TS 8th Class Biology Study Material Lesson 3B The World of Story of Microorganisms Part 2

Telangana SCERT 8th Class Biology Study Material Telangana Pdf 3B The World of Story of Microorganisms Part 2 Textbook Questions and Answers.

TS 8th Class Biology Lesson 3B Questions and Answers Telangana – The World of Story of Microorganisms Part 2

Question 1.
How vaccines work in our body? (or) We are giving vaccines to children. How does it works in our body?
Answer:
Vaccines: The killed or weakened disease causing micro-organisms which are put into our body are called vaccines.

• When the vaccine is injected our body reacts to the dead micro-organisms as if they are alive and produce antibodies.
• Next time when the same disease producing micro-organism enters the body, these antibodies will react and kill them.
• Thus, the person is not affected by the disease even if he is exposed to the disease-causing microbes.

Question 2.
What are the differences between Antibiotic and Vaccine?
Answer:

Antibiotic	Vaccine
1) Chemical substances produced by living organism which have a killing effect on other microorganism.	1) The killed or weakened disease causing micro organisms which are put into our bodies.
2) These are injected only when the person is affected with a disease.	2) These are prescribed at the early stages of life.
3) The immunity acquired by antibiotics is temporary.	3) The immunity acquired by vaccine lasts for a long time.

Question 3.
Invention of pencillin protected the world from deaths during first world war, explain.
Answer:

• Pencillin was discovered by Dr. Alexander Flemming.
• He was an army doctor. He observed that many injured soldiers died due to bacterial infections in World War – I.
• He was working on antibiotics in his lab. One day he observed that some fungi (mould) were preventing the growth of bacteria in the petridish, in which he was growing bacterial colonies.
• He separated the substances released by the fungus and tested it on some other disease causing bacteria.
• It also killed the other disease causing bacteria.
• The mould or fungus separated was identified as ‘Penicillium notatum”.
• The substance which was produced by the fungus Penicillium is named as Penicillin.
  The discovery of the antibiotic penicillin was announced in 1929. Alexander Flemming was awarded Nobel prize for his great discovery in 1945.

Question 4.
Take three bowls and mark as A, B, C. Pour lukewarm milk in bowl A, hot milk in bowl B, cold milk in bowl C. Add one tea spoon of curd or butter milk in three bowls and stir them slightly. Cover the bowls with lids. Keep the bowls undisturbed for five to six hours. In which bowl milk turned into curd? Give your reasons.
Answer:
The lukewarm milk turned into curd, because the atmosphere between 30°c – 40°c is favourable for the curdling of milk. The lukewarm condition of milk is favourable for the growth of micro organisms called Lactobacillus. Lactohacillus helps in curdling milk. The temperature below and above lukewarm conditions may lessen the growth of Lactobacillus bacteria which further slows down the curdling of milk.

Question 5.
Collect more information about scientists who invented and discovered other facts related to Microorganisms. How these discoveries helped mankind? Make a chart presentation and paste it on your classroom wall Magazine.
Answer:

’ No.	Scientist name	Discovery / Invention	Useful to mankind
1.	Dr. Alexander	Antibiotics from a	Fielps in killing of disease
	Flemming	fungal culture	causing micro organisms.
2.	Dr. Yellapragada Subba Rao	Aureomvcin	Cures bacterial diseases like Typhoid, Plague, TB.
3.	Dr. Jonas Salk	Vaccine (injection)	Cures polio disease in children
4.	Dr. Albert Sabin	Oral Vaccine	Cures polio disease in children
5.	Dr. Edward Jenner	Vaccine	Cures smallpox disease
6.	Dr. Ronald Ross	Malarial parasite life history	Helps in controlling malaria
7.	Louis Pasteur	Pasteurisation	Preserving milk and wine
8.	Anthony Van Leeuwenhoek	Microscope	Helps in finding and observing various micro organisms
9.	Lazzaro Spallanzani	Boiling technique	Micro organisms could be killed by boiling

Question 6.
Make an Album of scientists and their discoveries related to Micro-organisms.
Answer:

Question 7.
Visit the veterinary hospital and prepare a list of cattle diseases by asking questions to the doctor?
i) What are the diseases caused in cattle?
Answer: Vet. Dr: Foot and mouth disease, measles, mastitis, cholera, rabies etc.

ii) What are the organisms cause the above diseases?
Answer: Vet. Dr: Foot and mouth disease, measles, rabies etc are caused by viruses.

iii) Are there any diseases caused by fungi in cattle ? If so what are they?
Answer: Vet. Dr: Yes. There are diseases caused by fungi. Eg. Candidiasis.

iv) What are the ways of transmission of diseases in cattle?
Answer: Vet. Dr : Generally the diseases are caused in cattle by the following ways.

v) Are there any skin diseases caused in cattle?
Answer: Vet. Dr : Yes. There are some skin diseases caused due to unhygienic conditions.

