Mitochondria Flashcards
Label
Define cristae:
folds in the inner membrane of the mitochondria that allow for maximal surface area for reactions
Cristae are studded with ______including ATP synthase and cytochromes
proteins
______have prismatic cristae (for closer packing)
Astrocytes
Mitochondrial _______ and _______ typically counterbalance each other. Levels of nutrients and other criteria can tip the balance toward either or.
fusion, division
Mitochondria are moved around the cell on _______
microtubules
In ion-transporting cells, many mitochondria are often located _______
near basolateral cell membrane infoldings and provide locally needed ATP
The electron transport chain takes place on the ____________.
inner mitochondrial membrane
Oxidative metabolism of nutrients creates a ________ in the ETC.
proton gradient
Aerobic respiration requires
Oxygen in order to generate ATP. Pyruvate enters the mitochondrion in order to be fully oxidized by the Krebs cycle. The product of this process is energy in the form of ATP, by substrate level phosphorylation, NADH and FADH2.
Which complexes pump protons?
Complex I, III, and IV
Proton gradient is utilized to generate ______.
ATP
Label
Once protons are in the intermembrane space, they use a _________ to flow back into the matrix
stationary F0 channel
ATP synthase which rotates as it generates ATP from ADP
F1
From F1 ATP exits using ________
VDAC (voltage-dependent anion channel). Pyruvate (nutrients) also enter the cell using VDAC.
Unique phospholipid of the inner mitochondrial membrane that helps ATP transporter line up to face VDAC
Cardiolipin
Proteins have a matrix-targeting sequence (series of AA’s) that is recognized by _________ and ________.
TOM (transport outer membrane), TIM (transport inner membrane)
Imports cholesterol into mitochondria so it can undergo the first step in steroid synthesis
STAR Protein
Steroid cells have mitochondria with _______shaped cristae.
tubular
Maintains intracellular Ca2+homeostasis by transporting Ca2+ from the cell cytosol into the mitochondrial matrix.
Important for shaping Ca2+ signals and the activation of programmed cell death.
MCU (Mitochondria Calcium Uniporter)
Matrix granules are rich in ______.
calcium
Mitochondria have their own ______, ______, and ______ and even synthesize some of their own proteins
DNA, RNA, ribosomes
Mitochondria have [more/fewer] tRNAs than are used by the rest of the cell and follow relaxed pairing rules.
fewer
The genetic code also differs from that found in the rest of the cell.
Mitochondrial genes evolve more rapidly than nuclear genes.
Mitochondrial genes are inherited by a non-Mendelian mechanism known as ___________ from mother.
“cytoplasmic inheritance”
Mitochondrial numbers within a cell vary depending upon ______ and ______.
energy production, energy needs
When intracellular ATP becomes depleted, cells respond by:
- Metabolizing glycogen
- Increasing glucose uptake
- Increasing mitochondrial number and activity to produce more ATP
AMP-Activated Protein Kinase (AMPK) activated by:
- Increase in the AMP/ATP ratio
- Starvation (fuel deficiency)
- Increased phosphocreatine
AMPK function as a fuel senor for the cell
Activated AMPK alters the ________________and the
function of many proteins, transcription of many genes
Regulate the transcription of many mitochondrial genes
NRF-1 and NRF-2
Define apoptosis
Programmed cell death
Intrinsic apoptosis pathway:
- Cell damage or stress
- Permeability transition pore in the inner mitochondrial membrane opens
- Proton gradient dissipation
- Swelling of the mitochondrion
- Release of several apoptotic factors into the cytoplasm
Apoptotic factors released into the cytoplasm:
- Cytochrome C
- Apoptosis-inducing factor (AIF)
- Procaspases
Cytochrome c causes activation of the _____________________ by which other caspases are activated
caspase proteolytic cascade
A caspase is a
proteolytic enzyme
Cytochrome c activation results in _________ and leads to _________
massive protein degradation; destruction of the nuclear lumins
Apoptosis-inducing factor (AIF) is translocated to the nucleus and ______________
induces destruction of the chromatin.
Amyotrophic Lateral Sclerosis (ALS or Lou Gehrig Disease) is characterized by __________
death of motor neurons of the spinal cord.
It is associated with mitochondrial damage in neurons.
Relatively rare (2/100,000 in population)
Inherited form of ALS involves a misfolded enzyme __________ that may block VDAC
superoxide dismutase (SOD)
The flow of H+ ions cause a portion of _______ to rotate and simultaneously generate ATP
ATP synthase
AMPK Increase the Transcription of ___________
Nuclear Respiratory Factor NRF-1 mRNA
AMPK is Required for _________in response to starvation in muscle
mitochondrial biogenesis
