Questions tagged [cellular-respiration]

The process in which energy is liberated from organic molecules producing ATP.

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Plant respiration produces carbon dioxide, so why are plants regarded as decreasing its atmospheric concentration?

In the absence of sunlight, plants give out the greenhouse gas, carbon dioxide. So why is it said that plants increase the concentration of atmospheric oxygen? Do they not increase the concentration ...
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Is there any organism that is born with all the nutrients and resources needed for their entire lifetime?

I understand that adult mayflies have no mouth, but they do take in oxygen through openings in their exoskeleton. Is there any organism that does not need to ingest any type of nutrition and does not ...
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Why is ATP produced in photosynthesis used to synthesize glucose?

In photosynthesis ATP is produced in light-dependent reactions only to go to the Calvin cycle to be turned into glucose to make ATP during respiration: Why isn't this ATP just directly released into ...
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What are the differences between mammal and insect digestion of cellulose?

I know that digestion of cellulose is difficult in mammals and requires a lot of steps. But I am fascinated by the idea of one day achieving human digestion of cellulose. Which got me thinking about ...
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Stomata during night (respiration)

How does carbon dioxide from respiration diffuse out of the leaf during the night? Do stomata close completely during night?
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Where is the H+ ion in this step of glycolysis coming from?

(from Fundamentals of Biochemistry by Voet, 5th ed.) In this step of glycolysis, I'm not seeing where the $\ce{H+}$ ion on the product side is coming from. It seems to me that the G3P's aldehydic H ...
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Fructose vs glucose

I was watching a video on the dangers of fructose and comparing it to alcohol and all of this stemming from the fact that the liver can not break down fructose like it can glucose. But then I was ...
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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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Can Phosphogycolate buildup in a plant kill it?

I'm trying to think of some things for the science fair, for part of my experiment I need to know if Phosphogycolate build up in a plant can kill it. Also, are there any chemicals that may disrupt the ...
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What triggers the switch between aerobic and anaerobic respiration?

I understand that when there is a shortage of oxygen cells convert the pyruvic acid from glycolysis to lactic acid to regenerate NAD+. What I don’t understand is how they switch to anaerobic ...
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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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Stenothermal Exhalation: Warm or Cold?

The answer might be obvious, but I've wondered if stenotherms like a common house gecko, for instance, might produce sufficient respiratory heat to exhale warm air. Clearly, respiratory heat and ...
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Electron Transport Chain in Mitochondria [closed]

I was researching cellular respiration, and this is a rather confusing part. I need help understanding the purpose of Complex II and how the ATP Synthase generates the energy to turn ADP to ATP.
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Where do the protons in the mitochondrial intermembrane space originally come from?

I'm currently reviewing this concept in cellular respiration. The book which I'm using is Reece, Minorsky, Campbell's Biology and while it does a good job at explaining the process involved in the ...
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Electron Transport Chain Proton Pumping into the Intermembrane Space

In regards to the electron transport chain, I know that complex I pumps 4 H+, complex III pumps 4 H+, and complex IV pumps 2 H+, but where do these numbers come from? If someone could explain this, ...
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Why is ATP used as a source of energy rather than glucose?

I'm struggling to pinpoint a misconception, but I don't think I understand why ATP is used as an energy molecule instead of glucose. I understand that glucose is respired, oxidised or combusted and ...
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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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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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What is the source of the electrons generated in the Krebs cycle?

In the Krebs cycle, where do the hydrogens and electrons that NAD+ and FAD accept come from? It seems that citric acid only loses two hydrogens because it starts out with eight hydrogens and then ...
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Cellular Respiration in Boiling Conditions

Here's the question: Imagine that you are given 25 germinating pea seeds that have been placed in boiling water for 5 minutes. You place these seeds in a respirometer and collect data. Predict the ...
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Given ATP synthase's structure, how can 3.33 protons ultimately synthesize one and only one ATP?

I am familiar with the structure and function of ATP synthase, but one small detail doesn't seem to make sense. It also happens to be a detail that seems very hard to express. Depending on the ...
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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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In electron transport system the final acceptor of proton is?

My lecture notes say that the answer to this is inorganic phosphate (iP)..and the question is about proton not electron so the answer can't be oxygen. But I don't understand how is the answer iP
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Why does ATP contain ribose rather than deoxyribose?

I read in a textbook that ATP is made from ribose and not deoxyribose. Originally, I thought that the pentose sugar didn’t have functional importance. Is there a functional reason why the ATP used ...
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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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As electrons are moving through the ETC, how is ATP produced for the active transport to even happen?

