Questions tagged [mitochondria]

The organelle in eukaryotes where the main stages of respiration occur.

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Why does a respiring mitochondrion have less cristae?

I read the following- Number of cristae is more in resting-state of mitochondrion, but decreases with activity, hence less in the respiring state. cited: GK Pal, Textbook of Medical Physiology ...
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Why does mitochondrial DNA have a high mutation rate, even though the mitochondrial function is highly conserved?

My understanding is that genes that are functionally important are more highly conserved. The DNA coding for ribosomal RNA is one example of that. I was surprised to find out that mitochondrial DNA ...
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What is the difference between apoptosis caused by the release of enzymes from the electron transport chain vs that from the lysosome?

I know that the mitochondria is responsible for regulating apoptosis via release of enzymes from the electron transport chain. I believe that the release of hydrolytic enzymes from a lysosome is how ...
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Isolated mitochondria in glucose rich solution, what happens to ATP generation?

I'm taking intro to biology course this year, and I was thinking about this question. Isolated mitochondria were placed in a glucose rich solution. (With ADP and Pi). How would this affect the ATP ...
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Can proteins be located on the surface of the mitochondria?

I am learning about the mitochondria and I know there are proteins present in the mitochondrial matrix such as SOD2, but I was wondering for a protein to be located on the surface of the mitochondria ...
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Can fermentation and aerobic respiration occur at the same time?

In muscle cells during exercise, does lactic acid fermentation and aeorobic respiration occur at the same time, and does this mean the cell makes more or less ATP during this time? The cell can't ...
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Comparing maintenance energy costs of plant biomass vs bacterial biomass

Im interested if anyone has an idea if this research has been done or how you would approach it. What is the energetic maintenance cost of (e.g) 2kg of some given bacterial cells vs 2 kg of a plant (...
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Does Krebs cycle occur in fast glycolytic muscle fibres?

They have mitochondria. So they can have aerobic respiration. (?) Does Krebs cycle occur in their mitochondria?
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What is mitochondrial run length?

I am reading the following journal paper and I have come across the following statement: Overexpression of GSK-3β significantly increases motile mitochondria in a Tau protein-dependent manner. ...
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What keeps mitochondria from multiplying out of control?

What keeps mitochondria from multiplying out of control and killing the cell? According to endosymbiotic theory, mitochondria were once free-living bacteria that got ingested but not metabolized by ...
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Where are the ATP synthases synthesised? [duplicate]

The nano-machinary of energy production ATP synthase is well known to exist on mitochondrial inner membrane and chloroplasts. But how and where are they formed or synthesised ?
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Disproof mitochondrial eve is 6500 years old

Some creationists, such as Roger Liebi, actively exploit this article: A high observed substitution rate in the human mitochondrial DNA control region (published in Nature Genetics, April 1997). This ...
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mitochondria has more activity or the numbers of them are more?

If a cell is needing energy more than the other cells, does it mean that it has more mitochondria or the activity of them is more?
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What is the exact definition of mitochondrial depolarization?

As I understand as per literature reading and some khanacademy(https://www.youtube.com/watch?v=PtKAeihnbv0&t=315s): Proton gradient := the gradient created when hydrogen ions moves to the ...
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If there is such known "Mitochondrial Eve", does it means that all the mitochondrial dna in everyone's body is same?

P.S. I know not that much, just some basics, but this question really interested me :)
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Protein-coding introns in mitochondrial genomes

I am studying the mitochondrial genome and have read that some contain introns. However, these introns code for proteins. I cannot really understand this. Could someone tell me what intron in which ...
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Is molecular oxygen (O₂) consumed in any process (in humans) other than acting as an electron acceptor for the ETC? [duplicate]

I know that molecular oxygen (O2) serves as the electron acceptor in Complex IV of the electron transport chain, which maintains the proton gradient that produces ATP for, as far as I know, every cell ...
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A question about L-Citrulline

I know that L-Citrulline enters in the second step of urea cycle in the liver mitochondria and I wonder if a person takes an overdose of L-Citrulline wouldn't that cause mild hyperammonemia or at ...
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Source for 'EVERY living organism uses ATP as energy carrier', and can we make a synthetic one that doesn't?

I have read it repeatedly that 'all living organisms use ATP as an energy currency etc' and 'some use GTP in addition'. However I am yet to find a reliable resource, rather than just quora/reddit/...
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What will happen if mitochondria had a structure like lysosomes?

I wanted to know an explanation how the structure of mitochondria affects its function. Therefore, how would it turn out if its structure is like the structure of lysosomes, what is going to happen?
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Are cells guaranteed to get at least one mitochondrion when they divide?

If mitochondria exist at random within a cell, isn't there a possibility that cell division will result in a daughter cell with no mitochondria? If not, what is the process for guaranteeing at least ...
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Phenotypes caused by mutations in mitochondrial DNA?

Will mutations in mitochondrial DNA necessarily affect phenotypes? I have some cursory knowledge of serial endosymbiotic cell theory, and find it difficult to consider that the DNA of the former ...
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Are mitochondrial genes decoded in the same way as nuclear genes?

Mammalian mitochondrial genomes contain only 22 tRNA-coding genes, which is an insufficient number to decode mRNAs under the standard wobble rules. How is translation of mitochondrial mRNAs achieved ...
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Why don't mitochondria have plasmids?

According to the endosymbiotic theory, mitochondria are descended from specialised bacteria (probably purple nonsulfur bacteria) that somehow survived endocytosis by another species of prokaryote or ...
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How are mitochondrial diseases like MERRF inherited?