Question 8.
What is pasteurisation ? What is the use of it?
Answer:
Definition : Pasteurisation is a technique for preserving milk or wine. This is invented by “Louis Pasteur”.

Uses:

• This method is useful for keeping the quality of milk and to kill harmful bacteria.
• This method is applicable for preserving various foods including milk.

Question 9.
Edward Jenners collected fluid from cow pox pustule and injected to a eight year old boy. Then he exposed the boy to smallpox and the boy did not get smallpox. How do you appreciate the daring action of Edward Jenner?
Answer:

• The most remarkable experiment that was conducted by Dr. Edward Jenner in 1796, gave us the first vaccine against a disease caused in humans.
• His experiments paved the way for invention of various types of new vaccines.
• Now-a-days vaccines are made on a large scale from micro organisms to protect our lives and other animals from several diseases.

Question 10.
Visit a nearby milk chilling centre. Observe the process and make a note on it.
Answer:
Aim of the project : To collect the infornìation about process of preserving milk by using pasterurisation method.

Pasteurisation process:

• To keep the quality of the milk (prevent spoiling) and to kill harmful bacteria, a process called Pasterurisation is used.
• in this process, milk is heated to 72° C and kept at that temperature for 15 seconds. This treatment kills only harmful bacteria. Then the milk is quickly cooled to 10° C and transferred to sterile bottles or to polythene bags and sealed. These are stored at 100 C till distributed. This temperature inhibits the growth of micro-organisms that may have survived.

Question 11.
“Prevention is better than cure” comment.
Answer:

• We know that virus, bacteria, protozoa and helminth parasites enter the body and cause diseases.
• It is possible to cure several diseases with drugs and prevent the infection by taking appropriate vaccination.
• It is better to prevent the entry of disease causing organisms than to allow them into the body and taking medicines to cure the diseases.
• Steps to be taken to prevent transmission of the disease from person to person.

Question 12.
Raheem tells to his neighbours, “stagnation of sewage in our surroundings is harmful to our health.” Do you support this? Why?
Answer:
Yes, I support Raheem’s statement, because stagnation of sewage enables the entry of disease causing microorganisms. Polio, cholera, typhoid and amoebiasis and several worms spread through sewage water. The most common cause for the spread of diseases in many countries is by drinking contaminated water.

Question 13.
Jeevan said that “If there are no micro organisms earth will remain with wastes”, will you agree with this statement, why?
Answer:
Yes, I will agree with the statement because

• Undecomposed dead bodies of plants and animals would have occupied the earth.
• Lack of returning valuable nutrients to earth for plants and animals due to undecomposition of things.
• Indigestion of food problem in the animals and
• Stopping or supplying of required vitamins in our intestine could have affected.

Question 14.
Kavita is suffering from serious illness. Doctor prescribed antibiotics for five days. After three days of usage she stopped taking antibiotics. Is It right or not, discuss.
Answer:
Doctors prescribe a course of antibiotics for a period of time to eliminate the disease causing microbes. if the course is not followed, the disease causing microbes do not die completely. They increase in number and continue the disease. It is not right for Kavita to stop taking antibiotics of prescribed course as the disease occurs again.

Question 15.
What are the precautions to eradicate malaria?
Answer:
The precautions to eradicate malaria:

• The best way to control malaria is to avoid getting infected.
• This can be done by controlling the mosquito population and by using mosquito nets.
• Draining of stagnant water or spraying light oil or disinfectants on stagnant water prevents the development of mosquitoes and spread of malaria.
• Use of repellants to inhibit the entry of mosquitoes into our houses.
• Spraying of kerosene mud on the upper surface of open drainages to kill the larvae of mosquitoes.
• We should keep our surroundings clean and hygienic.
• We should close the drinking water vessels with lids or saucers to avoid mosquitoes entering the kitchens.

