Transcript Structure, function and growth of prokaryote and eukaryote cells

Structure, function and growth of
prokaryote and eukaryote cells
(iii) Differentiation of cells
into tissues and organs.
(iv) Cell and tissue culture
–Mammalian
cell cultures
–Bacterial and Fungal
Cultures
(v) Plant tissue culture
Development
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An organism starts life as a zygote (single
fertilised cell).
It undergoes three main stages to develop
into an individual
1.
2.
Mitotic division to form a group of cells called the
blastula.
Gastrulation
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Infolding of the cells to form a cup shape called a
gastrula
Development cont…
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The gastrula has three germ layers
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Endoderm
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Ectoderm
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Develops into the alimentary canal
Develops into skin and nervous system
Mesoderm
–
Develops into the muscles, skeleton, circulatory system,
excretory system
Development cont…
3.
Cell division and differentiation (specialisation)
results in tissue and organ formation.
Differentiation
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Nearly all cells in an organism have the
same DNA
Differentiation depends on gene expression
(the transcription of a gene into mRNA)
i.e. which genes are ‘switched on’ and which genes
are ‘switched off’.
Differentiation cont…
During development the control of gene
expression may be:
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Temporal (different genes expressed at different times
in development)
Spatial (cells in different places in the embryo
expressing different genes)
Example of differentiation to form an organism:
Drosophila melanogaster
Control of Gene Expression in Bacteria
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Lac operon (aka Jacob-Monod hypothesis)
Stem Cells
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A stem cell is an undifferentiated cell which can
undergo unlimited division to form other cells
Source of stem cells
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Adult e.g. bone marrow
Embryonic (from blastula stage ~ 150 cell stage)
Cancer cells
Umbilical Cord Blood
Stem cells have the ability to differentiate, unlike
specialised cells
Learning Activities
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Differentiation of Human Cells
Read DART pg 18-20
Scholar (Unit 1, no. 2)
Web animations from Biozone website
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http://www.sumanasinc.com/webcontent/anisamples/nonmajor
sbiology/stemcells.html
http://www.sumanasinc.com/webcontent/anisamples/majorsbio
logy/lacoperon.html
http://science.howstuffworks.com/stem-cell.htm