🚀 go-pugleaf

In article <2ju5gv$g76@agate.berkeley.edu> hcorbett@garnet.berkeley.edu () writes:
>Why do salmon die after reproduction (also worded as, why can't they 
>undergo gametogenesis more than one time in their lives)?

They never got selected for more than one?  Maybe going up a western American
river and breeding takes too much energy for them to be able to go back
downstream.  Remember their food scource is in the ocean.

I seem to remember hearing that atlantic salmon actually do make repeat
trips.

>Why can people usually only sleep withtheir eyes closed?

Light stimulates the optic centers, which in turn stimulates the
"wake up, dummy" part of the brain?

>Do alcoholics metabolize more alcohol for their energy source relative to
>glucose than non-addicted people?

Only if they drink enough.

>Why are people addicted to alcohol?

I don't think there's any one answer to this.

>Do men get breast cancer?

Yes.  Males have a small amount of female breast tissue because of estrogen
produced by the adrenal gland and this can get cancerous.

This, BTW, was the only answer I was remotely sure on.

hcorbett@garnet.berkeley.edu wrote:

: What is the percent (roughly) difference between a mammalian and a plant
: genome?

Do you mean difference in size or difference in amino acid composition of
related proteins? Concerning size, what I can recall from a discussion
a while ago on this newsgroup (bionet.general) plant genome sizes can
differ vastly in size. The genome of Arabidopsis thaliana (that's one
of the genomes currently being under intensive investigation) is a 
rather small one whereas certain plants (I think it was certain lily
species) can have genome sizes severalfold higher than the human genome.

--Cornelius.

--
/* Cornelius Krasel, Abt. Lohse, Genzentrum, D-82152 Martinsried, Germany */
/* email: krasel@alf.biochem.mpg.de                 fax: +49 89 8578 3795 */
/* "People are DNA's way of making more DNA." (Edward O. Wilson, 1975)    */

hcorbett@garnet.berkeley.edu  writes:
> Preamble: I am a TA for an introductory biology class (college level). To
> spark my students' interest a little, I had them each write questions to
> me, about anything in biology that interested them, and that at the 
> beginnning of each laboratory section I would briefly answer. I got some
> great questions! And with a resource such as your collective knowledge,
> I hope to be able to reliably answer the ones on which I have very
> little background or ideas for more local resources.
> 
> 
> How can one improve memory?
> 

Practice.

> Why can people usually only sleep withtheir eyes closed?

Light stimulation.

> 
> Do alcoholics metabolize more alcohol for their energy source relative to
> glucose than non-addicted people? Why are people addicted to alcohol?
> 

Alcohol is burned as a source of energy at 7 cal per gram.  I'm
not aware of differences in alcohol metabolism in alcholics.  

The addiction issue is one of intense controversy.  One camp
believes there will be an alcohol addiction gene.  Another camp
believes that there will be just an addiction gene with other
genetics factors influencing the type of addiction selected.

> What is the percent (roughly) difference between a mammalian and a plant
> genome?

Plant genomes vary alot in terms of their genome sizes, some
are smaller than humans, others are larger.

> 
> Do men get breast cancer?

Men develop breast cancer at a rate about 0.1% of women.  With
roughly 150,000 cases of breast cancer per year (in the USA),
the number for men is about 1500.

> 
> 	I think I have a handle on the other 25 or so questions, but I
> would appreciate a little detailed help with the above (not just yes/no).
> 
> Thank you!!

Good Luck!

hcorbett@garnet.berkeley.edu wrote:

: Why do salmon die after reproduction (also worded as, why can't they 
: undergo gametogenesis more than one time in their lives)?

All Atlantic salmon do not die after reproduction some (about 10 percent)
do make it back to sea to return next year. The life cycle of the Atlantic
salmon is complicated but a brief synopsis is as follows:

1. The eggs hatch into small fish known as parr
2. These parr live in fresh water for about a year
3. They migrate to the sea (where they go in the sea is an unsolved mystery)
4. Fish that have been at sea for one year return to fresh water to breed,
the fish are known as grilse.
5. Some of these fish return to the sea (these returning fish are known as
kelts)
6. Once a kelt has been to sea for another year or more these are then
known as salmon when they enter fresh water again for a second breeding.

For more information read any British book on salmon fishing.

Paul Davis

Someone asked about genome sizes ... from my intro genetics notes:
                  DNA length / cell              est. no of genes
Lambda phage           17 microns                   50-60
T4 phage 	       70                           200	
E Coli                 1 000                        3000
Drosophila             1 600                        approx 50 000
Homo Sapiens           1.74 metres                  apporx 200 000

BUT!

