Cell cycle Flashcards
Cell cycle stages
Interphase (most of time)
Mitotic phase
What happens in interphase?
DNA is replicated: DNA is decondensed in the form of chromatin
Organelles replicated
Nucleoli visible
ATP content increased so more energy stores in the cell
DNA condensing
DNA in cell is in form chromatin = appears as dark
Where they aren’t visible
But then condenses to be thick and visible in prophase
What forms after Chromatin condenses?
A chromosome
What is formed after DNA replication?
2 sister chromatids joined together by centromeres
Ready to be split apart in mitosis
Stages of mitotic phase in order?
Prophase
Metaphase
Anaphase
Telophase
What happens in prophase?
Centrioles formed at opposite ends of cell forming network of protein (spindle fibres)
Nuclear membrane breaks down so chromosomes lie free in cytoplasm
Chromosomes are visible and in the form of 2 sister chromatids: due to condensing
What happens in metaphase?
The chromosomes (consisting of 2 sister chromatids) line up in equator of cell, attached to spindle fibres at centromere
What happens in anaphase?
The centromeres divide into 2 which pulls sister chromatids apart to opposite poles as the spindle fibre shortens and contracts
This process requires ATP
Separated chromatids appear v shaped and are now counted as 1 chromosome
What happens in the first stage of telophase?
The spindle fibre apparatus breaks down As half the chromatids reach opposite side of the poles still with a centromere they decondense = long and thin now chromosomes
Nuclear membrane and nucleolus reappear = 2 nuclei
What happens in second stage of telophase -cytokinesis?
Central cell surface
membrane breaks down so cells divided into 2 genetically identical daughter cells
What does mitosis specifically refer to?
Division of the nucleus
What does cytokinesis refer to?
Division of the cell
What kind of process is mitosis?
Controlled
How are cancers and tumours formed?
By uncontrolled cell division
