Questions tagged [cellular-respiration]

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

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Is glycolysis the beginning part of fermentation, or does fermentation follow glycolysis?

Is glycolysis the beginning part of fermentation, or does fermentation follow glycolysis? I see conflicting information from different sources https://honchemistry.wikispaces.com/Lactic+Acid+and+...
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How lymphocytes in lymphatic system get oxygen?

We know that the gas-transporting protein hemoglobin is absent from the lymphatic system. So, how does gas transportation takes place in lymphatic system? Is mere diffusion from surrounding blood ...
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Cytochrome Oxidase activity in neuronal cells

The abstract of this article says "...the entire neuron is often not metabolically homogeneous; most of the oxidative activity is usually found in dendrites." Why would the activity of cytochrome ...
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Why do bacteria produce H₂O₂?

I recently read up that people with NADPH oxidase deficiency (Chronic granulomatous disease CGD) have a tendency to be infected by Catalase positive organisms. NADPH oxidase helps produce the $H_2O_2$ ...
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why on hydrolysis ATP bond releases energy? [closed]

While studying respiration all i came across was that ultimately all that cell does is for the energy currency the ATP and some useful intermediates used in the cell building but i could not figure ...
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How is NAD+ used in lactic acid fermentation after it is oxidized from NADH?

I am confused with the whole process of glycolysis and the fate of the products of this reaction. So, I understand that anaerobic glycolysis results in 2 pyruvate + 2 NADH and 2 net ATP. Is the whole ...
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1answer
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Is phosphofrucrokinase1 PFK1 found in the liver? [closed]

I am trying to understand glycolysis control. One thing I am stuck on is whether there is PFK1 in the liver, or only PFK2. Edit: As far as I am aware, there is no pfk2 in muscle cells, only pfk1. ...
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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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Do Alicyclobacilli produce carbon dioxide?

Do Alicyclobacilli, especially guaiacol producing ones, still produce carbon dioxide? Alicyclobacillus spp. are well known spoilage organisms in the fruit juice industry. Apparently there is no "...
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1answer
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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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Production of $CO_2$ basal metabolism test

Can the production of $CO_2$ be used as a type of basal metabolism test? Explain. The answer to this is obviously yes, but I don't know how to explain it. Would the following be a good explanation? ...
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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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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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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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Selectivity of anti-bacterial affect of oxygen [closed]

As far as I know, oxidizing agents (AKA reactive oxygen species or ROS) are potent antimicrobial agents that act on a broad range of bacteria and viruses, as well as inactivating certain toxins. Is ...
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Breathing's Role in Aerobic Respiration

It's my understanding that aerobic cellular respiration is summarized in the formula $C_6H_{12}O_6+O_2→CO_2+H_2O+ATP$ (unbalanced). The glucose is thrown through a series of chemical reactions, ...
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What is the circulation that allows for nutrient absorption and excrete of metabolic wastes in humans? [closed]

Pulmonary veins carry oxygenated blood from lungs to heart, while pulmonary arteries carry deoxygenated/CO2 rich blood from heart to lungs. On the other hand, systemic arteries carry oxygen-rich blood ...
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Can the respiratory quotient be calculated from a formula or must it be measured directly?

I found the following question on the Respiratory quotient: A normal human diet has a Respiratory quotient (RQ) of approximately 0.85. Given that pure oxidation of fatty acids has a Respiratory ...
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Does the formation of water inside the mitochondrial matrix help contribute to the proton gradient during the electron transport chain?

Does the synthesis of water in the final step of the electron transport chain significantly increase the electrochemical gradient across the matrix? I understand that pumping protons out of the matrix ...
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Respiration of an animal cell media

I want to do respiration process of an animal cell media in laboratory environment. I don't entirely sure how to supply it with Oxygen to the process because it is a gas, but not a liquid.
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Do all prokaryotes have ATP synthases and an electron transport chain?

I was looking this up and I'm wondering if so far I'm correct about the following: For the most part eukaryotes do aerobic respiration, which involves glycolysis, the Krebs cycle and oxidative ...
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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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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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Potential homogeneity across cell membrane

During respiration, individual bacteria (and mitocondria) produce a relatively large potential difference (∼100 mV) between the inside and outside, using energy to pump $H^+$ out of the cell to the ...
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Typical cellular respiration lab with a respirometer — why is potassium hydroxide (KOH) necessary?

For context, if you are unsure what this question is in reference to, feel free to take a look at this video by Bozeman science and go forward to about the 2:00 mark. In a typical cellular respiration ...
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Mechanism behind energy generation

I recently read about methanogens and methanotrophs. One converts CO2 to methane and vice versa respectively. I can't get exact mechanism for the methanotrophs and I know they can't be reversed ...
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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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In glycolysis, what is the source of the electron that makes NAD+ into NADH instead of NADH+? [closed]

I looked at the formula for the glycolysis reaction. The overall reaction seems balanced, however, I don't see anything on the left hand side of the equation that would provides the electron to ...
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How are muscle fibre size and oxygen consumption related?

