Flashcards in 8.29.16 Lecture Deck (73)
The cytosol of a mammalian cell is divided by ___ into specialized compartments.
Describe the basic composition of a mammalian cell vis a vis cytosol and organelles.
50% cytosol, 50% organelles
The majority of a cell's membrane is found ___.
What are the organelles typically found in a cell?
Nucleus, endoplasmic reticulum, mitochondrion, Golgi apparatus, peroxisome, lysosome, endosome, free polyribosomes
Approximately how many mitochondrion are found in the cell?
The nucleus is ~___ of cell volume and its membrane is continuous with the ___.
What organelles are involved in the sorting and exocytic networks?
ER, Golgi, secretory vesicles
What organelles are involved in the endocytic network?
Plasma membrane, endosomes, lysosomes
___ are derived from the ER.
Internal luminal compartments are ___ to the outside of the cell.
Translation occurs in the ___.
Gated transport takes place ___ between the cytosol and the ___.
Transmembrane transport takes place ___ between the cytosol and what 4 organelles?
unidirectionally; mitochondria, endoplasmic reticulum, plastids, peroxisomes.
Vesicular transport involves what 6 organelles?
Golgi, early endosome, late endosome, lysosome, secretory vesicles, cell exterior
Vesicular transport occurs bidirectionally from the Golgi to the ___, ___, and ___.
Late endosome, early endosome, secretory vesicles
Vesicular transport occurs unidirectionally from the Golgi to the ___, from the early endosome to the ____, from the late endosome to the ___, and from the secretory vesicles to the ___.
Cell exterior; late endosome; lysosome; cell exterior.
What are the three types of transport occurring in the cell?
1. Gated transport
2. Transmembrane transport
3. Vesicular transport
What do sorting signals do?
Direct proteins to specific compartments
Sorting signals are specified by ___.
the amino acid sequence of the protein
What are the two general types of sorting signals?
1. Linear sequences, often at the ends of proteins
2. Several separated regions that form a signal patch when folded
What are the general signal peptides for the following actions?
1. Import into the ER
2. Import into the mito
3. Import into the nucleus
4. Import into the peroxisome
5. Export from the nucleus
1. Hydrophobic center
2. Amphipathic alpha helices
The nucleus is bounded by a ___ that is perforated by ~4,000 ___ per cell.
Double membrane; nuclear pores
What is the nuclear envelope?
The inner and outer nuclear membranes
True or false - nuclear pores are only open sometimes.
False - nuclear pores are always open.
The nuclear pore is a complex structure with properties of a molecular ___.
Nuclear pores contain 8-fiber "___."
Fibrils of the nuclear pore extend into the ___ and the ___ and adhere to trafficking ___.
Nucleus; cytosol; cargo.
The nuclear pore is permeable to molecules ___. Larger cargo requires ___ and ___, and active energy-dependent gated transport.
Less than 60kDa; NES; NLS
For larger molecules, transport through the nuclear pore requires participation of what two things?
1. Cargo receptors
2. Ran, a small monomeric GTP binding protein