Unit 5 - E Cell and Nuclear Division

AS LEVEL
B I O LO GY

,5 The mitotic cell cycle .............................................3

5.1 Replication and division of nuclei and cells ....................3
Chromosomes .............................................................3
Mitosis ........................................................................6

The significance of telomeres ......................................10
Stem cells ..................................................................10
Cancer ......................................................................11
5.2 Chromosome behaviour in mitosis...............................13

, 5 THE MITOTIC CE
C YC L E
When body cells reach a certain size they divide into two. Nuclear division
followed by division of the cytoplasm. The mitotic cell cycle of eukaryotes in
replication followed by nuclear division. This ensures the genetic uniformity
cells.


Candidates will be expected to use the knowledge gained in this section to
in familiar and unfamiliar contexts.



5 .1 R E P L I C A T I O N A N
DIVISION OF NUCLEI A
CELLS
During the mitotic cell cycle, DNA is replicated and passed to daughter cel


Stem cells in bone marrow and the skin continually divide by mitosis to prov
continuous supply of cells that differentiate into blood and skin cells.


LEARNING OUTCOMES

C ANDIDATES SHOULD BE ABLE TO:

A. describe the structure of a chromosome, limited to DNA, histone protein
centromere and telomeres


Chromosomes