SysBio

ok....thanks for the replies...and cool example with the RV

yeah i didn't realize that you need a pure sound wave at a given frequeny, so that explains why even if the given frequency is produced in everyday noise, it would not cause resonance

But can someone comment on the resonating frequency of most common solid objects vs. the frequency of common sounds?

Hi everyone,

Im learning about the basics of resonance, and I am just wondering why it is not observed more often in everyday objects.

For example, if one produces a frequency that is just the right frequency of a wine glass, it shatters.

So why dont common objects around us start visibly vibrating even though there are many different sound waves constantly produced around us? (For example, there could be music played loudly, someone shouting or banging a table loudly, and arn't there a lot of other waves circulating around us from wireless devices?)

I'll take a shot:

Most solid objects around us vibrate at a frequency that is relatively HIGH, and most sound waves we precieve have low frequency? The type of waves that would be required to shatter common solid objects could not be produced "accidently"?

Thanks in advance....I hope someone answers this question !

Hello,

 

Because you are dealing with a tertiary center and therefore automatically confined to an SN1 mechanism... for either route going from the alcohol to the chloride or the chloride to the alcohol you will go through the same carbocation intermediate.

 

Thus to effectively convert the alcohol to the chloride it is necessary to have an excess of Cl- anion present compared to water molecules present (Le Chatelier's principle)... This overcomes the equilibrium issue that you are referring to..

 

When actually doing this reaction in the lab often times molecular sieves or anhydrous calcium chloride is added to remove the water thereby further driving the equilibrium towards the production of the desired product - the tertiary halide.

 

As far as the other examples with SOCl2 etc.. they go through SN2 mechanisms and will not work on a tertiary alcohol...

 

hope this helps. : )

yes that explained a lot

thanks again for the responses everyone

thanks for the responses...

ok, good point H20 is the actual leaving group. But halides are better leaving groups than water too. Cl-, Br-, and I- are very stable ions because they are the conjugate bases of strong acids

i would think a few H20 could pop off and be replaced by Cl-, but the equilibrium of this would lie much in the other direction.

....so i still dont see why this reaction would readily occur

In my orgo textbook, it says that that one of the most common ways of making alkyl halides is: SN1 rxn with tertiary alcohol

However, a halide is a much BETTER leaving group than an OH group...so why does this reaction work?

Thanks in advance

PDH is an enzyme that is activate/deactivated by kinases (adding P)....does this have anything to do with it following M-M kinetics?

Thanks

I want to get a good grasp of the BASICS of the different functional groups.

Does anyone know of any good websites or books that summarize this?

For example:

which have the highest melting points

which are most acidic

etc...?

thanks for the resopnses...

ok I think I get the point...it refers to reactions involving transfer of hydrogen ions....and there ARE reactions where hydrogen is transferred from one molecule to the next

thanks

Hi everyone,

Can someone please explain to the best of their ability:

WHAT does "proton transfer" mean?

There are no reactions that protons actually jump from one molecule to the next, are there? I thought only electrons move?

Hello,

I have been looking through publications inorder to find the maximum rates of a few transporters...

this is easy when data is shown as V vs. S

you can just find Vmax from where the graph is leveling off

however, some data for transporters is shown as DISTRIBUTION RATIO vs TIME (where distribution ratio = inside cell / outside cell)

does anyone know:

1) why would someone display the data like this?...(ie. is it for transporters with very fast kinetics)?

2) how can you find Vmax for a transporter with this data?

Wow....thanks a lot for the great information

I knew of the general molecular cloning procedure from class lectures, and I pieced together a procedure pertaining to malaria from a research paper that detailed its experimental techniques. But I'll remember the malaria journals for next time.....

I am still confused about the consumables though...it just seems overwhelming. How am I supposed to know HOW MUCH primers, plasmid vectors, etc to buy?

And thanks for tips regarding labspace and equipment. Its just a hypothetical grant application, so I will say that I have access to all necessary equipment and labspace through colaborators....can you explain what a BS2 lab space is though?

Hi all,

Question: how would you start to approximate the costs of gene knockout experiments?

I am doing a class project where I am writing a research grant proposal. My proposal involves using gene knockouts to validate malarial drug targets. (The steps include: take plasmid vectors, insert stuff using restriction enzymes, transfect into malaria, screen using southern blotting)

The problem is that I am actually mostly a computational researcher.

So I have no idea about how people practically buy and use these experimental items.

For example, I assume there are gene knockout kits???....how do you choose which kit to buy???....how many kits do you need???....how do you plan for mistakes/repeats????.....where do you find prices for experimental equipment???

As you can see I am completely lost in this....so if anyone has any idea about buying materials for gene knockout experiments....PLEASE HELP ME!

Thanks

Can someone explain the mechanism by which these work? (ie. what enzymes are involved, do transpoable elements have characteristic sequences?)

Also if you know of a link to a video/animation it would be greatly appreciated

Thanks

I believe there are only a few hundred complete sequenced genomes. I realize you mainly sequence the genome of an organism that is heavily involved in research, eg. model organisms such as E.coli, yeast, etc.

But my question is this: If I discover a new bacterium tmrw, what would be the time and cost to sequence its genome?

(obviously will vary with equipment, but please give approx guidelines)

Thanks!

oh yeah....very true

I still dont see how it adds up though, because I think bacterial cells are 10x smaller. But the remaining human body is surely more than 10x greater than the intestinal track.

I think the only way this can make sense is if the large surface area of the intestinal track is considered.

Thanks for those numbers....

however they dont make sense to me. How can the lining of the intestinal track have more cells than the entire body.....

Would it have to do with the idea that major portions of the intestinal track have folds in order to maximize surface area?....still its pretty mindboggling

Hi all,

I think I have heard that the number of microbial cells (from other species) in humans actually outnumbers human cells....is this true?

To elaborate, can someone say what type of organisms these mainly are, and total number of cells and/or percentage of the human body they make up?

thanks for any information!

Thanks for the answer Psycho

Yeah, there is a lot of uncertainity regarding the global species count (anywhere from 2 to 100 million) but probably in the 10's of millions

http://www.sciencedaily.com/releases/2003/05/030526103731.htm

Interestingly, most organisms are below surface level.

As for the DISTRIBUTION of life.....can anyone give more details? To be clear, I am interested in terms of total biomass. I would guess that over 90% of biomass on earth, exists as prokaryotes...

Hi everyone,

I was thinking about the following general questions about life on Earth:

1. How many species are there on the planet?

2. How many organisms are there on the planet?

3. How are these species/total organisms distributed among the different animal kingdoms (ie. what is life most commonly in the form of?)

I'll look around the internet over the next couple of days and post what I find. If anyone already has a good idea about these questions then please let us know.

Thanks!!!

(Also, I'm new here...I looked at a couple of the other science forums around and this one just seemed like the best....but I would like to hear from more experienced members.....how does this forum compare to others?)