MICROORGANISMS
AND VIRUSES – Friends and Foes! (Q and A) Prepared By Rabi Sir
Q1. Answer in one word.
1. Name two typical habitats of micro-organisms
Answer: Commonly found everywhere – in air, in water, inside the
bodies of living organisms.
2. Name a
disease caused by bacteria
Answer: Tuberculosis, Pneumonia
3. Name the
microorganism that is used for obtaining alcohol from sugar.
Answer: Yeast.
4. Name one
carrier of disease – causing microorganisms.
Answer: House Fly which causes many diseases like cholera, typhoid,
diarrhoea.
5. Where do
the external parasites of animals live?
Answer: External parasites like lice, flies, ticks, grubs etc. live on
the skins of the animals.
Q2. Short- Answer Questions (10-15 words)
1. Name the four major groups of microorganisms.
Answer:
Bacteria: Baccili, Cooci
Fungi: Prencillium, Bread Mould
Algae: Chlamydomonas, Nostoc
Protozoa: Amoeba, Paramecium
2. How do the blue –green algae and symbiotic bacteria convert atmospheric nitrogen into nitrogen compounds?
Answer: Rizobium bacteria con take atmospheric nitrogen and convert it into nitrates soluble in soil.
3. Name the modes of transmission of communicable disease.
Answer:
Direct Transmission: By direct contact, By droplet infection, sharing infected needles, syringes and razors, infected blood transfusion.
Indirect Transmission: Infected food, water or air, Through carriers like house fly, mosquitoes, rats etc., Through dirty hands.
4. What are the symptoms of food poisoning?
Answer: Headache, Fever, Vomiting, Diarrhoea
5. Name two food preservatives used for preserving fruit juices , Jam and Jellys.
Answer: Sodium Benzoate and Potassium metabisulphite.
Q3 Long answer type Questions (Answer in 20-25 words )
1. Why is yeast added to the mixture made for making cake? Explain.
Answer: Yeast contains enzymes zymase and invertase which ferment the dough and releases carbon dioxide gas. This gas makes dough rise and fluffly.
2. Write the beneficial action of :
(a) Bacteria
(b) Fungi
(c) Algae
Answer:
(a) Bacteria: Bacteriam Lactobacillus help in formation of curd from milk.
(b) Fungi: Yeast help in preparing bakery products like bread and cakes.
(c) Algae: Agar Agar (used in food preservatives and jellies) is obtained from red algae.
3. How are the disease caused by microorganisms classified ? Explain by giving suitable example ?
Answer: Disease causing micro-organisms are called pathogens. Pathogens enter the body of animals or plants, multiply and damage the body cells. Based on type of pathogens, diseases are classified as:
(a) Bacteria causing diseases: Pneumonia, Tuberculosis, Leprosy etc.
(b) Fungi causing diseases: Skin diseases, food poisoning.
(c) Protozoa causing diseases: Malaria, Dysentery, Kala-Azar
(d) Virus causing diseases: Chicken Pox, AIDS, Dengue, Common cold.
For example, virus causing cold spreads through air when an infected person sneezes. The virus enters the body of healthy person standing nearby and infects him.
4. What are the advantages of food preservation?
Answer:
1. Reduces food wastage.
2. Increases storage duration of perishable items.
3. Reduces chances of pathogen infection and getting food toxic.
5. Name the causative microorganisms which causes
(a) Rust in wheat
(b) Blast in paddy
(c) Yellow – vein mosaic in Bhindi (Okra)
Answer: (a) Fungi (b) Fungi (c) Virus
Q4. Tick the ODD one out giving reason
(a) Bacteria , Fungi , Virus , algae , protozoa
(b) Milk , curd , Renin , Lactobacillus
(c) Anaerobic bacteria , Blue – green algae ,Animal dung , Biogas
(d) Skin disease , malaria , dysentery , Giardiasis
(e) Salt , sugar , oil , clostridium botulism , sodium metabisulphite
Answer: (a) Virus (b) Renin (c) Blue Green Algae (d) Skin diseases (e) clostridium botulism
Q5. Define the following terms
(a) Fermentation
(b) Food poisoning
(c) Nitrogen cycle
(d) Food preservation
(e) Pasteurization
Answer: (a) Fermentation: The enzymetic break down of large organic molecules into smaller ones in the absence of air is called fermentation. e.g. Yeast is used to ferment sugar into alcohol.
