Questions tagged [mitochondria]
The organelle in eukaryotes where the main stages of respiration occur.
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How fast does the rotor in ATP synthase spin?
I'm sure the exact frequency varies, but does anyone know roughly how many revolutions per minute / second the rotating center part makes?
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Are mitochondria dead?
In the video "What is Life? Is Death Real?", the subject of mitochondria is raised at 2:58. At 3:12, the narrator says "[mitochondria] are not alive any more: they are dead."
What currents of thought ...
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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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How many times did endosymbiosis occur?
According to the endosymbiont theory, mitochondria and chloroplasts originated as bacteria which were engulfed by larger cells. How many times is it estimated that this occurred in the past? Are there ...
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The Origin of Mitochondria
For a long time I've just accepted, because it is just what everyone told me, that mitochondria became organelles in the cell when they were "engulfed" by another cell which acted like it's host. This ...
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Was the mitochondrion or chloroplast first?
I still don't know if the mitochondrion or chloroplast was first? I've looked for it on the internet and in various books but haven't found anything. Does anyone have the answer and a theory which ...
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Are mitochondria transferable between cell types, individuals and species?
I'm curious about what happens when you insert organelles from a cell into another. In particular, mitochondria.
Take two cells from your own body. Somehow extract a mitochondria from one cell and ...
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Does every mitochondrion in a cell contain the same DNA?
I know that mitochondria of eukaryotes have their own DNA, more similar to that of bacteria than to the rest of the cell's DNA. I also know that a cell can have plenty of mitochondria, and I ...
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Do mitochondria simply automatically convert glucose to ATP?
I wonder whether there is any intelligent decision-making in mitochondria in the timing of their operation.
Do they simply begin ATP production as soon as the correct reactants are present?
Or, ...
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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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How is the number of mitochondria in a cell regulated?
How does the cell regulate the number of mitochondria in a cell? What happens when there are too many or too few?
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Why is FAD, rather than NAD+, reduced in the succinate dehydrogenase reaction of the Tricarboxylic Acid Cycle?
FADH2 is produced in the conversion of Succinate to Fumarate in the tricarboxylic acid cycle. Why is this so? Why not NADH?
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What preceded ATP synthase?
ATP Synthase is ubiquitous throughout life on earth and so most probably evolved within the last universal common ancestor (LUCA) before that lineage diversified into the various kingdoms of life.
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Why aren't mitochondria and plastids considered symbiotes of eukaryotic cells?
Mitochondria and plastids have their own DNA, their own membranes, and their reproduction is not tied to the reproductive cycle of the host cell. However, they are considered to be organelles rather ...
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Mitochondrial DNA and recombination
Firstly I could do with a brief description of mitochondrial DNA. How does the structure of DNA in mitochondria compare to animal DNA (for the sake of simplicity let's say human - some animals might ...
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Origin of the double membrane of mitochondria and chloroplasts
Most websites and textbooks say that the double membrane of mitochondria and chloroplasts are a result of the endocytosis of ancient prokaryotes (the outer membrane is from the vesicle containing the ...
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Are there eukaryotes with fully working mitochondria but without mitochondrial genes?
Are there eukaryotic organisms with fully working mitochondria that do not have genes in the mitochondria? By fully working, I mean ones which can carry out oxidative phosphorylation, unlike reduced ...
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Which of the cell types commonly found in mammals has the greatest number of mitochondria?
This is basically a fun question, inspired by this answer on scifi.se. So, which cell type will have the greatest number of mitochondria? Obviously, I am talking about wild type, healthy individuals ...
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Pancretic Acinar Cell - ATP, calcium concentration data
I need to find a decent source of data for concentration of ATP and calcium in the pancreatic acinar cell.
So far all I can find is ATP or calcium 'levels' based on fluorescence , which are not ...
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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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Father with mutated mtDNA- why isn't his offspring at risk?
Mothers transmit their mitochondria (and therefore mtDNA) to their offspring and fathers don't. Lets assume that father had a mutation of the gene that encodes mtDNA, would then be his offspring at ...
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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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Why don't antibiotics affect mitochondria?
Given that mitochondria are evolutionarily closely related to bacteria, and antibiotics kill bacteria, why don't antibiotics also kill mitochondria?
