MCQ Questions for Class 8 Science Chapter 2 Microorganisms: Friend and Foe
Solving the Microorganisms: Friend and Foe Multiple Choice Questions of Class 8 Science Chapter 2 MCQ can be of extreme help as you will be aware of all the concepts. These MCQ Questions on Microorganisms: Friend and Foe Class 8 with answers pave for a quick revision of the Chapter thereby helping you to enhance subject knowledge. Have a glance at the MCQ of Chapter 2 Science Class 8 and cross-check your answers during preparation.
Question 1.
The host for malaria causing protozoan is:
(a) anapheles mosquito
(b) the cow
(c) the earthworm
(d) the tapeworm
Answer
(a) anapheles mosquito
Anopheles mosquito is the host for malaria causing protozoan
Question 2.
The bread or dosa dough rises because of the action of:
(a) heat
(b) grinding
(c) growth of yeast cells
(d) none of these
Answer
(c) growth of yeast cells
Due to growth of yeast cells, the breads or dosa dough rises
Question 3.
Malaria is spread by:
(a) plasmodium
(b) female anapheles mosquito
(c) male anapheles mosquito
(d) none of these
Answer
(b) female anapheles mosquito
Malaria is spread by female anapheles mosquito.
Question 4.
Protozoan shaped like a slipper is:
(a) amoeba
(b) paramecium
(c) euglena
(d) entamoeba
Answer
(b) paramecium
Potozoan shaped like a slipper is paramecium.
Question 5.
The bacterium that turns milk into curd is:
(a) lactobacillus
(b) acetobacter
(c) rhizobium
(d) none of these
Answer
(a) lactobacillus
Lactobacillus turns milk into curd.
Question 6.
The bacteria was first observed by:
(a) Louis Pasteur
(b) Antony Von Leuwen Hook
(c) Robert Hooke
(d) Robert Koch
Answer
(b) Antony Von Leuwen Hook
The bacteria was first observed by Antony Von Leuwen Hook.
Question 7.
Virus reproduce:
(a) only outside the cells of the host organisms
(b) only inside the cells of the host organisms
(c) both inside and outside the cells of the host organisms
(d) none of these
Answer
(b) only inside the cells of the host organisms
Virus reproduce only inside the cells of the host organisms.
Question 8.
Which of the following lives alone:
(a) amoeba
(b) fungi
(c) bacteria
(d) all of these
Answer
(a) amoeba
Amoeba lives alone whereas fungi and bacteria live in colonies.
Question 9.
The process of conversion of sugar into alcohol is known as:
(a) pasteurisation
(b) fermentation
(c) decomposition
(d) none of these
Answer
(b) fermentation
Fermentation is the process of conversion of sugar into alcohol.
Question 10.
In Pasteurisation the milk is heated to about:
(a) 100°C
(b) 50°C
(c) 70°C
(d) 110°C
Answer
(c) 70°C
In pasteurisation the milk is heated to about 70°C for 15 to 30 seconds and then suddenly chilled and stored.
Question 12.
The bacterium living in the root nodules of leguminous plants is:
(a) lactobacillus
(b) acetobactor
(c) rhizobium
(d) none of these
Answer
(c) rhizobium
The bacterium living in the root nodules of leguminous plants is Rhizobium.
Question 13.
Atmospheric nitrogen ¡s used for the synthesis of:
(a) plant proteins
(b) animal proteins
(c) plant carbohydrates
(d) none of these
Answer
(a) plant proteins
Atmospheric nitrogen is used for the synthesis of plant proteins
Question 14.
The percentage of nitogen in the atmosphere:
(a) increases during day time
(b) decreases during day time
(c) remains more or less constant
(d) can’t say
Answer
(c) remains more or less constant
The percentage of nitrogen in the atmosphere remains more or less constant.
Question 15.
Which of the folidwing is a preservative:
(a) sodium benzoate
(b) common salt
(c) vinegar
(d) all of these
Answer
(d) all of these
Sodium benzoate, common salt and vinegar are all preservatives.
Question 16.