Question 16.
One medical store owner is giving antibiotics to his customer who is suffering from fever without doctor’s prescription. But the customer’s daughter Malathi is telling her father not to take antibiotics without doctor’s prescription. Whom do you support and why?
Answer:

• I support Malathi, because we should not take antibiotics without doctors prescription.
• Specific disease causing organism will be eliminated from the victim by specific drug (antibiotic) that is prescribed by doctor.
• Unprescribed antibiotics sometimes cause side effects in the victim’s body.
• Unprescribed antibiotics may become fatal to the victim.

TS 8th Class Biology Lesson 3B The World of Story of Microorganisms Part 2 Activities

Activity -1:

Take some lukewarm milk in two small bowls. Add a few drops of butter milk or little curd in one of the bowls. In the second bowl do not add anything. Keep the two bowls in a warm place and observe the milk in the bowls after 5 to 6 hours.

Question 1.
What changes did you observe?
Answer:
The milk in the bowl in which butter milk is added turned into curd.

Question 2.
What is the reason for this?
Answer:
Butter milk drops contain lactobacillus bacteria which change the luke warm milk into curd.

Activity – 2:

Take 100 grams of maida in a bowl, add one or two spoons of yeast powder, add some water and knead it to make dough. Keep the dough in a warm place. Observe the dough after 34 hours.

Question 3.
You might have observed your mother preparing fermented food like idly and dosa. What will be the reason for preparing idli and Dosa dough before one day?
Answer:
Idli and Dosa dough should be fermented. This fermentation is done by certain bacteria. The bacteria makes the dough to produce CO₂. This gas fills the dough, increases its volume, makes spongy in nature. It will be easy to prepare dosas with fermented dough.

Question 4.
What might be the reason when yeast is kneaded with myda dough of one cup. Discuss with your friends and write about it ?
Answer:
When yeast is added to the dough for preparing bread, the dough rises. This is due to the production of carbondioxide gas by the process of fermentation. Bubbles of the gas fill the dough, increase its volume and make the dough spongy.

Activity – 3 : Commercial use of microorganisms:

Question 5.
Take half glass of water in two beakers or bowls separately. Add 5 to 10 spoons of sugar in the water, and add 2 to 3 spoons of yeast in one of the bowls. Close the bowls with lids and keep them in a warm place. After 3 to 4 hours remove the lids and smell.
Answer:
The bowl with yeast gives alcohol smell, whereas the bowl without yeast do not give such an odour.

1. What differences did you observe between the two bowls?
2. What will be the reason for odour in yeast mixed bowls?
Answer:
1. The cup containing yeast with sugar gives smell of alcohol.
2. Sugars are converted into alcohol by yeast by the process of fermentation.

Question 6.
Write the medicinal use of micro-organisms.
Answer:

• Medicines which are made of micro-organisms (fungus) are called antibiotics. These antibiotics help in curing many bacterial diseases like typhoid, gonorrhoea and prevent infections like septicaemia. Eg: Penicillin, streptomycin, erythromycin etc.
• Vaccines are another type of medicines containing dead micro – organisms. The dead micro organisms are made into a suspension and injected into humans. Vaccination gives prolonged immunity in humans. Eg: Polio vaccine.

Activity – 4:

Question 7.
Visit nearby PHC and collect Information about vaccination given to 0-15 years children. Meet a doctor or a health worker and ask what types of vaccines are there? Which disease can be prevented? When it should be taken? List them out
Answer:

Activity – 4 (a) :

Question 8.
Take two pots or dig two pits in the corner of the garden at home or ground at your school. Fill them up to half with loose soil. Put some biological wastes like fallen leaves, vegetable wastes, waste papers etc., in one of them. Fill the second one with plastic wastes, polythene bags and with some empty glass bottles. Now cover the pits or pots with some loose soil. Sprinkle some water on the pots I pits. Do this every day. After three to four weeks remove the upper soil from the pits and observe the changes.

a) What changes you have observed ? Note them down.
Answer:
We observed micro organisms present in the soil, air and water act upon wastes around us and decomposes them. They are converted into simple substances. Thus microorganisms help us in cleaning the environment.

