137512 réponses à ce sujet

[Yionel]

LegendaryAvenger wrote...

GUYSS do I need to bring out the giant stop sign again?

[Phil725]

Scalpels wrote...

Phil725 wrote...

I can't see how not being able to have a child would be any big obstacle in the relationship. It happens often in our world, there is a such thing as adoption if you really want a child. The fact that it doesn't have Tali and Shep's genetics doesn't mean it wouldn't be the same in every other sense. Plus the whole one human kid one quarian kid family strikes me as a better solution than a hybrid that would probably face significant problems in its lifetime from health to general acceptance.

As far as whether its possible, no point in debating that other than for fun I guess. If Bioware wants it to be possible, it will be. I can't see the story line progressing that far anyway, does anyone really expect a *and 5 years after they defeated the reapers...* epilogue?

For spacer Shepard. Could be pressure from mother. Disapproval and/or desire for genetic grand children. "Continue the family line." Am father. Have pressure for male child. Also. Disapproval from other species. None have love of Quarians. Batarians likely most vocal. Will use Tali to dirty Shepard's name. Quarians have respect for Shepard. Would be sad Tali not contributing to small Quarian numbers. Think interracial couples in 1950s-1970s era. Love adoption idea. Many orphans in Galaxy. Will be more after ME3.

While I've never played the spacer background, and have no information at all on Shep's parents, I have a hard time believing they would stand in the way of true love.  Plus you also have to invoke the whole connection with the game.  Bioware made sure that stuff like background didn't affect anything major in the game.  They wouldn't have 2/3s of backgrounds being able to live happily ever after with Tali, and 1 with Shep sitting in his mom's house getting fixed up with a nice human girl.

I also don't see the galaxy caring, or Shep/Tali caring if the galaxy cares.  The galaxy is a lot more accepting of interspecies relationships than our world was of interracial ones at that time period.  Plus if any of this is happening, it means Shepard destroyed the reapers.  If that doesn't buy you the leeway to have a quarian bride, then they need to start flying off to the next galaxy.

[Scalpels]

knight5923 wrote...

knight5923 wrote...

Hey what about this? Miranda was constructed completely from her father's dna, right? So why don't they have two kids gentically created from each of there dna, altered just enough to make them indivudals insteada clones, like Miranda was? That way they have kids, and it satisfies the whole wanting to have genetic offspring thing:)

^ ^ ^ ^ Valid? anybody?

Only works within same species. Human -:> Human or Quarian -> Quarian. DNA between species incompatible. Unable to create viable offspring from mixing. Adoption easier. Better for all involved. Shepard/Tali get child(ren). Child(ren) get loving parents.

[VettoRyouzou]

alickar wrote...

VettoRyouzou wrote...

alickar wrote...

VettoRyouzou wrote...

alickar wrote...

VettoRyouzou wrote...

I have no idea why this is being debated Quarians can not bare the children of humans there a dextro-protein species like Turians to quote mordin " do not swallow".

humans=mammals quarians= mammals= can breed

A dog is a mammal so is a human = can breed... no.. no it does not.

dog=differen dna=human or human like have almost the same or exact dna

.... Are you for real... Really.. REALLY!? DID YOU EVEN PAY ATTENTION TO ME2!?

dextro-protein species there dna is far different to us then a dog is to us! Let put it this way A human and a Quarians eat a apple... the human is fine.. the Quarians goes into deadly seizures, Quarians may look human but they are not there dna is VERY different.

then what about this mordin alters the semen to the stuff tht quarians need to produce offspring id be safe and itd still come from shep so its safe to have children with her

....You were dropped on the head as a child weren’t you..

Why does Shepard need to have a child by normal means.. i mean for the love of god has adoption just been removed fully? All this crap about dna , clone etc why not this insane idea of adoption but wait no.. that be simple and logical!

Modifié par VettoRyouzou, 27 février 2010 - 09:53 .

[solazz]

Ok guys. I'm out for now. Hopefully, by the time I get back, someone will have thrown a high school biology book at alickar.

[epoch_]

Ok guys, I'm ready for Mass Effect 3.

