Mitochondria And Peroxisomes Flashcards
Describe the structure and dynamic nature of mitochondria
The mitochondria contains a double membrane and a matrix which acts as the cytoplasm.
There are cristae in the mitochondria.
Function- site of aerobic respiration by using ATP.
Describe the endosymbiotic theory
The mitochondria originated from free living prokaryotic organisms that were engulfed by a larger host cell.
Bacteria + host cell have a mutualistic relationship bacteria becomes too independent so cannot live independently.
This causes host cells to gain significant advantages (e.g. produce energy more efficiently)
Explain how mitochondria is transported on cytoskeletal microtubules
1) Ca+ binds to SNPH on the mitochondria which prevents the mitochondria from moving.
2) Kinesin moves mitochondria towards the positive end (Milton and Miro which helps facilitate transport across microtubules)
3) Dynein moves the mitochondria towards the negative end. Milton and Miro aids this transport across the membrane.
Explain the mitochondrial life cycle
Mitochondrial life cycle:
1) Biogenesis:
New mitochondria are created by fission where existing mitochondria divides into 2 smaller ones.
2) Fusion:
-the 2 mitochondria join together, this allows them to share their contents.
3) Fission:
-the mitochondria divides allowing the removal of damaged parts.
4) Depolarisation and damage accumulation:
-occur when the mitochondria are no longer functioning properly.
5) Mitophagy:
-removes the damaged mitochondria, breaking them down for recycling.
explain the citric acid cycle
1) Acetyl-CoA Formation:
-Acetyl-CoA, (from pyruvate or fatty acids) enters the cycle.
2) Acetyl-CoA combines with oxaloacetate to form citrate.
3) Citrate is rearranged to form isocitrate.
4) Oxidative Decarboxylation: Isocitrate is oxidized to alpha-ketoglutarate, producing NADH and releasing CO₂.
5) Alpha-ketoglutarate is converted to succinyl-CoA, generating another NADH and releasing CO₂.
6) Succinyl-CoA is converted to succinate, producing GTP (or ATP).
7) Succinate is oxidized to fumarate, producing FADH₂.
8) Fumarate is hydrated to form malate.
Final Oxidation: Malate is oxidized back to oxaloacetate, generating another NADH.
describe the process of oxidative phopshorylation
1) NADH and FADH₂ donate electrons to the Electron transport gradient
2) Electrons pass through complexes I-IV, releasing energy to pump protons.
3) A proton gradient is established across the inner membrane.
4) Protons flow back through ATP synthase, synthesizing ATP.
5) Electrons reduce oxygen to form water.
Describe the structure of peroxisomes
- consists of a single membrane
-matrix which is referred to as the internal compartment and has multiple proteins.
-peroxisomes are typically between (0.1-1.0 micrometres)
-spherical/oval in shape.
Describe the functions of peroxisomes
1) Fatty acid oxidation- breakdown of very long fatty acids
2) Detoxification- neutralisation of toxic byproducts.
3) Biosynthesis- important for myelin and cell membranes
what are some similarities between mitochondria and peroxisomes
similarities are:
-both membranes are lipid bilayers
-both replicate by fission
-both organelles can move within the cell
-both play crucial roles in metabolic processes
-both organelles contain specific enzymes crucial for their functions
List all the genetic mitochondrial oxidative phosphorylation disorders
1) Strokes
2) Demyelination
3) Epilepsy
4) Ataxia
5) Parkinsonism
6) Cognitive decline
7) Psychiatric symptoms
8) Liver disease
List some inherited peroxisomal disorders
1) Zellweger Spectrum Disorders (ZSD)
2) X-Linked Adrenoleukodystrophy (X-ALD)
3) Peroxisomal Biogenesis Disorders (PBDs)
4) Refsum Disease
5) Acyl-CoA Oxidase Deficiency
