Questions tagged [mitochondria]
The organelle in eukaryotes where the main stages of respiration occur.
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Recombination between organelles?
In plants, organelles DNA inside chloroplasts and mitochondrias can undergo recombination, intra- or inter-molecular. In a single cell, there are numerous chloroplasts/mitochondria. Can we imagine ...
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Glycolysis of respiration
What process provides directly ATP for the cell?
It is glycolysis because it generates 2 ATP in cytoplasm.
How many times ΑΤP are available from glycolysis when compared to ΑΤP of cellular ...
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2answers
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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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1answer
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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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209 views
Why are there no multicellular prokaryotes [closed]
Why don't complex multicellular prokaryotes exits and also what made eukaryotes to become 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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1answer
90 views
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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Can metabolically inactive cells still replicate? pertaining to mitochondria specifically
If some drug acts on mitochondrial enzymes (probably dehydrogenases) and inhibits their activity; could cell still replicate or undergo mitosis via some other means? Is Cell proliferation possible ...
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Quantifying loss of mtDNA using genotyping arrays
I recently read that mitochondrial DNA (mtDNA) levels can be measured by relative real-time PCR. Would it also be possible to estimate the degree of loss of mtDNA from genotyping array data?
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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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1answer
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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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1answer
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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 do I work out the fraction as a percentage of the ADP in each mitochondrion converted into ATP?
So I was given the following concentrations ADP=1.3mM and ATP=4.8mM, and work out from this that in a given set of dimensions (2micrometers long and 1 micrometer in diameter) that there were 1....
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1answer
60 views
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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202 views
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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Direction of ATP synthase C ring under different circumstances
In a mitochondrial intermembrane space, the concentration of protons is much greater than in the mitochondrial matrix. In this condition, ATP synthase rotates in a counterclockwise (ccw) manner. In a ...
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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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1answer
103 views
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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1answer
141 views
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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2answers
570 views
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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1answer
178 views
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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Electron chain proteins are pointing the wrong way in the mitochondria of eukaryotes
When I look at the electron transport chain proteins in the mitochondria of eukaryotes, the above picture for example, I get the impression that a more efficient design is possible. This question is ...
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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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2answers
886 views
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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1answer
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How Mitochondria differs from Prokaryotes(probably regarding energy production)? [closed]
In other words, what evolutionary advantage is offered by mitochondria to eukaryotes(probably regarding energy production), which prokaryotes themselves cannot evolve or do?(here I am assuming that ...
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1answer
300 views
why do chaperones bring protein into mitochondria? why would mitochondria need protein?
Sounds trivial? Please help to sort out. I saw this picture while looking at dehydration reactions and cell revision.
And proceeded to the reference web page.
Protein Folding and Processing in ...
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1answer
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Do spermatozoa have mitochondria
This is something that I have heard/read so many different contradictory claims about over the years.
In high school I was taught that sperm cells have a lot of mitochondria because they need a lot ...
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1answer
421 views
Cell organels during cell reproduction
When one studies cell division, usually the process is explained through what happens with the DNA of the cell, particularly, that in eukaryotes the nucleus dissolves. But what happens to the rest of ...
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How many molecules NADH are produced in the Krebs Cycle?
I don't know which source i'm going to follow.
Some say its 3 molecules NADH per cycle → 2 cycles × (3 NADH) = 6 NADH
Some say its 4 molecules NADH per cycle instead?
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In what reaction of mitochondrial respiration is hydrogen peroxide an anomalous product?
I understand that hydrogen peroxide is produced in an anomalous manner during mitochondrial respiration, which also produces other by-products or free radicals. Does anyone know the details of the ...
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In what circumstances is ATP the limiting factor in performance for unicellular organisms?
I am interested in how enhanced energy levels in cells can contribute to elevated performance levels.
Perhaps there have been experiments where unicellular organisms, enriched with ATP, were able to ...
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Difference in ATP synthesis in mitochondria and chloroplast
The mechanism of ATP synthesis in mitochondria and chloroplasts are almost the same, but there is a big difference: the f1 particle in mitochondria uses 2 H+ ions to synthesize one ATP, whereas in ...
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1answer
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Detecting nuclear DNA in suspension of mitochondria
Is there a way to detect nuclear DNA in a suspension of mitochondria extracted from leukocytes? I need to make sure there is no nuclear DNA in the suspension before extracting mtDNA from the ...
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Can Oxaloacetate cross the outer mitochondrial membrane?
I am aware of the Malate–Aspartate Shuttle, but something is not clear to me and different sources seem to contradict each other. Some show oxaloacetate (OAA) being reduced to malate in the ...
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1answer
280 views
How to calculate the percent of mitochondrial heteroplasmy
How do people calculate the percent of mtDNA heteroplasmy?
Does 7% heteroplasmy out of 10 cells, represent a mutation found in the same position on the genome among 700 mtDNA genomes out of 10,000 ...
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2answers
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Do Gametes contain mitochondria/chloroplasts from their parent cell?
It has now been established (according to the Cambridge A level text book) that
organisms form a symbiotic
partnership, typically by one engulfing the other
– a process known as endosymbiosis. ...
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1answer
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Do mitochondria contain the genes to specify themselves?
My book says :
"Mitochondria contain their own genetic material so when a cell divides, the mitochondria replicate themselves under the control of the nucleus."
The book means that the mitochondria ...
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1answer
70 views
Is human mtDNA unique in its single origin? [closed]
Other than Humans, is there another primate who has a traceable “original Eve mtDNA”?
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Why are H+ ions pumped out instead of in during cellular respiration
During cellular respiration in both mitochondria and aerobic prokaryotes, the Electron Transport Chain pumps H+ ions out of the matrix or cytoplasm to create a H+ concentration gradient. This forces ...
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Does zygosity have meaning for mitochondrial variants?
I am working on a system that annotates variants in human DNA sequences. One of the pieces of information reported is the zygosity of the variant. I noticed that mitochondrial variants are also shown ...
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1answer
362 views
Can mitochondria with “depleted” mtDNA reproduce?
Background
There's a popular group of antibiotics known as fluoroquinolones, abbreviated FQs. They're quinolone abx with a fluorine atom added at position 6 to increase cell permeability. Popular ...
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3answers
950 views
What is the energy produced by the mitochondria? [closed]
I know that the mitochondria is basically the power house of the body,
it consumes amino acids, fatty acids, glucose, etc and oxygen.
When these molecules meet up in a enzyme, a series of reactions ...
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1answer
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Mitochondrial donation - why is the second woman needed?
Mitochondrial donation or the latest case procedure describes that an egg of the second woman is used as a host with healthy mtDNA.
Being a complete layman I'm interested in whether it is a ...
