Cell division Flashcards
Cell continuity definition
All cells can develop from pre existing cells
Chromosome definition
Coiled threads of DNA and protein that become visible in the nucleus at cell division
Gene definition
Section of DNA that contains the instructions for the formation of a protein
Haploid definition
1 set of chromosomes in the nucleus. For example Sex cells (n)
Cell cycle definition
Changes that take place in a cell during the period between 1 cell division and the next
Homologous pair definition
2 chromosomes of similar size with the same sequence of genes (bone cells)
Diploid definition
2 sets of chromosomes in the nucleus. For example muscle cells. (2n)
Mitosis definition
Form of nuclear division in which 1 nucleus divides to from 2 nuclei each containing the same number of chromosomes with identical genes
Order of mitosis
Prophase
Metaphase
Anaphase
Telophase
Interphase definition
Phase in the cell cycle where the cell is not dividing. Cells are making copies of their DNA and cell organelles.
Prophase steps
Chromatin contracts
Chromosomes seen as 2 strands held together at centromere
Nucleus disappears
Spindle fibres appear
Nuclear membrane/envelope breaks down
Metaphase steps
Nuclear membrane is broken down
2 spindle fibres attach to each centromere
Chromosomes line up along equator
Anaphase steps
Spindle fibres contract
Equal number of identical chromosomes is pulled to each pole
Telophase steps
Chromosomes elongate to form chromatin
Spindle fibres breakdown
Nucleoli reform (envelope)
2 nuclear membranes form
Function of mitosis in a single celled organism
Asexual reproduction (amoeba/bacteria)
Function of mitosis in a multicellular organism
Growth and repair (zygote and embryo)
Cancer definition
Group of disorders in which certain cells lose their ability to control both the rate of mitosis and the number of times mitosis takes place
Possible causes of cancer
Carcinogens
1. Smoking
2. Radiation exposure
3. Tanning beds
Meiosis definition
Form of nuclear division where 4 daughter nuclei contain half the chromosome number of the parent nucleus
Function of meiosis in multicellular organisms
- Sexual reproduction (gametes)
- New combination of genes formed (variation)
What happens during mitosis and meiosis in plant cells
Vesicles gather to form a cell plate which forms new cell walls
What happens during mitosis and meiosis in animal cells
A cleavage furrow forms and deepens to produce 2 new cells
