Cumulative General Science/Technology Quiz

[GoodGame]

STR---- guessing the TR stand for Terminating Repeats. I forget the S. Maybe Somatic (for somatic cells).

Vague recollection: They are random mutations that don't have an effect other than they accumulate in the DNA, and are conserved across generations. And because of the large number of them, a specific set of them helps fashion a 'fingerprint' for an individual.
If I'm recalling the right stuff, they are the basis for genetic fingerprinting of individuals in legal cases. E.g. Paternity tests or identifying perpetrators by DNA in their bodily fluids.

 

[Brighteye]

I'd guess it's more likely to be triplet repeats.

 

[nonconformist]

Short Tandem Repeats.

DNA identificiation along familial lines.

 

[StarWorms]

nonconformist got the definition right. GoodGame got the two uses right.

nonconfomist or GoodGame to post the next question (whoever gets there first).

 

[GoodGame]

I bow to Noncomformist as I butchered the acronym.

 

[nonconformist]

Part of my forensics course


Why, if the entropy of formation of glucose combusting to form CO2 and H2O is -ve enough for it to be spontaneous, does glucose not instantly burn on contact with atmosphere?

 

[Brighteye]

Because it's too stable. Oxygen can't attack the glucose bonds itself, but needs cofactors.

 

[nonconformist]

Nope, it's less to do with specifics, and more with generals.

 

[Brighteye]

Because you're talking about total entropy, but that's the sum of a number of stages, and the initial stage requires energy input to get it out of the entropy 'trough' it's in?

 

[Truronian]

Uninformed stab in the dark:

The pressure is too great?

 

[dutchfire]

Activation energy

 

[Truronian]

/\ Isn't that enthalpy rather than entropy?

 

[SS-18 ICBM]

He means that the activation energy is too high for spontaneous combustion at all temperatures. You need a flame to begin combusting glucose, even if the entropy is negative.

 

[nonconformist]

It's actually because the reaction is not kinetically favourable; theoretically it spontaneously forms the products, but it happens at such a slow rate it might as well be 0.

 

[SS-18 ICBM]

I've been wondering. What does the combustion of glucose have to do with forensics?

 

[Genocidicbunny]

I figure its a piece of trivia from a required chemistry course.

 

[GoodGame]

Dutchfire was the most close to scoring.

Enzymes help kinetically unfavorable reactions occur by lowering the activation energy of said reactions. The mechanism is presumably by stabilizing the intermediate step (transition state) of the said reactions.

http://en.wikipedia.org/wiki/Enzyme

Which is why us organic creatures can spontaneously combust glucose.

"Ummm...Donuts!!!"

It's actually because the reaction is not kinetically favourable; theoretically it spontaneously forms the products, but it happens at such a slow rate it might as well be 0.

 

[Mise]

So if I put some enzymes on my mars bar it'd blow up? Sweet... (no pun intended)

 

[GoodGame]

No, just you like don't when you eat a Mars bar, being in a biological system, heavily dissolved in H20, with the glucose stripped of its electrons (energy).. The net effect is similar to combustion, but the energy is transfered more gently, thankfully.

So if I put some enzymes on my mars bar it'd blow up? Sweet... (no pun intended)

 

[SS-18 ICBM]

Post the next question already!