IB Biology Topic D2.1.6 Condensation and Movement of Chromosomes as Shared Features of Mitosis and Meiosis Revision Notes (SL/HL)

IB Biology Topic D2.1.6 Condensation and Movement of Chromosomes as Shared Features of Mitosis and Meiosis Revision Notes (SL/HL) | RevisionDojo

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Chromosomes Must Condense and Move So Genetic Material Passes On Intact

The DNA in one human cell stretches about 2 metres but must fit inside a nucleus less than 10 μm wide.
If it were not tightly packed, the DNA would tangle or break when the cell tries to move it.
Both mitosis and meiosis share the same two solutions: condense the chromosomes, then move them with a spindle.

Analogy

Picture packing a 50-metre rope into a 5-centimetre box.
Coiling it tightly and neatly is the only way to fit it in without knots.

Supercoiling: DNA Winds Around Histones and Coils Tighter and Tighter

Histones are proteins that act as spools, and the DNA wraps around them to form nucleosomes.

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Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

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Chromosomes Must Condense and Move So Genetic Material Passes On Intact

The DNA in one human cell stretches about 2 metres but must fit inside a nucleus less than 10 μm wide.
If it were not tightly packed, the DNA would tangle or break when the cell tries to move it.
Both mitosis and meiosis share the same two solutions: condense the chromosomes, then move them with a spindle.

Analogy

Picture packing a 50-metre rope into a 5-centimetre box.
Coiling it tightly and neatly is the only way to fit it in without knots.

Supercoiling: DNA Winds Around Histones and Coils Tighter and Tighter

Histones are proteins that act as spools, and the DNA wraps around them to form nucleosomes.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

IB Biology Topic D2.1.6: Condensation and Movement of Chromosomes as Shared Features of Mitosis and Meiosis Notes

Chromosomes Must Condense and Move So Genetic Material Passes On Intact

Supercoiling: DNA Winds Around Histones and Coils Tighter and Tighter

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Chromosomes Must Condense and Move So Genetic Material Passes On Intact

Supercoiling: DNA Winds Around Histones and Coils Tighter and Tighter

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics