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15

Short answer This is a difficult question to answer. As far as I am aware, asphyxiation results in excitotoxicity, which causes unconsciousness, brain damage and eventually, death. Background Asphyxia is a condition of the body that occurs from severely inadequate oxygen supply, or because of excessive carbon dioxide in the body (First Aid and CPR courses)...


8

You are right in your reasoning: at any pH for any titratable group, there is a distribution between the protonated and deprotonated species. We can calculate this distribution and therefore the average charge of the species with the Henderson-Hasselbalch equation: $$\mathrm{pH = pKa + log\left(\frac{[B]}{[A]}\right)}$$ Or, rearranged: $$\mathrm{\frac{[B]}...


5

Proteins are polymers of amino acids. Each amino acid has a side chain. Many of these side chains contain ionisable groups. The ionization state of these groups is dependent on the pH. A group that is protonated at pH=2 and neutral, for example, may become deprotonated at pH=8 and become negative. See the Henderson-Hasselbalch equation. Protein structure is ...


5

From the derivation of Michaelis-Menten kinetics you can see that: $$K_m=\frac{k_f + k_{cat}}{k_r}$$ Where $k_f$ and $k_r$ are binding and unbinding rate constants (for Enzyme-Substrate binding), respectively, and $k_{cat}$ is the turnover number. This is for the Quasi-Steady-State approximation (QSSA). For the equilibrium approximation: $$K_m=\frac{k_f}{...


5

Short Answer: You need to define base state. Background: The point to keep in mind here is that the base state (as you call it) is not constant. As @jeppenielsen points out in the comments, amino acids are zwitterions. According to Wikipedia: In chemistry, a zwitterion, formerly called a dipolar ion, is a neutral molecule with both positive and negative ...


4

This is relatively easy. First: Look up the molecular weight of sodium hydroxide: Wikipedia gives a molar weight of 39.997 grams/mole (lets round this to 40 g/mole thats easier to calculate and the error in this is marginal). So when you dissolve 40 g of it in 1 l of water, you have a 1000 mM (or 1 M) solution. Since you only want to have a 400 mM solution, ...


4

Conversion of lactose to galactose and glucose is a part of the bacterial metabolism of lactose. So digested lactose would work. In fact, it should work for all kinds of 6-carbon sugars as lactic acid is produced from pyruvate (end product of glycolysis). See Wikipedia:lactic acid fermentation.


3

Enzymes have a more or less narrow optimal pH at which they work, depending on the conditions of their environment. Pepsin for example is active in the stomach which is pretty acidic and has an optimal pH of 2.0, while Trypsin, which is active in the small intestine has an optimal pH around 8.5. Changes in the pH first affect the form of the protein, ...


3

As discussed in the comments, there are theoretical and practical problems with arriving at such data. There have been controlled experiments using canines, but you have specifically stated your interest in humans. I offer a summary of a few observational studies that may be helpful. In this study, 117 patients in intensive care units (who are likely to ...


3

Often, in terms of a water body becoming acidified, it depends on the rate of acidification. Fish and other aquatic species, such as invertebrates, are fairly resilient to miniscule changes, but they also have a threshold at which not a lot of them, adapted or no, can survive. From the U.S. Environmental Protection Agency (http://www.epa.gov/acidrain/...


2

At typical physiological pHs glutamate does exist as glutamate. Broadly the acidity in the digestive track is enough to reduce glutamate to glutamic acid. The stomach for example has a healthy pH of between 1.5 to 3.5. Canadianer points out in the comments that the active site during catalysis are protonated. There are obviously a lot of examples of this ...


2

The pH profile of an enzyme is not necessarily symmetrical. As random examples, see Figure 7 here, or Figure 5b here. Or if you have access, a pH profile for Magnaporthe grisea catalase can be seen in Figure 7 of http://dx.doi.org/10.1042/BJ20081478 The reasons for this go back to why enzymes are pH dependent in the first place. One of the major reasons for ...


2

The following chemical equation explains why pH decreases with increased $CO_2$: $CO_2 + H_2O \rightleftharpoons H^+ + HCO^{-3}$ pH changes are the reason why oxygen binds to hemoglobin in you lungs and then dissociates from hemoglobin at other parts in your body where the oxygen is low because cellular respiration turned the oxygen into carbon dioxide. ...


2

Any acid that releases a proton when it dissociates in water will also produce a conjugate base. We can conceptualize this as $\ce{HA <=> H+ + A-} $. In this particular example, $\ce{HCO3-}$ is $\ce{A-}$. The strength of the acid is determined by the extent to which the acid, $\ce{HA}$, dissociates. This can be expressed using the equilibrium constant ...


