BIOL1006 Lecture Notes - Lecture 7: Metaphase, Nucleosome, Interphase
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Lecture 7
A eukaryote contains a well-defined nucleus, whereas in
prokaryotes the chromosome lies in the cytoplasm in an
area called the nucleoid.
In eukaryotic cells, DNA and RNA synthesis occur in a
separate compartment from protein synthesis.
In prokaryotic cells, both processes occur together.
What advantages might there be to separating the
processes? What advantages might there be to having
them occur together?
A eukaryote contains a well-defined nucleus, whereas in
prokaryotes, the chromosome lies in the cytoplasm in an
area called the nucleoid.
The size of the genome in one of the most well-studied
prokaryotes, E.coli, is 4.6 million base pairs.
So how does this fit inside a small bacterial cell? The DNA
is twisted by what is known as supercoiling.
Supercoiling means that DNA is either under-wound or
over-wound from its normal relaxed state.
Some proteins are known to be involved in the
supercoiling; other proteins and enzymes such as DNA
gyrase help in maintaining the supercoiled structure.
Eukaryotes, whose chromosomes each consist of a linear
DNA molecule, employ a different type of packing
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