Some examples of Energy transformation.
| Type of Energy Transformation | Example | |||||||||||||||
| Chemical to electrical | Nerve cell | |||||||||||||||
| Light to electrical | Retina of eye | |||||||||||||||
| Chemical to osmotic | Kidney | |||||||||||||||
| Chemical to mechanical | Muscles and cilia | |||||||||||||||
| Sound to electrical | Ear | |||||||||||||||
| more...
(1) In general, growth involves three processes or strategies namely cell proliferation, cell enlargement and secretion of large amount of extracellular matrix.
(2) Growth is an important part of development, continuing throughout life.
(3) Early embryonic developmental stages constitute prefunctional state of life.
(4) The biological process of growth and differentiation enables the animal to enter the functional state of life.
(5) Morphogenesis refers to generation of form and structure during development of an individual organism.
(6) Morphogenesis produces new forms by involving cell movements.
(7) Morphogenetic movements of large number of cells during development is particularly noticed during gastrulation.
(8) Differentiation results in increasing diversity of cells.
Death is the permanent breakdown and finally stopping of vital functions of body, especially heart beat and respiration.
Characteristics
(1) It is the last event in the degenerative processes of ageing.
(2) Death involves widespread be cell breakdown and cell death.
(3) Death of an organism involves the death of body cells. But all the body cells do not die at same rate e.g. ciliated cells lining the respiratory tract of mammals continue to beat their cilia for long time even after clinical death.
(4) There is no natural death in some protists e.g. Amoeba and monerans like bacteria, etc.
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 macro-biomolecules (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 important roles in metabolism :
(1) 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.
(2) Role of Oxygen : Oxygen is mainly utilized in aerobic cell respiration of the nutrients inside 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.
(3) Role of Sodium chloride (common salt -\[NaCl)\] : Sodium chloride plays important roles in metabolic functions of body especially when in ionic form.
(4) 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.
(5) 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.
(6) 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 esterbonds.
Complex lipids such as true fats are important organic molecules that are used to provides energy. Fats in animals also provide protection from heat loss.
(7) 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).
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.
Living beings are called
organisms. Living organisms are similar to non-living objects in being ? formed
of similar elements which combine in similar way to form similar molecules
(called biomolecules in living organisms) and follow similar physical and
chemical laws like gravitation, magnetism, action and reaction etc. living
organisms show a great biodiversity and are classified into different
kingdoms-Monera, Protista, Fungi, Plantae and Animalia. But all of these share
the following properties ?
(1) They have definite
organisation.
(2) They always have cellular nature so are either
unicellular (e.g. Amoeba, Paramecium etc.) or multicellular (e.g.,
Hydra, man etc.).
(3) They show
co-ordination between different parts of body to maintain homeostasis (constant
internal environment) inside the body.
(4) They have the ability
of movements and locomotion.
(5) They show metabolic functions in the presence of
energy.
(6) These have the ability
of intussusceptional (internal) growth and development.
(7) These have specific
receptors (e.g., sense organs to receive external and internal stimuli)
and specific effectors (e.g., muscles and glands to give specific
response).
(8) These have regulatory
mechanisms (e.g., nerves and hormonal in animals, and only hormonal in
plants) to maintain homeostasis inside the body.
(9) These show adaptations
to their environment to increase their chances of survival.
(10) These show variations
which help in speciation and evolution.
(11) These have reproductive powers for continuity of
their race.
(12) These have definite life span (period from birth to death).
(13) These undergo ageing after adulthood and then natural
death.
(1) Adaptation may be defined as any characteristic of an organisms which makes the organisms better suited to its environment.
(2) In other words, an adaptation improves the performance and survival of the organism in its the environment.
(3) Many adaptations are remarkable; they result from natural selection.
(4) Individuals with favourable characteristics replace those with less favourable characteristics.
(5) Adaptation improves the match between organisms and their environment.
(6) On the basis of their nature and role in evolution the adaptation are classified into short range or temporary and long range or permanent adaptation.
Differences between Short-range and Long-range adaptation
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