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

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Mitochondria - are they really separate organisms that once merged into eukaryotic cells?

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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Do macrophages engulf mtDNA?

Let us assume that in a human body, a mitochondrial DNA is released to extracellular environment. We know that mtDNA inheritance is solely matrilineal. So the question is, If your mitochondrial DNA ...
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56 views

Why is brown fat brown?

I read in Tortora and Derrickson Anatomy and Physiology that : Another type, called brown adipose tissue obtains its darker color from a very rich blood supply , along with numerous pigmented ...
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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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Plastid and mitochondria

I am not biologist, so please bear with me for this basic question. Although I tried googling, I am confused. What is difference between plastid, chloroplast and mitochondria? Are there any plant ...
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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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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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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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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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Why is FADH2 made instead of NADH in one of the reaction of Krebs cycle?

FADH2 is made in conversion of Succinate to Fumarate. Why is this so ? Why not NADH ?
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Why in some cells is GTP made in citric acid cycle and in some ATP?

In many animals GTP is produced in citric acid cycle. While in plants,bacteria and some animals ATP is produced. Why is this so ? What is the advantage ?
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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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Is there any advantage of having a 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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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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Do mitochondrial DNA have repair enzymes?

Mitochondria are considered endosymbionts originated from a prokaryote. So, do they have a DNA repair mechanism ?
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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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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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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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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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PGC-1β Sod2 limiters/blockers

I'd like to block a percentage of PGC-1β or Sod2 expression. According to the following paper's figure beta-blockers inhibit some expression of PGC-1α. Are there any medicines/chemicals which safely ...
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mutant down but not out

I am interested in a gene which is null lethal but I need to temporary induce diminished capacity. If a cell is homozygous is it possible to induce heterozygous phenotypes or a partial knockout from ...
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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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751 views

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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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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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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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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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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263 views

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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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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Substrates of cytochemical reactions in this immunostaining

Expression of extracellular protein Laminin 9 alpha-4 chain in human skeletal muscle. Indirect immunostaining with HRP immunostain marker. Ob.x40. I have unsuccessfully searched NCBI -database, JSTOR ...
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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 ...