Microorganisms and Bacteria Characteristics

Microorganisms 🦠

• Microorganisms are tiny living organisms that are too small to be seen with the naked eye and can be found almost everywhere, including extreme environmental conditions.
• They can survive in extreme heat or cold, form a hard outer covering called a cyst, and be beneficial or harmful to humans.

Where are Microorganisms Found?

• Microorganisms can be found in rocks, soil, water, air, deep inside the Earth, boiling hot springs, frozen glaciers, dry deserts, deep sea, homes, schools, and on the touchpad of mobile phones.

Classification of Microorganisms

• Microorganisms can be classified into five main types: Bacteria, Algae, Fungi, Protozoa, and Viruses.
• Each type has distinct characteristics, such as:
  • Bacteria: unicellular, single-celled, tiny organisms that live together in colonies.
  • Algae: simple plant-like organisms with cell walls, capable of photosynthesis.
  • Fungi: non-green organisms with bodies made of thread-like structures called hyphae.
  • Protozoa: unicellular organisms that have animal-like characteristics, lacking cell walls.
  • Viruses: extremely tiny organisms that can only be seen with an electron microscope, with characteristics of both living and non-living things.

Characteristics of Microorganisms

• Bacteria: shapes include spiral, spherical, rod-shaped, and comma-shaped; sizes range from 0.2 to 2 microns.
• Algae: types include unicellular (microalgae) and multicellular (macroalgae); examples include Chlamydomonas, Volvox, Fucus, and Spirogyra.
• Fungi: types include saprophytic and parasitic; examples include yeast, Rhizopus, Agaricus, and Penicillium.
• Protozoa: examples include Paramecium, Trypanosoma, and Amoeba.
• Viruses: examples include influenza virus, poliovirus, and bacteriophage.

Useful Microorganisms

• Microorganisms are useful in the food industry, medicine, and agriculture.
• Examples of useful microorganisms include those that:
  • Ferment food, such as making bread, dosas, idlis, and dhoklas.
  • Make antibiotics and vaccines.
  • Make fertilizers and control pests.

Harmful Microorganisms

• Microorganisms can cause diseases in humans, plants, and animals.
• Pathogens or germs are microorganisms that cause diseases.
• Examples of diseases caused by microorganisms include:
  • Cholera, typhoid, hepatitis, common cold, chicken pox, tuberculosis, and AIDS.
  • Vector-borne diseases such as malaria, dengue fever, and typhoid.

Force

• A force is a push or pull that affects an object in some way.
• The SI unit of the magnitude of force is the newton (N).
• Forces can:
  • Make a stationary object move.
  • Change the speed of a moving object.
  • Stop a moving object.
  • Change the direction of a moving object.
  • Change the shape of an object.

Types of Force

• Contact force: a force that requires physical contact between objects.
• Non-contact force: a force that arises due to interaction between objects that are not in physical contact.
• Examples of forces include:
  • Muscular force: a force that requires the action of muscles.
  • Frictional force: a force that opposes motion.
  • Mechanical force: a force generated by a machine.
  • Gravitational force: a force of attraction between objects.
  • Magnetic force: a force that arises due to the interaction between magnets or magnetic fields.
  • Electrostatic force: a force that arises due to the interaction between charged particles or objects.

Pressure

• Pressure is the force exerted per unit area on an object.
• The SI unit of pressure is the pascal (Pa).
• Pressure is calculated by dividing the force by the area over which the force is acting.
• Factors that affect pressure include:
  • The force acting on the surface.
  • The area over which the force is acting.

Physical Properties of Metals and Non-Metals

• Metals:
  • Have high melting and boiling points.
  • Are good conductors of heat and electricity.
  • Are malleable and ductile.
  • Are shiny and lustrous.
• Non-Metals:
  • Have low melting and boiling points.
  • Are poor conductors of heat and electricity.
  • Are brittle and non-malleable.
  • Are dull and non-lustrous.

Classification of Elements

• Elements are classified into three categories: Metals, Non-Metals, and Metalloids.
• Metalloids are elements that have some properties of metals and non-metals.
• Examples of metalloids include Boron, Silicon, Tellurium, Germanium, Arsenic, and Antimony.

Uses of Metals

• Metals are used in various applications, such as:
  • Alloys: a mixture of two or more metals or metals and non-metals.
  • Examples of alloys include Brass, Bronze, Solder, Stainless Steel, Magnalium, and Duralumin.
• Non-metals are also used in various applications, such as:
  • Graphite: used in making electrodes and crucibles.
  • Phosphorus: used in the match industry and in the manufacturing of fireworks.
  • Sulphur: used in vulcanizing rubber.
  • Copper and Aluminium: used to make electrical wires.
  • Lead: used to make paints.
  • Silicon: used in thermometers.
  • Nitrogen: used in the manufacturing of fertilizers.
  • Gold: used in various applications, but not in making machine tools due to its high cost and low strength.### Pressure
• Pressure is the force per unit area exerted by an object on another object.
• Pressure (P) = Force (F) / Area (A)
• The SI unit of pressure is N/m² or Pa (Pascal).
• Pressure is directly proportional to the force applied on the surface.
• Pressure is inversely proportional to the area of contact of a surface.