Necturus ('mud puppy') has 17.5 times longer DNA / cell than homo sapiens,
trilliums have 18.5 times more, and Amphiuma ('congo eel') have 26 times
more (approx 130 feet)	

so usually, it gets bigger as you go up the evolutionary ladder, but not 
always.

j

In article <1994Feb17.023022.13337@yuma> arsmith@lamar.ColoState.EDU (Alan Smith) writes:

   In article <2ju5gv$g76@agate.berkeley.edu> hcorbett@garnet.berkeley.edu () writes:
   >Why do salmon die after reproduction (also worded as, why can't they 
   >undergo gametogenesis more than one time in their lives)?

   They never got selected for more than one?  Maybe going up a western American
   river and breeding takes too much energy for them to be able to go back
   downstream.  Remember their food scource is in the ocean.

But, the steelhead and sea run cutthroat trout both go up stream and back
to the ocean many times.

   I seem to remember hearing that atlantic salmon actually do make repeat
   trips.

Atlantic salmon are trout, not true salmon.

In article <2k0dd7$4iu@homer.cs.mcgill.ca>,
Jacob BROSTOFF <jayjay@cs.mcgill.ca> wrote:
>Someone asked about genome sizes ... from my intro genetics notes:
>                  DNA length / cell              est. no of genes
>Lambda phage           17 microns                   50-60
>T4 phage 	       70                           200	
>E Coli                 1 000                        3000
>Drosophila             1 600                        approx 50 000
>Homo Sapiens           1.74 metres                  apporx 200 000
>
>BUT!
>
>Necturus ('mud puppy') has 17.5 times longer DNA / cell than homo sapiens,
>trilliums have 18.5 times more, and Amphiuma ('congo eel') have 26 times
>more (approx 130 feet)	
>
>so usually, it gets bigger as you go up the evolutionary ladder, but not 
>always.
>
>j

 I believe this is called the C value Paradox.  The ammount of DNA an
organism has, or chromosome number has very little to do with the
complexity of it.  Viruses have small ammounts of DNA/RNA due to size
constraints of the head.  Also large chains of DNA are a) hard to get
intoa host cell, and b) more suceptible to damage from restriction
enzymes.  With most other organisms, especially Eukaryotic ones BP#'s have
very little to do with complexity.

--Greg

In article <ART.94Feb17150745@world.std.com>,
Al Thompson <art@world.std.com> wrote:
>In article <1994Feb17.023022.13337@yuma> arsmith@lamar.ColoState.EDU (Alan Smith) writes:
>
>   In article <2ju5gv$g76@agate.berkeley.edu> hcorbett@garnet.berkeley.edu () writes:
>   >Why do salmon die after reproduction (also worded as, why can't they 
>   >undergo gametogenesis more than one time in their lives)?
>
>   They never got selected for more than one?  Maybe going up a western American
>   river and breeding takes too much energy for them to be able to go back
>   downstream.  Remember their food scource is in the ocean.
>
>But, the steelhead and sea run cutthroat trout both go up stream and back
>to the ocean many times.
>
>   I seem to remember hearing that atlantic salmon actually do make repeat
>   trips.
>
>Atlantic salmon are trout, not true salmon.
>

	It might have something to do with the length of time it takes to
get to their spawning area, remember that these fishes are undergoing
osmoregulation, which places a great stress on the metabolism of these
fish.  Plust they are swimming upstream, often up waterfalls.  Salmon may
not be as equiped to osmoregulate as a cutthroat trout.

