Nucleic acids Part 2'

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• Nucleic acids Part 2.
• The prokaryotic chromosome.
• The eukaryotic chromosome.
• RNA.

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Bacterial and eukaryotic DNA. Bacterial
circular one chromosomes few
proteins Eukaryotic linear multiple
chromosomes many protein histones.
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Bacterial chromosomes.
Supercoiling
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Supercoiling Topoisomerases Cut the DNA Wind
or unwind Rejoin ends.
There is both positive and negative supercoilin
g.
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Topoisomerase
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Bacterial chromosomes.
Supercoiling
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Most DNA in the cell is slightly negatively
supercoiled which provides energy for local
unwinding.. Local unwinding is necessary for
replication, repair, transcription and
recombination.
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• DNA in eukaryotes.
• A. binds to positively-charged proteins
• histones.
• B. Form nucleosomes

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• Types of RNA.
• A. Ribosomal
• B. Transfer
• C. Messenger
• D. Small RNAs enzyme activity.

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Stem-loop structure of RNA.