Dan.
The transporters that absorb the nutrients are proteins that are
synthesized in the cells lining the small intestine and they reside in
those cells membrane. The question if people ever get sick from
defective transporters is yes, among others it can lead so severe
diarrhea that can bee fatal. But I doesn’t know so much about
the deseases
The difference between an unpaired and a coupled is just that the
coupled need to have two or more different molecules and the unpaired
just one, bound to it to make the configuration change and transport
the molecules over the membrane, in or out.
Chylomicrones is only made in the cells lining the small intestine,
and it’s always secreted into the lymph. Similar lipoproteins,
(smaller and with less % triglycerides) are made and secreted by the
liver into the bloodstream, and this are called VLDL (very low density
proteins).
No you got it a little bit wrong, The free glucose in the intestine is
always transported to the blood by membrane bound transportproteines.
Then it floats through the bloodstream until it reaches a cell that
have Glut 4 or some other glucose transporter (Glut 4 is almost only
found in muscle and fat-cells, there is other glucose transporters in
other tissues.) It, isn’t so that we cave sugar when the cells
expressing a lot of Glut 4. The Glut 4 expression is high when we have
a lot of glucose in our blood, as a response on the secretion of
insulin that take place when the bloodsugar is high. Our hunger is
regulated by a center in hypothalamus but it’s not clear the
mechanisms that regulate it, it can bee that the neurons are sensible
to glucose.
I tried too look a little bit into Chron’s, but it seem that
none is really shore about the causes of the deasese. But it seems too
be a lot of research in the field and it look like many investigators
are thinking that it could bee bacterial caused.
Mikael
