Microorganism- friend and foe

Microorganism- friend and foe

class 8

Microorganisms

Microorganisms- The living organism around us that normally cannot seen with the naked eyes are known as Microorganisms or Microbes.

Microorganism can be seen with the help of magnifying glass or microscope.

Classification of Microorganism-

• Bacteria- lactobacciluss, E.Coil etc

• Fungi-Chlamydomonas, Spirogyra etc

• Protozoans- Amoeba, Paramaecium etc

• Algae-Bread mould, Penicillium, Aspergilles etc

• Viruses

Viruses

• Viruses are also considered as microorganisms

• They are different from other microorganisms because they reproduce only in the body of host organisms like bacteria, plants or animals

• Example : covid19 viruses etc

• Virus is smallest microorganism on earth

• Common aliments like cold, influenza (flu) and most coughs are also caused by viruses.

Multiple Choice

Amoeba belongs to

• Algae

• Fungi

• Virus

• Protozoa

Multiple Choice

Mushroom belongs to

• Algae

• Virus

• Fungi

• None of the above

Multiple Choice

What do you think microbe means ?

• A microorganism, or microbe, is a microscopic organism, which may exist in its single-celled form or in a colony of cells.

• It is a thing that enters the human body or an animal .

• It is an insect

• It is something that we found it in the ocean

Multiple Choice

What science tool is used to view organisms too small to see with a magnifying lens?

• telescope

• binoculars

• microscope

• netherscope

Multiple Choice

Cold, influenza and most cough are caused by ___?

• Bacteria

• Viruses

• Fungi

• None of these

Multiple Choice

The smallest microorganism on earth is known as  _____________

• a virus
• bacteria
• algae
• fungi

Multiple Choice

A tiny, nonliving particle that invades and then reproduces inside a living cell.

• Bacteria
• Virus
• Protist
• Fungi

Microorganism- friend

• Making of curd from milk: The bacterium called Lactobacillus reproduces in milk and helps to convert into curd.

• Making bread: The fungus called yeast reproduces in flour dough and produce carbon dioxide during respiration which makes the dough soft and helps in making bread, cakes, biscuits, pastries etc

Commercial use of microorganism

• Microorganism are used for the large scale production of alcohol, wine, and vinegar. Yeast used for commercial production of alcohol and wine.

• The process of conversion of sugar into alcohol is known as fermentation.

• louis Pasteur discovered fermentation in 1857

Medicinal use of Microorganisms

• Making Antibiotics that produced from bacteria and fungi. Streptomycin, tetracyline, penicillin and erythromycin are some of the commonly known antibiotics.

• The medicines kill or stop the growth of the disease- causing microorganisms.

• Alexander Fleming discovered penicillin.

• Making Vaccine.

• Edward Jenner discovered the vaccine for small pox in 1788

Increasing soil fertility

• Some bacteria and blue green algae are able to fix nitrigen from the atmosphere to enrich soil with nitrogen and increase its fertility. These microbes are commonly called biological nitrogen fixers

Cleaning the environment

• You often see large amounts of dead organic matter in the form of decaying plants and sometimes dead animals on the ground. You find that they disappear after sometime. This is because the microorganisms decompose dead organic waste of plants and animals coverting them into simple substances.

Multiple Choice

The algae that fixes atmospheric nitrogen from air and thus enriches the soil with nitrogenous compound for plants is

• Blue green algae

• Chlorella

• Diatoms

• Chlamydomonas

Multiple Choice

Yeast makes bread, rolls and cakes rise.

• True
• False

Multiple Choice

A preparation of weakened or killed pathogens.

• Bacteria
• Antibiotic Resistance
• Vaccine
• Capsid

Multiple Choice

Who discovered Fermentation ?

• Edward Jenner

• Alexander Fleming

• Louis Pasteur

• Selman Waksman

Multiple Choice

The process of conversion of sugar into alcohol is known as ...

• Budding

• Fusion

• Fermentation

• Fixation

Multiple Choice

Antibiotics

• kill disease-causing microorganisms

• slow down the growth of disease-causing microorganisms

• convert sugar into alcohol

• speed up the growth of micoorganisms

Multiple Choice

Fungi is beneficial to us beacause of the following reason

• They are a source of oxygen

• They can clean up pollution

• They are a source of antibiotics

• They help to clean run off from waste

Multiple Choice

Who discovered vaccine for smallpox?

