exam 1 major organelles Flashcards
what is the mitochondria responsible for
oxidative metabolism of carbohydrates, lipids, and amino acids
what are the protein-synthesizing organelles in cells
ribosomes
what is the ER responsible for
modification and maturation of integral membrane and secreted proteins, and for lipid synthesis
what is the golgi involved in
sorting center for proteins and membranes
modification of proteins
what is evidence for endosymbiotic theory
mitochondria contain ribosomes
mitochondrial inner membrane is rich in lipid, cardiolipin
what is the endosymbiotic theory
some organelles used to exist as free-living organisms
what does mitochondria generate
most of the cell’s ATP
what membrane structure do mitochondria have
double membrane - two membranes, unlike nucleus with folded
what is the outer membrane of the mitochondria full of
porins (channel proteins)
what is the outer membrane of the mitochondria similar to
plasma membrane
what is the inner membrane full of
cardiolipin - rare in eukaryotic, abundant in prokaryotic
what is the inner membrane folded into and why
cristae - increases surface area of inner membrane relative to outer membrane
what is the inner membrane the site of
electron transport chain - more surface area = more electron transport = more metabolism
what does the intermembrane space of mitochondria contain
cytochrome c and several factors that regulate programmed cell death
what is the mitochondrial matrix the site of
oxidative metabolism + contains mtDNA, ribosomes, and other components for expression of mitochondrial genome
what is oxidative metabolism
oxygen combines with electrons and protons to form water
who is the mitochondrial genome inherited from
the mother
who is mitochondrial Eve
single woman in Africa many years ago, who is the ancestor of all current living humans
where are ribosomes found
in cytoplasm and within mitochondria and chloroplasts
are ribosomes enclosed by a membrane
no
what are ribosomes made of
large complexes of protein + RNA, which are structural components
what are the two subunits of the ribosome
large and small
when do the ribosomal subunits assemble
when protein synthesis initiates
where does the ER extend throughout
the cytoplasm
what does endoplasmic mean
contained within cytoplasm
what does reticulum mean
mesh-like network
what is the ER continuous with
nuclear membranes
what does the ER lumen merge with
nuclear intermembrane space
what is the rough ER
associated with many ribosomes
what is the smooth ER
lacks attached ribosomes
what is the ER storage for
storage for calcium ions (for cell signaling)
what is the function of the smooth ER
lipid synthesis and detoxification of lipid-soluble compounds
what is the function of the rough ER
synthesis of transmembrane and secreted proteins
what is the purpose of scramblase
gets lipids into both ER leaflets - phospholipid molecules flip and there is symmetric growth of both halves of the bilayer
what is flippase
gets appropriate asymmetry in plasma membrane by selectively moving some lipids from outer leaflet to inner and vice versa
how are rough ER-synthesized proteins modified
by adding a common oligosaccharide
why is N-linked glycosylation called that
the attachment site is the -NH2 group of an asparagine
what does N-linked glycosylation help with
protein folding in ER - carbohydrates attach to amine group of asparagine
what indicated something is not properly folded
hydrophobic residue on outside
what does the golgi do along the secretory pathway
central sorting station for proteins and membranes
what does the golgi consist of that creates its shape
a series of flattened discs called cisternae arranged in a stack
what is the cis face of the golgi
closest to ER and receives vesicles containing ER-synthesized proteins
what is the trans face of the golgi
furthest from ER and represents the exit from golgi
what is the golgi the synthesis site of
most cellular carbohydrates
what happens to N-linked oligosaccharides in ER
in ER on asparagine - trimmed and further processed by addition of other sugars to generate high mannose oligosaccharides
what is N-linked glycosylation compared to
buying something off the rack - uses common carbohydrate
what is O-linked glycosylation compared to
getting clothes custom made - unique
what happens with O-linked glycosylation
proteins get carbohydrates added to the hydroxyl group of serine or threonine in Golgi
why does N-linked glycosylation use a pre-formed common carbohydrate that is later modified for each protein
the process simplifies regulation
the common carbohydrate has one function in the ER, and then new functions can be added by modifying the carbohydrate on individual proteins later
