25
votes
Accepted
Are cells guaranteed to get at least one mitochondrion when they divide?
Isn't there a possibility that cell division will result in a daughter
cell with no mitochondria?
Yes, there is always the possibility. However, there must be a strong negative selection pressure ...
- 6,272
13
votes
Are cells guaranteed to get at least one mitochondrion when they divide?
In addition to S Pr's excellent example, I wanted to point out that some very recent research describes some special behavior in oocyte development specifically related to mitochondria selection.
...
- 407
11
votes
Why is ATP synthase sometimes referred to as ATPase?
The way we were
To understand why you may encounter ATP synthase referred to as ATPase, you need to be aware of the historical context — the experimental work that preceded the knowledge of the ...
- 26.3k
11
votes
Are cells guaranteed to get at least one mitochondrion when they divide?
A typical animal cell has 1000-2000 mitochondria. From a statistical point of view, assuming a random distribution of the mitochondria and that the cell splits in half, the probability of having 0 ...
- 241
9
votes
How many molecules NADH are produced in the Krebs Cycle?
This is slightly depending on which reaction you want to include into the cycle. I count four:
One when Pyruvate is converted to Acetyl-CoA,
one when Isocitrate is converted to α-...
- 52.5k
7
votes
Do mitochondria contain the genes to specify themselves?
The answer is a bit more complicated than that. Mitochondria contain their own genome called mitochondrial DNA (mtDNA), encoding 13 proteins that are part of respiratory complexes I, III, IV, and V, ...
- 15.3k
7
votes
Accepted
Why do mitochondria have a phospholipid bilayer?
I think the question is based on a false premise:
Poster: Now, mitochondria are said to have been archaea, right?
Me: Wrong, I’m afraid.
The closest bacterial relation of mitochondria is ...
- 26.3k
7
votes
Accepted
How is a very small quantity of poison able to kill a large organism?
"Cyanide" doesn't refer to just one compound, but given the lethal dose you mention of "half a gram" you are probably referring to potassium cyanide, with a molecular weight of about 65g/mol, so 0.5 ...
- 46.5k
7
votes
How can the leakage of mitochondrial protons generate heat?
Uncoupling ATP synthesis from the ETC (electron transfer chain; this is where oxidation takes place) by thermogenin or any other method means that the energy used to generate or uphold the proton ...
- 4,391
7
votes
If there is such known "Mitochondrial Eve", does it means that all the mitochondrial dna in everyone's body is same?
The mitochondrial genome has a nonzero mutation rate, though estimates differ according to method. Estimates are approximately $10^{-8}$ per bp per year on average, and the mt genome is $\approx20,000$...
- 10.5k
7
votes
Accepted
What keeps mitochondria from multiplying out of control?
I'm guessing at the motivation for your question -- In the evolutionary history of eukaryotic cells, mitochondria were once free-living bacteria. What prevents them from acting as intracellular ...
- 8,326
6
votes
Accepted
Can mitochondria become cancerous?
Interesting question.
As a prelude, I should probably mention that single celled organisms cannot get cancer as we understand and define it. Mitochondria are not, of course, single celled organisms, ...
- 8,811
6
votes
If there is such known "Mitochondrial Eve", does it means that all the mitochondrial dna in everyone's body is same?
The M.DNA mutates about 1% in a million years, and because our Mt-Eve is 150,000 years old, our mitochondria are 0.15% different, or 99.85% the same globally, and 99.95% the same in Eurasia.
The ...
- 10.5k
6
votes
Accepted
How does mitochondrial uncoupling enhance performance in muscle cells?
Skeletal muscles have multiple systems that increase the rate of energy generation in response to faster energy consumption during excercise.
System
Rate
Sustainability
Phosphagen
highest
10-15s
...
- 212
5
votes
Why is FAD, rather than NAD+, reduced in the succinate dehydrogenase reaction of the Tricarboxylic Acid Cycle?
There is a simple straightforward answer to this question, which I present here because the poster of the accepted answer seems unsure which of his three suggestions is correct, and therefore there is ...
- 26.3k
5
votes
Accepted
How did mitochondria make energy long ago?
You are asking a very interesting question.
As you correctly mention, the substrates of mitochondrial metabolism (TCA or Krebs Cycle) are pyruvate and NADH, and, through oxidative reactions, ATP is ...
- 134
5
votes
Accepted
Origin of the double membrane of mitochondria and chloroplasts
The answer lies in the protein composition of mitochondrial membranes, which undoubtedly prove that the outer membrane (OM) is of alphaproteobacterial origin, and the phagosomal membrane (if there was ...
- 241
5
votes
What will happen if mitochondria had a structure like lysosomes?
Mitochondria are double membraned organelles with an outer membrane which is a rod-like shape, and a convoluted inner membrane (Figure 1).
Figure 1
On the other hand, a lysosome is a single-...
- 636
5
votes
Accepted
Protein-coding introns in mitochondrial genomes
Mitochondrial genomes differ greatly in size, coding potential and even whether they are circular or linear. Mammalian mitochondrial DNA is small (11–28 kbp) and intronless. However the mitochondria ...
- 26.3k
5
votes
Accepted
Is Chemiosmosis a hypothesis or a theory?
Preamble
Although there is a case for closing this question (it is two questions, the first of which is more linguistics, logic or philosophy of science, and the second well-covered in text books) I ...
- 26.3k
4
votes
Does zygosity have meaning for mitochondrial variants?
You abosolutely can have mixed populations of mitochondria in a cell (it is in fact very common). Therefore when you sequence the mtDNA you will get a completely variable percentace of reads ...
- 41
4
votes
Does all cells in individual has same mitochondrial DNA?
In a homoplasmic individual, all mitochondria is the same. Therefor will be the same amongst cells and between siblings/mother. Unless some mutation occurs. A homoplastic individual either has all ...
- 81
3
votes
Pyruvate as a final electron acceptor in the electron transport chain
Someone else may come along later with a definitive answer but I found this question intriguing so here are my thoughts:
The standard redox potentials of the mitochondrial ETC carriers are:
...
- 22.8k
3
votes
Detecting nuclear DNA in suspension of mitochondria
Centrifuge the suspension in Cesium Chloride solution at a particular g value which causes the mitochondria to settle to the bottom of the centrifuge tube but leaves nuclear DNA forming a layer near ...
- 506
3
votes
Accepted
Can Oxaloacetate cross the outer mitochondrial membrane?
In general the outer mitochondrial membrane is thought to be basically permeable (through porins) to small molecules such as OAA. As is typical in biology, the situation may actually be more complex --...
- 747
3
votes
Accepted
Do spermatozoa have mitochondria
The midpiece has a central filamentous core with many mitochondria spiralled around it, used for ATP production for the journey through the female cervix, uterus and uterine tubes. This is a good ...
- 56
3
votes
Is human mtDNA unique in its single origin?
You can trace back any piece of DNA (from any life form) to a single ancestor called LUCA (Last Universal Common Ancestor), so the short answer is 'yes'. But be careful in your interpretation.
If you ...
- 68.3k
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