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Cell Respiration and Oxidative Phosphorylation
Why and how does the proton travelling through the stalked particle in the inner mitochondrial membrane, cause a conformational change in the ATPase?
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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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How much DNA of mitochondrial origin is incorporated in main cell's DNA?
And especially three points :
in which chromosomes is it located (especially for the human case) ?
how do we know about it ?
does the proportion and composition vary a lot from one eukaryot to ...
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Why don't protons diffuse out of the mitochondria during chemiosmosis?
If the outer membrane of the mitochondria is very permeable, how do mitochondria maintain a proton gradient by pumping protons into the intermembrane space? Wouldn't they just diffuse into the cytosol?...
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Why is there sperm mitochondrial suicide?
The mitochondria in the sperm are digested upon entry into the egg, making mDNA inheritance exclusively female. What is the advantage of this? Wouldn't some male mDNA be beneficial because of the ...
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How many protons are pumped out per pair of electrons from NADH in oxidative phosphorylation?
I have searched the web and found that 10 protons are suppose to get pumped out during the electron cycle, but i'm a bit confused.
I'm trying to count, for every complex(1/3/4), the number of protons ...
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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 does mitochondrial uncoupling enhance performance in muscle cells?
As far aas I understand, in mitochondria, the citric acid cycle breaks down fatty acid or glucose to produce NADH and FADH2, which are then utilized by Complexes I through IV to generate a proton ...
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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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How are the physiological properties of mitochondria measured?
this is my first question on BiologySE. I am a Physics and Mathematics student currently doing a project on cell growth simulation. I am doing literature survey and I have a question about cellular ...
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What is the benefit for cells having the ATP production regulated in mitochondria compared to being from the nucleus?
Mitochondria have their own DNA and appear to be loosely connected to the nucleus and it role.
Why are the functions of mitochondria not in the nucleus? Why doesn't the nucleus control the ...
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Is there any advantage of having mitochondria for aerobic respiration?
If we consider the pathway of breakdown of glucose which includes glycolysis, the citric acid cycle and the electron transport chain, all these processes takes place in some prokaryotes and ...
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Can mitochondria be regenerated by the cell?
In the cell, division of mitochondria takes place on a regular basis, but what if there are no mitochondria present in cell (suppose all of them died), then can the cell make new mitochondria on its ...
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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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Mitochondria - are they really separate organisms that once merged into eukaryotic cells? [closed]
Theoretically, mitochondria are said to be a separate organism that is concerned with its own life and its own processes. In fact, it even duplicates individually. I know a similar question is here ...
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How does loss of the electrochemical gradient result in heat production?
As far as I understand, uncoupling of the flow of protons and ATP-synthase provides a bypass for protons between the outer and the inner membrane of mitochondria so that the protons don't have to go ...
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Why do brain cells use shuttles that pass electrons from NADH to FAD?
Brain cells are cells require one of the highest amount of energy of any cell of body. So why do they use a shuttle which will transfer electrons from NADH produced in glycolysis to FAD(and there by ...
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Slow-oxidative fibres vs fast-glycotic fibres
Why do slow oxidative muscle fibres contain more mitochondria compared to fast-glycolytic muscle fibres?
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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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Why doesn't mitochondrial DNA accumulate damage over successive generations?
From what I recall, mitochondrial DNA is very susceptible to damage from oxidative stress because it is a site where free radicals are generated and their DNA isn't packed into chromatin like nucleic ...
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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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Common Ancestry of ETCs and ATP Synthase complexes
Rickettsiales are widely regarded as the ancestor of eukaryotic mitochondria through endosymbiosis.
Cyanobacteria are widely regarded as the ancestor of eukaryotic chloroplasts through endosymbiosis.
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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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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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Plastid and mitochondria
I am not a biologist, so please bear with me for this basic question. Although I tried googling, I am confused.
What is the difference between plastids, chloroplasts and mitochondria?
Are there any ...
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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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How did mitochondria make energy long ago?
I've learned that mitochondria is thought to have been eaten by a larger cell, resulting the mitochondria to be part of a bigger cell. Well, here's my Q. If you look at how mitochondria works, you ...
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