Mitochondria Flashcards
What causes differentiation in cristae structure?
- cristae take on dif structures based on where mito sit within certain cells
What are 5 functions of mito?
- bioenergetics
- Apoptosis –> intrinsic pathway of cell death (when cytochrome c appear in cytoplasm)
- calcium homeostasis (mito-ER interactions)
- biogenesis –> to meet energy demands of cells
- oxygen sensors
distinguishing what cell types will have the most/least number of mito?
- based on whether or not cells live in anaerobic vs. aerobic environment
- do cells require large amounts of energy to perform functions
general properties of mito
- tissues of high energy have higher numbers of mito
- maternally inherited (diseases can be tracked)
- mito positioning is influenced by cytoskeleton & demand for ATP (pattern of microtubule & mito distribution similar)
What is the relationship between mito and the basal side of cells within striated ducts and kidney tubules?
- mito more concentrated on basal side
- ATP needed to pump Na+ out of cell to maintain gradient –> ATP not easily diffusible within cell
- PM has infolding at basal side to increase SA, mito interdigitate between infolds (almost looks like striations)
What role do mitochondria play within the cells of striated ducts?
- product in initial lumen is dif than product found at final location
- secretion being “remodeled” (isotonic in lumen but hypotonic in saliva)
- ions being taken up in ductal system –> need ATP to pump ions out of cells to maintain conc gradient
What don’t Na+/K+ pumps migrate to apical or lateral-basal surfaces of ductal cells?
- tight junctions prevent movement of lipids/proteins from one side of membrane to other side?
Why does cytoplasm of striated duct cells stain eosinophilic?
- have lots of mito
- mito is location of electron transport chain, which contains highly basic proteins
Which cells stain very eosinophilic due to mitochondria content?
- striated ducts
- parietal cells (stomach
- oxyphil (parathyroid)
How do different muscle fibers stain using immunohistochemistry?
- smaller, darker staining fibers are slow oxidative fibers
- large, lighter staining fibers are fast glycolytic fibers
What don’t neutrophil stain very eosinophilic in the cytoplasm?
- contain few functional mito
- don’t need energy aerobically
How does material move across the inner membrane of the mito?
- inner membrane very impermeable
- transport systems used to bring things into inner matrix
What accounts for the impermeability of the mito inner membrane?
- when looking a PM lipid composition, cardiolipin is highly restricted to the inner membrane of mito
- allows for membrane to be highly impermeable
How do mitochondria play a role in apoptosis?
- cytochrome c is a protein found within the intermembrane space of mito –> used in electron transport system
- when cyt c moves from mito into cytoplasm, it facilitates apoptosis
What are proteins destined for nucleus, mito, or peroxisomes made?
- proteins destined for mito/nucleus/peroxisomes are made on free ribosomes
How do cells get proteins to go to right location (mito)?
- signal sequences target proteins to mito
- use motifs that drive proteins made in cytoplasm to specific receptor complexes in mito
Where are proteins destined for outside the cell made?
- synthesized in ER, move in vesicle to PM, fuse with PM and are released outside cell
- N-linked glycosylations, GPI-linkages, etc
What does the mito genome encode for?
- 13 polypeptide chains
- encodes for its complete set of tRNA
- when number of damaged mito gets too high, start seeing disease states
What are some differences between nuclear and mito DNA?
- nuclear genome contains introns, mito genome does not
- nuclear encoded mRNA involves capping and is polyadenylated, mito encoded mRNA does not involve capping but is polyadenylated
What affects can antibiotics have on mito?
- in high enough amounts, antibiotics can disrupt mito transcriptional/translational processes
How do mito multiply? What is an advantage of this?
- energy of daughter cells must be maintained
- mito divide by fission, equal distribution of mito into daughter cells
- in opposite direction, two mito can come together in fusion
- if damage and normal mito fuse, damaged mito DNA is diluted out
