Leary Flashcards
What are mitochondria
cellular organelle
Double membrane bound
Contain mitochondrial DNA which is maternally inherited
Inner vs outer mitochondrial membrane
Inner mitochondrial membrane is protein loaded, contains the ETC, and is impermeable which is needed for the proton gradient
Outer mitochondrial membrane is permeable with many holes, doesn’t have many proteins
These properties are relevant to how the organelle functions as a whole and contributes to cellular homeostasis
Where is the mtDNA, Krebs cycle, and metals
matrix of mitochondria
What are cristae? Which enzymes are concentrated there?
Inner folds of the mitochondrial membrane
Used to increase surface are to put more proteins and enzyme to produce more ATP
Enzymes of oxidative phosphorylation are concentrated within the cristae
T/F the function of the inner membrane is different depending on where it is
true
What are the reducing equivalents used in the ETC
NADH feeds into complex I and FADH2 feeds into complex II
These are needed for the ETC to function
Why might one tissue have more cristae than another
The inner membrane architecture is optimized for the tissue it functions in
Tissues that need more ATP will have more cristae
T/F mitochondria are static
False its a dynamic reticulum that responds to intracellular cues and extracellular stimuli
What are some cues that can cause the mitochondria to hyperfuse to become one organelle
Starvation
Translation inhibition
Viral infection
Conditions when differentiation is important
When would the mitochondria hyperfragment?
Cancer, bacteria, OXPHOS poisons
Conditions when cell division is important
What enzymes drive Fusion
MFN1 and MFN2
L-OPA1 vs S-OPA2
L-OPA1 is required for fission
S-OPA1 is required for fusion
Why are mitochondrial dynamics important
Adapting organelle function to a broad range of cues
Failure to appropriately balance fission and fusion will impair organelle function and cellular homeostasis
What are some basic challenges of mitochondrial content
They have a large proteome and require many proteins to function
They have their own genome which encodes crucial polypeptides
They have to coordinate expression of nuclear and mtDNA-encoded protein products (crucial to maintaining or expanding existing populations of organelles)
Describe the number of organelles and mitochondrial volume across tissues
Number varies between 1 and 1000
Fold difference ranges from 2-40%
how is the balance of mitochondria maintained
maintained between rates of biogenesis and degradation
What is mitophagy
Self-eating process in mitochondria, way to degrade mitochondria
Mitochondria alter their _____ and ____ to fulfill diverse functions
shape and number
why are fission and fusion important
Allows mitochondria to respond to internal and external cues and adapt to their environments ot fulfill the necessary conditions to survive
What are the 6 essential processes for maintaining homeostasis that the mitochondria plays a role in
ATP production
Epigenetics
Peroxisome biogenesis
Fe-S cluster synthesis
Apoptosis & cell cycle control
Regulation of cellular metal ion homeostasis
How does cytochrome C initiate apoptosis
Cytochrome C is tethered to the inner membrane under normal circumstances but when the inner membrane is compromised cytochrome C can be released and initiate apoptosis
Which processes do cytochrome c oxidase assembly affect?
ATP production and regulation of cellular metal ion homeostasis
How many subunits are encoded in nuclear and mtDNA of the mitochondria
4 complexes responsible for making the ETC and fifth for creating ATP
only complex 2 is completely from nuclear DNA and the other complexes are a mix of mtDNA and nuclear
What are some basic characteristics of mtDNA
16.6kb double stranded, circular genome
genome was compacted because it is more efficient
Present in multiple copies per organelle
Maternally inherited
In the matrix in order to protect it
Encodes 13 proteins
Lacks introns
Where is the mtDNA bottleneck during oogenesis
QC step
Can mitochondrial diseases be heterogenic
no, will only be a carrier