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2) Once the membranes are in place they are very useful as an
organizational tool . They can be used to organize enzymes for
biochemical activities. BIO 1140 – SLIDE 2 3. Regulation of solute transport 4. Responses to external signals 5. In and out of cell and/or organelles
Uphill or downhill
Receptors and signal transduction
e.g. ß-adrenoreceptor Cell-to-cell communication Recognition, adhesion, exchange of
Gap junctions, plasmodesmata
Fig. 7-2, Becker et al. 2009 BIO 1140 – SLIDE 3 3) Membranes are also responsable for controlling solute
movement in and out of the cell or in and out of organelles.
Transport proteins in the membrane control the movements of
solute across that membrane. Think about the sodium pump for
example. The sodium potassium ATPase
4) The membrane also the first point of contact in the cell and its
environment. so the membrane contains receptors protein
receptors that allow it to respond to environmental signals. The
response takes the form of detecting the signal and turing it into a
cellular response, so both detection of the signal and signal
trasnduction, that is turning that signal into a cellular response.
This is the second major fuction of the membrane
5) In a multicellular organism, the membrane is a important spot
for recongizing other cells in the environment. so if cells are going
to be linked together, that linking occurs in the membrane. The
membranes have to recongize each other and form some kind of
attachment. They may also be an important site of exchange of
material b/w the cells, in both animal and plant cells u find
communicating juctions. Its a point were the cells exchange info
directly form one cytoplasm to another though these membrane
structures. Plasma membrane of Schwann
cell (myelin sheath) 18% protein
82% lipid Inner mitochondrial membrane 76% protein
24% lipid BIO 1140 – SLIDE 4 Figs. 6.8, 36.5 > In the fluid mosaic model u have a double layer of lipids
that are held together by non-colvalent interactions, so
they are highly fluid. There are no c...
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This note was uploaded on 02/19/2014 for the course BIO 1140 taught by Professor Fenwick during the Winter '07 term at University of Ottawa.
- Winter '07