Science Answer the following question.

• Clostridium are the bacteria that spoil food.
• Out of about 100 different species of this bacterium, some are free living in the soil whereas some live in the alimentary canals of humans and other animals.
• These bacteria are rod-shaped and produce bottle-shaped endospores in adverse conditions.
• One special characteristic of these bacteria is that they cannot withstand the normal oxygen level of the air because they grow in anaerobic conditions.

• Bio-remediation is a technique that involves the use of organisms to break down environmental pollutants.
• Generally, fungi like yeast and bacteria are used for bio-remediation.
• A yeast, Yarrowia lipolytica is used to absorb the toxins released during the production of palm oil and the heavy metals and minerals released in some other industrial processes.
• Saccharomyces cerevisiae is used for absorption of a pollutant, arsenic.
• Oil spills in oceans are cleaned with the help of Alcanivorax bacteria.

• Nowadays, seeds are coated with rhizobial solution or powder before sowing.
• After sowing, Rhizobia enter the plantlets.
• This is called Rhizobial inoculation.
• This experiment has helped in the supply of nitrogen to cereal and other crops, besides leguminous crops.

• They are the smallest organisms on earth.
• They are composed of prokaryotic or eukaryotic cells.
• They can be seen only with the help of a microscope.
• They are found in any kind of environment ranging from coolest polar regions to hottest of deserts. Also found in soil, water and air.
• Some of them are useful, whereas some of them are harmful micro-organisms.

• Lichen is a symbiotic association between a fungus and an algae (Cyanobacterium).
• Lichens are sensitive to environmental disturbances and are used in assessing air pollution in an area.
• Lichens are also used in making dyes, perfumes and in traditional medicines.
• A few lichen species are eaten by insects or animals such as reindeer.

• Fungi decompose the bodies of dead animals and convert them into simple carbon compounds. These substances easily mix with air, water and soil from where they are again absorbed by plants and enter the food chain.
• Some fungi living in symbiotic association with plants help to absorb water and inorganic compounds like nitrate and phosphate.
• Fungi are also used to derive antibiotics like penicillin which are useful to animals.
• Ants grow fungi in their anthill and obtain food from it.
• Some species of wasps and insects lay their eggs in the fungal bodies growing on trees, thus ensuring a food supply for their larvae.

• Nashik in Maharashtra is the leading grape producer in the country as it has the soil suitable for the production of grapes.
• Glucose and fructose, the sugars present in grape juice are fermented with the help of yeast to produce wines. Therefore, wineries are located near Nashik in Maharashtra.

• Symbiosis is a mutually beneficial relationship.
• Example: Rhizobium living in root nodules of leguminous plants supply nitrates, nitrites and amino acids to that plant and in exchange get energy in the form of carbohydrates.

• Smear a drop of fresh buttermilk on a glass slide.
• Stain it with methylene blue and put a coverslip over it.
• Observe the smear under the 10X objective of a compound microscope and then with the more powerful 60X objective.
• The blue rod-shaped organisms moving about are Lactobacilli.

• Bread is made using flour, yeast, salt and water. The yeast uses sugar as food.
• In the process of obtaining nutrition, yeast cells convert the carbohydrates into alcohol and carbon dioxide. This process is called fermentation.
  
  
• The bubbles of carbon dioxide given off cause the dough to rise.
• This dough can be used to make bread.
• When this dough is baked, more bubbles of carbon dioxide reformed due to heat. As the gas escapes, the bread rises and becomes soft and fluffy.

• Citrus canker is a bacterial disease that affects 1 trees of citrus fruits.
• Rust of wheat is a fungal disease that affects wheat crops.
• Yellow vein mosaic is a viral disease which affects vegetables like bhindi (okra).

Preventive Measures:

• Seeds which are healthy and disease-free should be selected for sowing.
• Infected plants should be removed.
• Plants should be sprayed with fungicides and germicides to prevent diseases.
  

  Animal diseases:

  • Anthrax is a disease that affects cattle. It is caused by a bacterium.
  • Foot and mouth is a dangerous disease in cattle caused by a virus.
  • Rabies is a viral disease that affects animals.

  Preventive Measures:

  • The place where animals are kept should be washed with germicides.
  • Animals should be dewormed regularly.
  • The animals should be treated with necessary antibiotics for infectious diseases.
  • They should be regularly vaccinated.
  • Take the animals to a veterinary hospital for proper treatment and vaccination.

