Science Quiz

[Pontiuth Pilate]

Strontium is similar to calcium - it gets into the bone marrow and damages the blood cells produced there. Not only that, it combines with fluorine to form Sr90F2, a combination which is eliminated from the body much slower than plain old fluorine - this raises the chances of fluoride poisoning [fluorosis]. Oh, and it's radioactive that doesn't help either.

I don't think there's an antidote, except to reduce exposure to radiation.

EDIT: darn, Maj was a nose ahead of me. Go ahead

 

[Maj]

Doesn't seem fair that I should ask the next question seeing how I only answered a 1/4 of the previous one.

But to keep things going I'll fire away.

Topic: Geology

What three forces are theorized to be responsible for the continued molten state of the Earth's core?

P.S. You would've beaten me Pont if you hadn't taken that time to get all fancy

 

[Achinz]

Between them maj and PP have got the why.
The strontium remains a long time in the bone ie in combination with the long physical half life of 28 years, it has an effective half-life of some tens of years - hence the longterm radiobiological hazard.

So maj (or PP) to go next.

 

[Pontiuth Pilate]

1. Heat converted from gravitational energy as particles of new Earth came together.

2. Heat from decay of isotopes?

3. Naturally the outer layers cool off first, while the innards will stay hot for billions of years.

Or in "fancy" terms:

1. Accretionary energy
2. Radiogenic energy
3. Unequal radiation of heat

 

[Maj]

Correct on all counts. Your go Pont.

 

[Pontiuth Pilate]

Righto.

A zygote is created by joining two gametes, each produced by a different organism. In the process of producing a gamete and fertilizing it, there are four sources of genetic recombination which shuffle up existing genetic material.

Please list all four [one occurs twice!] and the maximum potential combinations that can result from each step, assuming that the animal is a human [with 46 pairs of genes].

By the way, "mutation" is not one of the answers since it alters genetic material instead of recombining it.

 

[Perfection]

I can only think of four
Synapsis
The random of distribution homologous chromosomes in anaphase 1 to duaghter cells
The random of distribution chromosomes in anaphase 2 to duaghter cells

I think that's it

 

[Pontiuth Pilate]

One more, you missed the really obvious one.

Spores don't have it, for obvious reasons

 

[RoddyVR]

i have no clue what the answer is, but i want to know if i'm reading the question correctly.

should the answer include the answer to this question:
how many (max) kids would a human pair need to have before the next one would be born an identical twin to one of his/her brothers (though quite a few years later)?

sorry for the out of turn question, i just wanna know if that's what Pontiuth's question is asking.

 

[Pontiuth Pilate]

No, I mean how many possible permutations of genes are possible in each mixing up of the genes.

There are 8 answers, so far 3 have been given.

Synapsis [ie crossing over]
First independent assortment
Second independent assortment

I still need the last source of randomization and the permutations resulting from each in a human with 23 pairs of chromosomes.

Apparently biology is not our strong hand

 

[Perfection]

I hope you aren't refering to fertilization becase that is post-meotic

 

[Deep_Thought76]

Well, since you included "fertilizing it" in the question and mentioned that it's the obvious one, I'll guess you're talking about the random release of an egg/meeting of that egg with 1 sperm.

As far as the next part, you seem to be using 'genes' and 'chromosomes', not to mention 'permutation' and 'combination', interchangeably, so it's hard to tell what exactly you're expecting for an answer. Best guess: Synapsis doesn't change the combination of chromosomes, just swaps the copies of genes between 2 homologous chromosomes, so max combinations would be 1 (46 choose 46). Or, if you count a crossed-over chromosome as different and it happened between each pair that would be 46. But it can also happen on each end of the chromatid, so that would be 92, and it can happen multiple times, giving you an arbitrary number.
First assortment would be 46 choose 23, so about 8.233430728•10^12. Second assortment would be the same, and the random meeting of sperm and egg would be (#of sperm released choose 1) * (#of eggs in ovaries choose 1), so the product of total # of eggs times total # of sperm released. I'm guessing there are far fewer of either than 8 trillion.

 

[Perfection]

Sorry but your math doesn't add up, after the first seperation it would be 2^23 (8,388,608 combinations) because you need homolugous chromosomes not any 23. the second would be the same thing because it's the splitting of the homologous chromosomes.

so the total possible is 2^46 which is about 70 billion.

This like yours doesn't take into acount synapsis or fertilization, which varies much more often

 

[Pontiuth Pilate]

Perfection got it. Synapsis and random fertilization both result in approximately infinity possible outcomes. Independent assortment gives you 2^n [where a diploid cell is 2n] outcomes. Random fertilization counts because I specified "in the process of creating a gamete and fertilizing it"

So Perf gets the next question.

 

[Perfection]

If aluminum is so susceptible to oxidation, why doesn’t it rust or corrode like iron or copper?

 

[slothman]

It does but the oxide doesn't peel off and forms a protective layer.

 

[Perfection]

Al2O3 is practicly impermiable to oxygen and forms that protective layer.

 

[slothman]

Ok what percentage of bones are in your hands and feet?

 

[betazed]

Ok. to keep this thread alive I will take a random guess. Since half the number of human bones are in the hand and legs I will say my answer is 50 %.

 

[col]

I'd say its much more than 50 % since there are so many small bones. I'll go for 80%.