Some cells divide continuously, some do not divide and still some divide occasionally only when needed to replace dead, lost or injured cells. These cells exit from G1 phase and remain for a variable period in G0 phase.
During this sub-stage, the bivalents with four chromatids are visible due to further condensation of chromosomes. The most significant event of meiosis is the crossing over that occurs at this sub-stage
Cell Cycle is the sequence of events that occur between two successive mitoses. It includes interphase, which involves nuclear division. Interphase is divided into G1 phase(synthesis of RNAs, ribosomes, proteins and enzymes), S phase(DNA replication) and G2 phase(mitotic spindle formation starts).
Insulin is a protein (amino acid-derived) hormone consisting of two polypeptide chains, chain A having 21 and chain Been 30 amino acids. These chains are linked by two interchain disulphide bridges(S-S) and one interchain disulphide bridge.
mRNA (meesenger -RNA) is synthesized on DNA template in the nucleus. It carries information for protein synthesis from DNA and comes to cytoplasm through nuclear pore. In association with ribosome, it synthesizes protein.
Lipids are a heterogenous group of organic compounds which include fats and their derivatives. The main components of lipid are carbon, hydrogen and oxygen compounds are insoluble in water, contain large proportion of carbon-hydrogen bonds and release maximum energy when break down.
Compound microscope has two sets of lenses, the objective and the eyepiece. The basic principle behind it is to visualize the enlarged image of the object by the help of these lenses.
Cell is the basic unit of life in which all the fundamental functions of living organism are marked. Cell was discovered by Robert Hooke (1665). He coined the term cell (Gk. Kytos- cell, Lt. cella-hollow space) and described it in his book Micrographia. Purkinje (1839) named the jelly-like substance of the cell as protoplasm and Robert Brown (1831) discovered the nucleus. J. Huxley termed protoplasm as ‘physical basis of life’.
After World War I, public opinion in England was in favors of India. At this time, Mohandas Karamchand Gandhi (later called Mahatma Gandhi) returned to India after a stay of about 20 years in South Africa.
Food chain a food chain is formed by a series of organisms arranged in a linear manner based on their feedings habits. In this chain, each type of organism feeds on the type below it in the series.