Structure of Chromosomes


 
 
Concept Explanation
 

Structure of Chromosomes

Chromosomes are thread - like structures located inside the nucleus of animal and plant cells. Each chromosome is made of protein and a single molecule of deoxyribonucleic acid(DNA). Chromosomes are passed from parents to offspring. The structure of a chromosome is consist of different parts. These parts are as follows :-

Centromere, Chromatids, Secondary constriction and satellite, Telomere, Chromomere, Chromonema and Matrix

A brief description of these parts are given below :-

Centromere

 The region of chromosome with which spindle fibres are attached during metaphase is known as centromere or primary constriction or kinetochore. Centromere perform functions like orientation of chromosomes at metaphase, movement of chromosomes during anaphase, formation of chromatid and chromosome shape.

Chromatid 

One of the two distinct longitudinal subuits of a chromosome is called chromatid. These subunits of a chromosome get separated during anaphase. Chromatids are of two types :- sister chromatids and non - sister chromatids.

Secondary constriction 

The constriction or narrow region other than that of centromere is called secondary constriction. It has constant position and therefore can be used as useful marker. It is usually found in chromosome away from the centromere.

Telomere 

The terminal region of a chromosome on either side is known as telomere. Each chromosome has two telomeres. The telomere of one chromosome cannot unite with the telomere of another chromosome.

Chromomeres 

The linearly arranged bead like structures found on the chromosomes is known as chromomeres.

The linearly arranged bead like structures found on the chromosomes is known as chromomeres. These are clearly visible in the polytene chromosomes. Available evidences indicate that chromomere represents a unit of DNA replication, chromosome coiling, RNA synthesis and RNA processing.

Chromonema

Chromonema is a spirally coiled core of the chromosomes on which the genes are located. During the prophase of mitotic division, the chromosome material appears as thin filaments. These thin filaments are known as chromonema.

Matrix

Each chromosome is bounded by a membrane called pellicle. It is very thin and is formed of achromatic substance. This membrane encloses a jelly-like substance which is usually called matrix. In the matrix is present the chromonemata.

                     

Chapters
Pre-Historic Period
Indus Valley Civilization
Vedic Civilization
Religious Reform Movement
The Early Kingdoms
The Mauryan Empire
Post Mauryan Period
The Age Of The Guptas
Post Gupta Era
Age of Rajput
Khilji Dynasty
Slave Dynasty
Tughlaq and Sayyid Dynasty
Vijaynagar Empire And Bahamani Kingdom
Mughal Empire And Beyond
Lodhi Dynasty
Cholas, Chalukyas and Pallavas
Arab Invasions
Bhakti and Sufi Movement
Rise of Sikhs, Jats and Marathas
Administrative Structure of Delhi Sultanate
Architecture During Medivial India
Advent Of The Europeans
Post Mughal Period
Rise of New States in 18th Century
Growth of British Paramountacy
Socio Religious Reforms
Constitutional Development of India
Indian Struggle Against British Rule
The Revolt Of 1857
Education Under British Rule
Role of Press in Freedom Struggle
First Phase of National Movement
Second Phase of National Movement
Third Phase of National Movement
Constitutional Development in India
Constituent Assembly
Union And Its Territory
Structure of Indian Constitution
Fundamental Rights and Duties
The Union Executive
The Union Legislature
Constitutional Amendments and Provisions
Judiciary In India
Emergency Provisions
Center - State Relations
The State Executive
The State Legislature
Election Commission Of India
Constitutional Organisation
Non-Constitutional Organisation
Local Self Goverment
India - Size And Location
Geological History Of India
The Physical Features Of India
Climate Of India
Soils In India
Natural Vegetation
Windlife Conservation In India
Drainage System of India
Irrigation System Of India
Agriculture In India
Livestock And Fisheries In India
Minerals And Energy Resources In India
Means Of Transport In India
Major Industries In India
Tribes of India
Census of India 2011
Music
Dance
Theatre
Pantings
Art, Architecture & Culture of India
Bio-Diversity
Earth And Its Structure
Land Rock And Soil
Atmosphere, Climate And Weather
Oceanography
Human And Regional Geography
Economic Growth And Development
Sectors Of Indian Economy
Economic Planning Of India
Fiscal And Monetary Policy In India
Infrastructure In India
Effects Of British Rule On Indian Economy
National Income
Banking System In India
Poverty And Unemployment
Inflation And Trade Cycles
Major Institutions
Environmental Studies
Tissues In Organism
Cytology
Classifucation Of Plants
Structural Composition Of Plants
Nutrition In Plants, Harmones And Plant Disease
Ecosystem
Classification In Animals
Nutrition In Animals
Human Digestive System
Human Respiratory System
Human Skeleton System
Human Excretory System
Human Nervous System
Human Circulatory System
Human Endocrine System
Human Reproductive System
Genetics
Human Diseases
States Of Matter
Metals And Non Metals
Acid Bases And Salts
Periodic Classification
Fuel, Combustion And Flame
Environmental Chemistry
Rest And Motion
Work Power And Energy
Gravitation
Pressure And Its Effects
Simple Harmonic Motion
Sound and Waves
Heat And Temperature
Light - Reflection
Electricity And Magnetism
Modern Physics
Force And The Laws Of Motion
Light - Refraction
Dispersion And Human Eye
Magnetic Effect Of Electric Current
Atom And Molecule
Chemistry In Everyday Life
Units And Dimensions
Content / Category
Class / Course
 
 


Students / Parents Reviews [10]