BurningKrome

So the impression I get is the H2SO4 does nothing but provide free H+ for the protonation of the OH group. Would the reaction work as well with any strong acid (HCl or whatever)? Would this be considered an E2 reaction? Thanks!

Can anyone point me to, or diagram out, an electron pushing diag for the dehydration of formic acid by sulfuric acid to form carbon monoxide. I'm especially interested in how the the CO forms with a lone pair without picking up the free H+ to form either COH of formaldahyde (CH2O). I'm also curious abot how the dative bond forms, without picking up a free H+. Thanks!

You may be right. I get that a strong base like HCl is strong because Cl- is basically not a base at all and it disassociates completely in water. NaOH is considered a strong base because it also completely dissassociates completely in water and the Na+ is basically non-acidic. So, maybe my misunderstanding is this: My understanding of Kb (K-base) is the ability to which a base can accept electrons (Lewis) or RETRIEVE an H+ (Bronstead). Is this acurrate?

From the science fiction perspective...if the purpose is to convert the body's energy sources into electrical/mechanical energy, it would be better to devise a muscular motor. I.e. similar to an electrical stepping motor, except that instead of using pulses of electro-magnetism to initiate each step, it would use muscular contraction for each step. Kind of a ratcheting motion. Cloned sphincter muscles should provide the ideal motion. http://en.wikipedia..../Stepping_motor Then, instead of using ATP directly, you would simply need to tap the blood supply from the human host to feed the muscular portion of the cybernetic device. If the desire is to use the body's energy to create an electrical source exclusively (instead of doing mechanical work like spinning...say...an arm mounted mini chain gun ;-) then the muscular rotary motor could be attached to a small alternator. Actually, I wonder if the London Cybernetics institute is working on something like this. If I worked for them, I would be ;-D

It would probably kill your electrical work too. Try orthoboric acid instead.

So, another basic question (no pun intended). Acids and their conjugate bases. The definition of a conjugate base is the resulting base after the hydrogen(s) have been removed from the acid. I.e. acid CH3COOH has a conjugate base of CH3COO-. I also understand that, by definition, the stronger an acid the weaker the conj base. The fact that the conjugate base is weak is WHY the acid is strong because the base cannot hold onto the proton. I.E. H2SO4 (Very strong acid, Ka = 1.0 * 10^3) IS so strong specifically because HSO4- (Kb = 1x10^-17) is such a weak base that it can't hold onto the H+ in solution. The fact that Kb = Kw / Ka (where Kw = 1x10^-14) means expressly that the larger the Ka (stronger) the smaller the Kb (weaker). However, an axiom of acid/base (specifically buffer solutions) is that a weak acid has a weak conjugate base. This does not make sense to me based on the above. It seems more accurate to say that a "Moderate acid has a moderate base…whereas a weak acid has a strong base and a strong acid has a weak base". Is this simply a matter of semantics…where a weak acid has a relatively weak base when compared to other bases and acids…or am I missing something more critical here?

Of course That makes sense. Somewhat obvious, now that it is pointed out In the case of Oxygen (or more specifically H2O) does the third hydrogen actually form a covalent bond with a lone pair...or is the H+ held mostly by the charge (like a bastardized ionic bond)? If a covalent bond, am I correct in inferring that resonance plays a part in keeping the third hydrogen in place? Thanks! Oh...and to satisfy her curiosity... I know about carbocation intermediaries (loss of a bond) ...but are there any instances where carbon will PICK UP an ADDITIONAL (5th) bond...even transitorily? Thanks!

As mentioned by CharonY, viruses might best be considered naturally occurring biological devices, as opposed to living things. They have no metabolic functioning outside of a host cell...and pretty much do nothing but inject genetic material into the cell for the purpose of using the cells machinery to produce the proteins to make more viruses. The "choice" of using RNA over DNA to accomplish this should not infer a superiority or even an evolutionary precedence...any more than a car running on gasoline is superior than one running diesel. It is simply the mechanism by which the virus evolved to accomplish the task of reproduction.

