Questions tagged [ph]

pH is a measure of the acidity of a solution. It is defined as the negative logarithm (base 10) of the concentration of hydronium ions in a solution.

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Why is it possible to make yoghourt with lactose free milk?

The function of the Lactobacillus bulgaricus and Streptococcus thermophilus cultures is to ferment lactose to produce lactic acid. The increase in lactic acid decreases pH and causes the milk to clot,...
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Why does dissociation of carbonic acid cause a decrease in pH?

When a molecule of carbonic acid (H2CO3) dissociates, the two products are a bicarbonate ion (HCO3-) and a hydrogen ion/proton (H+). Because of the addition of a hydrogen ion, this process causes a ...
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What is the role of lactic acid bacteria (such as L. acidophilus and L. bulgaricus) in glycolysis during yogurt fermentation?

I am trying to prove that an increase in monosaccharides (glucose, fructose, galactose) that have been added to milk during fermentation will result in a decreased pH. My current argument is: "The ...
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What happens to Bacteria at a low pH?

I am conducting an experiment on how different pH levels effect the growth of E.coli. After researching, it is predicted that the most acidic pH level (pH 2) will be most effective at killing (or at ...
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What are the (statistically) normal pH levels in the most-outer part of human sexual organs?

What are the (statistically) normal pH values of the outer skin/epidermis of human sex organs (groin/crotch) in the male and female? e.g male testes, female vulva, male glans, the enveloping epiderm, ...
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Acidity and Alkalinity of Foods

Some foods leave an acidic effect on the body such as meat and dairy, while others leave an alkaline effect, like vegetables. However, are these effects significant enough to greatly alter the blood ...
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What is the pH of the mitochondrial intermembrane space?

The proton gradient is stored between the mitochondrial double membrane. More protons mean more hydronium ions and lower pH, but how much exactly?
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HELP! How will pH 14 affect enzyme structure? [closed]

If a substance is very alkaline/ basic, e.g. a pH of 14, does this mean that there are near to zero H+ ions (or it is possible to have such a situation where there are zero H+ ions and it is still ...
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Alternative to distilled water for pH test

I am looking to test soil pH in a remote location. The test results don't need to be perfectly precise, and a pH test strip should provide sufficient accuracy. However generally this kind of testing ...
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What is the resting human stomach pH?

This article in ThoughtCo.com claims we have a resting stomach pH of 4-5. Unfortunately, there are no references, so I can't verify what it says. I am slightly confused, however. The study says "...
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How do I know which molecular structure is glycine's “base state”?

I was looking up the chemical structure of glycine, and I found the following two images: and . My question is, what is the "base state", or the "natural state" of glycine? Under what scenarios ...
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What does a typical, perfectly healthy vaccinium corymbosum (highbush blueberry) leaf look like?

What does a typical, perfectly healthy vaccinium corymbosum (highbush blueberry) leaf look like? Colour (darkness of green, redness) Waxiness Veins I'm guessing that soil ph, nutrients, and other ...
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Deionized water - can it be beneficial for metabolic acidosis?

I ran into an interesting question today that examined the science around alkaline water and its advertised 'generalized health benefits' assumed to be (but incorrectly) stemming from a rise in blood ...
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Determining net charge of amino acid at given pH

I am trying to calculate the net charge on an amino acid, but I seem to be doing it wrong. The question I am trying to answer is "In a pH 7.0 buffer, what will be the charge of Methionine?" We are ...
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Why does the pH decrease, when adding pancreatin to different types of milk (cow milk, soy milk etc.)?

I'm experimentally observing how pancreatin affects the pH in different types of milk. Why does the milk's pH decrease when I add an enzyme solution to different types of milk (e.g., cow milk, soy ...
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The effect of pH on catalase

Why does catalase still produce oxygen when mixed with 1 mL of 0.1M NaOH (pH 13), but not when mixed with 1 mL of 0.1M HCl (pH 1)? Catalase's ideal from what ive researched is 7. In other words, since ...
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Do the pH and other ions affect the hydrolysis of ATP

ATP hydrolizes to ADP and phosphate in a strongly exergonic reaction and is used for energy transfer and short-term storage in cells. ATP is stable inside a cell, so a significant activation energy ...
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Catalytic Triad of Serine Proteases

Is serine considered an acid in the catalytic triad involved in the mechanism of action of serine proteases? It is donating a proton to His but I am not sure if this really qualifies as an acid?
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Chart of blood pH across different animal species?

How does blood pH vary across species? I can't find an article or chart listing this kind of information. So far I've found bits and pieces like: Human blood pH is nominally 7.4. 7.4 seems to be a ...
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How do you calculate the charge on a polypeptide chain with changing pH?

I understand the charge placement on the N & C-terminus and also the utilization of the R-side groups in the amino acids. For example, What is the overall charge for a chain Glu-Cys-Arg-Asp with ...
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Why do you die if you cannot breathe?

I was wondering what the actual reason for death by suffocation is. Obviously it is related to oxygen deprivation. But what is the underlying cause of death? Is it due to insufficient oxygen for ...
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Blood pH at Higher Altitudes

My Campbell's Biology Textbook says the following: "For example, when an elk or other mammal moves up into the mountains from sea level, physiological changes that occur over several days ...
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140 views

What are the metabolic concerns associated with hard water?

If humans can maintain a consistent blood pH, then what problems does alkalized water cause us? Why is it recommended that we filter and boil hard water? Is the issue that hard water can affect the ...
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Does pH affect Michaelis constant?

I have been trying to confirm the Km of a substrate (which is 34 +/- 4 mM). This value was obtained in 50 mM MOPS, pH 6.3. I conducted my kinetics assay in a buffer of pH 7 and obtained a Km value in ...
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Is there a biological environment that we can we assume glutamate exists as glutamic acid?

In the body we almost always assume that glutamate exists as glutamate rather than glutamic acid. It is so commonly glutamate yet glutamic acid and glutamate share the abbreviations of Glu and E. From ...
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How do I prepare a solution? (Calculation) [closed]

I have to make 100mL of 400mM NaOH. How do I go about calculating what I need to prepare this?
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Why does pH have an effect on enzymes?

I am currently studying biology and would like to know why enzymes work best in a particular narrow range of pH (the so-called pH optimum). Unlike temperature change, I do not think this has much to ...
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What are the highest and lowest possible pH, paCO2 and HCO3 in the blood of living human?

What are the highest and lowest possible values of pH, $paCO_2$, and $HCO_3$ in the (arterial or venous) blood of a living human being?
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How do fish tolerate pH changes in water?

I want to know how aquatic animals behave as a natural indicator of the acidity in lakes and rivers. How do they tolerate these pH change?
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409 views

Effect of pH on life? Use buffer or HCl? How about lactic acid?

I'm trying to find the effect of pH on living things like E. coli and such. At first I thought of using a buffer solution which maintains its level of pH, but it's possible that the inactive ions of ...
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How Do Acid and Base Loving Plants Get Enough PO4?

Acidic and Basic soils experience phosphate sequestration through binding with either calcium, aluminum, or iron. How do plant that thrive in acidic and basic soils obtain the necessary phosphate? ...