Human chromosomes, Biology

Assignment Help:

HUMAN CHROMOSOMES

The normal diploid (2N) chromosome number in human being is 46.

It was given by T.H. Tjio and A. Levan in 1956.

The chromosome complement of a cell depicting the number, size and form of the chromosome as seen in metaphase of mitosis is called karyotype.

The chromosomes are morphologically numbered into 7 groups. (size and position of centromere) by Denver and Colorado (1960)

Group (A)            : 1-3 chromosomes of largest size and submetacentric or metacentric centromere.

Group (B)            : 4-5 chromosomes with less larger size, submetacentric

Group (C)            : 6-12 chromosomes with medium sized and submetacentric centromere.

Group (D)            : 13-15 chromosomes, shorter than group 'c' with centromere near the end (Arcocentric). They are sat chromosomes or satellite.

Group (E)            : 16-18 chromosomes, short sized, with median or submedian centromere.

Group (F)            : 19-20 chromosomes, short sized with median centromere.

Group (G)           : 21-22 chromosomes, smallest in size, Acrocentric and are also satellites.

X chromosome is placed in 'C' group due to its larger size and submedian centromere and Y-chromosome is placed in group 'G' due to its short size and terminal centromere.


Related Discussions:- Human chromosomes

Regression of primitive streak, Regression of Primitive Streak As...

Regression of Primitive Streak As the inward migration of cells by the primitive streak ends progressively along its anterior to posterior regions the streak slowly regre

Endoplasmic reticulum, ENDOPLASMIC RETICULUM It is also known as Endosk...

ENDOPLASMIC RETICULUM It is also known as Endoskeleton of the cell, Endomembranous system of the cell. Garnier (1897) first observed them and called Ergastoplasm. E.R.

Chemical stress, Chemical Stress Survival of cells is dependent on car...

Chemical Stress Survival of cells is dependent on carrying out of a set of chemical reactions (metabolic reactions) in a particular order. This results in a net gain in mass a

Adaptations, Adaptations Every organism can live and reproduce within a...

Adaptations Every organism can live and reproduce within a certain range of climatic conditions. Organisms that live in hot or cold environments have behavioural and physiologi

Methods and Vectors, Match each of the methods or vectors below to an appro...

Match each of the methods or vectors below to an appropriate form of gene therapy, assigning two methods or vectors to each form. Use each method or vector only once. Methods/vec

Cellulose, CELLULOSE It is a linear polymer of b -D-glucose. It i...

CELLULOSE It is a linear polymer of b -D-glucose. It is the structural polysaccharide of plant cell walls, walls of some primitive fungi, some protists, and tunic of asci

Biology, how can i get an demo assignment to solve?

how can i get an demo assignment to solve?

Define features of male and female ascaris lumbricoides, Define Features of...

Define Features of male and female ascaris lumbricoides? i)  Ascaris  lumbricoides is  commonly called  round worm. ii)  Body  is elongated, cylindrical,  tapering at  bot

Stratification, Stratification On the basis of the variation in air tem...

Stratification On the basis of the variation in air temperature. the atmosphere has been divided vertically into four layers: (figure shown below) thee troposphere, stratospG,

Type of skull, what type of skull does amphibians possess in general?

what type of skull does amphibians possess in general?

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd