Dictionary » C » Chromosome

Chromosome

Definition

noun, plural: chromosomes

A structure within the cell that bears the genetic material as a threadlike linear strand of DNA bonded to various proteins in the nucleus of eukaryotic cells, or as a circular strand of DNA (or RNA in some viruses) in the cytoplasm of prokaryotes and in the mitochondrion and chloroplast of certain eukaryotes.


Supplement

In eukaryotes, the chromosomes appear as threadlike strand that condense into thicker structures and aligns on the metaphase plate during mitosis. Humans normally have 23 pairs of chromosomes, each with a characteristic length and banding pattern. Chromosomes occur in pairs (in most somatic cells) since one member of each pair comes from the mother and the other from the father. In most prokaryotes, the chromosome is usually a circular strand of DNA; hence, the entire genome is carried on only one chromosome. In viruses, the chromosome may appear as short linear or circular structure containing the DNA or RNA molecule often lacking any structural proteins.


Word origin: from the Greek chroma = color + soma = body.

Related forms: chromosomal (adjective).
Related terms: w chromosome, marker chromosome, ring chromosome, Y chromosome, X chromosome, lampbrush chromosome, homologous chromosome, chromosome puffs, chromosome rosette, chromosome satellite, Christchurch chromosome.


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Re: Mitochondrial DNA

There are genetic diseases caused by defects carried on the mitochondrial chromosome that can have clear phenotypic consequences. http://www.umdf.org/site/c.8qKOJ0MvF7LUG/b.7934627/k.3711/What_is_Mitochondrial_Disease.htm

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by jonmoulton
Mon Sep 08, 2014 5:23 pm
 
Forum: Genetics
Topic: Mitochondrial DNA
Replies: 2
Views: 138

Colorblindness Probability Help!

The incidence of an XXY karyotype is about 1 in every 1000 male births, the extra X chromosome coming either from the mother's egg or the father's sperm by nondisjunction during meiosis. Suppose the baby's father has red-green colorblindness. Would you predict that ...

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by kaylagh
Sun Sep 07, 2014 6:07 am
 
Forum: Genetics
Topic: Colorblindness Probability Help!
Replies: 0
Views: 48

Chromatin

I am all for skipping the mitochondrial chromosome for now:) Thank you for your explanation...it really helps:)

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by Hannamerika
Thu Sep 04, 2014 10:13 pm
 
Forum: Genetics
Topic: Chromatin
Replies: 2
Views: 186

Re: Chromatin

Before replication there were 23 pairs of molecules, 23 of maternal origin and 23 of paternal origin, plus the maternally-contributed mitochondrial chromosome (which I'll ignore for the rest of this post). Counting chromosomal centromeres, there are 46 centromeres total. After replication there ...

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by jonmoulton
Thu Sep 04, 2014 3:04 pm
 
Forum: Genetics
Topic: Chromatin
Replies: 2
Views: 186

Chromatin

... cell for it to replicate. Is that correct? That way once the chromatin replicates and does all of it's twisting and coiling, we then have our 23 chromosome pairs. Yes?

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by Hannamerika
Thu Sep 04, 2014 9:12 am
 
Forum: Genetics
Topic: Chromatin
Replies: 2
Views: 186
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