Activity – 5:

Question 9.
Meet a doctor of your locality and ask him about the different types of diseases, caused by different micro-organisms. Note them down and discuss with your friends. Write down modes of transmission and preventive measures.
Answer:
TABLE: SOME COMMON DISEASES CAUSED BY MICRO ORGANISMS IN HUMAN:

Question 10.
Collect the information on some of plant diseases, causative microorganisms and mode of transmission. Collect the pictures of plant products.
Answer:
TABIE : Shows some of plant diseases, causative microorganisms and mode of transmission.

Activity – 6:

Question 11.
Explain the following biological phenomenon. Nitrogen fixation in root nodules of legumes.
Answer:
Rhizobium is present in the root nodules of many leguminous plants such as beans, peas and groundnut. The bacterium Rhizobium fixes atmospheric nitrogen which is taken up by plant root. Growing pulse crop helps in increasing soil fertility.

TS 8th Class Biology Lesson 3B The World of Story of Microorganisms Part 2 Important Questions

Question 1.
Name the bacterium present in curd or buttermilk.
Answer:
Curd or buttermilk contains bacterium named lactobacillus or lactic acid bacterium.

Question 2.
What is the use of lactobacillus bacterium?
Answer:
Lactohacillus converts the milk into the form of curd.

Question 3.
What is ‘fermentation?
Answer:
The process of conversion of sugars into alcohol by yeast is known as fermentation.

Question 4.
What is the use of molasses ? Where is it produced?
Answer:
Molasses are produced in sugar industry. It is used in preparation of ethyl alcohol by the fermentation by adding yeast.

Question 5.
Name the micro organism from which the antibiotic penicillin is obtained.
Answer:
The fungus penicillium notatum is used to obtain the antibiotic penicillin.

Question 6.
What is the disadvantage in over use or unnecessay use of antibiotics?
Answer:
Overuse or unnecessary use of antibiotics affects blood cells that fight against infections. Sometimes they may kill useful bacteria in our intestine and increases resistance towards antibiotics.

Question 7.
Who discovered vaccine for polio ? What was his unique generous nature?
Answer:
Dr. Jonas Salk discovered vaccine for polio in 1952. He wanted to distribute it freely to every one. So he never patented his polio vaccine.

Question 8.
Who discovered oral polio vaccine?
Answer:
Dr. Albert Sabin discovered oral polio vaccine in 1957.

Question 9.
What are vaccines?
Answer:
The killed or weakened disease causing microorganisms, which are put into our bodies are called as vaccines.

Question 10.
Who invented vaccine for smallpox?
Answer:
Dr. Edward Jenner invented vaccine for smallpox in 1796.

Question 11.
Define’pathogens’.
Answer:
Microorganisms which cause diseases are called ‘pathogens’.

Question 12.
What are “Communicable diseases”?
Answer:
The diseases which spread from infected people to healthy ones are known as communicable diseases.

Question 13.
What are the ways of communicable diseases?
Answer:
Communicable diseases spread through air, water, food or through physical contact of infected person or through insects.

Question 14.
How do houseflies carry diseases?
Answer:

• House flies carry disease causing micro organisms of typhoid, cholera, amoebic dysentery, T.B etc.
• When they sit on garbage, excreta of infected persons or animals, pathogens stick to their bodies.
• When these flies sit again on a uncovered food, they transfer the disease causing bacteria into the food.
• Whoever eats this food may have chances to get these diseases.

Question 15.
What diseases can be prevented if we can control mosquitoes or mosquito bites?
Answer:
Denguee malaria, chikungunvd, japanese encephalitis filaria etc., can he prevented if we control mosquitoes or mosquito bites.

Question 16.
Which diseases can be prevented by vaccination?
Answer:
Tuberculosis, chickenpox, measles, polio, swineflu etc., are prevented by vaccination.

Question 17.
What are antibodies? When do they develop? How do they help us?
Answer:

• Antibiotics are chemical substances produced by living organisms (fungus) which have a killing effect on other micro-organisms.
• They help us in diseased conditions.
• Antibiotics either destroy or inhibit the disease causing organisms (bacteria). They can stop growth of microorganisms temporarily.

Question 18.
What is the right time for taking vaccine and antibiotic ? Why?
Answer:
Vaccine: A person has to take vaccine in early stages of life. If vaccine is taken once, the immunity persists for Life time.
Antibiotics: Antibiotics are useful only after the disease attacks the victim. They eliminate or kill the disease causing microbes in the patient’s body. Antibiotics prescribed by a doctor should be taken, otherwise they cause side effects.

