Thursday, August 30, 2007

Lectures On Genes -part 1

What is a gene?

The genes are hereditary units that control our characters .Characters include everything ,right from our eye colour,hair colour,skin colour.............to our behaviour,our looks,our sound,the way we look,physical characters such as tallness,shortness.......etc.This is passed on from one one generation to another.
So what do we call this "characters "that pass from our parents to us .They are called as "Traits".

How we can we define genes?(2-Mark )

Genes are the hereditary units which control the characters of living beings.A gene brings about its action by specifying the amino acid sequences of proteins.
(Proteins form the major component of the functioning of a cell. Like other biological macromolecules such as polysaccharides and nucleic acids; proteins are essential parts of organisms and participate in every process within cells. Many proteins are enzymes that catalyze biochemical reactions, and are vital to metabolism.Proteins also have structural or mechanical functions, such as actin and myosin in muscle, and the proteins in the cytoskelton, which forms a system of scaffolding that maintains cell shape. Other proteins are important incell signalling, immune responses ,cell adhesion and the cell cycle. Protein is also a necessary part of our diet, since animals cannot synthesise all the amino acids and must obtain essential aminoacids from food. Through the process of digestion, animals break down ingested protein into free amino acids that can be used for protein synthesis).
So a gene can also said to contain the directions for building all the proteins present in a cell.
Genes are present in long thread like structures called "Chromosomes" that are present inside the nucleus of a cell.Both the genes and chromosomes are made up of DNA .
A single chromosome can contain many genes .