Applications of Pressure

• We use a sharp knife to cut things rather than a blunt knife because the edge of a sharp knife has a very small area of contact, producing a very large pressure with a small applied force.
• Various objects such as board pins, needles, and nails have pointed ends, reducing the area of contact and making it easier for these objects to penetrate the targets.
• High-rise buildings have wide foundations to reduce the pressure on the ground.
• Wooden/concrete sleepers are used below railway tracks to reduce the pressure exerted by rails on the ground.
• School bags have wide straps to increase the surface area of contact and reduce the pressure exerted on the shoulders by the weight of the bag.
• Tractors have broad tyres to reduce the pressure on the ground and prevent sinking on soft ground.

Pressure Exerted by Liquids

• Liquids exert pressure on the base due to their weight.
• Liquids exert pressure on the walls of the container in which they are kept or enclosed.
• Liquid pressure varies with depth.
• The pressure exerted at different points at the same depth is equal.

Measurement of Liquid Pressure

• Manometer is used to measure liquid pressure.

Implications of Liquid Pressure

• Deep sea divers need to wear specially designed suits to withstand the enormous liquid pressure at great depth.
• In submarines, the hulls have to be specially strengthened to withstand the liquid pressure at great depth.
• The bottom of a dam is made thicker than its top to withstand the large liquid pressure at the bottom of a dam.

Pressure Exerted by Gases

• Gases exert pressure on the walls of the container in which they are confined.
• Gases exert pressure on the inner surface of a container, causing it to inflate.
• Atmospheric pressure is the force per unit area exerted by the weight of the air.

Atmospheric Pressure

• The atmospheric pressure is maximum at the surface of the earth and decreases as we go to higher altitudes.
• Our bodies are well adapted to withstand atmospheric pressure.
• Atmospheric pressure is the force exerted by the weight of the atmosphere over a unit area.
• Atmospheric pressure is measured by an instrument called a barometer.

Factors Affecting Atmospheric Pressure

• Height: Atmospheric pressure decreases with an increase in height above sea level.
• Location: Atmospheric pressure varies with location.

Measuring Atmospheric Pressure

• A barometer is used to measure atmospheric pressure.
• The basic principle of the barometer is to use atmospheric pressure to balance a vertical column of mercury sealed at the top.

Units of Atmospheric Pressure

• 1 atmosphere (atm): The pressure equivalent to the 76 cm column of mercury, approximately 1.013 × 10^5 N/m².

The Magdeburg Experiment

• In 1657, Otto von Guericke conducted an experiment to demonstrate the concept of atmospheric pressure.
• He took two identical metallic hemispheres with smooth edges, pumped out the air from inside to create a vacuum, and eight horses pulled the hemispheres from each side, but they could not separate them, proving the immense pressure exerted by the atmosphere.

Key Concepts

• Liquid Pressure: Force exerted by a liquid over a unit area.
• Barometer: Instrument used for measuring atmospheric pressure.
• Manometer: Instrument used for measuring liquid pressure.
• Force: A push or a pull that tends to affect an object in some way.
• Pressure is force applied on a surface per unit area.

Metals

• Uses of metals: Copper and aluminum are used to make electrical wires, iron is used to make utensils, buildings, and bridges, etc.
• Iron is used extensively for making magnets and steel is used for the construction of buildings and bridges.

Non-Metals

• Uses of non-metals: Nitrogen is used in the manufacturing of fertilizers, phosphorus is used in the match industry, etc.

Alloys

• Alloys are mixtures of two or more metals or a metal and a non-metal that have immense applications due to their better characteristics than their individual components.

Reactivity Series and Displacement Reaction

• Reactivity Series: The arrangement of metals in the order of their decreasing reactivity.
• Displacement Reaction: A more reactive metal displaces a less reactive metal from its salt solution.

Reaction with Water and Dilute Acids

• Reaction with Water: Metals react with water to produce metal oxide (or metal hydroxide) and evolve hydrogen gas.
• Reaction with Dilute Acids: Metals react with dilute acids to form a salt with evolution of hydrogen gas.

Reaction of Non-Metals with Oxygen

• Non-metals such as carbon, sulphur, and phosphorus, burn in the presence of oxygen to form their corresponding oxides.

Reaction of Non-Metals with Water

• Non-metals do not generally react with water.
• Oxygen dissolves in water in very less amount, which ensures the sustenance of aquatic living organisms as their lives depend on the oxygen which dissolved in water.
• Chlorine, another non-metal, dissolves in water to form an acidic solution.

Corrosion and Rusting

• Corrosion is the process where a metal gets eaten away due to a chemical reaction in the presence of atmospheric gases and moisture.
• Iron metal is slowly oxidized to produce rust (iron oxide) in the presence of moist air.
• Similarly, copper articles develop a greenish coating of basic copper carbonate on exposure to air.

Learn about the characteristics of microorganisms, types of bacteria, and their survival mechanisms. Discover how microorganisms form hard outer coverings and adapt to harsh conditions.