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1. Cell and Genome
• Cell is defined as the basic unit of life. All things in this world are made up
of cells that are enclosed by a membrane having internal material composed
of chemical compositions. Internal chemical composition of cell is aqueous
in nature and has the ability to divide in copies by growing.
• Cell Biology is study of functions and structure of the cell. It describes that
cell is the basic unit of life and the related study of cell is called as Cytology.
• Molecular Biology is the science that concerns with the internal biological
activities of cell at molecular level.
• Chromosomes are present inside the nucleus of the cell and have the
ability to control heredity features as it is made up of heredity material.
Chromosomes are made up of two chromatids that are being attached with
the centromere in each and every cell.
Figure1.1: Chromosome with its chromatids
• Heredity is central to life and it is the phenomenon of passing of
characteristics and traits from parents to kids. Proteins, DNA and RNA are
required for processing heredity.
• Hereditary Material is DNA (deoxyribonucleic acid) that is present in all
living cells including humans and other organisms. Interestingly, in a human
the entire cells contain same DNA (hereditary material). All of the cells living
on earth do store their information in DNA molecules the double stranded
• Building Blocks of DNA are simple subunits consists of nucleotides, sugar-
phosphate with one of the nitrogen side molecule and a base.
• Structure of DNA is formed by paired, long and un-branched chains. All
type of chains contains four same monomers. The single strand DNA
nucleotides join with another strand by sugar-phosphate and develop into
double stranded DNA. Here sugar-phosphate acts as backbone of strands and
it is of asymmetric nature.
• Monomers or Bases are nucleotide compounds made up of chemical
combinations and these nucleotides encode genetic information by having
long linear sequencing. These nucleotides are Adenine-A, Thymine-T,
Guanine-G and Cytosine-C.
• Polymerization is a chemical reaction having two or more smaller
molecules that combine to form repeating molecule structures that originates
from the basic original molecule. It is also called as replication as one
fundamental unit replicates here into longer chains. Monomers attach to
each other by sugar-sulphate and made polymers and the phenomenon is
referred as polymerization.
Figure1.3: Genetic Material or DNA Copying by Replication