Questions tagged [mitochondria]
The organelle in eukaryotes where the main stages of respiration occur.
111
questions
24
votes
3answers
4k views
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 ...
1
vote
2answers
35 views
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 ...
4
votes
2answers
78 views
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 ...
0
votes
0answers
10 views
Rhodamine 123 Staining Function
How does Rhodamine 123 act as a probe for Mitochondrial Staining? What is the Exact Biochemical Basis? and can it Stain Chloroplast as well?
Thanks in Advance
0
votes
1answer
52 views
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 ...
0
votes
1answer
38 views
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, ...
6
votes
2answers
129 views
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 ...
0
votes
0answers
27 views
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 ...
3
votes
2answers
174 views
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. ...
11
votes
1answer
237 views
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 ...
1
vote
1answer
1k views
Why are there no multicellular prokaryotes [closed]
Why don't complex multicellular prokaryotes exits and also what made eukaryotes to become multicellular ?
2
votes
1answer
163 views
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 ...
2
votes
1answer
233 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 ...
1
vote
2answers
1k views
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?
3
votes
1answer
87 views
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 ...
3
votes
0answers
53 views
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 ...
0
votes
0answers
65 views
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 ...
1
vote
1answer
31 views
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 ...
4
votes
1answer
128 views
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 ...
1
vote
1answer
74 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 ...
0
votes
2answers
63 views
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.
4
votes
2answers
353 views
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 ...
1
vote
1answer
313 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 ...
0
votes
0answers
176 views
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 ...
2
votes
1answer
110 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 ...
3
votes
2answers
229 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 ...
3
votes
0answers
63 views
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 ...
4
votes
2answers
796 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 ...
0
votes
1answer
290 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.
1
vote
0answers
66 views
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 ...
0
votes
0answers
56 views
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 ...
2
votes
0answers
17 views
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 ...
4
votes
2answers
1k 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 ...
0
votes
1answer
103 views
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 ...
3
votes
1answer
378 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 ...
2
votes
1answer
92 views
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 ...
3
votes
1answer
516 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 ...
7
votes
2answers
4k views
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?
2
votes
0answers
364 views
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 ...
2
votes
0answers
1k views
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 ...
2
votes
1answer
55 views
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 ...
7
votes
2answers
2k views
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 ...
0
votes
1answer
359 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 ...
2
votes
2answers
568 views
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. ...
2
votes
1answer
123 views
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 ...
0
votes
1answer
74 views
Is human mtDNA unique in its single origin? [closed]
Other than Humans, is there another primate who has a traceable “original Eve mtDNA”?
5
votes
4answers
5k views
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 ...
1
vote
0answers
277 views
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 ...
3
votes
1answer
412 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 ...
0
votes
3answers
1k 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 ...
