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71 Cards in this Set

  • Front
  • Back
What do Mitos and Chondrion mean in greek?
Threadlike + granules
What did mitochondria evolve from?
purple bacteria
How did mitochondria evolve?
By endosymbiosis
Importance of mitochondria:
(2 things supplied)
-Major source of ATP
-Major supplier of proteins and enzymes for mitochondrial biogenesis and functions
What has to be coordinated in order for proper synthesis, assembly, and functioning of ETC enzymes?
Mitochondrial and Nuclear DNA
2 Major functions of Mitochondria:
1. Complete oxidative metabolism of Carbs, AAs, and FAs
2. Coupling of ETC and oxidative phosphorylation -> ATP
4 Compartments of the Mitochondrion:
1. OMM outer membrane
2. IMS inter space
3. IMM inner membrane
4. Matrix matrix
What special things are in the outer membrane?
What special things are in the Intermembrane space?
Cytochrome c
What special things are in the inner mito membrane?
-ETC enzymes
-Transport proteins
What special things are in the Matrix?
-Krebs cycle enzymes
What can go through a porin in the OMM?
Things less than 1 kDa large
What is cytochrome c?
The substrate for Complex IV in the ETC.
What is cardiolipin?
A receptor for creatine Kinase in the inner mito membrane.
What is the structure of the IMM like?
-70% protein
-30% lipid
What important enzymes are in the IMM?
The respitory chain enzymes
Which one is cytochrome c oxidase?
Complex IV (last one)
Which one is NADH dehydrogenase?
Complex I
Which one is cytochrome c reductase?
Complex III
Which one is succinate dehydrogenase?
Complex II
What is TIM?
Translocase of Inner Membrane - a transport protein that uses ATP to bring things in and ADP to get them out.
5 things in the mitochondrial matrix:
1. Krebs cycle enzymes
2. Peptidases
3. Mitochondrial DNA
4. Ribosomes
5. Calcium granules
What is the intermediary for coupling of the ETC and oxidative phosphorylation?
the proton motive force that is generated by passing protons into the intermembrane space as electrons flow thru ETC.
What is the theory called?
Chemiosmotic theory
2 Components to the PMF:
-Membrane potential LARGE force
-H+ gradient -> SMALLER force
What direction is the net force of the PMF directed?
Inside - toward the matrix
What 3 things are driven by the active transport of the PMF?
-ADP/ATP antiport
-H+/Pi symport
-H+/Pyruvate symport
So in terms of electrical gradients the matrix is what?
Which protein in the mitochondria is not bigenomic?
Succinate dehydrogenase
How do mitochondria multiply?
By binary fission of existing mitochondria
How much DNA is in mitochondria?
~16,500 bp
What is the DNA in mitochondria like?
-Heavy and Light chains
-Closed circular
-no introns
What does mitochondrial dna encode for?
2 rRNAs
22 tRNAs
13 polypeptides
What is the nature of all that DNA? (where it comes from)
Bigenomic - composed of both nuclear and mitochondrial DNA except for succinate dehydrog.
What is replication of mtDNA like?
Bidirectional and asynchronous
what is the D loop?
The portion of the DNA loop that contains mitochondrial DNA
What is most of the DNA in ring a transcript for?
Where do we get our mitochondrial DNA from?
Maternal inheritance
Does mtDNA replication depend on cell division?
What happens to mtDNA during mitosis and meiosis?
It undergoes replicative segregation
How does mtDNA accuracy compare to nuclear DNA?
Mutation rate is 10-20x higher
What is the Threshold expression for mtDNA mutation?
The threshold of accumulations of mtDNA mutations; when reached dysfunction will occur.
What does the universal codon for Arg encode in mitochondria?
What does the universal codon for Ile encode in mitochondria?
What does the universal codon for STOP encode in mitochondria?
What does nuclear DNA encode in mitochondria?
-All enzymes of matrix
-protein/RNA import machinery
-Transcription factors for mtDNA transcription and replication
So what controls the translation of specific mitochondrial mRNAs?
the NUCLEAR genome
How much mitochondrial protein has to be imported?
What is the mechanism for protein import into mitochondria?
Targeting sequence
(signal, leader, or presequence)
Targeting sequence
-rich amino acids
-20-70 aa long
-rich in Ser/Thr at N-term
-can be amphipathic
-cleaved by specific peptidases in mitochondria
What is required for proteins to be able to be imported?
Unfolding via HSP70 + ATP
What are the Import receptors?
What are the insertion proteins?
What does GIP match up with?
What is the translocation motor?
mt Hsp70
What happens after protein import?
-Proteolytic removal of sequence
-Refolding, assembly, and intramito sorting
What 3 proteins aid in the things that happen after import?
3 possible sources of mutation in mtDNA:
-Nuclear DNA
-Cytoplasmic DNA (mt)
what type of inheritance will be seen in each type of mutation?
-Nuclear DNA: mendelian
-Cytoplasmic: maternally transmitted
3 causes of mtDNA mutation:
1. Linked to IMM - the source of oxygen radicals
2. Lacks protective histones
3. Has limited repair system
What disease is caused by missense mutations in mtDNA?
LHON - leber's hereditary optic neuropathy
What 2 diseases result from tRNA point mutations that affect protein synthesis in mtDNA?
Myoclonus epilepsy and ragged red fibers
mitochondrial encephalomyopathy, lactic acidosis, strokelike symptoms
What 2 disease result from insertion-deletion mutations of mtDNA?
1. KSS (kearns sayre)
2. PEO (progressive external ophthalmoplegia)
What kind of damage occurs in insertion-deletion mutations?
Deletions of 1.3-7.6 kb flanked by direct repeats of nts
Are insertion-deletion mutations inherited?
No - usually no family history
-new mutations that occur during development
What are 3 diseases of aging where mitochondrial dysfunctions are implicated?
-normal aging
What is an early event in apoptosis involving mitochondria?
Release of cytochrome c
What blocks the release of cytochrome c?
Bcl-2 family proteins
So what is the result of Bcl-2 proteins?
Block apoptosis and promote cell survival.