2

pH affects the structure of all macromolecules that compose bacteria, and indeed all cells. Here's a shortlist of examples: Lipids Lipids are hydrolyzed by extreme pH levels. They undergo chemical reactions and fall apart into constituent molecules, which may be toxic. The membrane is made of lipids; if it is disrupted, the cell ceases to exist. Nucleic ...


2

Extracellular acid base homeostasis in human physiology is maintained primarily by the bicarbonate buffer, as regulated by both the kidneys and the lungs (and to a certain extent, the intracellular phosphate buffer). Outside of illness or injury, (arterial) blood pH is kept between 7.35 and 7.45. There is an excellent review of acid base homeostasis in ...


2

I agree with @alina that it is well accepted that the pH difference across the inner membrane is ~0.5-1 units. However, the absolute value of the pH in the IMS will vary between organisms and even cells. It is experimentally difficult to measure it, therefore most of the times only the matrix pH has been reported. Using the output from the BioNumbers ...


2

According to the authorities Roos and Boron the difference of pH across the inner-membrane of mitochondrion is 0.5 with pH outside the membrane equal 7.0 and inside the pH is 7.5 (pH-mit = 7.5, pH-out = 7.0) according to Intracellular pH


2

Fermentation pH will differ a great deal depending on the bacteria or fungi being used and the process. But it is not uncommon to have a relatively narrow range of pH as a target. Remember pH is the -log[H+] so the pH scale is not linear. Also some fermentation reaction involve very expensive pharmaceuticals or intermediates, a single fermentation batch may ...


1

Vaccinium species are ericaceous plants (acid soil loving) so they will not do well in alkaline soils, and/or being watered with hard water. In fact they have a narrow optimum pH range 4.8 - 5.2 (Source http://www.westernfarmpress.com/management/blueberry-iron-chlorosis-has-multiple-causes) The pH of the soil will effect the plants ability to access the ...


1

This is a very chemical explanation. Here goes. $\ce{pH = -log[H+]}$ $\ce{pOH = -log[OH-]}$ $\ce{pH + pOH = 14}$ Therefore, at a $\ce{pH}$ of $14$, $\ce{pOH}$ is zero, so there is 1 mole of $\ce{OH-}$ and $10^{-14}$ moles of $\ce{H+}$ in a liter of your substance.


1

The h2co3 content of unadulterated rain is 15 micromoles of H+/Kg at room temp. The pHBC of average field soil from a 3000km transect in asia varied from 10 to 188 - mmol-kg-ph unit... from 40 localities. This other research found soil values of 45-1000 pHBC. https://www.science.gov/topicpages/s/spiked+soil+samples.html That means that H2CO3 would affect ...


1

Rainwater might not be the best option. Rain water is naturally acidic due to the reaction of CO2 forming some weak carbonic acid [see here for explanation]. Source: Wikipedia As a result, pH of "pure" rainwater is usually between 5-6; usually around pH 5.6. See here. Most rainwater has a pH of 5.6 to 5.8, simply due to the pressence of carbonic ...


1

the pancreatic fluid contains lipase which breaks down the fat in the milk in to fatty acids and glycerol. The fatty acids produce lower and create a more acidic pH.


1

Right now, there is no evidence shows hard water can cause any healthy problem. Previously people were concerned about the high mineral content, such as calcium and magnesium, may cause disease such like cardiovascular disease. But from the report World Health Organization published in 2003 Hardness in Drinking-water, it says "Although a number of ...


1

OK. Let’s answer the questions you pose: How does the pH affect the hydrolysis of ATP? High concentrations of hydrogen ions or hydroxyl ions (“extremes of pH” — as you quote) cause acid or alkaline hydrolysis. The mechanism of alkaline hydrolysis is presumably through a cyclic intermediate, as with the hydrolysis of RNA. Acid hydrolysis of ATP requires ...


1

Stability of ATP is largely due to Mg2+. ATP in cell is actually Mg2ATP2- The Mg ions stability the negative charges on the phosphates. pH is also important of course, but Mg is key, hence you see Mg2+ all the time in biochemical reactions where ATP is involved.


1

It depends how you define an acid. For what it‘s worth, the chemical definition Google presents when I search is “a molecule or other species which can donate a proton or accept an electron pair in reactions”. On that basis the serine residue in the catalytic triad is acting as a weakly ionizing acid. Of course in aqueous solution a free serine hydroxyl ...


1

In theory, you can calculate the charge on every individual ionizable group (i.e. looking up their pKa and calculating charge by henderson hasselbalch) and just add them up to get the total net charge. In practice you would need to measure it with something like isoelectric focusing, since polypeptides fold and certain groups end up interacting with other ...


1

Enzyme function is largely determined by its 3-D shape. Enzyme shape is affected by pH among a couple other things. The enzyme only retains its optimal shape at the optimal pH, as you creep outside of it the enzymes shape changes and hence so does its function.


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