[DarkwanderStorm]

meh heres my view if bioware allows i laugh at the people who said it couldnt happen and if not then it doesnt matter

[knight5923]

NuclearBuddha wrote...

knight5923 wrote...

knight5923 wrote...

Hey what about this? Miranda was constructed completely from her father's dna, right? So why don't they have two kids gentically created from each of there dna, altered just enough to make them indivudals insteada clones, like Miranda was? That way they have kids, and it satisfies the whole wanting to have genetic offspring thing:)

^ ^ ^ ^ Valid? anybody?

Tali could theoretically (based on the Miranda method) have a child composed solely of her own DNA.  That is pretty close to just being a clone, though, and would most definintely not be Shepard's kid (if that matters).  We're still not talking an actual hybrid.  And then who knows what Miranda's dad paid to have that done.  If we're headed that direction, a donor father would be a lot more practical.

If Shep wanted a kid from his own DNA, he'd have to have a surrogate.  It's not like Tali could carry it for him.

Ya, I'm just talking 2 test-tube babies, lil Shep and lil Tali, modified so that they're not direct clones, just so it's less weird. They won't be related to each other gentically, like adoption, but at least they'll be related to a parent gentically. Basically similar to adoption but with a single genetic link insteada none.
And it's friggin Shep, if he can't come up with the money, he'll get it done at gunpoint:devil:

[AventuroLegendary]

GODDARNIT, Enough about Tali's child! How about we say that there is a slim chance of producing a biological child and call it a day?

[wolfstanus]

VettoRyouzou wrote...

alickar wrote...

having babies with tali is most possible but the deformities can be minor or sometimes be major

No it cannot happen Quarians are  dextro-protein aka the DNA does not match up.

I reject your reality and substitute my own

From http://en.wikipedia....lity_(chemistry)

Chirality (chemistry)

From Wikipedia, the free encyclopedia

Jump to: navigation, search
L-form redirects here. For the bacterial strains, see L-form bacteria.



Two enantiomers of a generic amino acid



(S)-Alanine (left) and (R)-alanine (right) in zwitterionic form at neutral pH
A chiral molecule is a type of molecule that lacks an internal plane of symmetry and has a non-superimposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom.[1][2]
The term chiral (pronounced /ˈkaɪrəl/) in general is used to describe an object that is non-superposable on its mirror image. Achiral (not chiral) objects are objects that are identical to their mirror image. Human hands are perhaps the most universally recognized example of chirality: The left hand is a non-superposable mirror image of the right hand; no matter how the two hands are oriented, it is impossible for all the major features of both hands to coincide. This difference in symmetry becomes obvious if someone attempts to shake the right hand of a person using his left hand, or if a left-handed glove is placed on a right hand. The term chirality is derived from the Greek word for hand, χειρ (cheir). It is a mathematical approach to the concept of "handedness".
In chemistry, chirality usually refers to molecules. Two mirror images of a chiral molecule are called enantiomers or optical isomers. Pairs of enantiomers are often designated as "right-" and "left-handed."
Molecular chirality is of interest because of its application to stereochemistry in inorganic chemistry, organic chemistry, physical chemistry, biochemistry, and supramolecular chemistry.





Contents[hide]