I am doing a project on the disorder MERRF in Mitochondrial DNA. I have to make a pedigree and explain how it is transferred on from generation to generation. I know that it is inherited maternally, ...
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Why is ATP synthase sometimes referred to as ATPase?

Quite a few times I have seen the term ‘ATPase’ used for what I would consider ATP synthase. For example, my text has: “The phosphorylation of ADP to ATP is also catalysed by the enzyme ATPase.” I ...
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How can the leakage of mitochondrial protons generate heat?

I read the following about thermogenin: "When thermogenin is inserted into the inner mitochondrial membrane, it accentuates mitochondrial proton leak and dissipates the proton motive force. ...
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Can mitochondria become cancerous?

Given that mitochondria have their own DNA and can replicate independently, can they ever become cancerous? For example, could a mutation in their DNA cause them to rapidly replicate, ultimately ...
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Why are there no multicellular prokaryotes [closed]

Why don't complex multicellular prokaryotes exist and also what makes eukaryotes multicellular?
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Is the number of protons in the mitochondrion sufficient for ATP synthesis?

If the proton concentration in the mitochondrial matrix (based on its pH) is multiplied by its volume, the total number of protons in somewhere in between 2 and 8. My question is whether this is ...
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Does all cells in individual has same mitochondrial DNA?

I read that genetic code is universal except for mitochondrial DNA. However, I want to clarify (generally speaking, regarding humans especially): does all mitochondria in the same cell have almost ...
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What is the pH of the mitochondrial intermembrane space?

The proton gradient is stored between the mitochondrial double membrane. More protons mean more hydronium ions and lower pH, but how much exactly?
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Do the genes encoded by the nucleus for mitochondrial proteins have introns?

Mitochondria are believed to have transferred much of their genome to the nucleus. I know that mitochondrial protein-coding genes lack introns, but is this true for mitochondrial genes encoded by the ...
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How rapidly do human mitochondrial ribosomes turn over?

How rapidly do human mitochondrial ribosomes turn over? The inside of the mitochondrion is a highly oxidizing environment that can damage RNA and DNA. How long do mitochondrial ribosomes last before ...
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What are the interactions between mtDNA and nucelus' DNA?

In an exam situation I have been presented with the following question by the teacher: What are the interactions between the mitochondrial DNA and the cell's nuclear DNA? To my knowledge there is ...
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Confusion about mitochondrial electron transport chain Complex I Wikipedia article title

The Wikipedia article title for Complex I (the NADH dehydrogenase enzyme complex) is "NADH dehydrogenase (ubiquinone)". This is confusing to me because this title sounds like ubiquinone is another ...
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How is a very small quantity of poison able to kill a large organism?

Take cyanide for example: it prevents mitochondria from producing energy in form of ATP but, in the process, it binds with it and hence it's spent. It's theorized that half a gram of cyanide can ...
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How to measure the length of mitochondria from z stack fluorescent microscopy image?

I have been working on yeast cells to analyse the effect of DNA damaging agents on mitochondrial structure. I have imaged my culture treated with MMS for a period of 6 hours and while observing the ...
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Do different people have the same number of mitochondria in comparable cell types?

e.g. will a lymphocyte in one person have roughly the same number of mitochondria as a lymphocyte in another person.
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Why do mitochondria have a phospholipid bilayer?

So, a thought came up and I couldn't find all that much info online, so I thought I'd ask some professionals here! The endosymbiont theory states that: mitochondria came to be ingested by bigger ...
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How are mitochondrial ATT (Ile) start codons translated as Methionine?

In some vertebrate species, some mtDNA start codon sequences are ATT but these are translated as Methionine rather than Isoleucine. What is the mechanism for this non-standard translation? The main ...
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Effects of Free Electrons In a Cell?

I am very new to biology, currently just a student. Recently I learned of the electron transport chain used in cellular respiration. This got me thinking. At the end of the chain, the electrons are ...
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Evolution of the energy generating system in mitochondria

Both yeast and humans have mitochondria. Given that yeast have a much shorter time between generation I would expect evolution to have had more time to optimize mitochondria of yeast. The main ...
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How is Coenzyme A Transported to the Matrix?

So, I've been researching cellular respiration on my own, and trying to keep track of most of the major processes. However, I do have one question left: I can't seem to find any sort of information ...
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Why are animal mitochondrial genomes so conserved and small in comparison to those of plants?

Background Levings and Brown (1989): Higher plant mitochondrial genomes are much larger and more complex than those of other organisms. They vary in size from about 200 kb in Brassica species ...
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Can yeast survive without mitochondria?

Some yeast cells have very low mitochondria copy number (see number of mitochondria in non budding cell, you can count mtDNA). This makes them susceptible to fluctuations, and one can conceive that ...
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Are porins on the inner or on the outer membrane of mitochondria? [closed]

I've looked at multiple resources and they are saying different things.
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Mitochondria - ETC

I read somewhere that the Malate aspartate shuttle transfers the electrons to complex 1 in the ETC while Glycerol phosphate shuttle uses complex 2. Does anyone know if this is true? Also a lot of ...
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Can a crowded mitochondrial membrane limit O2 uptake?

The mitochondrial inner membrane is crowded with proteins (electron transport chain complexes, ATPases, etc.). As the proteins are packed more and more densely in this membrane, the diffusion of any ...
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Pyruvate as a final electron acceptor in the electron transport chain

During anaerobic respiration, why are electrons carried by NADH not transferred to the electron transport chain (ETC)? What happens is that lactate dehydrogenase reduces pyruvate to lactate, while ...
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