--Greg

`





wq






````````````````````````````````````````````````````````````````````````````````````````In
article <2jvpcsINN191l@sat.ipp-garching.mpg.de>, krasel@alf.biochem.mpg.de
(Cornelius Krasel) writes:
> hcorbett@garnet.berkeley.edu wrote:
> 
> : What is the percent (roughly) difference between a mammalian and a plant
> : genome?
> 
> Do you mean difference in size or difference in amino acid composition of
> related proteins? Concerning size, what I can recall from a discussion
> a while ago on this newsgroup (bionet.general) plant genome sizes can
> differ vastly in size. The genome of Arabidopsis thaliana (that's one
> of the genomes currently being under intensive investigation) is a 
> rather small one whereas certain plants (I think it was certain lily
> species) can have genome sizes severalfold higher than the human genome.
> 
> --Cornelius.
> 
> --
> /* Cornelius Krasel, Abt. Lohse, Genzentrum, D-82152 Martinsried, Germany */
> /* email: krasel@alf.biochem.mpg.de                 fax: +49 89 8578 3795 */
> /* "People are DNA's way of making more DNA." (Edward O. Wilson, 1975)    */

exit
1516
>1516
log

In article <2jvpcsINN191l@sat.ipp-garching.mpg.de>,
krasel@alf.biochem.mpg.de (Cornelius Krasel) wrote:

> hcorbett@garnet.berkeley.edu wrote:
> 
> : What is the percent (roughly) difference between a mammalian and a plant
> : genome?
> 
> plant genome sizes can
> differ vastly in size. The genome of Arabidopsis thaliana (that's one
> of the genomes currently being under intensive investigation) is a 
> rather small one whereas certain plants (I think it was certain lily
> species) can have genome sizes severalfold higher than the human genome.
> 
> --Cornelius.
> 

Not even mentioning the tendency for some species (such as corn with mans
aid) to happily exist in a state of polyploidy.

Stephen
-- 
Macintosh Consultant                              Marshall@kauri.vuw.ac.nz
Victoria University of Wellington
New Zealand

In Article <2ju5gv$g76@agate.berkeley.edu> "hcorbett@garnet.berkeley.edu ()" says:
> Preamble: I am a TA for an introductory biology class (college level). To
> spark my students' interest a little, I had them each write questions to
> me, about anything in biology that interested them, and that at the 
> beginnning of each laboratory secFrom -6893434098533936382
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 105a11,adbedc34cdad8faa
X-Google-Attributes: gid105a11,public
X-Google-Thread: 1119a6,adbedc34cdad8faa
X-Google-Attributes: gid1119a6,public
X-Google-ArrivalTime: 1994-02-18 09:22:39 PST
Xref: gmd.de bionet.general:5287 bionet.molbio.methds-reagnts:9873
Newsgroups: bionet.general,bionet.molbio.methds-reagnts
Path: gmd.de!newsserver.jvnc.net!howland.reston.ans.net!pipex!uunet!nih-csl!jowens.nci.nih.gov!jow
From: Jim Owens <jow@helix.nih.gov>
Subject: Re: Taq polymerase - what exonuclease activities?
Message-ID: <1994Feb18.172239.21177@alw.nih.gov>
X-Xxmessage-Id: <A98A63D3D4015621@jowens.nci.nih.gov>
X-Xxdate: Fri, 18 Feb 94 12: 23:47 GMT
Sender: postman@alw.nih.gov (AMDS Postmaster)
Organization: NIH, Lab of Genetics
X-Useragent: Version 1.1.3
References: <CLAF5n.Is6@massey.ac.nz>
Date: Fri, 18 Feb 1994 17:22:39 GMT
Lines: 20

In article <CLAF5n.Is6@massey.ac.nz> P. Hirst, PHirst@massey.ac.nz writes:
>I'm trying find out exactly what exonuclease activities Taq polymerase
>has, and which polymerase it is/ or which it's derived from.  The
>literature I've found so far is far from precise in its description, so
>any information anyone has would be greatly appreciated.

According to David Gelfand in Chapter 2 of PCR Technologies: Principles
and Applications for DNA Amplification, Henry A. Erlich (ed), Stockton
Press, 1989:

"Purified 94 kDa Taq DNA polymerase does not contain an inherent 3'-5'
exonuclease activity...  It is not known if T. aquaticuys contain a
separate 3'-5' exonuclease activity which may be associated with the
polymerase in vivo....  Taq DNA polymerase has a DNA synthesis-dependent,
strand replacement, 5'-3' exonuclease activity.  (more details omitted)" 
(p.19)

Hope this helps,

Jim Owens

In article <2ju5gv$g76@agate.berkeley.edu>,
 <hcorbett@garnet.berkeley.edu> wrote:
>
>Do men get breast cancer?

Someone already answered this, but I wanted to give a more descriptive 
view.  Human males do get breast cancer but this is quite rare.  One 
reason is the presence of testosterone in the body.  As far as I know, 
the reason for cancer of the breast is not quantitatively known.  That is 
to say that we have models of how cancer can occur, but we don't know 
whether our models hold for humans.  

It is generally thought that proliferation of cells has something to do 
with cancer.  In the male, proliferation of the breast epithelial cells 
can be due to estrogen and other hormones such as prolactin and 
corticoids and even growth factors.  



-- 
***********************************************************************
Rhett V. Pascual   :   gldnbear@uclink.berkeley.edu   :   Cal '90
If you are an alum from UC Berkeley, ask me about the private e-mail 
directory I am compiling.  GO BEARS!!!