So, the chemical energy stored in ATP is really completely different than electrical energy (for functional puposes). Electrical energy is the result of electrons moving through a substrate (copper wire, silicon/germanium chips) to carete force...often in the form of light, heat, or a magnetic field (craeting a magnetic field is how electric motor operate). ATP energy really is used by depositing one of it's phosphates onto a protein, which then has a conformational change, which can then drive things like Kinesin Motor proteins (see ) In the animation, ADP (ATP minus one phosphate) is attached to one of the "heads"...which causes it to bind to the microtubule. When an ATP molecule attaches to it, it causes a conformational change (the yellow part) which twists the second head (with ADP bound) to move forward and attach to the strand. Then a phosphate on the first ATP (attached to the first head) disassociates, causing the first head to unbind. When an ATP attaches to the second head, IT has a conformational change which drags the first head around...and the process continues causing the Kinesin to "walk" down the mircotubule. However, if you;re trying to come up with something for a science fiction novel...you could, potentially, device something to strip electrons off the phosphates, leaving an ionized phosphate waste. Of course, it would pretty much take every ATP molecule in your body to create enough current to run an LED for about half a second. Also, ATP does not float around in the blood. It's locked inside cells.

Biochemistry is a LOT of chemistry. Pure Molecular biology is also a lot of chemistry when training...but I use it probably a quarter as much as a biochemist would.

Hi. Here is a link to a different thread which discusses the units. http://www.scienceforums.net/topic/37222-international-unit-iu-conversion-in-enzyme-kinetics/ Also, when using many enzymes (restriction digest enzymes in this case) a "unit" is defined as ... "One unit is defined as the amount of enzyme required to digest 1 µg of λ DNA in 1 hour at 37°C in a total reaction volume of 50 µl." Be sure to check the manual for the enzyme in question for definitions to be sure you've got the right unit

Sorry. That is true. I forgot to check the footnotes ;-D

Thanks for the info. Gives me more to work with. However, when discussing the bonding energy for ADDITIONAL bonds (ionizing bonds or those bonds beyond that which forms a completed valence)...what is the controlling factor for these (electron affinity, electron negativity, resonance, ETC.?) Sticking with hydrogen for ease...if HCl was added to a solvent containing 50% H2O and 50% methane...the H20 would have observable amounts of H30 to absorb the excess H+, however the Methane would have non-observable amounts. For lack of a better description, the Kb of H2O >>> Kb of CH4. (The K base of Water is much much greater than the K base of Methane). WHY? What controls the affinity of additional ionizing hydrogen bonds causing Water to have such a significantly higher affinity than Ch4?

Hey...I'm not the one who asked the question...but, after studying the McMurray reaction, I'm still unsure about the electron movement during this particular reaction. I wonder if someone could generate a mechanism document with the electron pushing arrows for this. You can send it to me via email if you don't want to spoil the asker's training When I try to figure it out from the Wikipedia diags and from the diags at http://www.organic-chemistry.org/namedreactions/mcmurry-reaction.shtm I keep ending up with a lone pair not accounted for. Thanks!

Usually refers to bacterial or yeast growth medium. There are varying recipes. For e. coli we use "LB" ... 10g tryptone. 5g yeast extract. 10g NaCl. Bring to 1 Liter Adjust pH to 7.5 with NaOH. autoclave For HeLa cell we use Eagle's MEM

I'm assuming you're discussing a PCR reaction to clone...and not discussing the process of sequencing the clone. You may want to verify your melting and annealing temps using a calculator such as this one... http://www.basic.northwestern.edu/biotools/oligocalc.html It may be as simple as lengthening your extention time after annealing.

My understanding is the majority of organic molecules found in life on earth are L- (left handed). There is no functional reason that life could not have evolved (here or elsewhere) using predominantly D- (right handed) molecules...however, we cannot substitute D- for L- in our biological needs.* For example, Motrin is a chiral molecule. Because of the difficulty in separating D- from L-, Motrin tablets contain an equal dispersion (racemic) mix of L- and D-...however only the L- enantiomer is functional. The D- enantiomer is simply disposed of by the liver. Thus, theoretically, when Captain Kirk (or Stargate Universe if I want to update) travel around foreign planets to find food, there is at least a 50/50 odds that the food they found would be incompatible with our biology. I don't know under what circumstances this incompatibility would be toxic...but the aforementioned Motrin example infers it would just be a waste of food. Perhaps the real purpose in engineering D- enantiomer foodstuffs would be to create the next big diet craze? Interesting link... http://en.wikipedia....popular_fiction * From the MIT lecture series "MIT OCW: 7.012: Introduction to Biology" available from iTunes"