Hepatitis-A is transmitted through:
(a) water
(b) air
(c) food
(d) contact
Answer
(a) water
Hepatitis-A is transmitted through water.
Question 17.
Communicable diseases are spread from an infected person to a healthy person through:
(a) air
(b) water
(c) food
(d) all of these
Answer
(b) water
Communicable diseases are spread from an infected person to a healthy person through air, water, food and physical contact.
Question 18.
A group of micro organisms that have the characters of both living and non-living are:
(a) bacteria
(b) protozoa
(c) virus
(d) fungi
Answer
(c) virus
Virus have the characters of both living and non-living.
Question 19.
is the process by which alcohol and Co2 are produced by yeast cells.
(a) respiration
(b) digestion
(c) evaporation
(d) fermentation
Answer
(a) respiration
Respiration is the process by which alcohol and Co2 are produced by yeast cells.
Question 20.
Cause of malaria is:
(a) fungi
(b) bacteria
(c) protozoa
(d) virus
Answer
(c) protozoa
Protozoa called plasmodium is the cause of malaria.
Question 21.
The algae commonly used as fertilisers are called:
(a) chlorellin
(b) blue-green algae
(c) spirogyra
(d) none of these
Answer
(b) blue-green algae
Blue-green algae are used as fertilisers because they can fix atmospheric nitrogen to usable compounds which help in crop growth and improves the water holding capacity of soil.
Question 22.
Which of the following drug is an antibiotic?
(a) alcohol
(c) streptomycin
(b) insulin
(d) none of these
Answer
(c) streptomycin
Streptomycin drug is an antibiotic
Question 23.
Leprosy is caused by:
(a) bacteria
(c) virus
(b) protozoa
(d) fungi
Answer
(a) bacteria
Bacteria causes leprosy.
Question 24.
The cause of whooping cough is
(a) bacteria
(c) virus
(b) fungi
(d) algae
Answer
(a) bacteria
Bacteria is cause of whooping cough.
Question 25.
Virus is.
(a) non-living
(c) living as well as non-living
(b) living
(d) none of these
Answer
(c) living as well as non-living
Virus is living as well as non-living.
Question 26.
Tuberculosis is a disease caused by:
(a) bacterium
(b) protozoan
(c) virus
(d) malnutrition
Answer
(a) bacterium
Tuberculosis is causes by bacterium.
Question 27.
BCG vaccine is used to curb:
(a) cholera
(b) tuberculosis
(c) polio
(d) typhoid
Answer
(b) tuberculosis
BCG vaccine is used to curb tuberculosis.
Question 28.
Cholera is due to:
(a) virus
(b) fungus
(c) protozoan
(d) bacterium
Answer
(d) bacterium
Bacteriun causes cholera.
Question 29.
Which of the following is air-borne disease:
(a) typhoid
(b) tuberculosis
(c) cholera
(d) polio
Answer
(c) cholera
Tuberculosis is an air-borne disease.
Question 30.
Breathing in polluted air causes:
(a) kidney trouble
(b) heart problem
(c) respiratory diseases
(d) none of these
Answer
(c) respiratory diseases
Breathing in polluted air causes respiratory diseases.
Question 31.
Yeast helps in the production of:
(a) sugar
(b) alcohol
(c) oxygen
(d) none of these
Answer
(b) alcohol
Yeast helps in the production of alcohol.
Match the Column-A with Column-B:
Question 1.
| Column-A | Column-B |
| (a) Dysentery | (i) Bacteria |
| (b) Chicken pox | (ii) Protozoa |
| (c) Tuberculosis | (iii) Fungi |
| (d) Athlete’s foot | (iv) Virus |
Answer
| Column-A | Column-B |
| (a) Dysentery | (ii) Protozoa |
| (b) Chicken pox | (iv) Virus |
| (c) Tuberculosis | (i) Bacteria |
| (d) Athlete’s foot | (iii) Fungi |
Question 2.
| Column-A | Column-B |
| (a) Citrus canker | (i) Virus |
| (b) Rust of wheat | (ii) Bacteria |
| (c) Yellow vein mosaic of bhindi | (iii) Fungi |
Answer
| Column-A | Column-B |
| (a) Citrus canker | (ii) Bacteria |
| (b) Rust of wheat | (iii) Fungi |
| (c) Yellow vein mosaic of bhindi | (i) Virus |
Question 3.
