2.3. Intracellular Compartments and protein sorting 1. Flashcards
Where are proteins translated?
On ribosomes in the cytosol
Define protein sorting
Identifying their destination
Define protein trafficking
More about movement than the destination.
What are the 3 basic compartments that the cell is divided in?
Nucleus-cytosol. Secretory/Endocytic pathway organelles, and mitochondria.
What is the nucleus-cytosol bridge by?
Nuclear pores
What is the secretory/Endocytic pathway organelles bridged by?
Vesicles
Is the nuclear membrane of the nucleus continous with the ER?
yes
What is the function of the nucleus?
Where DNA, RNA synthesized. Ribsomes are assembled in the nucleolus
What does the cytoplasm consist of?
Cytosol + organelles
What is the function of the cytoplasm?
Metabolism
What if the function of the ER?
Ca storage and signaling.
What is the function of the R ER?
protein/lipid syntheses
What is the function of the S ER?
Protein folding+quality control
The rough ER has the highest what?
Surface area. Saying proteins are important.
What is the function of the golgi?
Protein/lipid modifications. Trafficking center
What is the function of lysosomes?
Degradation of organelles and biomolecules.
How many membranes does the mitochondria have?
2
What is the function of the mitochondria?
Energy metabolism
What is one way to add surface area?
folding
What does it mean that the mitochondria is the 2nd with most volume?
Much energy is needed for the cell
What is the function of the chloroplast?
photosynthesis
What is the function of the peroxisome?
Like lysosomes but use Oxidation rxns unlike the lysosomes who use low PH
What is the endosymbiosis theory?
Mitochondria was engulfed by another cell. Slowly becoming part of that cell itself.
What is the matrix equivalent to in an intact cell?
Cytosol
What do your answers mean for carbohydrate metabolism in bac?
Across outer membrane in bac
Why do mitochondria contain DNA?
Originally were an intact cell, that got engulfed.
What genes are in the mitochondrial genome?
Not enough to sustain life anymore. Just important ones to perform functions in the mitochondria
Whu is the universal genetic code not used in mitochondria?
They use a modified genetic code. This was engulfed before out current genetic code was the universal genetic code
Why is the mitochondria not equivalent to any other compartment?
So many membranes to cross
What are the 3 types of transport?
Gated, Transmembrane and vesicular
What uses gated transport?
Cytosol nucleus. Equivalent compartments
What uses Transmembrane transport?
Cytosol –> organelle. distinct compartments
What uses vesicular transport?
Organelle Organelle. Equivalent compartments
What is a vesicle and what does it do?
Is a membrane bubble. Created by budding off an exisiting membrane. It fuses with target membrane, leacing its cargo into the next organelle.
What is the facilitator for Gated transport?
NPC
What is the facilitator for Transmembrane transport?
Translocator
What is the facilitator for vesicular transport?
vesicle
Which of the two transports leads to the membrane being crossed?
Gated and transmembrane
What are sorting signals?
Determine where proteins end up.
What is a signal patch?
Not all sorting signals are in a single location. Signal patch consolidates many scattered sequences.
Are sorting signals necessary or sufficient for protein targeting?
Both.
How and when are sorting signals cleaved?
With signal peptidase after protein reaches final destination
What is the biochemical feature and location on the protein of a signal sequence that is importing to nucleus?
+ charge, internal
What is the biochemical feature and location on the protein of a signal sequence that is exporting from nucleus??
amphipathic, internal
What is the biochemical feature and location on the protein of a signal sequence that is importing to mitochondria?
+ charge, N-term
What is the biochemical feature and location on the protein of a signal sequence that is importing to ER?
hydrophobic core, N-term
What is the biochemical feature and location on the protein of a signal sequence that is returning to ER?
AA sequence: KDEL. Mixed. C-term.
What is the biochemical feature and location on the protein of a signal sequence that is importing to plastid?
hydroxlys, N-term
What is the biochemical feature and location on the protein of a signal sequence that is importing to peroxisomes?
Mixed, C-term
What are some features of Nucleus to cytosol and vice versa?
Gated, selective, bidirectional.
What signal is needed to go from Nucleus –> cytosol?
NES
What signal is needed to go from Cytosol to nucleus
NLS
What signal is needed to go bi direction from either Nucleus to cytosol or cytosol to nucleus ?
NES and NLS
True or False? Nucleur pores are gaping holes.
False. Gated and selective
What are NPCs?
Nuclear pore complexes that allows fast simultaneous bidirectional passage to molecules.
What are the 4 categories of nuclear porins?
Scaffold, ring, channel, fibrils
What does the scaffold do?
Stabilize membrane
What does the ring do?
Anchors to membrane
What is the channel?
Connectors and gates (FG repeats)
What are the fribrils?
Neither structured nor symmetrical