Advanced Higher Biology Miss Aitken The Cell Cycle Mitosis is the process of cell division Some cells are able to reproduce and make copies of themselves by following this sequence of events The cell cycle consists of 2 phases interphase not dividing and mitosis dividing ID: 1042294
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1. The Cell CycleUnit 1 – Cells and ProteinsAdvanced Higher BiologyMiss Aitken
2. The Cell CycleMitosis is the process of cell division.Some cells are able to reproduce and make copies of themselves by following this sequence of eventsThe cell cycle consists of 2 phases: interphase (not dividing) and mitosis (dividing)
3. InterphaseInterphase is a very active period of growth and metabolism and is split into a further three phases:G1 PhaseFirst growth stage – makes new proteins and copies all of the organelles.S phaseDNA is copied (replication)G2 PhaseSecond growth stage – cell makes more new proteins and prepares for mitosis.
4. Mitosis (also known as the M phase)Mitosis can be split into a series of visible changes within the cell. Spindle fibres move the chromosomes during mitosis.1 Prophase2 Metaphase3 Anaphase4 Telophase5 Cytokinesis
5. Mitosis and Cytokinesis: What do I need to know?You must know the stages in order and in brief detail.There is a good diagram which shows the stages on page 45 of your textbook.
6. ProphaseFirst sign of cell divisionChromosomes condenseMicrotubules disassemble and reassemble to form spindle fibres and asters by polymerisationSome spindle fibres attach to kinetochore and tension sensitive proteins make sure that each chromatid is attached to a centrosome.Nuclear membrane disintegrates
7. MetaphaseChromosomes move and line up along metaphase plate on the equator.This movement happens because of the polymerisation and depolymerisation of microtubules in spindle fibres
8. AnaphaseAnaphase is rapidThis is where the two chromatids are pulled apart by the depolymerisation of kinetochore proteinsOnce chromatids are separated they are then called chromosomes in their own right
9. TelophaseSeparated chromosomes are pulled by spindle fibres to opposite poles of the cellDuring this time, cell briefly has two daughter nuclei.Chromosomes start to uncoil and two nuclear membranes are made.
10. CytokinesisDivision of the cytoplasm2 daughter cellsDifferent mechanisms are done in different cells:In animal cells, a circle of actin and myosin fibres pinch the cell membrane in a process known as cleavageIn plant cells, a new cell wall and middle lamella are made before the end of mitosis.