Question 19.
Visit a nearby verterinary hospital in your locality. Collect the data on the diseases caused in cattle, sheep or goat.
Answer:
The data on various diseases caused in cattle, sheep and goat.

• Diseases in cattle: Foot and mouth disease, measles, mastitis cholera etc.
• Diseases in sheep: Anthrax, blue tongue, small pox, dermatitis etc.
• Diseases in goat: Dermatitis, diarrhoea, small pox. rabies, anthrax etc.

Question 20.
Latha advised her brother Rajesh to rinse mouth with water after eating chocolates or ice creams. Is this statement correct? Why?
Answer:
The given statement is correct. He should rinse mouth after eating anything especially ice creams and chocolates. If any food particles are left in the gaps of teeth they are contacted by micro-organisms which enter our mouth. These microbes decay the left over food particles between the teeth. Finally this decayed food affects the teeth and cause dental problems. It is called tooth decay. The sweetness in the chocolates and ice-creams lead to growth of micro organisms which in turn spoil the teeth.

Question 21.
If there are no micro organisms on the earth what will happen?
Answer:
If there are no micro organisms on the earth, the following disasters would have been affected–

• Undecomposed dead bodies of plants and animals would have occupied the earth.
• Lack of returning valuable nutrients to earth for plants and animals due to undecomposition of things.
• Indigestion of food problem in the animals and
• Stopping or supplying of required vitamins in our intestine could have affected.

Question 22.
Why should we keep our surroundings clean?
Answer:
We should keep our surroundings clean for the following purposes.

• To prevent spreading of diseases from other areas.
• To avoid pollution.
• To protect our body from diseases.
• To stop microbes, houseflies, mosquitoes into the places.

Question 23.
Name the diseases which are transmitted by contaminated water?
Answer:
Polio, cholera, typhoid etc, diseases are transmitted by contaminated water.

Question 24.
Can you name some diseases which are transmitted by Air ?
Answer:
Tuberculosis, chickenpox, measles, polio, swineflu, common cold etc., are diseases transmitted by air.

Question 25.
Name the disease which is transmitted by both air and water ?
Answer:
Polio is transmitted by both air and water.

Question 26.
Name the diseases which are transmitted by water food and vector.
Answer:
Cholera, typhoid are the diseases transmitted by contaminated water, food and vector.

Question 27.
Which bacterium is responsible for food poisoning?
Answer:
‘Clostridium botulinum a bacterium is widely responsible for causing food poisoning.

Question 28.
What is pasteurisation ? Who invented this?
Answer:
Pasteurisation is a technique to preserve milk in containers. In this process milk is heated upto 70°c for 15 to 30 seconds and then suddenly chilled and stored. This process was invented by ‘Louis Pasteur’.

Question 29.
What are antibodies?
Answer:
When a disease causing microorganisms enter our body, our body produces some defenders to fight against them. They are called Antibodies.

Question 30.
Who discovered vaccine for Rabies?
Answer:
Vaccine for Rabies was discovered by Louis Pasteur.

Question 31.
Which one is better to take ? Antibiotics or vaccines? Why?
Answer:
It is better to take vaccines rather than antibiotics, because vaccines protect us from getting the diseases over a long period of time. Often they protect throughout our life. Antibiotics are useful to kill the disease causing micro organisms only during diseased conditions. They temporarly eliminate the disease.

Question 32.
Refrigerator helps us in saving health and money. Can you explain?
Answer:

• Microbial growth is retarded when food material is stored at low temperature.
• When the food is stored in low temperature decomposition and the growth of micro organisms is slowed down considerably.
• Hence refrigerator helps us in saving health and money.
• But the method of refrigeration of food is not always safe and healthy, because consumption of prolong preserved food sometimes cause health problems.

