Presentation by Andreas Schleicher Tackling the School Absenteeism Crisis 30 ...
Cell cylce and cell division, an introduction
1.
2. All organisms reproduce.
Reproduction has a cellular
basis.
All cells come from pre-
existing cells
Cell division enables living
things to repair damage,
grow and produce offspring
3. • Sexual reproduction, two parents are involved
and the genetic material combines. Union of
sex cells (egg and sperm).
• Some organisms reproduce by simple cell division
(asexual reproduction). Ex. Paramecium (unicellular),
and Sea stars (multicellular).
4. Cell
division
Process by which a parent cell
divides into two daughter
cells.
Mitosis Meiosis
Each daughter cell
is genetically
identical to the
parent cell.
Chromosomes in
the daughter
cell is reduced
by half
5. Eukaryotic cells
undergo a
sequence of
events known as
the CELL CYCLE.
The cell cycle goes
from the birth of a
cells until it
reproduces.
6. 90% of the cell cycle in
interphase
S phase 3-6 hours.
Duplication of
chromosomes.
Cell increases
supply of proteins
and # of many
organelles.
Cell carries out
metabolic processes
S DNA
Synthesis.
G
Gap.
Chromosomes are
loosely packed as
chromatine fibers.
G
Gap.
Cell is ready for
mitosis.
7. Includes 2 processes:
Mitosis
Cytokinesis.
Mitosis: Nucleus and chromosomes
divide.
Cytokinesis: is the process by which
the cytoplasm is divided in two.
Error in chromosome distribution is 1
in 100 000 cell divisions.
8. Centrioles are only present in
animal cells.
They help organize the
microtubules.
16. Concept check
1. Describe a significant event that occurs in each
of the four stages of mitosis.
2. Compare and contrast cytokinesis in animal
and plant cells.
3. In what sense may prophase and telophase in
mitosis be characterized as opposites?
17. homework
Mitosis
Meiosis
Allele
Somatic Cells
Nucleus
G1 Phase
Interphase
G2 Phase
Chromatin
Research two different biological concepts for the
following words indicating the source of each
concept: