what are the 2 types of cell division
mitosis
meiosis
Mitosis
-growth, repair and asexual reproduction
- produces 2 genetically identical diploid daughter cells
interphase
where the cell prepares for division
stages of interphase
Gap 1
synthesis
gap 2
gap 1
the cell grows and performs its normal functions
- organelle replication
- protein and enzyme synthesis
synthesis
- DNA is replicated
- chromosomes consists of 2 identical chromatids
gap 2
- cell continues to grow and additional proteins are synthesized
- production of energy
prophase
- chromatin fibres coil and condense into chromosomes
- the nuclear envelope breaks down
- the spindle fibres begin to form, and attach to the centromere of each chromosome
- centrioles move to opposite poles of the cell
metaphase
- chromosomes align at the equator
- spindle fibres attach to the centromeres
anaphase
- centromere splits, and spindle fibres shorter, pulling sister chromatids to opposite poles
- chromatids become individual chromosomes
telophase
- nuclear membrane reforms around the 2 sets of chromosomes, forming 2 nuclei
- chromosomes decondense to chromatin
- spindle fibres break down
cytokinesis
- cytoplasm divides into 2 daughter cells.
- cleavage furrow forms, splitting the cell into 2
(in plant cells- cell plate forms between 2 daughter cells developing into a cell wall)
importance of mitosis
- allows organisms to grow
- cell replacement
- asexual reproduction
- genetic stability
what should be present for chromosomes to get paired
- centromere should be at the same position
- size of chromosome should be the same
- same gene on same locus
locus
position of a gene on a chromosome
why are gene loci said to be linked
if they are on the same chromosome
sex-linked
if genes are located on the same sex chromosome
autosomal linkage
- occurs on any chromosomes that aren’t sex chromosome
- 2 or more genes on the same autosome do not assort independently during meiosis
- they stay together in an original paternal combination