Question 33.
Can you give some important key points you noticed that scientists followed in their inventions and discoveries?
Answer:
Important key points I noticed that scientists followed in their inventions and discoveries.
a) Dr. Alexander Flemming: He separated the substances released by the fungus and tested it on some other disease causing bacteria.

b) Dr. Yellapragada Subba Rao: He developed methods for the production of several drugs such as folic acid, tetracycline anticancer drugs.

c) Dr. Jonas Salk : He discovered vaccine for polio. He wanted to distribute it freely to everyone. So he never patented his vaccine.

d) Dr. Albert Sabin: He discovered oral polio vaccine in 1957.

e) Dr. Ronald Ross : He allowed mosquitoes that had fed on malaria patient to bite a healthy man. He hypothesised that the malaria disease is communicated by the bite of the mosquito which injects fluid of small quantity.

f) Louis Pasteur: He studied the problem and hypothesised that micro organisms may be the cause of wine spoilage. He thought that these microorganisms can be controlled by heat. This led to the invention of pasteurisation.

Question 34.
Which invention is most important related to micro organisms? Can you explain the reasons why it is so Important?
Answer:

• Invention of antibiotics by Dr. Alexander Flemming is so important related to micro organisms.
• Flemming invented the first antibiotic called penicillin in 1929.
• The discovery of penicillin paved the way to the discovery of many antibiotics.
• After invention of antibiotics several scientists worked on micro-organisms and invented new techniques of medical treatment.
• In the later years vaccines were also invented by famous scientists with the help of culturing of micro organisms.

Question 35.
Who is the inventor of Aureomycin ? Write his whereabouts and other inventions or contributions to the world of medicinal sector ?
Answer:
Aureomycin was discovered by Dr. Yellapragada Subba Rao.
He was born in Bhimavaram in West Godavari of Andhra Pradesh state, India,
Aureomycin i.e, tetracycline cures number of bacterial diseases like Typhoid, plague, tuberculosis etc.

Question 36.
Answer the following.
A) Have you taken polio drops, when you are a child? Pulse polio programme?
B) Do you know about pulse polio programme?
C) What did government do in that programme?
D) Why are polio drops given to children?
E) What is the use of polio drops?
Answer:
A) I have taken polio injection when I was a child.
B) But now-a-days pulse polio programmes are conducted twice or thrice in a year for the past few years.
C) Government is conducting polio vaccine campaign all over India to give vaccine to the children for free of cost below five years.
D) Polio drops are given to children who are below 5 years, because polio virus cause infantile paralysis in children. Children are more vulnerable to the polio virus.
E) Polio drops prevent entry of polio virus into the child’s body and inhibit the paralysis.

Question 37.
You know that polio is a dangerous disease. What could be done to make the society polio free? Discuss in your class room about polio contamination and its prevention.
Answer:

• Polio is otherwise known as infantile paralysis.
• The virus enters the body along with food and water.
• It affects nervous system.
• The affected muscles do not function normally.
• Infected children cannot walk or stand without support. There will be reduction in the size of the limb muscles.
• To make society polio free, the disease can be prevented by oral vaccine called anti-polio drops given in early childhood.
• Every member in the society should educate with each other about cause and effect of the polio disease.
• Families with below 5 year old children should attend polio-drop vaccine programmes.

Question 38.
Write the live experiment of Dr. Edward Jenner on smallpox.
Answer:
Dr. Edward Jenner set up his medical camp in a small village. He keenly observed that the milkmaids who developed cowpox a less serious disease did not develop the deadly small pox. He thought they are developing immunity which is preventing small pox.

In 1796 Jenner took the fluid from a cowpox pustule on a dairy – maids hand and inoculated a 8 years old hoy with his parents permission.

Six weeks later, he exposed the boy to smallpox and the boy did not develop any symptoms of smallpox. This invention of smallpox vaccine saved millions of people from deadly disease.

Question 39.
Write the uses of microorganisms in soil fertility. (Appreciation)
Answer:

• Micro organisms like Rhizobium, Nostoc, Anabini, Azotohactor etc., help to provide proteins to the plants by fixing atmospheric nitrogen to form certain compounds.
• The micro organisms like fungi and bacteria present in the soil degrade biological wastes into small compounds which are essential for plants.

Question 40.
Now-a-days this word is widely used called B.T. Write a brief note on ¡t.
Answer:

• B.T. means Bacillus Thuringiensis is name of a bacterium.
• It produces a toxin which kills pests on plants or crops.
• The bacterium is used as biopesticides.
• In transgenic crop plants this toxin producing gene was seperated from the bacterium and transferred into the crop plants.
• So this can protect it from pests. Eg: B.T. cotton.

