I am trying to understand if a chromosome is made of one DNA molecule or just a part of a DNA molecule. If one human has replica of the same DNA molecule or replica of different DNA molecules? The way it is taught seems to indicate that each human beings has DNA molecules that are all the same. Then how can the same molecule make different chromosome with different size?
DNA molecule , chromosome ...
- Thread starter bobrilla
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Hi and welcome.
Good question, it makes us pause to reflect on the nuances of technical language.
Since DNA is "a molecule" made up of "molecules" (chromosomes) made up of "molecules" (e.g. genes within chromosomes) made up of molecules (e.g., codons within genes), it can be confusing which is "the molecule". For this reason it's simpler to use the more specific words to identify the specific instance of "molecule" you mean.
Assuming no genetic anomalies ("birth defects") every person has within every one of their cells a full copy of the 23 "chromosome molecules" produced by the mother plus the 23 "chromosome molecules" produced by the father. These are each single stranded sets which combine to form the 23 double-stranded chromosomes we each possess.
You may be interested in looking for information on mitosis. There you see the chromosomes fan out so there will be a clean break when the cell divides.
http://highered.mcgraw-hill.com/sit...pter2/animation__mitosis_and_cytokinesis.html
Good question, it makes us pause to reflect on the nuances of technical language.
Since DNA is "a molecule" made up of "molecules" (chromosomes) made up of "molecules" (e.g. genes within chromosomes) made up of molecules (e.g., codons within genes), it can be confusing which is "the molecule". For this reason it's simpler to use the more specific words to identify the specific instance of "molecule" you mean.
Assuming no genetic anomalies ("birth defects") every person has within every one of their cells a full copy of the 23 "chromosome molecules" produced by the mother plus the 23 "chromosome molecules" produced by the father. These are each single stranded sets which combine to form the 23 double-stranded chromosomes we each possess.
Because DNA replication doesn't depend on the length of the sequence.
You may be interested in looking for information on mitosis. There you see the chromosomes fan out so there will be a clean break when the cell divides.
http://highered.mcgraw-hill.com/sit...pter2/animation__mitosis_and_cytokinesis.html
Write4U
Valued Senior Member
This may give you a good idea of what DNA is and how it works.
http://www.ted.com/talks/drew_berry_animations_of_unseeable_biology.html
Another consideration is, condensed chromosomes, by being so compact define the lowest DNA entropy configuration. For DNA to condense into chromosomes, the entropy of the DNA has to lower to a minimum, which goes in the opposite direction of the second law. The second law says entropy has to increase. This is a useful situation from an evolutionary POV, since because entropy has to increase, movement toward separation of the chromosomes is already cued up, and would have been possible even without much of the modern bells and whistles. It might take a while, but separation would follow the second law and be favorable with highest entropy DNA open for business.