intracellular processes Flashcards
where does protein synthesis begin?
it starts in the cytosol on ribosomes
how are proteins dispatched to different locations within the cell?
it is done according to their specific address labels contained in their amino acid sequence
what are nuclear pores?
selective gates for nuclear proteins
what are protein translocators?
for proteins moving from cytosol into ER, mitochondria , peroxisomes
what are transport vesicles?
for proteins moving from the ER onwards
where is the final destination for epidermal growth factor?
extracellular
where is the final destination for DNA polymerase?
nucleus
where is the final destination for keratin?
cytosol
where is the final destination for melanin?
melanosomoes
what is SRP?
signal-recognition particle is in the cytosol and binds to the ER signal peptide when its exposed on ribosome. The SRP receptor is embedded on the ER membrane (postman)
what is the translocon?
protein channel in the ER membrane which it is threaded through (letterbox)
what is the SRP receptor
it is in the ER membrane (name plate on door)
what is the Golgi apparatus?
the sorting organelle of the cell located in the cytoplasm. proteins from the RER are sent to the Golgi. As they move through the Golgi they are modified and packaged into vesicles.
what is the endosome?
an organelle that contains molecules to be degraded
what is the cis cisterns
the cisterna nearest the ER which proteins pass through
what is phosphorylation
addition of a phosphate which alters the activity of the protein
what is acetylation
addition of an acetyl which regulates gene expression
what is farnesylation
addition of a farnesyl group which targets proteins to cytoplasmic face of the plasma membrane
what is ubiquitination
the addition of a ubiquitin chain which targets protein for degradation
what are lysosomal enzymes
used for lysosomal degradation and are activated by an acidic environment
what is proteasomal degradation?
it takes place in the cytosol at proteasomes which are cylindrical protein complexes . walls formed from protease enzymes and the active site is inside the cylinder. there are protein stoppers at either end which have to be open to allow the protein that is going to be degraded in.
what is S?
Svedberg, a non linear measurement dependent on mass density and shape.
what is sedimentation rate?
how quickly it will settle at the bottom after centrifugation
what are nuclear pores?
selective gates for nuclear proteins
what are protein translocators?
for proteins moving from the cytosol into the ER, mitochondria, peroxisomes
what are transport vescicles?
for proteins moving from the ER onwards
what is the signal peptide?
a specific sequence on the N-terminal amino acids
how do proteins know to go to the ER?
because of the signal peptide on the protein being made
what type of protein degradation would be used for a protein with a short half life?
proteasomal degradation
what type of degradation would be used for a protein with a longer half life?
lysosomal degradation
what are the subunits that make up a ribosome?
large - peptide transferase centre
small - decoding site
How do proteins travel from ER to golgi?
Transport vesicles