(b) Food gets spoiled by the action of microbes. Toxins produced by microbes make the food rancid. This is called food poisoning.
(c) Nitrogen Cycle: The circulation of nitrogen in various chemical forms in nature is called Nitrogen Cycle. Nitrogen in air is fixed by lightening and by the action of Rhizobium bacteria into nitrates. These nitrates are absorbed by plants and animals. When plants and animals die, nitrates are decomposed into nitrogen and is released to air, thus completing the cycle.
HOTS - HIGH ORDER THINKING SKILLS : THINK AND ANSWER
1. Why is virus not included in the category of microorganisms?
Answer: Viruses possess characteristics of living and non-living. It does not have well defined body apparatus like other microbes or living beings have. That's why viruses are not included in the category of micro-organisms.
2. Why does curd sets faster in summer than in winter?
Answer: Summer temperature is suitable to microbes to grow fast as compared to low temperatre in winter. Higher growth of bacteria leads to faster curd formation.
3. What is meant by causative microorganisms ? Illustrate by giving a few examples ?
Answer: Causative microbes, also called pathogen, enter host body, multiply and cause diseases. Fungi, Virus, Bacteria and Protozoans are causative microbes. e.g. On mosquito bite, dengue virus enters the host body and attacks blood cells. It causes fever, and severe pain.
4. What are the internal and external parasites ?Give one example for each ?
Answer: Parasites get their food from the body of the animal and make it weak. Parasites are of two types:
External Parasites: They live on skin and mainly cause skin diseases. e.g. Lice, ticks.
Internal Parasites: These are worms which live and grow inside the body of host. e.g. Tape worms and round worms grow in human intestines.
1. Name the four major groups of microorganisms.
Answer:
Bacteria: Baccili, Cooci
Fungi: Prencillium, Bread Mould
Algae: Chlamydomonas, Nostoc
Protozoa: Amoeba, Paramecium
2. How do the blue –green algae and symbiotic bacteria convert atmospheric nitrogen into nitrogen compounds?
Answer: Rizobium bacteria con take atmospheric nitrogen and convert it into nitrates soluble in soil.
3. Name the modes of transmission of communicable disease.
Answer:
Direct Transmission: By direct contact, By droplet infection, sharing infected needles, syringes and razors, infected blood transfusion.
Indirect Transmission: Infected food, water or air, Through carriers like house fly, mosquitoes, rats etc., Through dirty hands.
4. What are the symptoms of food poisoning?
Answer: Headache, Fever, Vomiting, Diarrhoea
5. Name two food preservatives used for preserving fruit juices , Jam and Jellys.
Answer: Sodium Benzoate and Potassium metabisulphite.
Q3 Long answer type Questions (Answer in 20-25 words )
1. Why is yeast added to the mixture made for making cake? Explain.
Answer: Yeast contains enzymes zymase and invertase which ferment the dough and releases carbon dioxide gas. This gas makes dough rise and fluffly.
2. Write the beneficial action of :
(a) Bacteria
(b) Fungi
(c) Algae
Answer:
(a) Bacteria: Bacteriam Lactobacillus help in formation of curd from milk.
(b) Fungi: Yeast help in preparing bakery products like bread and cakes.
(c) Algae: Agar Agar (used in food preservatives and jellies) is obtained from red algae.
