DNA Organisation and Chromosomes

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  • Created by: odionj01
  • Created on: 27-01-19 16:53
Why is efficient packaging of DNA important?
A lot of DNA needs to fit inside a small space. Being compact is necessary.
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What are histones?
Proteins that help package and order DNA into units called nucleosomes.
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Name some examples of nucleosomes?
H2A, H2B, H3, H4, H1 (Linker)
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State the order of organisation from DNA to chromosomes?
DNA--> Histones--> Nucleosomes-->Solenoid-->Chromatin--> Chromosomes
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What is the function of a solenoid?
This produces a supercoiled arrangement of DNA created by the string of nucleosomes.
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What are the properties of Euchromatin?
uncoiled, active, acetylated, not methylated
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What are the properties of Heterochromatin?
condensed, inactive, low level acetylation, methylated
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What is a karyotype?
A full chromosome arrangement, they match their respective homologous partner.
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State and briefly explain the 2 types of Karyotyping?
Gremsa stain (G banding)- A and T are gene poor--> stain more darkly. Each chromosome= specific pattern. FISH (Fluorescence in situ hybridisation) used to locate genes using hybridisation probe with a short fluorescent dye attached.
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What is a telomere?
A telomere is a region of repetitive nucleotide sequences (Tandem repeats)
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Briefly explain what telomeres have to do with ageing?
Telomeres shorten after cell division. Due to discontinuous replication at the lagging strand pf DNA.
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How does Telomerase aid the shortening of Telomeres?
Telomerase contains a RNA sequence that acts as a template for the synthesis of telomerase tandem repeats.
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What is a chromosome numerical abnormality?
This is caused by the failure during chromosome division. This results in an extra chromosome deficiency.
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What is a chromosome structural abnormality?
This is cause by loss/rearragement of genetic material.
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Other cards in this set

Card 2

Front

What are histones?

Back

Proteins that help package and order DNA into units called nucleosomes.

Card 3

Front

Name some examples of nucleosomes?

Back

Preview of the front of card 3

Card 4

Front

State the order of organisation from DNA to chromosomes?

Back

Preview of the front of card 4

Card 5

Front

What is the function of a solenoid?

Back

Preview of the front of card 5
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