• Robert Koch

• Edward Jenner

• Louis Pasteur

• Alexander Fleming

Multiple Choice

Penicillin was discovered by

• Edward Jenner

• Louis Pasteur

• Alexander Fleming

• Robert Brown

Harmful Microorganism

• Microorganisms are harmful in many ways. Some of the microorganisms cause diseases in human beings, plants and animals. Such disease-causing microorganisms are called pathogens.

Multiple Choice

Are microorganisms helpful or harmful?

• Helpful
• Harmful
• Both
• Neither

Multiple Choice

Gas that makes up almost 78% of Earth's atmosphere

• Oxygen

• Carbon dioxide

• Nitrogen

• Hydrogen

Multiple Choice

Organism that breaks down dead plants & animals and releases nitrogen back into atmosphere

• Bacteria

• Plants

• Animals

• Producers

Multiple Choice

How nitrogen is "fixed" into useable form for plants

• Only through action of bacteria

• Only through lightning

• Through action of bacteria & lightning

• Through photosynthesis

Multiple Choice

Which of these is an example of an antibiotic?

• Pencillin

• Tylenol

• Advil

• Tumms

Multiple Choice

Nitrogen-fixing bacteria are important because...

• They are decomposers

• They are salt lovers

• They provide protection for plants from diseases

• They make nitrogen available to plants in form they can use

Multiple Choice

_________________ bacteria are in your _________________ to help digest food.

• Helpful; throat

• Helpful; stomach

• Harmful; esophagus

• Harmful; lungs

Multiple Choice

A student sets up a compost bin outdoors. Inside the bin microorganisms convert the student’s vegetable and paper scraps into rich fertilizer. Which of the following best describes the role that these microorganisms play in natural habitats?

• The microorganisms help balance the numbers of producers and consumers.
• The microorganisms help keep nutrients cycling through the ecosystem.
•  The microorganisms turn solar energy into sugars.
• The microorganisms function as autotrophs.

Multiple Choice

Turberculosis is a disease that was widespread during the turn of the century.  This disease is an example of.....

• A helpful bacteria
• A helpful fungi
• A harmful bacteria
• A harmful probiotic

Multiple Choice

Which is not an example of a harmful microorganism?

• Mold growing on a kitchen sponge

• Bacteria found in yogurt

• Bacteria that causes turberculosis

• Salmonella on uncooked chicken

Multiple Choice

Which of the following statements are true?

• All microorganisms are bad
• All microorganisms are good
• Some microorganisms are harmful, while some can be helpful
• Microorganisms are too small to do anything to anyone

Multiple Choice

Which of the following is an example of a harmful microorganism?

• Fungi used as antibiotics
• Ecoli on food that makes people sick
• Bacteria found in yogurt.
• Microorganisms helping dead matter to decay

Multiple Choice

Rhizobium bacteria

• Help in Digestion

• Help in nitrogen fixation

• Cause diseases

• All the above

Multiple Choice

Diseases anthrax caused by

• Virus

• Bacteria

• Fungi

• None of these

Multiple Choice

Female Aedes mosquito is the carrier of

• Corona virus

• Dengue virus

• Common cold virus

• Measles virus

Multiple Choice

Plant diseases rust of wheat is caused by

• Bacteria

• Virus

• Fungi

• Protozoa

Multiple Choice

The most common carrier of communicable diseases is

• Ant

• Housefly

• Dragonfly

• Spider

Multiple Choice

Cholera is caused by

• Bacteria

• Protozoa

• Virus

• Fungi

Multiple Choice

Carrier of malaria causing protozoan is

• Female Anopheles mosquito

• Cockroach

• Housefly

• Butterfly

Multiple Choice

The algae that fixes atmospheric nitrogen from air and thus enriches the soil with nitrogenous compound for plants is

• Blue green algae

• Chlorella

• Diatoms

• Chlamydomonas

Multiple Choice

Food preservation can not be done by

• adding salt

• adding sugar

• drying under the sun

• adding kerosene

Multiple Choice

The microorganisms that cause diseases in human beings, plants and animals are called _

• Carriers

• Spirogyra

• Pathogens

• Antibodies

Multiple Choice

Conversion of nitrogen to ammonia is

• nitrification

• phosphorylation

• denitrification

• nitrogen fixation

Multiple Choice

Consumption of food spoiled by some micro-organisms causes ____.

• Food-poisoning

• Cancer

• Lungs

• None of these