3. How are the disease caused by microorganisms classified ? Explain by giving suitable example ?
Answer: Disease causing micro-organisms are called pathogens. Pathogens enter the body of animals or plants, multiply and damage the body cells. Based on type of pathogens, diseases are classified as:
(a) Bacteria causing diseases: Pneumonia, Tuberculosis, Leprosy etc.
(b) Fungi causing diseases: Skin diseases, food poisoning.
(c) Protozoa causing diseases: Malaria, Dysentery, Kala-Azar
(d) Virus causing diseases: Chicken Pox, AIDS, Dengue, Common cold.
For example, virus causing cold spreads through air when an infected person sneezes. The virus enters the body of healthy person standing nearby and infects him.
4. What are the advantages of food preservation?
Answer:
1. Reduces food wastage.
2. Increases storage duration of perishable items.
3. Reduces chances of pathogen infection and getting food toxic.
5. Name the causative microorganisms which causes
(a) Rust in wheat
(b) Blast in paddy
(c) Yellow – vein mosaic in Bhindi (Okra)
Answer: (a) Fungi (b) Fungi (c) Virus
Q4. Tick the ODD one out giving reason
(a) Bacteria , Fungi , Virus , algae , protozoa
(b) Milk , curd , Renin , Lactobacillus
(c) Anaerobic bacteria , Blue – green algae ,Animal dung , Biogas
(d) Skin disease , malaria , dysentery , Giardiasis
(e) Salt , sugar , oil , clostridium botulism , sodium metabisulphite
Answer: (a) Virus (b) Renin (c) Blue Green Algae (d) Skin diseases (e) clostridium botulism
Q5. Define the following terms
(a) Fermentation
(b) Food poisoning
(c) Nitrogen cycle
(d) Food preservation
(e) Pasteurization
Answer: (a) Fermentation: The enzymetic break down of large organic molecules into smaller ones in the absence of air is called fermentation. e.g. Yeast is used to ferment sugar into alcohol.
(b) Food gets spoiled by the action of microbes. Toxins produced by microbes make the food rancid. This is called food poisoning.
(c) Nitrogen Cycle: The circulation of nitrogen in various chemical forms in nature is called Nitrogen Cycle. Nitrogen in air is fixed by lightening and by the action of Rhizobium bacteria into nitrates. These nitrates are absorbed by plants and animals. When plants and animals die, nitrates are decomposed into nitrogen and is released to air, thus completing the cycle.
HOTS - HIGH ORDER THINKING SKILLS : THINK AND ANSWER
1. Why is virus not included in the category of microorganisms?
Answer: Viruses possess characteristics of living and non-living. It does not have well defined body apparatus like other microbes or living beings have. That's why viruses are not included in the category of micro-organisms.
2. Why does curd sets faster in summer than in winter?
Answer: Summer temperature is suitable to microbes to grow fast as compared to low temperatre in winter. Higher growth of bacteria leads to faster curd formation.
3. What is meant by causative microorganisms ? Illustrate by giving a few examples ?
Answer: Causative microbes, also called pathogen, enter host body, multiply and cause diseases. Fungi, Virus, Bacteria and Protozoans are causative microbes. e.g. On mosquito bite, dengue virus enters the host body and attacks blood cells. It causes fever, and severe pain.
4. What are the internal and external parasites ?Give one example for each ?
Answer: Parasites get their food from the body of the animal and make it weak. Parasites are of two types:
External Parasites: They live on skin and mainly cause skin diseases. e.g. Lice, ticks.
Internal Parasites: These are worms which live and grow inside the body of host. e.g. Tape worms and round worms grow in human intestines.
MIICROORGANISMS : FRIEND AND FOE
Q1. Fill in the blanks:
Answer:
(a) Microorganisms can be seen with the help of a microscope.
(b) Blue green algae fix nitrogendirectly from air to enhance fertility of soil.
(c) Alcohol is produced with the help of yeast.
(d) Cholera is caused byBacteria.
(a) Microorganisms can be seen with the help of a microscope.