1 History
2 Symmetry
3 Naming conventions

3.1 By configuration: R- and S-
3.2 By optical activity: (+)- and (−)-
3.3 By configuration: D- and L- 4 Nomenclature
5 Stereogenic centers
6 Properties of enantiomers
7 In biology
8 In inorganic chemistry
9 Chirality of amines
10 See also
11 References
12 External links [/list][edit] History
The term optical activity is derived from the interaction of chiral materials with polarized light. A solution of the (−)-form of an optical isomer rotates the plane of polarization of a beam of plane polarized light in a counterclockwise direction, vice-versa for the (+) optical isomer. The property was first observed by Jean-Baptiste Biot in 1815,[3] and gained considerable importance in the sugar industry, analytical chemistry, and pharmaceuticals. Louis Pasteur deduced in 1848 that this phenomenon has a molecular basis.[4] Artificial composite materials displaying the analog of optical activity but in the microwave region were introduced by J.C. Bose in 1898,[5] and gained considerable attention from the mid-1980s.[6] The term chirality itself was coined by Lord Kelvin in 1873.[7]
The word "racemic" is derived from the Latin word "racemus" for "bunch of grapes"; the term having its origins in the work of Louis Pasteur who isolated racemic tartaric acid from wine.
[edit] Symmetry
The symmetry of a molecule (or any other object) determines whether it is chiral. A molecule is achiral (not chiral) when an improper rotation, that is a combination of a rotation and a reflection in a plane, perpendicular to the axis of rotation, results in the same molecule - see chirality (mathematics). A simplified, if incomplete, rule is that a chiral molecule lacks a plane of symmetry. For tetrahedral molecules, the molecule is chiral if all four substituents are different.
A chiral molecule is not necessarily asymmetric (devoid of any symmetry element), as it can have, for example, rotational symmetry.
[edit] Naming conventions
[edit] By configuration: R- and S-
For chemists, the R / S system is the most important nomenclature system for denoting enantiomers, which does not involve a reference molecule such as glyceraldehyde. It labels each chiral center R or S according to a system by which its substituents are each assigned a priority, according to the Cahn Ingold Prelog priority rules (CIP), based on atomic number. If the center is oriented so that the lowest-priority of the four is pointed away from a viewer, the viewer will then see two possibilities: If the priority of the remaining three substituents decreases in clockwise direction, it is labeled R (for Rectus), if it decreases in counterclockwise direction, it is S (for Sinister).
This system labels each chiral center in a molecule (and also has an extension to chiral molecules not involving chiral centers). Thus, it has greater generality than the d/l system, and can label, for example, an (R,R) isomer versus an (R,S) — diastereomers.
The R / S system has no fixed relation to the (+)/(−) system. An R isomer can be either dextrorotatory or levorotatory, depending on its exact substituents.
The R / S system also has no fixed relation to the d/l system. For example, the side-chain one of serine contains a hydroxyl group, -OH. If a thiol group, -SH, were swapped in for it, the d/l labeling would, by its definition, not be affected by the substitution. But this substitution would invert the molecule's R / S labeling, because the CIP priority of CH2OH is lower than that for CO2H but the CIP priority of CH2SH is higher than that for CO2H.
For this reason, the d/l system remains in common use in certain areas of biochemistry, such as amino acid and carbohydrate chemistry, because it is convenient to have the same chiral label for all of the commonly occurring structures of a given type of structure in higher organisms. In the d/l system, they are nearly all consistent - naturally occurring amino acids are nearly all l, while naturally occurring carbohydrates are nearly all d. In the R / S system, they are mostly S, but there are some common exceptions.
[edit] By optical activity: (+)- and (−)-
An enantiomer can be named by the direction in which it rotates the plane of polarized light. If it rotates the light clockwise (as seen by a viewer towards whom the light is traveling), that enantiomer is labeled (+). Its mirror-image is labeled (−). The (+) and (−) isomers have also been termed d- and l-, respectively (for dextrorotatory and levorotatory). Naming with d- and l- is easy to confuse with d- and l- labeling.
[edit] By configuration: D- and L-
An optical isomer can be named by the spatial configuration of its atoms. The d/l system does this by relating the molecule to glyceraldehyde. Glyceraldehyde is chiral itself, and its two isomers are labeled d and l (typically typeset in small caps in published work). Certain chemical manipulations can be performed on glyceraldehyde without affecting its configuration, and its historical use for this purpose (possibly combined with its convenience as one of the smallest commonly used chiral molecules) has resulted in its use for nomenclature. In this system, compounds are named by analogy to glyceraldehyde, which, in general, produces unambiguous designations, but is easiest to see in the small biomolecules similar to glyceraldehyde. One example is the amino acid alanine, which has two optical isomers, and they are labeled according to which isomer of glyceraldehyde they come from. On the other hand, glycine, the amino acid derived from glyceraldehyde, has no optical activity, as it is not chiral (achiral). Alanine, however, is chiral.
The d/l labeling is unrelated to (+)/(−); it does not indicate which enantiomer is dextrorotatory and which is levorotatory. Rather, it says that the compound's stereochemistry is related to that of the dextrorotatory or levorotatory enantiomer of glyceraldehyde—the dextrorotatory isomer of glyceraldehyde is, in fact, the d- isomer. Nine of the nineteen l-amino acids commonly found in proteins are dextrorotatory (at a wavelength of 589 nm), and d-fructose is also referred to as levulose because it is levorotatory.
A rule of thumb for determining the d/l isomeric form of an amino acid is the "CORN" rule. The groups:

COOH, R, NH2 and H (where R is a variant carbon chain)
are arranged around the chiral center carbon atom. Sighting with the hydrogen atom away from the viewer, if these groups are arranged clockwise around the carbon atom, then it is the l-form. If counter-clockwise, it is the d-form.
[edit] Nomenclature

• Any non-racemic chiral substance is called scalemic.[8]
• A chiral substance is enantiopure or homochiral when only one of two possible enantiomers is present.
• A chiral substance is enantioenriched or heterochiral when an excess of one enantiomer is present but not to the exclusion of the other.
• Enantiomeric excess or ee is a measure for how much of one enantiomer is present compared to the other. For example, in a sample with 40% ee in R, the remaining 60% is racemic with 30% of R and 30% of S, so that the total amount of R is 70%.

[edit] Stereogenic centers
In general, chiral molecules have point chirality at a single stereogenic atom, usually carbon, which has four different substituents. The two enantiomers of such compounds are said to have different absolute configurations at this center. This center is thus stereogenic (i.e., a grouping within a molecular entity that may be considered a focus of stereoisomerism).
Normally when an atom has four different substituents, it is chiral. However in rare cases, two of the ligands differ from each other by being mirror images of each other. When this happens, the mirror image of the molecule is identical to the original, and the molecule is achiral. This is called pseudochirality.
A molecule can have multiple chiral centers without being chiral overall if there is a symmetry between the two (or more) chiral centers themselves. Such a molecule is called a meso compound.
It is also possible for a molecule to be chiral without having actual point chirality. Common examples include 1,1'-bi-2-naphthol (BINOL) and 1,3-dichloro-allene, which have axial chirality, (E)-cyclooctene, which has planar chirality, and certain calixarenes and fullerenes, which have inherent chirality.
It is important to keep in mind that molecules have considerable flexibility and thus, depending on the medium, may adopt a variety of different conformations. These various conformations are themselves almost always chiral. When assessing chirality, a time-averaged structure is considered and for routine compounds, one should refer to the most symmetric possible conformation.
When the optical rotation for an enantiomer is too low for practical measurement, it is said to exhibit cryptochirality.
Even isotopic differences must be considered when examining chirality. Replacing one of the two 1H atoms at the CH2 position of benzyl alcohol with a deuterium (²H) makes that carbon a stereocenter. The resulting benzyl-α-d alcohol exists as two distinct enantiomers, which can be assigned by the usual stereochemical naming conventions. The S enantiomer has [α]D = +0.715°.[9]
[edit] Properties of enantiomers
Normally, the two enantiomers of a molecule behave identically to each other. For example, they will migrate with identical Rf in thin layer chromatography and have identical retention time in HPLC. Their NMR and IR spectra are identical. However, enantiomers behave differently in the presence of other chiral molecules or objects. For example, enantiomers do not migrate identically on chiral chromatographic media, such as quartz or standard media that have been chirally modified. The NMR spectra of enantiomers are affected differently by single-enantiomer chiral additives such as Eufod.
Chiral compounds rotate plane polarized light. Each enantiomer will rotate the light in a different sense, clockwise or counterclockwise. Molecules that do this are said to be optically active.
Chacteristically, different enantiomers of chiral compounds often taste and smell differently and have different effects as drugs – see below. These effects reflect the chirality inherent in biological systems.
One chiral 'object' that interacts differently with the two enantiomers of a chiral compound is circularly polarised light: An enantiomer will absorb left- and right-circularly polarised light to differing degrees. This is the basis of circular dichroism (CD) spectroscopy. Usually the difference in absorptivity is relatively small (parts per thousand). CD spectroscopy is a powerful analytical technique for investigating the secondary structure of proteins and for determining the absolute configurations of chiral compounds, in particular, transition metal complexes. CD spectroscopy is replacing polarimetry as a method for characterising chiral compounds, although the latter is still popular with sugar chemists.
[edit] In biology
Many biologically active molecules are chiral, including the naturally occurring amino acids (the building blocks of proteins), and sugars. In biological systems, most of these compounds are of the same chirality: most amino acids are L and sugars are D. Typical naturally occurring proteins, made of L amino acids, are known as left-handed proteins, whereas D amino acids produce right-handed proteins.
The origin of this homochirality in biology is the subject of much debate.[10] Most scientists believe that Earth life's "choice" of chirality was purely random, and that if carbon-based life forms exist elsewhere in the universe, their chemistry could theoretically have opposite chirality. However, there is some suggestion that early amino acids could have formed in comet dust. In this case, circularly polarised radiation (which makes up 17% of stellar radiation) could have caused the selective destruction of one chirality of amino acids, leading to a selection bias which ultimately resulted in all life on Earth being homochiral.[11]
Enzymes, which are chiral, often distinguish between the two enantiomers of a chiral substrate. Imagine an enzyme as having a glove-like cavity that binds a substrate. If this glove is right-handed, then one enantiomer will fit inside and be bound, whereas the other enantiomer will have a poor fit and is unlikely to bind.
D-form amino acids tend to taste sweet, whereas L-forms are usually tasteless. Spearmint leaves and caraway seeds, respectively, contain L-carvone and D-carvone - enantiomers of carvone. These smell different to most people because our olfactory receptors also contain chiral molecules that behave differently in the presence of different enantiomers.
Chirality is important in context of ordered phases as well, for example the addition of a small amount of an optically active molecule to a nematic phase (a phase that has long range orientational order of molecules) transforms that phase to a chiral nematic phase (or cholesteric phase). Chirality in context of such phases in polymeric fluids has also been studied in this context.[12]
[edit] In inorganic chemistry

