Question

Define cell and discribe the structure and functions of nucleus

Answer 1

A cell may be defined as the smallest unit of a structure and functions of living organisms. The nucleus is bounded by a double membraned, porous, selectively permeable nuclear envelope. It is filled with a clear jelly like ground substance named nucleoplasm. At least one nucleolus and a network of thread-like structures called chromatin reticulum are found in the nucleoplasm. The nucleolus is concerned with the formation of ribosomes. The chromatin reticulum condenses into small and thick rod-like structures called chromosomes during cell division.
The following functions are performed by the nucleus :-
I) It controls all the functions of a cell directly or indirectly.
II) It helps in the transmission of characters from parents to offsprings.
iii) It controls cell division.
iv) Changes in the chromatin fibres, present in the nucleus, cause variations.
v) These variations help in evolution.

Answer 2

cell is the basic component of the living organisms. it is discovered by Robert Hooke in 1665.
the structure, it is the eukaryotic cell the ribosomes studded double membranes of the nuclear envelope the DNA and the nucleolus. within the cell nucleus is a viscous liquid called nucleoplasm.
functions, it stores the cell's hereditary material or DNA and it coordinates the cell's activities which include growth intermediary metabolism protein synthesis and reproduction.