Cells fixed at various time points post pulse-chase
"labeled" proteins closer and closer to PM over time
Movement is
towards apical
side
Green Fluorescent
Protein (GFP)
Transfection
Uses live organism
allows to watch prot. from start to finish
GFP DNA isolated
fused with target
section of DNA
Stop codon removed
two protein blueprints fused
One protein
coded by two
"Blueprints"
fused
Originally from
RNA
Example of
use:
study temp. sensitive
muts.
allows
observation of
location of
specific protein
Cell-Free Systems
Homogenization
Microsomes
Formed from the
homogenate
formed by endomembrane
system
Different microsomes
Different enzymes
Still contain transmembrane proteins
Centrifugation
density gradient
TM proteins isolated
Production of anti-bodies against
protein
endomembrane markers
allow to tack protein trafficking
Separates ER from Golgi
Explain the
use as a
marker
Endoplasmic
Reticulum
Rough
ER
Exported Proteins
Every known
cell has the
same function
for RER
Excretory
cells are
polarized
most
organelles
smooshed to
basal end
vesicles
at apical
end
Smooth
ER
Very tubular/Not flat
remove
hydrophobic
"invaders"
Annotations:
This process can be problematic though. It can sometimes form molecules that are just as or more dangerous than the hydrophobic predecessors.
Ex. Large molecules, once oxygenated, may become very flat. here flattened molecules may slide between base pairs in DNA and will be carcinogenic.
Why hasn't this faulty trait been weened out of the population through natural selection?
The answer is simple, traits are only selected during the pre-reproductive phase. Cancer is a disease that appears later in life. Therefore, it will not affect pre-reproductive populations
Detox
Varying
functions
Ca2+
ions
Synth.
Steroid
hormones,
cholesterol
synth. of
hormones
Signal Hypothesis
General Idea
Annotations:
Proteins to be secreted contain a specialized amino acid sequence in the first few amino acids. This is called the signal sequence.