Main article: Complex Chemistry
Many coordination compounds are chiral; for example, the well-known tris(bipyridine)ruthenium(II) complex in which the three bipyridine ligands adopt a chiral propeller-like arrangement.[13]


In this case, the Ru atom may be regarded as a stereogenic center, with the complex having point chirality. The two enantiomers of complexes such as [Ru(2,2'-bipyridine)3]2+ may be designated as Λ (left-handed twist of the propeller described by the ligands) and Δ (right-handed twist). Hexol is a chiral cobalt complex that was first investigated by Alfred Werner. Resolved hexol is significant as being the first compound devoid of carbon to display optical activity.
[edit] Chirality of amines

Tertiary amines (see image) are chiral in a way similar to carbon compounds: The nitrogen atom bears four distinct substituents counting the lone pair. However, the energy barrier for the inversion of the stereocenter is, in general, about 30 kJ/mol, which means that the two stereoisomers are rapidly interconverted at room temperature. As a result, amines such as NHRR' cannot be resolved optically and NRR'R" can only be resolved when the R, R', and R" groups are constrained in cyclic structures as in Tröger's base.http://en.wikipedia....lity_(chemistry Actually in reality it can. It gets absorbed  or ignored by the body... if it getts absorbed then possible baby time..

[AventuroLegendary]

epoch_ wrote...

Ok guys, I'm ready for Mass Effect 3.

YOU GOT TALI KILLED?! you dirty son of a beachball!!

[Daskworx]

Scalpels wrote...

Only works within same species. Human -:> Human or Quarian -> Quarian. DNA between species incompatible. Unable to create viable offspring from mixing. Adoption easier. Better for all involved. Shepard/Tali get child(ren). Child(ren) get loving parents.

Aye adoption would be the best option, sure there will be enought orphans around when ME3 is over...

[Jakegnosis]

epoch_ wrote...

Ok guys, I'm ready for Mass Effect 3.

Okay, I laughed.

[Yionel]

epoch_ wrote...

Ok guys, I'm ready for Mass Effect 3.

Holy smoke how did you fail that bad?

[alickar]

solazz wrote...

Ok guys. I'm out for now. Hopefully, by the time I get back, someone will have thrown a high school biology book at alickar.

ok ill just say this if bioware wants tali shep to have a  child they will if they wont then they wont

[Scalpels]

knight5923 wrote...

NuclearBuddha wrote...

knight5923 wrote...

knight5923 wrote...

