Summary Topic 3 Mitosis and Meiosis

Mitosis

4 stages
cytokinesis follows mitosis


S.I units 1. Interphase cell
chromatin >
-
(uncondensed chromosomes)
complex of DNA with histome proteins


2. Stage 1 -



prophase
to 4 centrioles - pairs
mitotic spindle starts
form >
-




↳ microtubules
+ move to the
poles of the cell
-

chromosomes start to condense
histomes
↳
supercoiling
- DNA wraps
tightly around
nucleolus is
gone
-




nuclear
envelope breaks down
-




(visible
chromosomes
fully condensed
-




-Asters small projections
are from spindle fibres towards
the membrane it in place
.
holding
3
. Stage 1 . (metaphase
-


chromosomes line up at metaphase plate (equator)
-
attach to spindle via centromere


4.
Stage .
3 (Anaphase
-microtubules pull sister chromatids towards poles and centromere

splits

5
. Stage 4 .
(Telophase



1 reversea
-

chromosomes start to condense
- nucleolus reappears
-

spirale fibres disappear
nuclear membranes reforms
-




-contractile/activ
ring pinches
the cell and creates a cleavage furrow

, .
0
Cytokinesis
cytoplasmic division
-




-



fluidity allows this
-
phospholipids can move in the
plane of
S.I units the membrane

-




Genetically identical
daughter cells (diploid)
G
3

4
Sets
3
of
DNA 2

↑

O

62
I
S I
G2 'P'MIAITIc



1


x
.




·
X

3
. ↳.
-
t
I




·
i
d .




" ↑
T ⑭
!