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25 Cards in this Set
- Front
- Back
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Characteristics of mitochondria
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Plastic (can change shape)
Undergo fusion + fission mobile |
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1. how many mitochondria per cell?
2. % volume? |
1. 100-10000 per cell
2. up to 25% of volume of cytoplasm |
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4 major uses of Energy
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1. Mechanical work (muscle contraction, movement)
2. Active transport 3. Macromolecule synth from precursors 4. Regulation (growth, division, secretion) |
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Outer membrane
im/perm? large # of__ involved in __ |
permeable due to large # of porin molecules
enzymes involved in lipid synthesis |
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Inner Membrane
1. has __ to inc surface area/atp synth 2. contains |
1. Cristae (# folds)
2. prot: transport, etc, atp synthase |
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Matrix
enz involved in___ |
TCA (and fa ox), mtDNA, ribiosomes
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Mitoch required for movement of ___
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Mictrotubules, sperm (midpiece)
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Fusion
1. __ then __ |
1. outer memb then inner membrane
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Mitoch undergo fission during ___ and inhibition of fission leads to a ___
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apoptosis
delay in apoptosis |
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diseases with mitoch fusion/fission abnormalities
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CMT (charcot-marie-tooth) mfn2 (mitofusion mutation)
ADOC (aut dom optic atrophy) OPA1 |
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mtDNA
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duoble helical circular
distributed in several clusters in matrix (nucleoids) replicated during interphase lacks introns small (few base pairs) attached to memb? |
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what is cytoplasmic inheritance
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at cell division: random segregation of mitoch to daughter cells
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interesting notes:
genetic code size |
code for AA is different among species
size varies |
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why is there such a high mutation rate in mtDNA??? 5-10x higher
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lack of histones (to protect dna)
no (efficient) DNA repair machinery high oxygen content (ROS) |
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heteroplasmy
ex case |
cells contain mixture of wild-type and mutant mtDNA
mother has no symptoms but has diseased children because she has mixture of mutant DNA and wild-type (normal) |
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Transport of proteins from nuclear DNA into mitochondria
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Contain signal peptides located on N-terminus which contains an amphipathic helix (+arg-lys+ on 1 side, uncharged/hydrophobic on other)
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protein translocaters in mitoch (2)
contain __ and __ |
translocase of outer/inner membrane [TOM + TIM]
receptors and channels |
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what always passes thru both mitoch membranes?
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precursor proteins
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Stages of transport
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1. signaled prot binds to TOM complex
2. TOM moves to region where 2 memb are close 2 eachother 3. Protein binds to TIM complex, drawn into matrix 4. signal petidase cleaves signal peptide, freeing prot precursor into matrix, assembles into mature prot |
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prot must be ___ before entering mitoch
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unfolded
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other ways of importing proteins into mitoch
1. SAM 2. Oxa |
1. binds to TOM, into outer memb space, anchored into memb by SAM
2. TIM-attached signal seq is cleaved, reveals seq which is attached to Oxa |
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mitoch diseases
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LHON Leber Hereditary Optic Neuropathy
assoc with: parkinsons + alzheimers (-mitoch damage due to aging), diabetes, prostate cancer |
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Mitoch diseases specific to which tissues/functions
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tissues with high requirement for ATP by ox P
[[muscle (cardiac,skeletal), neuronal tissues]] |
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Severity of disease depends on: 4
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1. nature of mutation
2. mutant:wildtype mtDNA (heteroplasmy) 3. dependence of organs in oxP for E 4. nuclear background (mtDNA and nuclear) |
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Warburg Hypothesis
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cancer is due to switch from oxidative to glycolytic pathway (bc cancer cells metabolize glucose and produce lactic acid)
modern explanation: tumor hypoxia |
