mitochondria

Question 1

Matrix

Answer 1

high concentrated solution of proteins energy metabolism: pyruvate dehydrogenase (Pyr –> acetyl coA) citric acid cycle (Acetyl coA oxidation) Fatty acid beta oxidation protein processing: heat shock proteins - expressed under stress processing peptidase - hydrolysis of peptide bond –> break expression of proteins: mitochondrial DNA mitochondrial ribosomes tRNA enzymes for transcription and translation

Question 2

Inner membrane

Answer 2

proton gradient across inner membrane Respiratory enzymes (Complexes) for oxidative phosphorylation - converts to E intermediate (ATO) impermeable to protons, proteins needed for protons to cross ATP synthesis Carrier proteins - ATP/ADP, phosphate, uncoupling proteins Protein import - TIM complexes - move proteins from nuclear DNA in

Question 3

intermembrane space

Answer 3

transphosphorylation enzymes - adenylate kinase creatine kinase shuffle high E phosphates! cytochrom c - dissociate from e- chain

Question 4

outer membrane

Answer 4

permeable to may solutes less than 5000 dalton porin - huge pore for solutes to go in and out VDAC - voltage gated anion channel protein import: TOM - import of precursor proteins SAM - sorting and assembly, mediate insertion of beta barrel proteins lipid synthesis heat shock proteins

Question 5

isolation of mitochondrial compartments

Answer 5

1. put mitochondria in a hypotonic buffer - H2O goes in - swells and outermsmbrane ruptures, inner membrane remains intact but inter membrane space contents out 2. centrifuge - contents of inter membrane space removed 3. transfer mitoc to solution of high osmolarity - causes shrinkage 4. centrifuge - density gradiant - separates outer membrane from dense matrix and surrounding inner membrane (mitoplast) 5. disruption and centrifuge to sep inner membrane from matrix. inner membrane forms small vesicles

Question 6

MINOS

Answer 6

Mitochondrial Inner Membrane Organizing System regulation for keeping cristae membrane attached to inner boundary membrane - interacts w proteins on the outer membrane if KO MINOS - still have cristae but not connencted to inner membrane talks to TOM and SAM of outer membrane through intermembrane space

Question 7

mitochondrial phospholipids

Answer 7

PC - phosphatidylcholine

PE - phosphatidylethanolamine

CL - cardiolipin - inner membrane onlu

Question 8

diabetes

Answer 8

defect in protein processing, altered composition of mitochondria

Question 9

parkinson

Answer 9

defect in fission-fusion - insufficient removal of damaged mitochondria

Question 10

Aging

Answer 10

defect in respiratory chain - increased formation of free radicals - electrons may bump into things they aren’t supposed to

Question 11

fission-fusion equilibrium

Answer 11

dynamic

break apart and fuse

alter mitoc morphology

Question 12

endosymbiotic hypothesis

Answer 12

3-4 B years ago

anaerobic eykaryote at aerobic prokaryote, transfered some genes from prokaryote to nucleus of eukaryote

Question 13

where did 02 come from

Answer 13

prokaryotic photosynthesis - began 3b years ago

aerobic prokaryotes - respiration, precursors of present day mitochondria

residual genetic info in mitoc and chloroplasts

Question 14

mt DNA

Answer 14

13 polypeptides

dense gene packing

relaxed codon usage (fewer tRNAs needed)

variant geetic code

Question 15

Transcription in mitochondria

Answer 15

mtDNA - transcribes mRNAs, tRNAs, rRNAs

RNA polymerase - imported from the cytosol

Question 16

translation in mitochondria

Answer 16

ribosomes: mt makes small and large rRNA and tRNA

import ribosomal proteins, amino acids, aninacyl tRNA synthase

Question 17

maternal inheritance

Answer 17

mitochondria in sperm - very high ATP production - oocite mitochondria aredormant with slow metabolism

keep paternal mitochondira out

disease expression in both boys and girls but passed from mom

Question 18

heteroplasmy

Answer 18

multiple copies of mtDNA in each cell

coexistence of normal and mutated tDNA

threshold effect - 50% has to be mutated for disease phenotype

mutations only affect some mitchondria, some are unaffected

each cells has 100s of mitochondria with low level variants - a single mutation is rare –> clonal expansion –> dominate mt gene pool –> reach threshold

Question 19

mitotic segregation

Answer 19

random distribution of organelles during cell division - mitosis - some cells have more mutant mitochondria

non equal distribution of normal/mtDNA among daughter cells –> variable clinical presentation with age

load of diseased mitochondria NOT constant - divid dieseased mutations in different organs

Question 20

cardiomyopathy

Answer 20

heart failure - insufficient drainabge - decrease in effective lung volume gas exchange