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Packaging of DNA

STUDY
PLAY
State the name given to the structures that DNA wraps around
Proteins (Histones)
Explain why these structures are found only in the structure of eukaryotic chromosomes and not in the chromosome found in prokaryotes
Eukaryotic chromosomes help package the DNA into smaller pieces. Prokaryotes don't have histones and have to use supercoiling
Identify the phase of the cell cycle in which DNA is most likely to be supercoiled
Prophase
Outline how nucleosomes help regulate transcription
•Supercoiling condenses the DNA molecule by a factor of x15,000
•Histones are responsible for the packaging of DNA
•The metaphase chromosome is an adaptation for mitosis and meiosis
•The fibre must be less condensed for transcription to occur during the interphase
•Condensing controls if the genes are transcribed or not
Nonsense DNA
A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein
Satellite DNA
Short, highly repeated eukaryotic DNA sequences, usually clustered in heterochromatin and generally not transcribed
Nonsense and satellite DNA
Both the same thing. Non-coding regions of DNA.