Mitochondria Flashcards
What are the benefits of the symbiosis?
A single bacterial cell can generate enough energy to sustain about 10000 genes.
When the host cell acquired multiple oxidative bacteria, the bacterial energy could be pooled to provide the required energy could be pooled to provide the required energy for adding more genes to the host cell’s DNA to create more complex anatomical structures.
What is the cost of gene expression?
Whereas the energetic cost of possessing genes is trivial (2%), the cost of expressing them as protein (75%) is not and consumes most of cell’s energy budget.
Mitochondria increased the number of proteins that cells can evolve, inherit and express by 4-6 orders of magnitude.
It still requires mitochondrial DNA.
What do the mitochondria consist of?
- Outer mitochondrial membrane.
- Intermembrane space (the space between the outer and inner membranes).
- The inner mitochondrial membrane.
- The cristae (space formed by infoldings of the inner membrane).
- The Matrix.
What are the primary cellular functions of the mitochondria?
- Supply energy to the cell in form of ATP.
- Generate and regulate reactive oxygen species.
- Buffer cytosolic calcium ions.
- Regulate apoptosis through the mitochondrial permeability transition pore.
What metabolic pathways take place in the mitochondria?
- Electron transport chain – oxidative phosphorylation.
- Tricarboxylic acid cycle or Krebs cycle.
- Beta oxydation of fatty acids.
- Gluconeogenesis.
- Urea synthesis.
What does the outer membrane contain?
Contains numerous protein complexes including enzyme systems for metabolic steps and mitochondrial import protein complexes.
What does the inner membrane contain?
Contains the enzyme systems for partial fatty acid oxydation and the Electron Transport System (ETS).
Contains protein complexes for protein import and export.
What does the mitochondrial matrix contain?
- Contains the enzyme systems for the Krebs cycle and ketone metabolism.
- Contains the mitochondrial DNA (mtDNA).
- Contains quality control proteases and chaperones.
What happens during glycolysis?
- Glycolysis produces its energy 100 times faster than aerobic respiration.
- Glycolysis is the preferred energy source of rapidly growing cell populations.
- Glycolysis is important in early development – early zygote is highly dependent on glycolytic energy production as development progresses to he blastocyst stage.
- Glycolysis is predominant in dividing cells while oxydative phosphorylation dominates energy production in differentiated cells.
- Energetic shift from oxidative phosphorylation to glycolysis may correlate to disease (e.g. age related neurodegeneration, cancer – Warburg effect).
What happens during the Krebs cycle?
What happens to mitochondrial NADH?
It gets oxidised by the electron transport chain, which pumps protons across a membrane and generates ATP through oxidative phosphorylation.
What is the role of FADH2?
To carry high-energy electrons used for oxidative phosphorylation.
What is the role of Coenzyme Q10?
It functions as an electron carrier from enzyme complex I and emzyme complex II to complex III.
What is the role of Cytochrome C?
It carries an electron in the ETC and is also an intermediate in apoptosis.
What is cardiolipin?
Cardiolipin is an important component of the inner mitochondrial membrane, where it constitutes about 20% of the total lipid composition. It can also be found in the membranes of most bacteria.
It regulates numerous enzyme activities.
Defects in cardiolipin can produce protein independant uncoupling.
What happens during the mitochondria Life Cycle?
What happens during the pathways of apoptosis?
What are the differences between mtDNA and nuclear DNA mutations?
