Chp. 15 Flashcards
Contains many metabolic pathways, protein synthesis, and cytoskeleton
Cytosol
Synthesis of most lipids, synthesis of proteins for distribution to many organelles and to plasma membrane
ER
Modification, sorting, packing of proteins and transport
Golgi
Intracellular degradation
Lysosomes
Sorting of endocytosed material
Endosomes
oxidative breakdown of toxic molecules
Peroxisomes
Membr ane-enclosed organelles occupy nearly __ of the cell volume
50%
Membrane-bound organelles allow __ of different cellular functions
spatial separation
With the exception of the nucleus, these organelles communicate extensively with one another and with the outside of the cell via
vesicular traffic
Nuclear envelope and the membranes of the ER, Golgi apparatus, endosomes and lysosomes likely originated by
invagination of the
plasma membrane
Mitochondria and chloroplasts likely evolved from
bacteria that
were engulfed by primitive eukaryotic cells
Mitochondria and chloroplasts remain…
isolated from the vesicular traffic
Protein transport begins with a
Signal sequence
The synthesis of virtually all proteins begins in the
Cytosol
The fate of each protein depends on whether it contains a
signal sequence, which directs the protein to a particular
organelle
Proteins that lack a signal sequence remain in the
Cytosol
The mechanism by which a protein is transported into an
organelle depends on the
Organelle
Transport of folded proteins into
Nucleus through nuclear pore
Transport of unfolded
proteins into the
ER, mitochondria or chloroplasts across their membranes by
protein translocators
Transport of proteins in
transport vesicles that
pinch
off from the ER and fuse
with a compartment of the
endomembrane system
On the cargo protein is it sequence specific signal
Yes
Signal sequence is recognized by
receptor proteins
Directional movement by transport machinery requires
Energy
Large pore, competent for fully folded proteins/complexes. GTP hydrolysis provides energy
nuclear import