Does anyone know of a paper which correlates the muscle fibre size to oxygen consumption in mammals? I am trying to find a correlation between muscle fibre type, size and (absolute and specific) ...
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1answer
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Are there differences in energy of glucose isomers?

There are many isomers of glucose, including galactose and fructose. Do they have different chemical energy levels, and why? What makes galactose and fructose useful compared to glucose, and would ...
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What is the name of cellular respiration that Prokayotic cells use?

Eukaryotic cells use mitochondria using anaerobic or aerobic respiration. Prokayotic cells lack mitochondria but are bacteria. Mitochondria originated from bacteria and can be used in the same way. ...
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1answer
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ATP yield of fermentation: study to cite?

Everywhere I find the ATP yields of respiratory and fermentative metabolism of glycolysis. While that of oxidative phosphorilation I could find in Stryer to cite one study where this was addressed (...
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What product of cellular respiration creates an acid when in solution with water?

What product of cellular respiration creates an acid when in solution with water? Topic question really, haven't been able to find a direct answer.
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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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Why do we breath oxygen? [closed]

I like this contradiction. But seems like my Biology teacher doesn't. If oxygen oxidates us, why do we breath it? Why can't we evolve into a new kind of human being that breaths other component of ...
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Membrane Permeability to Pyruvate

Pyruvate seems to pass easily through the outer membrane of the mitochondrion but has difficulty entering the inner membrane (and gets in by H+ symport). I have two questions: (1) what property of ...
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If oxygen deficiency is bad even for a short while, why do people swim?

This may be trivia to many of you. Textbook says the oxygen deficiency, even for a short while can injure our cells. Then why do people go for sports like swimming? (where rhythmic breathing is ...
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Cellular Respiration/Fermentation Problem Leading to Lack of Energy

A young animal has never had much energy. He is brought to a veterinarian for help and is sent to the animal hospital for some tests. There they discover his mitochondria can use only fatty acids and ...
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If higher levels of atmospheric oxygen can lead to larger animals, can it also lead to larger plants?

According to some information, in the ancient past (at least some) animals grew larger due to a higher levels of oxygen in the atmosphere. So for example there is this study regarding dragonflies. ...
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Need for two oxygen sensors in E. coli

E. coli has two oxygen sensors: FNR (fumarate-nitrate reductase) and ArcBA (Anoxic Redox Control, two component control systems). FNR directly senses the oxygen, while the interaction of ArcB with ...
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Why is the Krebs cycle considered a part of aerobic metabolism if molecular oxygen is not involved in any of the reactions in the cycle

Why is the Krebs cycle considered a part of aerobic metabolism if molecular oxygen is not involved in any of the reactions in the cycle? I originally thought that Krebs cycle was aerobic metabolism ...
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Fermentation to acetic acid

How much time is needed for the fermentation to acetic acid production cycle, and the conversion of apple vinegar in a sealed container incubated at 37 °C? Should be in the fully closed? What is ...
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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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Why is oxygen needed for the electron transfer phosphorylation?

I understand that oxygen is the acceptor of electrons and hydrogen ions during the electron transfer phosphorylation, the last step off the ATP-producing aerobic respiration. But why? Aren't there ...
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Source of hydrogen in reduction of oxygen in electron transport?

What's the source of hydrogen in the reduction of oxygen to water in metabolism? Is this implying that half the hydrogen comes from NADH and the other half from lone protons?
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Why don't we breathe nitrogen when it makes up most of the air?

Why don't we breathe nitrogen while it makes most of the air? Why do we always tend to breathe oxygen, not hydrogen and nitrogen?
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Missing 4 $\ce{H_2O}$ (per glucose) in Cellular Respiration… Where can they be?

I having trouble understanding the equation of the cellular respiration. The thing that bothers me is the number of $\ce{H_2O}$ molecules. Generally, cellular respiration is written thus : $\ce{C_6H_{...
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What's the point of glycolysis in fermentation?

In order to initiate glycolysis, 2 ATP are necessary. In the glycolytic process, you generate an additional 4 ATP, which results in a net gain of 2 ATP. If you don't undergo glycolysis, however, then ...
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Diffusion of FAD+

Why is NAD+ free to diffuse within the mitochondrion whereas FAD+ is not ? What biochemical properties cause this difference ?
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Why is succinate dehydrogenase attached to the inner mitochondrial membrane?

Succinate dehydrogenase is attached to the inner mitochondrial membrane. All the other enzymes of the Krebs cycle are located within the matrix of mitochondria, though. In biological systems, there ...