A lot of websites aren't being specific and they are just saying that when electrons move from a high to low energy state during the ETC, "energy" is being released and that energy is used to pump (...
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Why isn't Fluorine, or Neon, the final electron acceptor in cellular respiration?

I'm a Chemistry student learning about periodic trends. I know that in (many organisms') cellular respiration, oxygen serves as the final electron acceptor due to its high electronegativity. However, ...
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Where does the 'C' in exhaled CO₂ mostly come from?

When a human being exhales CO₂, what is, by the numbers, the main source of carbon atoms exiting the body in this way? I mean what class of cells, or which tissues are the biggest on a pie chart of ...
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ATP production via aerobic respiration

Just started learning about aerobic respiration today, specifically Glycolysis. We were told that aerobic respiration produces 38 ATP, while anaerobic respiration produces only 2. However, we're ...
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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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The effect of sugar on rate of yeast Respiration

In my experiment, I am investigating the effect of different types of sugar on the rate of respiration of immobilized yeast (yeast trapped in calcium alginate balls). I am looking at glucose, fructose,...
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What happens to the ATP after it stores energy?

The title says it all. After the procceses of cellular respiration happen, the energy is used in different activities that use it, but which are them, more specifically?
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Pyruvate oxidation - where did the hydrogen come from?

As shown in the diagram above, NAD+ is reduced and becomes NADH by gaining two electrons Now, where did the hydrogen come from? In the diagram, pyruvate has 3 hydrogen, but it still has 3 hydrogen ...
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Why does NAD+ become reduced if it gains a hydrogen proton?

I've heard that $\ce{NAD^+}$ gains a Hydrogen proton during glycolysis and the Krebs cycle and becomes reduced to $\ce{NADH}$. However, isn't reduction when a molecule receives an electron? Maybe I'...
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How do prokaryotes perform cellular respiration without membrane-bound organelles?

In order to survive, prokaryotes such as bacteria need to produce energy from food such as glucose. In eukaryotic cells, respiration is performed by mitochondria, but prokaryotic cells do not have ...
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Negative Oxygen Consumption Rate

Oxygen consumption rate (OCR) is defined as the rate at which cells consume oxygen. I reason that for cells not capable of photosynthesis, OCR is strictly non-negative. That was until I read this ...
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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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fermentation in soil bacteria

I am doing a project on microbial fuel cell. For the purpose of the efficiency of the question, MFCs can be summarized to: Devices that use anaerobic bacteria as the catalysts to oxidize organic ...
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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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How much oxygen does a plant use up at night?

Given the fact that plants cannot do photosynthesis at night but need respiration for their energy needs, they use up oxygen and generate carbon dioxide. But how much is this? If I fill a room with ...
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Intermediate of Krebs cycle that can form Chlorophyll?

This was a question in a test in my school today. Q) Which intermediate of Krebs cycle further can form chlorophyll? A) Oxaloacetic acid B) Citric acid C) Succinyl CoA D) Fumarate Given answer was ...
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Why do zoologists classify sponges as animals rather than plants?

Sponges are fixed, do not move settle at one place, do not have a reproductive apparatus, respiratory apparatus, or organs, and live in marine environments. Why then zoologists consider that sponges ...
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Viability of argon-oxygen atmosphere

Can humans breathe an Argon-Oxygen atmosphere, where Argon substitutes the inert Nitrogen gas which currently populates our atmosphere? I didn't quite know which forum to stick this one in; I put it ...
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Entropy increase or decrease in an reaction

My question is how would you tell if the product of an reaction has more or less entropy than the reactants? For example, in glycolysis, when glyceraldehyde-3-phosphate becomes 1-3 ...
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What is the ultimate source of ADP/ATP in humans?

I am teaching myself Cell Biology from the internet. Despite my usually good Googling skills, I'm stuck in a loop with this question. Q: What is the source of ATP? A: ADP Q: What is the source of ...
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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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Is oxygen a respiratory substrate

I know that carbohydrates such as glucose are respiratory substrates for cellular respiration, but in this process, oxygen is also used to produce ATP so is it also a respiratory substrate?
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Role of ATP and AMP in functioning of Phosphofructokinase

I know that when ATP is more then it inhibits PFK and hence regulate the number of ATP. But how does PFK reactivates itself? Is it due to removal of ATP from allosteric site that just reconfigures the ...
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How long can algae survive with no air recycling (closed bottle)

In a small bottle nearly filled of Chlorella in water and grow medium, how long would it take for them to die (with or without light). Thanks in advance ;)