| Column-A | Column-B |
| (a) Yeast | (i) produces antibiotics |
| (b) Blue green algae | (ii) making of cheese |
| (c) Fungi | (iii) production of alcohol |
| (d) Bacteria | (iv) increases soil fertility |
Answer
| Column-A | Column-B |
| (a) Yeast | (iii) production of alcohol |
| (b) Blue green algae | (iv) increases soil fertility |
| (c) Fungi | (i) produces antibiotics |
| (d) Bacteria | (ii) making of cheese |
State whether the following statements are True or False:
Question 1.
Viruses reproduce only inside the cells of the host organism.
Answer
True
Question 2.
Typhoid is caused by protozoa.
Answer
False
Question 3.
Polio is caused by viruses.
Answer
True
Question 4.
All the micro organisms can be seen with the unaided eye.
Answer
False
Question 5.
Vegetable peels, remains of animals are organic wastes.
Answer
True
Question 2.
Bacterium Rhizobium promotes the formation of curd.
Answer
False
Question 3.
The process of conversion of sugar into alcohol is known as fermentation.
Answer
True
Question 4.
Cholera, common cold, chicken pox are communicable diseases.
Answer
True
Question 5.
Some of the micro organisms growing on our food causes food poisoning.
Answer
True
Question 6.
All micro organisms are unicellular.
Answer
False
Question 7.
Sodium bicarbonate is an antibiotic.
Answer
False
Question 8.
Carrier of malaria-causing protozoan is housefly.
Answer
False
Question 9.
The bread or idle dough rises because of growth of yeast cells.
Answer
True
Question 10.
Yeast is used in the production of hydrochloric acid.
Answer
False
Question 11.
Jams, jellies and squashes are preserved by sugar.
Answer
True
Fill in the blanks:
Question 1.
Our atmosphere has …………………… nitrogen gas.
Answer
78%
Question 2.
Micro organisms are organisms that cannot be seen by …………………… eye.
Answer
unaided
Question 3.
…………………… discovered penicillium.
Answer
Dr. Alexender Fleming
Question 4.
When a disease-carrying microbe enters our body, the body produces …………………… to fight the invader.
Answer
antibodies
Question 5.
Medicines called …………………… kill or stop the growth of the disease causing micro organisms.
Answer
antibiotics
Question 6.
…………………… is mode of transmission of disease citrus canker.
Answer
Air
Question 7.
…………………… is used to preserve meat and fish.
Answer
Common salt
Question 8.
Microbial diseases that can spread from an infected person to a healthy person through air, water or physical contact are called ……………………
Answer
communicable diseases
Question 9.
…………………… mosquito acts as carries of dengue virus.
Answer
Female Aedes
Question 10.
Disease causing micro organisms are called ……………………
Answer
pathogens
Question 11.
Penicillium is an example of ……………………
Answer
fungi
Question 12.
…………………… promotes the formation of curd.
Answer
Lactobacillus
Question 13.
…………………… discovered the vaccine for small pox.
Answer
Edward Jennner
Question 14.
AIDS is caused by virus called …………………… virus.
Answer
HIV
Question 15.
Blue green tilgae fix …………………… directly from air to enhance fertility of soil.
Answer
nitrogen
Question 16.
Micro-oganisrn decompose the organic waste and dead plants and animals into …………………… substances and clean up the environment.
Answer
simple
Question 17.
Micro-organism can be seen with the help of a ……………………
Answer
Answer: (a)
Microscope
Question 18.
Microbes are of five kinds (a) ………………. (b) ………………. (c) …………………. (d) …………………… (e) ………………….
Answer
(a) Bacteria
(b) Alage
(c) Fungi
(d) Protozoa
(e) Viruses
Question 19.
Pasteurisation prevents the growth of …………………… in milk.
Answer
microbes
Question 20.
Mode of transmission of disease ‘Yellow vein mosaic of bhindi is ……………………
Answer
insect
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