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AAT Bioquest

Is chromatin the same as a chromosome?

Posted July 20, 2022


Answer

Chromatin and chromosome are two types of structures of the DNA double-helix with several differences between them.  

Basis of differentiation ChromatinChromosome
DefinitionIs one of the two identical halves of a chromosome that has been replicated in preparation for cell division Is a threadlike structure that carries the genetic information cells need to grow, thrive, and reproduce 
CompositionComposed of nucleosomes – it is the unraveled condensed structure of DNA Composed of packaged proteins and DNA – the DNA is tightly coiled several times around histone proteins 
StructureConsists of 2 DNA strands joined together by their centromereConsists of a single, double-stranded DNA molecule
OccurrenceFormed only when the cell undergoes mitosis or meiosis – occurs only in the interphase of the cell cycleOccurs throughout the life cycle of the cell
AppearanceAppears as a thin, long, fibrous structureAppears as a thick, compact, ribbon-like structure
SimilaritySister chromatids are exact replicas of one anotherAre not the exact copies of one another – one copy of the gene comes from each parent 
SizeApproximately 10nm Approximately 1 to >20 μm 
Type of microscope used for visualizingVisualized under electron microscopeVisualized under light microscope
PairingSingle, unpaired fibersExist as pairs
Order of hierarchyIs a lower order of DNA organization Is the highest order of DNA organization
Extent of condensationCondensed 50 times more than the normal DNA double helixCondensed 10,000 times more than the normal DNA double helix
Metabolic activitiesDNA Replication, RNA SynthesisDoes not exhibit any metabolic activity
FunctionPackages DNA into the cell nucleus and facilitates DNA replication; Regulates gene expressionCarries the genetic material ; Compresses the DNA structure into a compact unit so it can fit in the nucleus; Ensures proper arrangement of genetic material in the cell equator so it can be distributed equally between the two daughter cells
Additional resources

Micromechanics of chromatin and chromosomes

DNA and RNA Quantitation