cell division - mitosis Flashcards
what are the two types of cell division
mitosis & meiosis
what is cell division
Cells division is the process that produces new cells.
what is cell division used for
In unicellular organisms, cell division is a form of asexual reproduction.
In multicellular organisms, cell division is used for growth and repair of the organism and to produce reproductive cells.
what are somatic cells
Somatic cells are all cells except reproductive cells (muscle cells, skin cells, nerve cells, etc.)
what form of cell division is mitosis
Mitosis is a form of cell division that occurs in somatic cells.
what form of cell division is meiosis
Meiosis is a form of cell division that produces gametes.
what are gametes
Gametes are reproductive cells (sperm in males and ova in females)
when does mitosis occur
mitosis occurs when a parent cell splits into two daughter cells
what is mitosis responsible for
Mitosis is responsible for growth, repair and replacement of cells within living organisms as well as during asexual reproduction
what are the five stages of mitosis
prophase
metaphase
anaphase
telophase
cytokinesis
is interphase a stage in mitosis
no
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during the interphase DNA appears in _________ ____
chromatin form
explain what happens in prophase
- The nuclear membrane around the nucleus disappears.
- Each chromosome and its copy condense to form a double stranded chromosome
- Spindle fibres form and attach to chromosomes.
explain what happens during metaphase
Spindle fibres move the double stranded chromosomes towards the equator of the cell.
exlpain what happens at the end of metaphase
by the end of metaphase:
- double stranded chromosomes are lined up along the equator of the cell.
- Spindle fibres are attached to the centromeres
explain what happens during anaphase
1.Spindle fibres contract and pull the double stranded chromosome apart.
2.Sister chromatids separate at the centromere.
when does anaphase end
Anaphase ends when the chromatids are at opposite poles of the cell.
explain what happens during telophase
1.The spindle fibres disappear.
2.Two new nuclear membranes form around the two bundles of chromatids
3.As the new nuclear membranes form, the chromosomes unravel again to form chromatin.
explain what happens during cytokinesis
The cell membrane moves inwards dividing the cytoplasm, forming two new daughter cells.
what happens after cytokinesis finishes
both daughter cells re-enter interphase until the cell is ready to divide again.