Question 41.
Two pots are taken. One Is filled with biological wastes (leaves, vegetable wastes, waste papers etc.) and the other is filled with polythene, plastic wastes. Both the pots are covered with some loose soil. Sprinkle water on both. Do this for 3-4 weeks. After 4th week open them. Write your findings.
Answer:
The pot with biological wastes showed some changes. The biological wastes turned into decomposing substance. It is decayed. There were no raw biological wastes. Whereas the plastic and polythene wastes in the other pot showed no change.

Question 42.
Write about any three methods of food preservation.
Answer:
We preserve food from spoilage. Certain types of methods are given below.

• Heat and cold method: Boiling helps in killing several types of micro organisms present in milk. We preserve fruits and vegetables and some other food items in the refrigerator.
• Pasteurisation : Milk is heated up to 70°C for 15 – 30 seconds and then suddenly chilled and stored. This prevents growth of most micro organisms.
• Storage and packing: Now-a-days, dry fruits and even vegetables are sold in sealed and air tight packets. which prevents the entry of microbes from outside. In addition to above methods there are some other methods like smoking, mechanical drying, salting etc.,

Question 43.
What are the uses of Preservation of food material?
Answer:
Preservation of food helps us, in the following ways.

• This prevents spoilage of food.
• We can preserve food for a longer period.
• Quality of food is preserved for a long time.
• A variety of food items may be available in far away places, in any season.

Question 44.
Which invention led to implementation of sterilization process? Explain. Write the use.
Answer:
Invention of pasteurisation led to the invention of sterilization process. In this process microbes are killed. Then the materials are kept in sterilisation chamber and heated upto very high temperature for 30 minutes.
Use: While doing operations doctors use sterilized instruments and other sterilized material which avoid infections to patient’s wounds.

Question 45.
Rajani added buttermilk to milk. But it does not turned into curd. Guess what is the reason.
Answer:
The milk, might be in cold condition or not boiled.

Question 46.
You know oral polio drops are used in eradication of Polio. To get more information about Vaccines what type of questions do you pose to a doctor.
Answer:

• What is the importance of Vaccines?
• Why Vaccines play a major role in immunity?
• What type of Vaccines are available?
• How are Vaccines prepared?

Question 47.
Read the table:

Plant disease	Causative Micro organism	Mode of transmission
Citrus-Canker	Bacteria	Air
Red rot-sugarcane	Fungi	Air, seedlings
Tikka-ground nut	Fungi	Air, seedlings
Tobacco Mosaic	Virus	Insects
Smut in paddy	Fungi	Air

1. Write the diseases which are transmitted through air.
Answer:
Citrus-canker, Smut in paddy, Red rot-sugarcane and Tikka disease.

2. Name the diseases caused by fungal.
Answer:
Red rot in sugarcane, Tikka disease in ground nut.

3. What are the ways to control of viral diseases?
Answer:
Killing infected plants using pesticides.

4. What would you do to prevent the transmission of diseases in plants?
Answer:
Using resistant varieties, maintaining crop – rotation methods.

Question 48.
What questions will you prepare about micro organism to ask in a quiz corn petition?
Answer:

• What are micro organisms?
• Can we see them with naked eye?
• Where do we find micro organisms?
• How do micro organisms help us?

Question 49.
A baker placed a pastry in bacillus less environment What changes might have observed after a day?
Answer:
Naturally bacillus bacteria spoil the food. If pastry is kept in environment where bacillus is not present, the pastry will remain unchanged and ready to eat.

Question 50.
Separate the useful and harmful micro organisms among the following in a tabular form:
Plasmodium, Lacto bacillus, Rhizobium, Penicillin, Yeast, Varus
Answer:
Useful micro organisms: Lacto bacillus, Penicillin, Yeast.
Harmful micro organisms: Plasmodium, Rhizohium, Virus.

