Metabolism

Types. Metabolism is of two kinds, catabolism and anabolism. Anabolism includes all the “ building up” reactions It is also called constructions metabolism since it involves the synthesis of complex substances from simpler ones e.g. synthesis of organic compounds from CO2 and H2O during photosynthesis, formation of starch from glucose production of proteins from amino acids, formations of lipids from fatty acids and alcohols. Energy is stored in the process.

                                   Chlorophyll, light energy, enzymes      

6CO2 + 12H2O                          →                             C6H12O6 +H2O+6O2

                                          enzymes  energy

          nC6H12O6                           →             (C6H12O5)n + nH2O

Catabolism constitutes “Breakdown reactions” It is also known as destructive metabolism because it involves braking of complex substance into sipper ones. Potential energy present in the complex substances is converted into kinetic energy. Respiration is an example of catabolism. It releases energy for performing different body activities.

1.      Growth. Growth is irreversible increase in mass of an individual. A multicellular organism increases its mass by cell division. In plants growth continues throughout life as they have meristematic areas where cell divisions occur regularly. In animals, growth occurs to a certain age after which cells divide only to replace worn out and lost cells. Unicellular organisms also grow by cell division. However, cell division is also a means of reproduction in them. In higher animals and plants, growth and reproduction are exclusive.

Living organisms show internal growth due to addition of materials and formation of cells inside the body. Such a method is called intussusceptions. A dead organisms does not grow. However , some nonliving articles can increase in size e.g., mountains, boulders, crystals, stones, It is due to addition of similar materials to their outer surface. The process is called accretion. In living being growth production substances are of two types, protoplasmic and apoplasmic. Protoplasmic substance are components of living matter components of living matter like cytoplasm and nucleus. Apolasmic substances are nonliving materials formed by the cells which become component of tissues, e.g., cell wall fibres  of connective tissue , matrix of bone and cartilage. For growth to occur, three processes are involved – cell division, cell enlargement and secretion of apoplasmic substances. All the three can be studied during development of embryo from zygote.

2.      Consciousness. It is awareness of the surroundings and responding to external stimuli. The external stimuli can be physical, chemical, or biological. The stimuli are perceived by sense organs in higher animals, e.g., eyes, nose. Plants do not possess such water, temperature, pollutants, pollutants, other organisms, etc. Photoperiods influence reproduction in those animals and plants which breed during particular season.

All organisms, from primitive prokaryotes to most advanced and complex eukaryotes, are able to sense and respond to environmental factors. Organisms also handle chemicals entering their bodies. Human being have an additional faculty of self consciousness or Jiva bhava. Old India scriptures have quantified chetan tatwa  

or consciousness in the units called Kalas. Plants are believed to have one kala,

small animals two, oviparous animals three while viviparous animals have four kalas. Human have five or more than five kalas, some even 16 kalas. Consciousness, is said to be the defining property of living organisms.