chemical reaction:
It is a process that always results in the interconversion of chemical substances.[1] The substance or substances initially involved in a chemical reaction are called reactants. Chemical reactions are usually characterized by a chemical change, and they yield one or more products, which usually have properties different from the reactants. Classically, chemical reactions encompass changes that strictly involve the motion of electrons in the forming and breaking of chemical bonds, although the general concept of a chemical reaction, in particular the notion of a chemical equation, is applicable to transformations of elementary particles, as well as nuclear reactions.
Different chemical reactions are used in combination in chemical synthesis in order to get a desired product. In biochemistry, series of chemical reactions catalyzed by enzymes form metabolic pathways, by which syntheses and decompositions ordinarily impossible in conditions within a cell are performed.
Types Of Chemical Reactions:
1)Combination Reaction:
It is a cChemical Reaction in which 2 or more substances combine to form a single substance.
2)Decomposition Reaction:
It is a reaction in which a compound is decomposed into smaller compounds or elements: Eg: 2 H2O → 2 H2 + O23)Displacement Reaction:
It is characterized by an element being displaced out of a compound by a more reactive element: Eg: 2 Na(s) + 2 HCl(aq) → 2 NaCl(aq) + H2(g)4)Double Displacement Reaction:
It is a reaction in which two compounds exchange ions or bonds to form different compounds: Eg: NaCl(aq) + AgNO3(aq) → NaNO3(aq) + AgCl(s)5)Redox Reaction:
It is a reaction in which oxidation and redution takes place simontaneously.
Eg: 2 S2O32−(aq) + I2(aq) → S4O62−(aq) + 2 I−(aq)6)Neutralization Reaction:
It is a reaction in which acid reacts with base to form salt and water.
Eg: NaoH+Hcl→Nacl+H2O.7)Isomerisation Reaction:
It is a reaction in which a chemical compound undergoes a structural rearrangement without any change in its net atomic composition; see stereoisomerismBiology:
Our Environment:
Environment- natural surroundings and external conditions of an organism, which
include all living and non-living factors that affect the organism
Organism- is the basic unit of an ecological hierarchy, can be unicellular such as
Amoeba and paramecium or multicellular such as humans
Population- a group of individuals of the same species inhabiting a given
geographical area at a particular time and functioning as a unit
Community- includes all individuals of different species living within a certain
geographical area
Ecosystem- includes both living and non-living components of an area
Components of an ecosystem
Abiotic factors- light, temperature, water, air etc.
Biotic factors- living organisms
Autotrophs- organisms that can manufacture their own food from inorganic
raw materials, also known as producers
Heterpotrophs- cannot synthesize their own food, are dependent on other
organisms
Herbivores- feed only on plants e.g., deer, horse, sheep etc.
Carnivores- eat other animals e.g., frog, cat, spider etc
Omnivores- feed on both plants and animals e.g. bear, monkey, man etc.
Decomposers- obtain nutrients by breaking down remains of dead plants and
animals, includes some bacteria and fungi
Functions of an ecosystem:
productivity- rate of production of organic matter (food) by producers
decomposition- breakdown of organic matter or biomass with the help of
decomposers
Energy flow through an ecosystem
Trophic level - level of species in an ecosystem on the basis of the source of
nutrition
Producers- form the first trophic level, they manufacture food
trophic levels are connected through food chains
Food chain- a linear sequence of organisms in which each organism is eaten by
the next member in the sequence e.g.,
plants grasshopper frog snake eagle
Food web- interconnected network of food chains
10% law of energy transfer- only 10% energy is transferred from a lower
trophic level to a higher trophic level, which means that energy keeps on
decreasing as one moves up different trophic levels
Biomagnification- increase in the concentration of pollutants or harmful
chemicals with each step up in the food chain
Human influence on the environment:
Global warming- increase in the average temperature of the Earth’s surface
Greenhouse gases- CO2, CH4, O3, CFCs etc.
Ozone layer- present in the stratosphere, absorbs ultraviolet radiations
Ozone layer is getting depleted due to an increased concentration of chlorine
in the atmosphere- 3 2 Cl O ClO O
Biodegradable wastes- produced mainly from plant and animal sources,
which can be broken down by living organisms
Non-biodegradable wastes- includes wastes such as plastic, metals etc.,
which cannot be broken down by living organisms
BY PASS SURGERY (STENT) :
