1. CREATED BY V.O NGWENYA
200728427

2.  Chromosomes form when the chromatin network in the
nucleus of the cell, coil up, shortens and thickens.
 Each organism has a specific amount of chromosomes.
 All humans have 46 chromosomes.
 These chromosomes are arranged in identical pairs
called homologous chromosome pairs –
 Therefore humans have 23 homologous pairs of
chromosomes.
 These chromosomes is only visible during cell division
processes.
 One chromosome consist of 2 chromatids and one
centromere that attach the chromatids together.
 Each chromatid consist of genes which in turn consist of
DNA.

3. X and Y chromosomes:
gonosomes/sex-chromosomes
Colored bands
represents different
genes

4. The cell cycle includes the following phases:
 Interphase (include G1- , S- [DNA synthesis]
and G2 phase)
 Prophase
 Metaphase
 Anaphase
 Telophase
The result is 2 identical cells.

5.  Allow an organism to
grow.
 Repairs damaged
cells/tissue.
 Replace dead cells/tissue.
 Reproduction in some
simple organisms.

6.  In all somatic cells (include all body cells and
excludes the sex cells – sperm/egg cells)

7.  CONSIST OF A FEW PHASES:
 INTERPHASE
 PROPHASE
 METAPHASE
 ANAPHASE
 TELOPHASE

8.  Cell builds up enough energy for division
process.
 DNA replication occurs
 Cell look normal, like before division

9.  Nuclear envelope and nucleolus
disappear.
 Chromatin become more tightly
coiled, and condenses into
individual chromosomes.
Chromosomes arrange randomly
in the cell.
 Centrioli move to opposite poles,
with spindle fibers stretching
between them.

10.  The centrioli reached the opposite poles with
the spindle fibers in between.
 The chromosomes arrange randomly on the
equator, each single chromosome attaching
to a separate spindle fiber by means of the
centromere.

11.  The spindle fibers pull tight.
 The centromers attaching the chromatids of
the chromosomes split in half.
 Daughter chromosomes move to opposite
poles.

12.  Daughter chromosomes reach
poles.
 Nuclear envelope surrounds
chromosomes.
 Nucleolus reappear at each pole.
 Chromosomes become less
condense forming chromatin.
 Two identical nuclei has been
formed

13.  Invagination of the cytoplasm and plasma
membrane occurs. (Cleavage furrow forms in
animal cells and a cytoplasmic plate forms in
plant cells)
 Continues until the cell in divided into 2
separate cells. (Identical to one another and
to the original cell)