• Salt acts as a preservative. It prevents the growth of bacteria by forcing the microbes to lose water by osmosis. Hence, salt is applied on the inner surface of pickle jars.
• Pickle is covered with oil as oil acts as preservative. It seals off the air from the item that is being pickled and provides an environment in which microbes cannot grow.

• The chapatti dough has water, which on heating converts into steam and tries to escape.
• While doing so, it lifts up the upper layer of the chapatti. Therefore, the chapatti swells up.
• Bread is made by adding yeast to the flour.
• In the process of obtaining nutrition, the yeast cells convert the carbohydrates into alcohol and carbon dioxide.
• When this dough is baked, the carbon dioxide escapes out making the bread spongy, soft and easy to digest.

• Ethanol is a smokeless and high quality fuel. So it helps to reduce pollution when mixed with petrol or diesel.
• As petrol or diesel is a fossil fuel less consumption of it will lead to resourceful use of it and making the country self-efficient by moving towards sustainable fuel like ethanol.

• The Lactobacilli present in yoghurt or buttermilk help to restore the natural microbial flora in the intestine, thus helping in digestion and absorption of nutrients.
• Also buttermilk helps to cool down the stomach and works as a laxative to ease the congestion during abdominal discomfort.

• Spores of fungi can germinate when there is sufficient moisture.
• During summer or winter the weather is hot and dry and so fungus cannot grow in such weather.
• Also microbes cannot survive extreme hot or cold temperatures of summer or winter. Therefore, these articles do not get spoilt during summer or winter.

• A black powder or white disc floating on the pickle or murabba are fungi.
• Different fungal species depend on host (pickle and murabba) for their growth and reproduction.
• During this process, fungi secretes mycotoxins which are poisonous chemicals; which ultimately spoil the food. Consuming such food can cause food poisoning.
  
  
• Therefore, such food items are not good to eat.

• Milk contains sugar called lactose which is broken down with help of Lactobacilli.
• Lactobacilli converts lactose into Lactic Acid. This process is called fermentation. As a result, the pH of milk decreases causing coagulation of milk proteins.
• Thus, milk proteins are separated from other constituents of milk and milk changes to yoghurt.

• Pathogens are microbes which can cause diseases in us.
• For the preparation of a vaccine, a particular pathogen is cultured and grown in a laboratory.
• If these pathogens are not safely stored, they many get modified due to environmental factors, resulting in decrease in the efficiency of the vaccine.
• Also, the live pathogens may escape and cause diseases in us.

• Vaccines are made using the disease causing bacteria or virus but in a form that will not harm the human beings.
• Vaccine is made from dead or weakened microbes or their toxins.
• Vaccine stimulates the immune system to produce antibodies which give life-long protection against the disease.
• There are specific vaccines for specific diseases.

• Hepatitis A and B, DTP (Diphtheria, Tetanus, Pertussis.) Polio, MMR (Measles, Mumps, Rubella), Chicken pox, Influenza, Tetanus, BCG, Rotavirus, etc.
• Vaccines consist of dead or weakend microbes. When these are swallowed or injected, the body produces antibodies to fight them.
• These antibodies remain in the body and protect it from any future attack of the disease causing microbes.
• Therefore, vaccines are given to infants for preventing diseases.

• Carbon compounds obtained from some bacteria and fungi for destroying or preventing the growth of harmful micro -organisms are called antibiotics.
• Antibiotics, a discovery of the 20th century, have brought a revolution in the field of medicine.
• Antibiotics mainly act against bacteria. Some antibiotics can destroy protozoa.
• Some antibiotics are useful against a wide variety of bacteria they are called broad-spectrum antibiotics. Examples – Ampicillin, amoxicillin, tetracycline, etc.
• When the pathogen cannot be identified even though the symptoms of the disease are visible, broad-spectrum antibiotics are used.
  
  
• Whenever a pathogenic micro-organism is definitely known, then narrow-spectrum antibiotics are used. Examples: Penicillin, gentamycin, erythromycin, etc.

• Yeast uses sugar for food.
• Yeast grows and multiplies rapidly due to the carbon compounds in the sugar solution.
• In the process of obtaining nutrition, yeast cells convert the carbohydrates in the food into alcohol and carbon dioxide.
• Also, the bacteria Lactobacilli convert lactose, the sugar in milk into lactic acid.
• This process is called fermentation.