Hey what about this? Miranda was constructed completely from her father's dna, right? So why don't they have two kids gentically created from each of there dna, altered just enough to make them indivudals insteada clones, like Miranda was? That way they have kids, and it satisfies the whole wanting to have genetic offspring thing:)

^ ^ ^ ^ Valid? anybody?

Tali could theoretically (based on the Miranda method) have a child composed solely of her own DNA.  That is pretty close to just being a clone, though, and would most definintely not be Shepard's kid (if that matters).  We're still not talking an actual hybrid.  And then who knows what Miranda's dad paid to have that done.  If we're headed that direction, a donor father would be a lot more practical.

If Shep wanted a kid from his own DNA, he'd have to have a surrogate.  It's not like Tali could carry it for him.

Ya, I'm just talking 2 test-tube babies, lil Shep and lil Tali, modified so that they're not direct clones, just so it's less weird. They won't be related to each other gentically, like adoption, but at least they'll be related to a parent gentically. Basically similar to adoption but with a single genetic link insteada none.
And it's friggin Shep, if he can't come up with the money, he'll get it done at gunpoint:devil:

Renegade option. Paragon option would talk way into discounted/free service. "I am Commander Shepard and this is my favorite Genetics Laboritory in the Galaxy."

[VettoRyouzou]

wolfstanus wrote...

VettoRyouzou wrote...

alickar wrote...

having babies with tali is most possible but the deformities can be minor or sometimes be major

No it cannot happen Quarians are  dextro-protein aka the DNA does not match up.

-snip-

Aka : Waaah lemme post this over the top load of BS So i can feel like can be right in some ****ed up kinda way.

[epoch_]

LegendaryAvenger wrote...

epoch_ wrote...

Ok guys, I'm ready for Mass Effect 3.

YOU GOT TALI KILLED?! you dirty son of a beachball!!

That one hurt the most.

[knight5923]

Scalpels wrote...

knight5923 wrote...

knight5923 wrote...

Hey what about this? Miranda was constructed completely from her father's dna, right? So why don't they have two kids gentically created from each of there dna, altered just enough to make them indivudals insteada clones, like Miranda was? That way they have kids, and it satisfies the whole wanting to have genetic offspring thing:)

^ ^ ^ ^ Valid? anybody?

Only works within same species. Human -:> Human or Quarian -> Quarian. DNA between species incompatible. Unable to create viable offspring from mixing. Adoption easier. Better for all involved. Shepard/Tali get child(ren). Child(ren) get loving parents.

not talking mixing, a human child and a quarian child, based off of Shep's dna and Tali's dna respectively and individually. Baby Shep clone, Baby Tali clone

[mortons4ck]

LegendaryAvenger wrote...

epoch_ wrote...

Ok
guys, I'm ready for Mass Effect 3.

YOU GOT TALI KILLED?! you dirty son of a beachball!!
../../../images/forum/emoticons/sad.png../../../images/forum/emoticons/crying.png

Nah, its cool. I'm sure she's out chillin' with the migrant fleet or something.

Modifié par mortons4ck, 04 mars 2010 - 06:13 .

[wolfstanus]

VettoRyouzou wrote...

wolfstanus wrote...

VettoRyouzou wrote...

alickar wrote...

having babies with tali is most possible but the deformities can be minor or sometimes be major

No it cannot happen Quarians are  dextro-protein aka the DNA does not match up.

-snip-

Aka : Waaah lemme post this over the top load of BS So i can feel like can be right in some ****ed up kinda way.

 In other words im right

Modifié par wolfstanus, 27 février 2010 - 09:58 .

[Jakegnosis]

phonypapercut56 wrote...

Was researching my earlier question and came across something interesting. Apparently D-amino acids are sweet tasting i.e. TALI TASTES LIKE SUGAR.

Awwwwww!!!

That's the best!

[knight5923]

phonypapercut56 wrote...

Was researching my earlier question and came across something interesting. Apparently D-amino acids are sweet tasting i.e. TALI TASTES LIKE SUGAR.

now that's hot:wub:

[NuclearBuddha]

epoch_ wrote...
That one hurt the most.

WHY U DO THIS?