Answer 1:
The Golgi complex is definitely my favorite
organelle -- what a cool name! Unfortunately,
you've got things a little turned around. The
Golgi complex is involved in the chemical
processing and folding of proteins. After
proteins are assembled from amino acids on the
ribosome, they enter the endoplasmic reticulum,
where they get folded up into their proper shape.
After that, some proteins are transferred to the
Golgi apparatus, where bits of sugars and fats are
added to the proteins and their final structure is
completed. The Golgi then packages
proteins into vesicles and delivers them to other
organelles or to the cell membrane.
Sometimes the Golgi might be involved in
defending the cell against bacteria and toxins,
but only indirectly. At lot of cells
use protein receptors on the surface of their cell
membrane to immobilize toxins or defend against
bacteria. Multicellular animals with immune
systems also secrete antibodies that immobilize
toxins and pathogens. These protein receptors
and antibodies are probably packaged by the
Golgi. There are other organelles that deal
with bacteria and toxic stuff inside cells --
these are the lysosomes and peroxisomes.
When the cell has some toxic waste to destroy, it
bottles it up in a vesicle. The vesicle can then
fuse with a lysosome or peroxisome, and the
strong chemicals in those organelles will break
down whatever was in the vesicle. Then the cell
can either expel the waste, or reuse the digested
bits.There are some cells in our body, called
macrophages, that work for our immune
system. The macrophages (the name is Greek for
'big eater') go around and eat up bacteria and
other nasty pathogens in our bodies. Peroxisomes
and lysosomes inside the macrophage then digest
the bacteria. You should also know that when we
get a bacterial infection, the bacteria are
usually outside our cells, not inside our
cells (there are a lot of spaces between the
cells in our bodies where bacteria can hang out).
The reason we get sick is because bacteria
often make toxins that damage our cells.
Usually the only time bacteria get inside our
cells is when macrophages eat bacteria. On the
other hand, viruses do get inside our
cells, and they cause damage by taking
over the cell, forcing it to make more viruses,
then killing the cell. The way our body deals
with viral infections is that a macrophage will
eat a whole infected cell, then use peroxisomes
and lysosomes to destroy the whole thing,
including the virus. Wow, that was a long answer.
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Answer 2:
Part of the Golgi apparatus is a set of
special vacuoles called Lysosomes. These are
membrane sacks that break off from the main Golgi
apparatus, and they are filled with enzymes that
break down other substances. When Lysosomes
contain beneficial substances like nutrients or
worn out cell parts that can be recycled, they
break down those substances and make them
available to the rest of the cell for use or
re-use. When Lysosomes contain harmful substances
like bacteria or poisons, they break down those
substances too, then they move them out of the
cell. Once those substances are out of the cell,
they're usually not harmful anymore, because the
enzymes in the Lysosomes have deactivated or
destroyed them. Many scientists are
working very hard to figure out how the Lysosomes
can tell the difference between beneficial
substances and harmful ones. Excellent question!
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