Revision:Cell Division - Mitosis

TSR Wiki > Study Help > Subjects and Revision > Revision Notes > Biology > Cell Division - Mitosis

State where cells arise from

Cells are derived from pre-existing cells by cell division (Mitosis and meiosis) It is the third statement of the cell theory.

Describe the cell cycle

The cell cycle is an alternation between interphase and mitosis.

Define interphase

Interphase is the largest sect of the DNA cycle, where a cell, which has been newly formed, increases in size and produces any organelles lost during the previous division. In this time, the DNA number is multiplied by 2. Prior to the next cell division, the chromosomes replicate, so there are 2 chromatids which are attached together at the centromere. As there is alot of activity which requires energy, ATP is produced during this period.

Outline how replicated DNA molecules (chromosomes) are moved to opposite ends of the cell by microtubules

In prophase the mitotic spindle forms.

In prometaphase the chromosomes attach to the mitotic spindle at the centromere.

In metaphase, the condensed chromosomes align in a plane across the equator of the mitotic spindle.

Anaphase follows as the separated chromatids move abruptly toward opposite spindle poles.

Finally, in telophase a new nuclear envelope forms around each set of unraveling chromatids.

The mitotic spindle is composed of microtubules, each of which is a tubular assembly of molecules of the protein tubulin.

Microtubules can grow or shrink by the addition or removal of tubulin molecules. This change in length propels attached chromatids to the spindle poles, where they unravel to form new nuclei.

State the products of mitosis

show us the hairy bean

State what tumours are the result of

Tumour are the result of uncontrolled cell division and that they can occur in any organ.

Comments