Diagrams 

Question 1.
Draw the sketches of blue green algae (anabina) that you observed under microscope?
Answer:

Question 2.
Draw the diagrams of symptomatic pictures of any 2 diseases that you observe in Citrus and Sugarcane.
Answer:

Choose the correct answers :

Conceptual & Understanding

Question 1.
One of the scientists who did not find vaccine: ( )
A) Dr. Jonas Salk
B) Dr. Albert Sabin
C) Dr. Y. Subba Rao
D) Dr. Edward Jenner
Answer:
C) Dr. Y. Subba Rao

Question 2.
The other name of aureomycin: ( )
A) streptomvcin
B) tetracyclin
C) chloromycin
D) seomvcin
Answer:
B) tetracyclin

Question 3.
Rabies is caused by a microorganism: ( )
A) Virus
B) Fungus
C) Bacterium
D) Protozoan
Answer:
A) Virus

Question 4.
The vaccine for rabies disease is invented by ( )
A) Dr. Edward Jenner
B) Dr. A. Flemming
C) Dr. Salk
D) Louis Pasteur
Answer:
D) Louis Pasteur

Question 5.
Antibodies fight with ( )
A) body cells
B) tissues
C) disease causing microbes
D) All
Answer:
C) disease causing microbes

Question 6.
The bacterium used as biopesticide is ( )
A) Bacillus thuringiensis
B) Lactobacillus
C) Clostridium
D) Salmonella
Answer:
A) Bacillus thuringiensis

Question 7.
One of the following is not a viral disease: ( )
A) Common cold
B) Typhoid
C) Small pox
D) Swine flu
Answer:
B) Typhoid

Question 8.
House fly is the vector for the following: ( )
A) Cholera
B) Malaria
C) T.B
D) Both A and C
Answer:
D) Both A and C

Question 9.
Japanese Encephalitis is caused by ( )
A) bacteria
B) viruses
C) fungi
D) protozoa
Answer:
B) viruses

Question 10.
Malaria is caused by a micro organism ( )
A) Virus
B) Fungus
C) Protozoan
D) Algae
Answer:
C) Protozoan

II. Asking questions and making hypothesis

Question 11.
What happens if our surroundings are filled with stagnant water?
A) It produces foul smell
B) Mosquitoes breed
C) Diseases causing microbes may increase
D) All the above
Answer:
D) All the above

Question 12.
Kavita said “Spoiled food emits bad smell and tastes bad.” The reason is
1) Microbial activity
2) Colonies in the food
3) Toxic substances grow in the food
4) Moisture
A) 1,2,3 and 4
B) 1 and 4
C) 1,2,3
D) 2 and 3
Answer:
C) 1,2,3

III. Experimentation and field investigation

Question 13.
Given below are the steps to be followed for performing fermentation process: ( )
1) Take Sugar solution in two beakers
2) Add 2 spoons of yeast in two beakers
3) Close both the beakers with lids
4) Add 2 spoons of yeast to one of the beakers only Which one of the following sequences should the students follow to get the correct result?
A) 1,4,2,3
B) 1,4,3
C) 1,2,3,4
D) 1,2,4
Answer:
B) 1,4,3

Question 14.
The apparatus required to perform the activity of milk conversion into curd:
A) Lukewarm milk, bowl, butter milk, lid
B) bowl, butter milk, lid and hot milk
C) Lukewarm milk, bowl, lid
D) Cold milk, bowl, butter milk, lid
Answer:
A) Lukewarm milk, bowl, butter milk, lid

IV. Information skills and Project

Read the following Table and answer the following.

Name of the Disease	Causative microorganism	Mode of Transmission	Preventive measures
Measles, mumps	Virus	Air	Vaccination (MMR)
Cholera, Typhoid	Bacteria	Contaminated water & food Housefly (vector)	Personal hygeine, Drink boiled and cooled water
Malaria	Parasite	Anapheles mosquitoes (vector)	Control mosquitoes, Use mosquitoes nets, repellents
Swine flu	Virus	Air	Vaccination
Tuberculosis	Bacteria	Air	Vaccination (BCG) Aviod infected persons

Question 15.
Vector borne disease is ( )
A) tuberculosis
B) polio
C) malaria
D) measles
Answer:
C) malaria

Question 16.
BCG vaccine is used to prevent ( )
A) T.B.
B) malaria
C) swine flu
D) typhoid
Answer:
A) T.B.

Question 17.
From the above table, the diseases which transmit through air are ( )
A) measles, mumps
B) measles, swine flu, tuberculosis
C) malaria, cholera, typhoid
D) None of the above
Answer:
B) measles, swine flu, tuberculosis

Question 18.
Causative microorganism for malaria ( )
A) Bacterium
B) Parasite (plasmodium)
C) Virus
D) Culex
Answer:
B) Parasite (plasmodium)