(b) Blue green algae fix nitrogendirectly from air to enhance fertility of soil.
(c) Alcohol is produced with the help of yeast.
(d) Cholera is caused byBacteria.
Q2. Tick the correct answer:
(a) Yeast is used in the production of
(i) sugar
(a) Yeast is used in the production of
(i) sugar
(ii) alcohol
(iii) hydrochloric acid
Answer: Alcohol
(b) The following is an antibiotic
(i) Sodium bicarbonate
(ii) Streptomycin
(iii) Alcohol
(iv) Yeast
Answer: Streptomycin
(c) Carrier of malaria-causing protozoan is
(i) female Anopheles mosquito
(ii) cockroach
(iii) housefly
(iii) housefly
(iv) butterfly
Answer: Female Anopheles mosquito
(d) The most common carrier of communicable diseases is
(i) ant
(i) ant
(ii) housefly
(iii) dragonfly
(iv) spider
Answer: Housefly
(e) The bread or idli dough rises because of
(i) heat
(i) heat
(ii) grinding
(iii) growth of yeast cells
(iv) kneading
Answer: Growth of yeast cells
(f) The process of conversion of sugar into alcohol is called
(i) nitrogen fixation
(i) nitrogen fixation
(ii) moulding
(iii) fermentation
(iv) infection
Answer: Fermentation
Q3. Match the
organisms in Column I with their action in Column II.
|
Column I
|
Column II
|
|
|
(i)
Bacteria
|
(a)
Fixing Nitrogen
|
|
|
(ii)
RhizobiumÂ
|
 (b)
Setting of curd
|
|
|
(iii)Lactobacillus
|
(c)
Baking of bread
|
|
|
(iv)
Yeast
|
(d)
Causing Malaria
|
|
|
(v)
A protozoan
|
(e)
Causing Cholera
|
|
|
(vi)
A Virus
|
(f)
Causing AIDS
|
|
|
.
|
(g)
Producing antibodies
|
Answer:
(i) Causing Cholera,
(ii) Fixing Nitrogen
(iii) Setting of curd
(iv) Baking of bread
(v) Causing Malaria
(vi) Causing Aids
Q4. Can microorganisms be seen with the naked eye? If not, how
can they be seen?
Answer: No, the microorganisms cannot be seen with the naked eyes. It
can be seen only with the help of a microscope.
Q5. What are the major groups of microorganisms?
Answer: The major groups of microorganisms are :
A: Bacteria
B: Fungi
C: Protozoa
D: Some algae.
Q6. Name the microorganisms which can fix atmospheric nitrogen
in the soil.
Answer: Some bacteria like Rhizobium and blue green algae are able to
fix nitrogen from the atmosphere and increase the fertility of the soil. These
microbes are commonly called biological nitrogen fixers.
Q7. Write 10 lines on the usefulness of microorganisms in our
lives.
Answer: Microbes are used for various purposes. They are very useful
in our lives. Some of their uses are mentioned below:
1.
The bacterium Lactobacillus promotes the formation of curd.
2.
Bacteria are also involved in the making of cheese, pickles and
many other food items.
3.
Yeast is used for commercial production of alcohol and wine.
4.
Yeast us also used for baking breads, cakes etc.
5.
Microorganisms are used for the manufacturing of antibiotics
6.
Vaccines for various diseases are made from microorganisms to
protect the human beings and animals.
7.
Some bacteria like Rhizobium and blue green algae are able to
fix nitrogen from the atmosphere and increase the fertility of the soil
8.
Some microorganisms decompose the organic waste and dead plants
and animals into simple substances and clean up the environment.
9.
The bacteria in our intestine help in digestion of food.
10. The algae are a
food for some breeds of fish.
Q8. Write a short paragraph on the harms caused by
microorganisms.
