Archive of Chat With Andrew Pohorille

[ Keli/NASAChatHost - 8 - 10:25:25 ]
Andrew Pohorille joined the staff of Exobiology Branch at NASA-Ames in 1996 and currently heads the Biomolecular and Cellular Modeling Group. Since 1986 he has been principal investigator in the NASA Exobiology Program. His NASA-related research projects involve molecular-level computer simulations of the structure, functions and evolution of the earliest living cells, the structure and properties of cometary ices and high-performance computing. His other research activities are devoted to studying interfacial phenomena, the mechanism of anesthetic action and functioning of cellular receptors.

[ Keli/NASAChatHost - 9 - 10:25:33 ]
Once the chat begins, Andrew Pohorille will attempt to answer as many of your questions as he can, but please be patient. The chat will be "moderated". This means that only a few questions will be posted to the chat room at a time. Don't worry if your questions do not appear on your screen immediately. They will be posted as Andrew Pohorille answers those ahead of you.

[ Keli/NASAChatHost - 10 - 10:25:49 ]
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[ Keli/NASAChatHost - 11 - 10:26:01 ]
At the conclusion of today's chat, we ask that you take a few minutes to let us know what you thought about it. For your convenience, you may use our online feedback forms at http://quest.arc.nasa.gov/qchats/qchat-surveys. We look forward to hearing from you!

[ Amy/NewJersey - 14 - 11:22:10 ]
Every once in a while, it would be helpful if Dr. Pohorille would what slide we shoudl be on (ie slide33.html) to make sure we are in the rigth place.

[ Amy/NewJersey - 15 - 11:22:10 ]
I think I heard that in RNA evolution experiments, you made 10 to the 15th power of different kinds of molecules. Was it really that many different molecules or just that many copies of a sfew different molecules.

[ Amy/NewJersey - 16 - 11:22:10 ]
Wow. Great lecture. Thanks. I can only stay for another 10 minutes or so, but I'll ask as many questions as ai can and then come back after school to read the answers. Thanks again.

[ Amy/NewJersey - 17 - 11:22:10 ]
Hello, I had to come late but the lecture is very interesting. The audio is comingthrough very clear and the slides are helpful.

[ Amy/NewJersey - 18 - 11:22:10 ]
I'm going to ask a few questions even though I know Dr. Pohorille won't be answering until later. I'm afraid I may have to go before the end.

[ Amy/NewJersey - 19 - 11:22:10 ]
I think I heard that only water can help matter organize into cell-like structures. Why can't other liquids do this? what is so special about water?

[ Andrew - 20 - 11:22:27 ]
Hallo, I am here to take your questions. Go ahead! Andrew

[ Keli/NASAChatHost - 21 - 11:22:43 ]
Thanks for waiting folks!

[ Amy/NewJersey - 23 - 11:23:41 ]
Please explain why sometimes you would do an experiment on a computer and sometimes with real chemicals.

[ Keli/NASAChatHost - 24 - 11:24:30 ]
Amy, you've got quite a few questions; Andrew is trying to catch up! Please be patient.

[ Keli/NASAChatHost - 26 - 11:28:09 ]
Hi George, Andrew is answering questions but there are quite a few ahead of you, as you can see. He will get to your questions as soon as he can. Thanks for coming today!

[ Andrew - 27 - 11:28:26 ]
RE: [Amy/NewJersey] Will we ever know if the pre-biotic pathways originated on Earth or from comets? What approach can be used to determine this for sure?
Amy, Thanks for your questions. Yes the are 10 to 15th DIFFERENT RNA molecules. And yes, we may never know where the organicss came from. We try to estimate what was infall of material on earth and how much organics it contained. Then, we can estimate whether there was enough of the right stuff. Your last question is about the nature of the hydrophobic effect. It is a difficult subject, and also my specialty. If you want to know more, write me separately.

[ Keli/NASAChatHost - 30 - 11:31:06 ]
RE: [Amy/NewJersey] I am patient. But I will have to go and I'll be excited to read the answers later. Thanks for exposing me to all of this. It is very interesting.
Thanks Amy, and remember there is another lecture next week at this time (hopefully on time!) and day by Bill Borucki.

[ Andrew - 31 - 11:32:40 ]
RE: [George] Hello, I'm a Junior High teacher. I caught the lecture during my teacher prep. Very interesting. Can you say a little bit more about how cells are multiplied, like as part of the RNAS evolution experiment.
George, Cell division is a complicated process, and highly regulated too. Protocell division may have been much simpler. They could have captured memrane-forming material from the environment or make it inside. It would get incorporated into the membrane making the cell envelope bigger. At sufficiently large size the envelope looses thermodynamic stability and spontaneously divides

[ George - 33 - 11:34:34 ]
I am trying to take it all in. My head is still swimming a bit from all of interesting information.

