The Living World
Building blocks of life and their functions:
Living organism is formed of many types of inorganic as well as organic
biomolecules. Inorganic compounds include water, minerals etc. and are
always micro-biomolecules (small sized, low molecular weight, readily soluble
in water and diffusible) while organic molecules may be micro (e.g.
monosugars, amino acids etc.) or macrobiomolecules (large sized, high
molecular weight, insoluble or slightly soluble and non-diffusible e.g., proteins,
fats, nucleic acids, etc.). These both types of biomolecules play imp ortant roles in metabolism:
• Role of Water: Water forms 70-90% of the cellular pool. It forms 65% (about two-thirds) of
human body. It is formed of H and O in the ratio of 2:1. 95% of water is found in free state and 5%
in combined form in the cell. Water helps in sustaining the life processes. So water is called elixir or
cradle of lip as life is not possible in the absence of water.
• Role of Oxygen : Oxygen is mainly utilized in aerobic cell respiration of the nutrients i nside the
mitochondria to produce energy-rich ATP molecules so is essential for life. In the absence of oxygen,
only 5% of energy available is released.
• Role of Sodium chloride (common salt): Sodium chloride plays an important role in
metabolic functions of body especially when in ionic form.
• Role of Carbohydrates: Carbohydrates are organic compounds formed of C, H and O
generally in the ratio of 1:2:1. These are commonly called saccharides (Gk. saccharon = sugar)
Carbohydrates are the main storage molecules and most organisms use carbohydrates as an important
fuel, breaking these bonds and releasing energy to sustain life.
• Role of Proteins : Proteins are polymeric compounds formed by interlinking of amino acids
(monomers) by peptide bonds. Out of about 100 types of amino acids, only 20 types of amino acids
are of biological importance, so are called Magic 20. Proteins play a vital role in the formation of
structures in living organisms. Like carbohydrate and fat protein can be broken down with the release
of energy. Protein is not stored as such in the body and it is normally only used as a substantial
source of energy in conditions of starvation.
• Role of lipids: Lipids comprise a major group of insoluble hydrocarbons having many functions.
These are polymers of alcohols (e.g. glycerol) and fatty acids interlinked by ester bonds. Complex
lipids such as true fats are important organic molecules that are used to provide energy. Fats in
animals also provide protection from heat loss.
• Role of Nucleic Acid: These are polymers of nucleotides interlinked by phosphodiester
bonds, so called polynucleotides. Each nucleotide is formed of 3 components: a pentose sugar (e.g.
ribose in RNA and deoxyribose in DNA), a phosphate group and an inorganic nitrogen -base (a
purine or a pyrimidine).
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, DNA acts as genetic material in most organisms and controls the synthesis of structural and. functional
proteins. RNA also act as genetic material in all plant viruses e.g. TMV and helps in protein synthesis.
Systematics
1. The term ‘Systematics’ was proposed by Linnaeus in 1735.
2. It includes description of external morphological characters of plants or living organisms.
E.g., morphological characters of root, stem, leave, flowers.
3. New systematics or Neo systematics or Biosystematics is a new branch. Its
name was given by Julian Huxley (1940).
4. The term taxonomy was coined by A. P. de Candolle.
5. Carolus Linnaeus is called the father of taxonomy.
6. H. Santapau is called the father of Indian taxonomy.
7. Taxonomy is of 3 types:-
• Alpha taxonomy- Only morphological characters are used for identification and
classification of plants.
• Beta taxonomy- Involves genetical, anatomical, cytological, palynological,
physiological and other characters.
• Omega taxonomy - Analysis and synthesis of all information and types of data to
develop classification system based on phylogenetic relationship.
8. Cytotaxonomy – The use of cytological characters of plants in classification or in solving taxonomic
problems is called cytotaxonomy.
9. Chemotexonomy – The use of chemical compounds present in plants for classification or in solving
taxonomic problems is called chemotaxonomy or chemical taxonomy. The basic chemical compounds
used in chemotaxonomy are alkaloids, carotenoids, tannins, polysaccharides, nucleic acids, fatty acids,
aromatic compounds etc.
10. Karyotaxonomy – It is based on the characters of nucleus and chromosomes. Pattern of chromosomal
bands (dark bands and light bands) is most specific character for classification of organisms.
Nomenclature
1. Nomenclature is giving distinct scientific names to various structures including living organisms for
their identification.
