Mitochondria

Question 1

First Eukaryotic Common Ancestor (FECA)

Answer 1

○ Formed from prokaryotic ancestor cell developing some internal membrane compartments (i.e. nucleus)
FECA engulfed and maintained endosymbiotic organisms and other addition changes gave rise to cellular features now common to all eukaryotic cells

Question 2

Drp1

Answer 2

Dynamin-related protein-1- membrane of dynamin GTP-binding protein family responsible for scission of other cellular membranes

Question 3

Cardiolipin

Answer 3

mitochondrial specific membrane phospholipid

Found at constriction site (recruits Drp1 and ER tubules)

Question 4

OPA1

Answer 4

Optic Atrophy 1
Integral inner membrane bound GTPase (similar to Mfn1/2)
Contains intermembrane space facing GTPase domain

Question 5

Presequence

Answer 5

15-50 aa long targeting signal on most matrix proteins

Located on N terminus

Contains an amphipathtic alpha helic (one side of helix has positive aa)

Question 6

TOM Complex

Answer 6

Translocase of the mitochondrial Outer Membrane

Recognizes presequence on protein

Question 7

TIM 23 Complex

Answer 7

Translocase of the mitochondria Inner Membrane 23

Multiprotein complex that forms a channel that allows for matrix protein translocation across inner membrane

Physically connected to TOM complex

Question 8

TIM 22 Complex

Answer 8

Responsible for the insertion and assembly of inner membrane proteins
Proteins passed from the TOM to TIM22 and then laterally transferred into the inner membrane bilayer

Question 9

mtHSP 70

Answer 9

Mitochondria- Heat-Shock Protein of 70 kDA

Acts as a molecular motor (ratchet)

Undergoes ATP dependent conformational changes that pulls the protein into the matrix and prevents it back into the cytoplasm

Question 10

MPP

Answer 10

Mitochondrial Processing Peptidase

Cleaves presequence from protein in matrix

Question 11

Mitochondrial RNA Cloud

Answer 11

mRNAs encoding mitochondrial proteins are often enriched in the cytoplasm immediately surrounding mitochondria

Mediated by the cytoskeleton and RNA binding proteins located on the mitochondrial outer surface

Unique sequences in mitochondrial mRNA untranslated regions (UTRs) link to the cytoskeleton, move as ribonucleoprotein complexes to mitochondria, and then binds to the cytoplasmic facing domain of certain outer membrane proteins (serve as mRNA anchors)