Mitochondria and peroxisomes Flashcards
Name 3 diseases mitochondria can be linked to
Cancer, cardiovascular disease, dementia
What does the endosymbiotic theory suggest?
All existing mitochondria can be traced back to one original prokaryotic cell. The prokaryotic cell was then engulfed by a primitive form of a eukaryotic cell. They formed a symbiotic relationship. The prokaryote divided inside its host, producing daughter cells for when the host cell divided.
Describe and explain the evidence for endosymbiotic theory
From phylogenetics
Name the membrane and membrane related structures of the mitochondria
Double membrane - Inner, outer
Between - Inter membrane space
Within inner membrane - Mitochondrial Matrix, where metabolic reactions occur
Where are the protein complexes responsible for oxidative phosphorylation
Inner membrane
What is the evidence that mitochondria exists from a prokaryotic ancestor
Presence of two membranes, presence of small circular genome (own DNA)
Name the other parts of the architecture of the mitochondria
ATP synthase particles
Cristae
Ribosome
Granules
How are mitochondria organised in skin fibroblast cells?
Interconnected, forming dynamic networks, mitochondria constantly moving in cell.
Individual mitochondria can separate, divide and fuse (fission/fusion)
How are mitochondria organised in cardiac cells
Highly abundant in distinct zones. Subcellular populations perform zonal specific functions
How do mitochondria move
Requires motor proteins dynein and kinesin, mitochondria must bind to them
What two adapter proteins does mitochondria have on its surface and what do they do
Milton and Miro - Bind to kinesin and dynein
Why is transport of mitochondria in neuronal axons for example important
Required for neuronal signalling and function in synapses
How are new mitochondria made
Grow the mass of existing mitochondria, which then undergo fission to produce new mitochondria.
What happens when as a result of time macromolecules such as DNA in mitochondria are damaged
Mitochondria undergo mitophagy to restore overall cellular health.
Name some functions briefly of the mitochondria
- ATP synthesis (oxidative phosphorylation)
- Central hubs of metabolism, not just energy metabolism (Anabolic synthesis of nucleotides for example, used in DNA replication)
- As a result of 2, mitochondria can be used in cancer therapy
- Calcium homeostasis for muscle contraction
- Production of amino acids e.g. glutamate, neurotransmitters.
6.Apoptosis - Mechanism of cell death/suicide - Immune respones - protein receptors detect viral RNA molecules, located on outer membrane of mitochondria. Activates innate immune response.
Name some functions briefly of the mitochondria
- ATP synthesis (oxidative phosphorylation)
- Central hubs of metabolism, not just energy metabolism (Anabolic synthesis of nucleotides for example, used in DNA replication)
- As a result of 2, mitochondria can be used in cancer therapy
- Calcium homeostasis for muscle contraction
- Production of amino acids e.g. glutamate, neurotransmitters.
6.Apoptosis - Mechanism of cell death/suicide - Immune response - protein receptors detect viral RNA molecules, located on outer membrane of mitochondria. Activates innate immune response.
What is the citric acid cycle
Final common pathway for oxidation of fuel molecules (carbohydrates, fatty acids and amino acids)
What happens to acetyl-coenzyme A in the citric acid cycle
Completely oxidised to carbon dioxide
Name the important functions of the citric acid cycle
Produce electron donors - NADH and FADH2
Which are then used to synthesise ATP in oxidative phosphorylation
(Catabolic state - breaking into smaller molecules)
- To provide biosynthetic precursors for the biosynthesis of fatty and amino acids (Anabolic state - synthesising bigger molecules)
Describe first reaction of the citric acid cycle
Acetyl-CoA (2C) combines with oxaloacetate (4C) to make citrate (6C), catalysed by citrate synthase
What happens to citrate after it is formed in the citric cycle
Citrate isomerised into first cis-aconitase then isocitrate, catalysed by aconitase
What happens to isocitrate in the citric cycle
Isocitrate (6C) oxidised into alpha-ketoglutarate (5C) catalysed by isocitrate dehydrogenase
One molecule of NAD reduced to NADH, and one molecule of CO2 produced.
What happens to alpha-ketoglutarate
Converted into succinyl-CoA (4C) by alpha ketoglutarate dehydrogenase. NAD reduced to NADH, CO2 produced
What happens to succinyl-coenzymeA
Converted to succinate by succinyl coenzyme A synthetase, GTP molecule produced