2. The names are of two types – vernacular (common name) and scientific names.
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Building blocks of life and their functions:
Living organism is formed of many types of inorganic as well as organic
biomolecules. Inorganic compounds include water, minerals etc. and are
always micro-biomolecules (small sized, low molecular weight, readily soluble
in water and diffusible) while organic molecules may be micro (e.g.
monosugars, amino acids etc.) or macrobiomolecules (large sized, high
molecular weight, insoluble or slightly soluble and non-diffusible e.g., proteins,
fats, nucleic acids, etc.). These both types of biomolecules play imp ortant roles in metabolism:
• Role of Water: Water forms 70-90% of the cellular pool. It forms 65% (about two-thirds) of
human body. It is formed of H and O in the ratio of 2:1. 95% of water is found in free state and 5%
in combined form in the cell. Water helps in sustaining the life processes. So water is called elixir or
cradle of lip as life is not possible in the absence of water.
• Role of Oxygen : Oxygen is mainly utilized in aerobic cell respiration of the nutrients i nside the
mitochondria to produce energy-rich ATP molecules so is essential for life. In the absence of oxygen,
only 5% of energy available is released.
• Role of Sodium chloride (common salt): Sodium chloride plays an important role in
metabolic functions of body especially when in ionic form.
• Role of Carbohydrates: Carbohydrates are organic compounds formed of C, H and O
generally in the ratio of 1:2:1. These are commonly called saccharides (Gk. saccharon = sugar)
Carbohydrates are the main storage molecules and most organisms use carbohydrates as an important
fuel, breaking these bonds and releasing energy to sustain life.
• Role of Proteins : Proteins are polymeric compounds formed by interlinking of amino acids
(monomers) by peptide bonds. Out of about 100 types of amino acids, only 20 types of amino acids
are of biological importance, so are called Magic 20. Proteins play a vital role in the formation of
structures in living organisms. Like carbohydrate and fat protein can be broken down with the release
of energy. Protein is not stored as such in the body and it is normally only used as a substantial
source of energy in conditions of starvation.
• Role of lipids: Lipids comprise a major group of insoluble hydrocarbons having many functions.
These are polymers of alcohols (e.g. glycerol) and fatty acids interlinked by ester bonds. Complex
lipids such as true fats are important organic molecules that are used to provide energy. Fats in
animals also provide protection from heat loss.
• Role of Nucleic Acid: These are polymers of nucleotides interlinked by phosphodiester
bonds, so called polynucleotides. Each nucleotide is formed of 3 components: a pentose sugar (e.g.
ribose in RNA and deoxyribose in DNA), a phosphate group and an inorganic nitrogen -base (a
purine or a pyrimidine).
Courseaaly.com
, DNA acts as genetic material in most organisms and controls the synthesis of structural and. functional
proteins. RNA also act as genetic material in all plant viruses e.g. TMV and helps in protein synthesis.
Systematics
1. The term ‘Systematics’ was proposed by Linnaeus in 1735.
2. It includes description of external morphological characters of plants or living organisms.
E.g., morphological characters of root, stem, leave, flowers.
3. New systematics or Neo systematics or Biosystematics is a new branch. Its
name was given by Julian Huxley (1940).
4. The term taxonomy was coined by A. P. de Candolle.
5. Carolus Linnaeus is called the father of taxonomy.
6. H. Santapau is called the father of Indian taxonomy.
7. Taxonomy is of 3 types:-
• Alpha taxonomy- Only morphological characters are used for identification and
classification of plants.
• Beta taxonomy- Involves genetical, anatomical, cytological, palynological,
physiological and other characters.
• Omega taxonomy - Analysis and synthesis of all information and types of data to
develop classification system based on phylogenetic relationship.
8. Cytotaxonomy – The use of cytological characters of plants in classification or in solving taxonomic
problems is called cytotaxonomy.
9. Chemotexonomy – The use of chemical compounds present in plants for classification or in solving
taxonomic problems is called chemotaxonomy or chemical taxonomy. The basic chemical compounds
used in chemotaxonomy are alkaloids, carotenoids, tannins, polysaccharides, nucleic acids, fatty acids,
aromatic compounds etc.
10. Karyotaxonomy – It is based on the characters of nucleus and chromosomes. Pattern of chromosomal
bands (dark bands and light bands) is most specific character for classification of organisms.
Nomenclature
1. Nomenclature is giving distinct scientific names to various structures including living organisms for
their identification.
2. The names are of two types – vernacular (common name) and scientific names.
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