大学课程英汉对照分子生物学导论教学Chapter 3课件
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Chapter 3 Nucleic Acid1. Physical and chemical structure of DNA●Double-stranded helix● Major groove and minor groove● Base pairing● The two strands are antiparallel● G+C content (percent G+C)● Satellite DNASatellite DNA consists of highly repetitive DNA and is so called because repetitions of a short DNA sequence tend to produce a different frequency of the nucleotides adenine, cytosine, guanine and thymine, and thus have a different density from bulk DNA — such that they form a second or ’satellite’ band when genomic DNA is separated on a density gradient。
2。
Alternate DNA structureTwo bases have been extruded from base stacking at the junction. The white line goes from phosphate to phosphate along the chain。
O is shown red, N blue, P yellow and C grey.3. Circular and superhelical DNADNA can also form a double-stranded, covalently-closed circle。