Mitochondria And Peroxisomes Flashcards
What is the endosymbiotic theory?
All the mitochondria that has ever existed comes from one singular prokaryote
How did life come to be from one eukaryote and one prokaryote?
- Prokaryote engulfed by eukaryote
- they formed a symbiotic relationship
- the prokaryote divided inside its host by producing daughter cells and increasing their number so when the host cells divide, the daughter cells would be passed on too
Do all eukaryotes have mitochondria?
No, some have lost it through evolution by they retain a similar organelle and some destroy theirs during maturation
Give the structural features of mitochondrion
- double membrane
- between the membranes are the intermembrane space
- within the inner membrane is the matrix
- large proteins in the mitochondrial membrane
- small, circular genome
- granules
- ATP synthase particles
What takes place in the mitochondrial matrix?
The vast majority of metabolic reactions
What are the large proteins in the mitochondrial membrane responsible for?
Oxidative phosphorylation
How are the mitochondria arranged in fibroblasts?
Interconnected networks which are highly dynamic
How are the mitochondria arranged in cardiac cells?
Lots of mitochondria found in distinct zones
What does mitochondria need to be transported on cytoskeletal microtubules?
Dyenin and kinesin
How does mitochondria move on the cytoskeletal microtubules?
They bind to the dyenin and kinesin via adaptor proteins (Milton and miro) which are located on the surface of the mitochondria
Why is mitochondrial transport important in neurons?
The mitchondria has to be delivered to the synapses where it is needed for neuronal sequencing
How are new mitochondria produced?
Fission - they grow and split
Why do mitochondria fuse together?
We don’t know
Give the functions of mitochondria
- anabolic synthesis of nucleotides
- role in calcium homeostasis
- production of amino acids which function as a neurotransmitter
- important in apoptosis
- important in immune responses
How are mitochondria important in immune responses?
Protein receptors detect invading viral RNA (on the outer membrane of the mitochondria) which activates an innate immune response
What is the process in which ATP is generated?
Oxidative phosphorylation
What is a synonym for the citric acid cycle
Krebs cycle
What are the two important functions of the citric acid cycle
- to produce NADH and FADH2 which are used as electron donors for oxidative phosphorylation which produces ATP
- biosynthetic precursors for the biosynthesis of the creation fatty acids and amino acids
What is the only enzyme in the citric acid cycle found in the mitochondrial membrane?
Succinate dehydrogenase
Go write out the citric acid cycle
..
Give an overview of oxidative phosphorylation
Generation of a proton motive force. Flow of electrons means that protons are pumped out of the matrix into the intermembrane space which builds up a proton motive force
What are the 5 protein complexes in the mitochondrial membrane that help in oxidative phosphorylation
I- NADH2 hydrogenase II - succinate hydrogenase III- cytochrome vet IV- cytochrome (oxidase) V- ATP synthase
What are the two small electron carriers called in oxidative phosphorylation
Ubiquitin and cytochrome C
Which protein complexes contribute to the proton motive force
I, III and IV
Through which protein complex do the protons flow back through
V
What type of membrane does a peroxisome have?
Single bilayer
Do peroxisomes have DNA
No
What are the two main functions of peroxisomes
- fatty acids are broken down inside them
- detoxification of hydrogen peroxide
How is hydrogen peroxide toxic?
Reacts with and damages DNA and proteins which contributes to the ageing process
Why does beta oxidation take place in both the peroxisomes and the mitochondria?
Mitochondria cant break down long chain fatty acids so peroxisomes have to do it
What proteins are used in both peroxisomal and mitochondrial fission?
DNMIL and FIS1
What proteins are used in only peroxisomal fission?
PEX11A, B and G
Give the common features shared between mitochondria and peroxisomes
- important in fatty acid metabolism
- the protein machinery needed to divide is on the outside of the organelles
- antiviral signalling (MAVs) found on the outer membrane of both
