Flashcards in Mitosis Deck (14):
What is mitosis?
-Process of cell division in eukaryotic cells, but mainly nuclear division.
-Ensures both daughter cells produced when parent cell divides are genetically identical.
What is mitosis necessary for?
-When all daughter cells have to be identical so for, growth and repair of tissues.
-Also, for asexual reproduction.
What is asexual reproduction?
-Production of genetically identical offspring from one parent in organisms like plants and fungi.
What is a chromosome?
What is a chromatid?
-Two identical DNA molecules.
What happens to chromosomes during interphase?
-Each chromosome is converted into chromatids.
What is the centromere?
-Region where two chromatids are joined together.
What are the four stages of mitosis?
-Prophase, metaphase, anaphase and telophase.
What happens during prophase?
-Chromatin fibres begin to coil and condense to form chromosomes. The nucleolus disappears and nuclear membrane breaks down.
-Protein microtubules form spindle shaped structures linking the poles of the cell. Fibres are necessary to move chromosomes.
-Two centrioles migrate to opposite poles.
-Spindle fibres attach to centromeres and move chromosomes to centre of cell.
-By the end, nuclear envelope had disappeared.
What happens during metaphase?
-Chromosomes moved by spindle fibres to form a plane in the centre called the metaphase plate and held in position.
What happens during anaphase?
-Centromeres holding the pair of chromatids in each chromosome divide.
-Sister chromatids separated and pulled to opposite poles.
-4 "V" shaped chromatids at each pole.
What happens during telophase?
-Chromatids have reached poles and now called chromosomes.
-Two new sets of chromosomes assemble at each pole and nuclear envelope reforms.
-Chromosomes uncoil and nucleolus forms.
How is cytokinesis performed in animal cells?
-Cleavage furrow forms around middle of cell.
-Cell-surface membrane pulled inwards by cytoskeleton until close enough to fuse.
-Forms two identical daughter cells.