Chromosomes are the long, thin thread like structurefound inside the nucleusof a cell containing genes insideit.

Chromosomes are located inside the nucleus of a cell.

The different types of chromosomes are:
- Meta centric.
- Sub-metacentric.
- Acrocentric.
- Telocentric.

The literal meaning of chromosomes are:
Chrome: color.
Soma: body.

Chromosome are made of the gentle material DNAand protein.
A gene is the segment of DNA which can form exact copies by the process of replication.
It is locatedin chromosomes.

The two identical stands of a chromosomes is called chromatids.
The constricted part where the chromatids are attached firmly to each other is called centromere.

Metacentric chromosomes are the chrosomes in which the centromere is located at the center dividing the chromatids into two halves.

Acrocentric chromosomes are the chrosomes in whichthe centromere is located away from the center.
Telecentre chromosomes are the chrosomes in whichthe centromere is located at the end of chromatids.

The gametes cell that contains haploid number ofchromosomes is called haploid cell.

Any 3 functions of chromosomes are:
- It acts as ahereditary vehicles.
-It control protein synthesis, cell growth and cell-repair.
-It forms link between parents and their off-springs.

Name	Diploid	Haploid
Human	23 pairs	23
Pea	7 pairs	7
Onion	8 pairs	8
Rice	12 pairs	12

The chromosomes that carry gene for the sexualcharacters called sexchromosomes.
Chromosome of this type is different from autosomesis that autosomes determines various characteristicsof thebody where as sex chromosomes determines sex of anindividual.

Sex chromosomes are responsible for the determination ofsex in human body. Sex is determinedby the geneticinheritance.Sexchromosomesthat carries genes formalecharacters are Y and female Y. So,

A disorder that occurs in the human body due to theincrease or decrease in the number ofchromosomesis called chromosomaldisorder.
Any 3examples are:
-Down's syndrome.
- Klinefelter's syndrome.
-Turner'sSyndrome.

The cause of chromosomal disorder are:
- Dilation.
- Duplication.
- Translocation in the chromosomes.

Down's Syndrome is a genetic disorder caused by thepresence of all or part of an extrachromosomes.
Its major symptoms are:
-Difficultiesin physical activities.
-Slanting eyes and small ears.
-Short sightedness.
-Congenitalheart defects.

Kilenfelter syndrome is a genetic disorder causeddueto the increase in sex chromosome in male
Its major symptoms are:
-Tendency to loose chest hair.
-Poor beard growth.
-Breast development.
-Small tastes.
-Frontal baldness absent.

Turner's syndrome is a chromosomal disorder occurredin female due to the decrease of sex chrosomes.
Its major symptoms are:
-Swelling of hands & feet of newborn baby.
-Broad chest.
-Low-set ears.
-Obesity.
-Poorly developed ovaries.

Turner's syndrome occurs due to the lack of x chromosomein female.