Answer: Although microorganisms are useful but there are some microorganisms
which are harmful for us. Microorganisms cause diseases in human beings, plants
and animals. Some microorganisms spoil food, clothing and leather. Some of the
diseases caused by microorganisms are cholera, common cold, chicken pox and
tuberculosis etc. There are some insects and animals which act as carriers of
disease causing microbes. Some microorganisms cause diseases in plants like
wheat, rice, potato, sugarcane, orange etc. Microorganisms that grow on our
food sometimes produce toxic substances which are poisonous and cause illness
and even death.
Q9. What are antibiotics? What precautions must be taken while
taking antibiotics?
Answer: The medicines produced by microorganisms that kill or stop the
growth of disease are called antibiotics. There are number of antibiotics that
are being produced by bacteria and fungi. The precautions which must be taken
using antibiotics are:
·
They should be taken on the advice of a qualified doctor.
·
We must complete the course prescribed by the doctor.
Q10: Where can we find Microorganisms?
Answer: Microorganisms are found everywhere i.e. in air, water, soil. They are found inside the bodies of plants and animals. They can live under different kinds of environment i.e. from very cold climate to hot springs and from deserts to marshy lands.
Q11: Name diseases caused by protozoa?
Answer: Malaria, Dysentery
Q12: Name the diseases caused by a virus.
Answer: common cold, flu, AIDS, polio, measles, hepatitis (jaundice)
Q13: Give examples of algae
Answer: Spirogyra, Chlamydomonas
Q14: Give names of fungi.
Answer: Rhizopus, Penicillium
Q15: Name any two protozoa.
Answer: Paramecium, Amoeba.
Q16: Name the organism and its type which converts milk into curd.
Answer: Lactobacillus - a type of bacteria.
Q17: Which microbe is used in production of alcohol.
Answer: Yeast
Q18: Give an example of an antibiotic.
Answer: Streptomycin
Q19: Name the most common vector of communicable diseases.
Answer: housefly
Answer: Microorganisms are found everywhere i.e. in air, water, soil. They are found inside the bodies of plants and animals. They can live under different kinds of environment i.e. from very cold climate to hot springs and from deserts to marshy lands.
Q11: Name diseases caused by protozoa?
Answer: Malaria, Dysentery
Q12: Name the diseases caused by a virus.
Answer: common cold, flu, AIDS, polio, measles, hepatitis (jaundice)
Q13: Give examples of algae
Answer: Spirogyra, Chlamydomonas
Q14: Give names of fungi.
Answer: Rhizopus, Penicillium
Q15: Name any two protozoa.
Answer: Paramecium, Amoeba.
Q16: Name the organism and its type which converts milk into curd.
Answer: Lactobacillus - a type of bacteria.
Q17: Which microbe is used in production of alcohol.
Answer: Yeast
Q18: Give an example of an antibiotic.
Answer: Streptomycin
Q19: Name the most common vector of communicable diseases.
Answer: housefly
Q20: Define the term fermentation.
Answer: The conversion of sugar solution into alcohol and liberation of carbon dioxide is known as fermentation.
Q21: Why are children vaccinated?
Answer: When a disease causing microbe enters human body, the body produces antibodies to fight the microbe. During vaccination, dead and weakened micro-organisms are introduced in a healthy body, the body produces antibodies, fights and kills them. Thus the body adapts to fight against that micro-organism and is immunized.
Q22: What is pasteurization?
Answer: Pasteurization is a technique applied to check the growth of micro-organisms in milk. The milk is heated to about 70 degrees and then suddenly chilled and stored.
Q23: What is the full form of AIDS?
Answer: Acquired Immuno Deficiency Syndrome
Q24: Define Immunity.
Answer: Immunity is the capacity of the body to defend itself against the disease.
Q25: List the type of bacteria recognised based on shape.
Answer:
1.
Rod shaped - Bacilli (singular term is Bacillus)
2.
Spherical Shaped - Cocci
3.
Spiral Shaped - Spirillum
4.
Comma Shaped - Vibrio
