1.2.2 the synthesis and transport of proteins Flashcards
what sort of system do eukaryotic cells have
a system of internal membranes, which increases the total area of the membrane
why do eukaryotes have a relatively small surface area to volume ratio
because of their size
how does the small surface area to volume ratio of eukaryotic cells create problems for them?
the plasma membrane is too small an area to carry out all the vital functions carried out by membranes
what does the endoplasmic reticulum do
it forms a network of membrane tubules continuous with the nuclear membrane
what is the golgi apparatus
a series of flattened membrane discs
what are lyosomes
membrane bound organelles containing a variety of hydrolases that digest proteins, lipids, nucleic acids and carbohydrates
what does a vesicle do
transport materials between membrane compartments
what is the difference between rough endoplasmic reticulum and smooth
RER has ribsomes on its cytosolic face, while SER lacks ribosomes
where are lipids synthesised
in the SER, and inserted into its membrane
where does the synthesis of all proteins begin
in cytosolic ribosomes
where is the synthesis of cytosolic proteins completed, and where do they go upon completion
cytosolic ribosomes, and they just remain there once they have been synthesised
what do transmembrane proteins do
they carry a signal sequence, which halts translation and directs the ribosome synthesizing the protein to dock with the ER, forming the RER.
what is a signal sequence
a short stretch of amino acids at one end of the polypeptide that determines the eventual location of a protein in a cell
does translation continue after docking
yes
what happens after docking
translation continues, and the protein is inserted into the membrane of the ER
