The importance of protein targeting Flashcards
Light microscopy resolution is limited
by…
the wavelength of light (300 – 900
nm; visible light).
Light microscopy wavelength?
300 - 900 nm; visible light
the nucleus contains…
… genetic information, chromosomes (23 homologous pairs in
humans)
the nucleus is highly structured because…
…double membrane and pores (nuclear envelope)
strict control over nuclear traffic
where is the nucleolar organising region located?
in the nucleolus on p arms of chromosomes; 13, 14,
15, 21 & 22 aggregate
what does the nucleolar organising region contain?
rRNA and rRNA protein
what is the ER encrusted with?
Usually encrusted with ribosomes (rough ER),.
the ER is the site of…
…protein translation
what is the ER?
The ER is a highly organised folded
membrane structure with a distinct
lumen biochemistry
Post-translational modifications
may occur (cleavage of pro-forms)
What may occur in the ER?
Post-translational modifications
may occur (cleavage of pro-forms)
what does the ER interface with?
Interfaces with golgi Cis membrane
as part of the secretory pathway
what is the golgi?
Folded stack of membrane stack; contains a lumen where post
translational protein modification occurs
Function of the golgi?
Packaging system creating vesicles destine for secretion or for proteins
destined to be expressed on plasma membrane
Golgi is a central component in…
the cells secretory
pathway
The golgi has what faces?
Has Cis and Trans membrane faces
mitochondria membrane?
Double membrane, highly folded membrane lumen (cristae)
what is mitochondria the site of?
Site of aerobic respiration (citric acid cycle); double membrane
required to generate proton-gradient (proton motive force) for
ATPsynthetase
the mitochondria has its own…
…genome (37 genes)
- trna
- NADH dehydrogenase
- Cyt-B
Mitochondria arose by…
…endosymbiosis
what are the chloroplasts structure?
Double membrane, highly folded and organised inner structure, thylocloid membrane stacks and stromal space
How did chloroplasts arise?
Arose through endosymbiosis (cyanobacter ancestor) – own genome
What are chloroplasts the site of?
Site of photosynthesis in photo-autotrophs
size of chloroplasts?
5-8 um diameter and 1-3 um thick
What do the chloroplasts contain?
Contains pigments; chlorophylls,
phycobilins and carotenoids
What is the lysosome?
The ‘stomach’ of the cell that is formed by the fusing of endosomes
and Trans golgi face vacuoles
What do lysosomes contain?
Contain acid hydrolases, site of autophagy and hydrolysis of foreign
agents
What do peroxisomes contain?
Contain NADPH oxidase (NOX) generate an oxidative burst
What are peroxisomes important for?
Important for viral / bacterial infections.
Functions of the cell membrane?
- Partitions the intracellular matrix from the extracellular matrix
- Controls what enters and leaves the cel
What do cell membranes differ in?
Cell membranes differ in the protein expression between cell types
What are highly specialised membrane receptors also known as?
ligand specific
Highly specialised membrane
receptors (ligand specific) involved in …
…extracellular signal perception and
channels
What do highly specialised membrane receptors do?
Allow signals that are not membrane permeable to be transduced in the
cell.
What do MHC proteins do?
MHC proteins identify self cells from non-self cells.
what does the cell contain an array of?
Thus the cell contains an array of highly specialised compartments (organelles), which have a distinct biochemical properties (proteins)
Why do proteins in the cell know where to go?
because they contain signals
(amino acid sequences) within the primary and tertiary structure
Amino acids are coded for in the…
…genome
Mutations in the
genome may mean
that …
… a protein targeting signal lost
