatic food sources and oxygen decline
(d) Decrease in temperature
Answer:
(c) Loss of aquatic food sources and oxygen decline
Question 18.
The cell structure that controls the entry and exit of substances is the
(a) Nucleus
(b) Cell wall
(c) Cell membrane
(d) Cytoplasm
Answer:
(c) Cell membrane
Question 19.
Spirulina is best known for its:
(a) role in bread-making
(b) rich protein content
(c) ability to cause disease
(d) use in producing alcohol
Answer:
(b) rich protein content
Question 20.
Why do bakers use yeast in baking bread?
(a) To change color
(b) To add flavor
(c) To make it rise and fluffy
(d) To increase fat content
Answer:
(c) To make it rise and fluffy
Question 21.
In which area Dr. Ananda Mohan Chakrabarty got patent on bacteria that break down oil spills?
(a) 1892
(b) 1980
(c) 1984
(d) 2000
Answer:
(b) 1980
The Invisible Living World Beyond Our Naked Eye Class 8 Assertion Reason Questions
The following questions consist of two statements. Assertion (A) and Reason (R). Answer the following questions by selecting the appropriate option given below
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Question 1.
Assertion (A) Plant cells possess a distinct cell wall.
Reason (R) The cell wall provides structural support and rigidity to the plant cell.
Answer:
(a) Both A and R are true and R is the correct explanation of A.
Question 2.
Assertion (A) Microorganisms are always harmful to humans:
Reason (R) Certain microorganisms cause diseases such as cholera and tuberculosis.
Answer:
(d) A is false, but R is true. The Assertion can be corrected as Microorganisms are not always harmful; many are beneficial and play important roles in food production, health, and the environment.
Question 3.
Assertion (A) Yeast is considered useful in the preparation of bread and cakes.
Reason (R) Yeast releases oxygen during fermentation, which causes the dough to rise.
Answer:
(c) A is true, but R is false. The Reason can be corrected as Yeast releases carbon dioxide, which makes a dough rise.
Question 4.
Assertion (A) Rhizobium bacteria contribute to enhancing soil fertility.
Reason (R) Rhizobium reside in the root nodules of leguminous plants and help fix atmospheric nitrogen into the soil.
Answer:
(a) Both A and R are true and R is the correct explanation of A.
Question 5.
Assertion (A) Microalgae are regarded as beneficial to both humans and aquatic life.
Reason (R) They produce oxygen through photosynthesis and serve as a food source for aquatic organisms.
Answer:
(a) Both A and R are true and R is the correct explanation of A.
Question 6.
Assertion (A) All cells have a nucleus.
Reason (R) The nucleus controls most functions of the cell.
Answer:
(a) Both A and R are true and R is the correct explanation of A
Question 7.
Assertion (A) The structure of cheek cells and onion cells is exactly the same.
Reason (R) All cells have the same shape and outer covering.
Answer:
(d) A is false, but R is true
Question 8.
Assertion (A) Some microorganisms help in cleaning water.
Reason (R) Microorganisms feed on waste and organic matter in water.
Answer:
(a) Both A and R are true and R is the correct explanation of A
The Invisible Living World Beyond Our Naked Eye Class 8 Case Based MCQ Questions
Question 1.
Ria observed her grandmother placing dry leaves and vegetable peels into a pit in the backyard. After a few weeks, she noticed that the contents of the pit had turned into a dark, soil-like substance. Her science teacher explained that this process is known as decomposition, carried out by certain microorganisms that convert organic waste into nutrient-rich manure.
Ria also learned that similar microorganisms help clean the environment and are important (Competency Based Que.)
(i) What caused the vegetable peels and leaves to turn into manure in the pit?
(a) Sunlight alone
(b) Earthworms only
(c) Microorganisms like bacteria and fungi
(d) Oxygen from the air
Answer:
(c) Microorganisms like bacteria and fungi
(ii) What is the benefit of the dark, soil-like substance formed in the pit?
(a) It removes all weeds from the soil
(b) It makes the soil dry
(c) It increases soil fertility
(d) It reduces soil nutrients
Answer
(c) It increases soil fertility
The Invisible Living World Beyond Our Naked Eye Class 8 Fill in the blanks
1. The outer boundary that encloses the contents of an animal cell and controls the movement of substances in and out is known as the ____________ .
Answer:
Cell membrane
2. In plant cells, a firm outer covering that provides structural support and is absent in animal cells is called the ____________ .
Answer:
Cell wall
3. Microorganisms can be seen with the help of a ____________ .
Answer:
microscope
4. Alcohol is produced with the help of ____________ .
Answer:
Yeast
5. Blue-green algae fix ____________ directly from air to enhance fertility of soil.
Answer:
nitrogen
6. The ____________ protects plant cells and gives them shape.
Answer:
Cell wall
7. Yeast produces ____________ gas while growing in wet dough.
Answer:
Carbon dioxide
8. ____________ is a unicellular organism that cause rise of cakes and idli.
Answer:
Yeast
The Invisible Living World Beyond Our Naked Eye Class 8 True or False
1. The nucleus controls all activities of the cell.
Answer:
True
2. All microorganisms are harmful to living organisms.
Answer:
False Some microorganisms are useful too (e.g., in making curd, fixing nitrogen, etc.)
3. Yeast is a type of fungus used in baking.
Answer:
True
4. Rhizobium bacteria reduce soil fertility.
Answer:
False Rhizobium bacteria improve soil fertility by fixing nitrogen.
5. Microalgae produce a major portion of Earth’s oxygen.
Answer:
True
6. Microorganisms are visible to the naked eye when they multiply.
Answer:
False
7. Cytoplasm is found outside the cell membrane.
Answer:
False
8. Spirulina algae improve soil fertility by fixing carbon dioxide.
Answer:
False
The Invisible Living World Beyond Our Naked Eye Class 8 Match the following
Question 1.
Match the Column I with Column II.
| Column I | Column II |
| A. Nucleoid | 1. Curd |
| B. Lactobacillus | 2. Bacteria |
| C. Cell wall | 3. Spirulina |
| D. Microalgae | 4. Found only in plants |
| D. Biogas | 5. Methane |
Answer:
A – 2, B – 1, C – 4, D – 3, E – 5
| Column I | Column II |
| A. Nucleoid | 2. Bacteria |
| B. Lactobacillus | 1. Curd |
| C. Cell wall | 4. Found only in plants |
| D. Microalgae | 3. Spirulina |
| D. Biogas | 5. Methane |
Question 2.
Match the Column I with Column II.
| Column I | Column II |
| A. Bacteria | 1. Branched filament without chlorophyll having sac-like structure |
| B. Bread mould | 2. Presence of chlorophyll |
| C. Algae | 3. Motile cell having irregular |
| D. Amoeba | 4. Have hair like projections |
Answer:
A → 4, B → 1, C → 2, D → 3
| Column I | Column II |
| A. Bacteria | 4. Have hair like projections |
| B. Bread mould | 1. Branched filament without chlorophyll having sac-like structure |
| C. Algae | 2. Presence of chlorophyll |
| D. Amoeba | 3. Motile cell having irregular |