[ George - 34 - 11:36:23 ]
Hello, U am still trying to digest this all. My head is swimming with new thoughts.

[ Andrew - 35 - 11:36:27 ]
RE: [Amy/NewJersey] I thought that the RNA experiemnts were actually done with real biologicial matter. But in reading the intro for Dr. Pohorille, it seems like he is more into computational biology. so were the experiemnts actually all done with digital models?
Amy, RNA evolution experiments are made in the laboratory. The reasons why we use computer simulations is about the same as we do any other design on a computer. Imagine, for example, that you can build a simple enzyme. You can use a trial-and-error approach or you can build a computer model and simulate whether it works, and only then go to the lab and test it.

[ Keli/NASAChatHost - 36 - 11:36:48 ]
RE: [George] Hello, U am still trying to digest this all. My head is swimming with new thoughts.
What subject to you teach George?

[ Keli/NASAChatHost - 37 - 11:38:21 ]
Are there any more questions for Dr. Pohorille?

[ George - 39 - 11:39:40 ]
I help run the technology lab in my school and I help various teachers use the lab. We have Internet, CD players, some video stuff.

[ Keli/NASAChatHost - 40 - 11:41:00 ]
RE: [George] I help run the technology lab in my school and I help various teachers use the lab. We have Internet, CD players, some video stuff.
Well, I hope you encourage them to bring their students to more Quest events!

[ George - 41 - 11:41:09 ]
I have one last qustion. It sounds like the computer simulation is only used for some basic modelling. Is that right?

[ Keli/NASAChatHost - 42 - 11:41:19 ]
As a reminder, please provide feedback to us about today's chat, at http://quest.arc.nasa.gov/qchats/qchat-surveys. Those of you observing today's chat may also use our feedback surveys.

[ Andrew - 43 - 11:41:30 ]
RE: [George] So did life likely form on Earth in one place (like from one meteor strike) and spread out everywhere from there? Or did it likely form aproximately simulateoulsy from many similar events (ie several comet strikes or random mutations)?
A very good question George. Unfortunately, in the area of the origin of life we answer most questions by saying "we don't know" or "we are not sure". This is one of such questions. I am in favor of the global origin of life, since it would be more robust, but this is only my personal taste.

[ George - 45 - 11:43:44 ]
Thank you for this. I will certainly be back next week. I am learning a lot.

[ Keli/NASAChatHost - 46 - 11:43:44 ]
We should be wrapping up after these last questions. Please join us for our next Astrobiology chat on November 5 with Bill Borucki on the topic "How Can other Biospheres Be Recognized?" . Check the Astrobiology chat schedule page at http://quest.arc.nasa.gov/ltc/astrobio/index.html

[ Keli/NASAChatHost - 48 - 11:46:17 ]
RE: [George] It is so intersting I can't leave and am going to be late. Anyway, one more. If the origins aren't global butall tied to one event, would there be any way to find evidence of that in the cells/genes. etc, kind of like I can be traced to my parents through DNA
George, if you'd like to come back later, this will be archived. Thanks for your questions! If you can, please help us with feedback at http://quest.arc.nasa.gov/qchats/qchat-surveys.

[ Andrew - 49 - 11:47:36 ]
RE: [George] Onbe more thing. Where does most of the research dollars go. Is it for salaries, bioloical material, travel, equipment, etc. Who provides the dollars in the first place (is it all NASA?)
George, It depends. It could be salaries or equipment. For example, good electron microscope that allows you to look at the Mars sample with resolution of 100 angstrom costs a bundle. On the other hand, molecular biology experiments are very labor-extensive and salaries of grad students and postdocs constitute a good fraction of the budget

[ Andrew - 50 - 11:50:53 ]
RE: [George] It is so intersting I can't leave and am going to be late. Anyway, one more. If the origins aren't global butall tied to one event, would there be any way to find evidence of that in the cells/genes. etc, kind of like I can be traced to my parents through DNA
Probably not. Even if life started locally, it went global pretty soon, probably before the true genetic information storage system evolved

[ Keli/NASAChatHost - 52 - 11:52:33 ]
Please join us for our next Astrobiology chat on November 5 with Bill Borucki on the topic "How Can other Biospheres Be Recognized?" . Check the Astrobiology chat schedule page at http://quest.arc.nasa.gov/ltc/astrobio/index.html

[ Keli/NASAChatHost - 53 - 13:16:47 ]
RE: [Keli/NASAChatHost] A special thanks to Andrew Pohorille for sharing his time and expertise with us online today!
His address is pohorill@max.arc.nasa.gov.