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Ph and buffers

The pH of a solution indicates its acidity or alkalinity. The pH scale is, as previously mentioned, an inverse logarithm and ranges from 0 to 14 ( [link] ). Anything below 7.0 (ranging from 0.0 to 6.9) is acidic, and anything above 7.0 (from 7.1 to 14.0) is alkaline. Extremes in pH in either direction from 7.0 are usually considered inhospitable to life. The pH inside cells (6.8) and the pH in the blood (7.4) are both very close to neutral.

The pH scale, which ranges from zero to 14, sits next to a bar with the colors of the rainbow. The pH of common substances are given. These include gastric acid with a pH around one, lemon juice with a pH around two, orange juice with a pH around three, tomato juice with a pH around four, black coffee with a pH around five, urine with a pH around six, distilled water with a pH around seven, sea water with a pH around eight, baking soda with a pH around nine, milk of magnesia with a pH around ten, ammonia solution with a pH around 11, soapy water with a pH around 12, and bleach with a pH around 13.
The pH scale measures the concentration of hydrogen ions (H + ) in a solution. (credit: modification of work by Edward Stevens)

So how can organisms whose bodies require a near-neutral pH ingest acidic and basic substances (a human drinking orange juice, for example) and survive? Buffers are the key. Buffers readily absorb excess H + or OH , keeping the pH of the body carefully maintained in the narrow range required for survival. Maintaining a constant blood pH is critical to a person’s well-being. The buffer maintaining the pH of human blood involves carbonic acid (H 2 CO 3 ), bicarbonate ion (HCO 3 ), and carbon dioxide (CO 2 ). When bicarbonate ions combine with free hydrogen ions and become carbonic acid, hydrogen ions are removed, moderating pH changes. Similarly, as shown in [link] , excess carbonic acid can be converted to carbon dioxide gas and exhaled through the lungs. This prevents too many free hydrogen ions from building up in the blood and dangerously reducing the blood’s pH. Likewise, if too much OH is introduced into the system, carbonic acid will combine with it to create bicarbonate, lowering the pH. Without this buffer system, the body’s pH would fluctuate enough to put survival in jeopardy.

An H2O molecule can combine with a CO2 molecule to form H2CO3, or carbonic acid. A proton may dissociate from H2CO3, forming bicarbonate, or HCO3-, in the process. The reaction is reversible so that if acid is added protons combined with bicarbonate to form carbonic acid.
This diagram shows the body’s buffering of blood pH levels. The blue arrows show the process of raising pH as more CO 2 is produced and exhaled. The purple arrows indicate the reverse process: the lowering of pH as more bicarbonate (HCO 3 ) is generated from the CO 2 being produced by cellular respiration. In short, when more CO 2 is exhaled, blood pH goes up and the blood is more basic, and if CO 2 is converted to bicarbonate, blood pH goes down and the blood is more acidic.

Other examples of buffers are antacids used to combat excess stomach acid. Many of these over-the-counter medications work in the same way as blood buffers, usually with at least one ion capable of absorbing hydrogen and moderating pH, bringing relief to those that suffer “heartburn” after eating. The unique properties of water that contribute to this capacity to balance pH—as well as water’s other characteristics—are essential to sustaining life on Earth.

Enzyme function and buffers

On the cellular level, cells need to maintain a relatively constant internal environment, because many important cellular functions only take place within a narrow of conditions, such as temperature and pH. Enzymes function is influenced by the pH of its environment and only function optimally within a narrow pH range. Losing function of just one enzyme can mean death for a cell, or tissue, or organ or and entire organism. In addition, there are many reactions occurring in a cell that either produces or consumes Hydrogen ions thereby changing the pH of the cells environment. How do cells maintain pH within the range necessary for enzymes to function properly? The answer is buffers, just as learned earlier about your whole body using buffers to maintain its pH.

Questions & Answers

anyone know any internet site where one can find nanotechnology papers?
Damian Reply
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
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what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
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Source:  OpenStax, Principles of biology. OpenStax CNX. Aug 09, 2016 Download for free at http://legacy.cnx.org/content/col11569/1.25
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