"Cell lines", technically, simply refers to any batch of cells which have been immortalized so they can be grown continuously and reputably for study. HeLa (for example) have a number of well identified “cell lines” which are immortalized, and cataloged by the NIH. Frequently, cell lines are immortalized by introducing portions of cancerous genes into the origin cells. HeLa (again) contain segments of the cancer causing HPV-18 virus which is what allows them to continue reproducing without entering normally induced apoptosis (cell death cycle). Usually, only a portion of the cancerous genome is used. You cannot catch HPV-18 from HeLa cells, as the genome is not complete and does not produce the majority of the HPV proteins including the capsule. Once immortalized, and able to consistently reproduce with consistent traits…the “line” is classified, categorized, and stored by the NIH. Google HeLa and Henrietta Lacks. This will give you the entire sorted history of the HeLa cell line. http://en.wikipedia.org/wiki/HeLa

The question is regarding the electron transport chain within the mitochondria, specifically how the electrons transport protons through the first and third complex. The basis of this question can be found at the tutorial at ... http://www.johnkyrk.com/mitochondrion.swf As each pair of electrons passes through each individual complex, they cause the transport of two protons across that complex from the matrix to the outer chamber. The electrons move by passing from the NADH/FADH2, to the flavin inside the complex (FMN) and then “bouncing” between the iron cores of Heme molecules (porphyrin rings) also within the complex. In the process of jumping between the iron cores they manage to “drag” (?) protons with them. Question: How, exactly (if we know) is this “dragging” accomplished? - I.e. Are the high energy electrons in orbitals around these protons (perhaps in a higher energy state and thus a higher shell than the S1) and, thus, form partial bonds (semi-covalent / semi-ionic???) between the iron AND the proton? If this were the case, would these protons have to come from the Nitrogen bound hydrogens off the NADH/FADH2 themselves? One proton appears to come from the NADH/FADH2, but not the second. - Or, are the electrons being passed resonance style between the iron cores (like electrons passing through a silicon/germanium microprocessor chip) and the protons just follow the magnetic pull through the membranes? - If so, since the complex membranes are normally proton impermeable, are there passive/active proton channels? Do the electrons perhaps directly activate these channels? Thanks!

The question is regarding the electron transport chain within the mitochondria, specifically how the electrons transport protons through the first and third complex. The basis of this question can be found at the tutorial at ... http://www.johnkyrk....tochondrion.swf As each pair of electrons passes through each individual complex, they cause the transport of two protons across that complex from the matrix to the outer chamber. The electrons move by passing from the NADH/FADH2, to the flavin inside the complex (FMN) and then "bouncing" between the iron cores of Heme molecules (porphyrin rings) also within the complex. In the process of jumping between the iron cores they manage to "drag" (?) protons with them. Question: How, exactly (if we know) is this "dragging" accomplished? - I.e. Are the high energy electrons in orbitals around these protons (perhaps in a higher energy state and thus a higher shell than the S1) and, thus, form partial bonds (semi-covalent / semi-ionic???) between the iron AND the proton? If this were the case, would these protons have to come from the Nitrogen bound hydrogens off the NADH/FADH2 themselves? One proton appears to come from the NADH/FADH2, but not the second. - Or, are the electrons being passed resonance style between the iron cores (like electrons passing through a silicon/germanium microprocessor chip) and the protons just follow the magnetic pull through the membranes? - If so, since the complex membranes are normally proton impermeable, are there passive/active proton channels? Do the electrons perhaps directly activate these channels? Thanks!

OK…for as much chemistry as I’ve taken, my High Schooler asked me a question I can’t actually explain…so I’m hoping for help. We were discussing basic chem: the number of bonds for atoms and how they form bonds based on the number of needed electrons in the valence shell. HOWEVER we also discussed how they can transiently form lesser or more bonds than predicted by the periodic table. I.e. H2O regularly picks up transient H+ ions to form H30+ in acidic solutions. And carbon will form a very brief carbocations (carbon with only three bonds and a pos charge) during Sn1 and E1 reactions. Since H20 can relatively readily form transient H3O+ in an acidic solution, she assumed that carbon could also readily form a transient additional bond (I.e. CH5+) in an acidic solution. When I said it doesn’t she asked the horrifying question “why not?” So, I guess I don’t actually know. So my question is: Why does a molecule like water readily pickup a transient excess hydrogen bond and carbon does not? Another good example for us would be perchlorate (ClO4-)…where the Chloride has four oxygen even though it only has one unsatisfied valence electron. Thanks!