Mitosis Flashcards
What happens in interphase?
G1 phase - The cell grows and makes a new set of organelles and proteins for the daughter cells.
S phase - The DNA in the cell is replicated. There is also checking of genetic material in this phase.
G2 phase - Cell growth continues and there is synthesis of special proteins in preparation for mitosis.
What occurs in prophase?
The chromosomes thicken and condense, becoming visible.
The nuclear envelope breaks down
Spindle fibres develop from centrioles and span from cell to cell
What occurs in metaphase?
Chromosomes are pulled along the spindle apparatus
The chromosomes align in the EQUATOR of the cell.
Spindle fibres begin to attach to each sister chromatid
What occurs in anaphase?
The centromeres divide in two and move to opposite poles of the cell, pulled by microtubules
The sister chromatids are pulled apart to opposite poles of the cell and now referred to as daughter chromosomes
Energy for this phase is provided by mitochondria
Chromatids appear in a V shape
What happens in telophase/cytokinesis?
The start of the cell division where the spindle fibres degenerate
Chromosomes reach the opposite poles
The nuclear envelope and nucleus reform around each set of chromosomes to form 2 nuclei
Cytoplasm divides
2 daughter cells that are genetically identical
The cell splits into two at the end of mitosis, forming a new nuclear envelope and plasma membrane
What is chemotherapy?
A type of cancer treatment that; prevents DNA replication or inhibits metaphase by damaging spindle fibres so the chromosomes cannot travel to the poles of the cell
To which exact part of the chromosome do the spindle fibres attach?
Centromere
What is cancer?
A tumour that invades surrounding tissue
How to squash the tissue on the slide to avoid damaging the chromosomes?
Coverslip over specimen
What does an abnormally high mitotic index suggest could be occurring in the tissue sample?
The tissue may be undergoing repair
Or
Cancerous growth may be occurring
What is an eyepiece graticule?
A transparent ruler with numbers, fitted onto the eyepiece
to measure the size of objects viewed
What is the purpose of a stage micrometer?
Allows you to be able to measure the cells being viewed and calculate their actual size and the magnification
Explain why chemotherapy prevents cancerous cells from dividing.
If DNA is not synthesized mitosis does not occur leading to a prevention of uncontrolled mitosis.
