3.2.2 Mitosis (all cells arise from other cells) Flashcards
what is the eukaryotic cell cycle
G1 - growth
S - DNA synthesis
G2 - growth and preparation for mitosis
M - mitosis
what occurs in the G1 stage
cell increases in size and new organelles are made, cell activity occurs
when occurs in the S phase
DNA replication occurs to produce 2 identical copies of the DNA strand - these are called chromatids which join at the centromere to form chromosomes
what occurs in G2 phase
cell increases in size and new organelles are made in preparation for mitosis
what occurs during mitosis
- prophase
- metaphase
- anaphase
- telophase
what occurs during prophase
- nuclear envelope breaks down (prometaphase)
- chromosomes become visible/condense
- centrioles move to opposite ends of the cell
- spindles begin to form
what occurs during metaphase
- chromosomes attach to spindles at their centromere
- replicated chromosomes line up down the middle of the cell
what occurs during anaphase
- identical/sister chromatids move towards opposite poles of the cell
- the centromeres divide
- the chromatids look V-shaped
- chromatids reach opposite poles and the spindles contract and shorten
- the sister chromatids separate
what occurs during telophase
- the nuclear membrane begins to form to create 2 nuclei
- chromatids uncoil and become long and thin
- two genetically identical daughter cells are produced
what occurs during cytokinesis
the cytoplasm divides
what are tumours a result of
uncontrolled cell division forming abnormal cells
what is a benign tumour
local to one area and grown locally
what is a malignant tumour
invade other tissues via the blood the is constantly growing
what is metastasis
cells breakaway from an original tumour caused by metastasis
what is apoptosis
programmed cell death
characteristics of malignant tumours
- faster growing
- invasive to other organs
- spread and metastasis
- create irregular surfaces
characteristics of benign tumours
- slowly growing mass
- regular surface
- non-invasive to other organs
- no spread or metastasis
what are secondary tumours
grown from metastasis of primary tumours via the blood
can all cells divide
no not all of them retain the ability to divide
what increases the rate of gene mutation
mutagenic agents
