Glycine, the smallest amino acid, is often conserved in amino acid sequences. Why?
350998
It's the least reactive. It's non-polar. It's pKa is simply the average of the N and C terminus. It's also Ambivalent, meaning it can be inside and outside a protein. Because of these properties, if it was replaced with a polar AA, it would change the protein property, and in 99% of time, change in AA is deleterious.
189318
there are tRNAs (transfer RNAs) for each amino acid. tRNAs have a three-nucleotide anticodon sequence which matches the opposing codon on messenger RNA (mRNA).  During translation, when RNA is translated into a protein sequence, the ribosome brings tRNA and mRNA together.  The 3 nucleotide sequence for a given amino acid is matched to the anticodon of the appropriate tRNA.  The ribosome then links successive amino acids together as it shifts to the next 3 nucleotide frame.  When a termination sequence is encountered, the amino acid chain is terminated and the mRNA is released.  Hope this helps
770132
On a smaller scale, but no less important, is how does the amino acid sequence in proteins determine it's folding pattern, and how can we design a protein that forms a certain shape? Most attempts so far result in a blob protein with no set shape. If we solve this, then we can design proteins as drugs that can treat any number of conditions. IBM has been working on a new supercomputer that can work with all the information from protein structures.
1150818
All other common amino acids have a primary amino group. The primary amino group is essential for the formation of the purple chromophore.\nProline has a secondary amino group so the reaction is different\n\nHave a look at the link below
657137
there are three STOP codons: uaa, uag, uga...\nSo the only STOP codon of these you've mentioned is uag...
678368
Amino acids is the answer
891448
This would be (d).\n\nThe presence of an amide bond (R-NH-CO-R) is the main part of a peptide bond.\n\nB may look like this too, however in a peptide bond, but the amino group should be on the alpha-carbon of an amino acid.
457527
Amino acids are organic molecules with amino groups (-NH2) and acidic groups (-COOH).  When the amino group (-NH2) of one amino acid reacts with the acidic group (-COOH) of another, the bond is called a "peptide" bond (IIRC.)\n\nIf you link a small number of amino acids in this way, the product is often just called a "peptide".  The better term is "oligopeptide", as "oligo" comes from Greek, meaning "few".\n\nReally long peptides are called polypeptides or proteins.  ("poly" comes from Greek, too, meaning "many")\n\nSome proteins have different polypeptides that stick together, held by weaker forces such as electrostatic attraction.\n\nDoes that help?
173345
a) The mRNA replaces thymine with Uracil (T for U)\nCTCCTCAGGAGTCAGCGTGCAACA becomes.... in mRNA\nGAGGAGUCCUCAGUCGCACGUUGU\n\nb) This would code for the amino acid MET GLY GLU LEU GLU GLU LEU LEU \nsepearte the mRNA into several part codons of three necleutides long and look up what they translate to\n\nc) The new one would could forMET GLY GLU STOP  \n\nd) The proteins in b and d are different because the latter is much shorter
958152
A single nucleotide change in a DNA sequence can result in a change in the codon that could then lead to a change in the amino acid that is made in the protein.  When proteins have a mutation in their amino acid sequence due to the change in DNA sequence, you can get a protein that no longer functions.  This often leads to a disease, and that is a profound effect on a phenotype.  If a DNA change occurs in the promoter of a gene, it's possible that gene which is normally transcribed won't be any more because the transcription factor does not bind recognize the new sequence.  You can also get frame shifts, which would result in a nonsense amino acid sequence.
686786
It's possible to have mutations in the DNA that won't change the amino acid sequence. Usually only 2 of the 3 bases of a given codon are necessary to specificy the particular amino acid.\n\nAs a result, a mutation could occur in the DNA which would not change the protein. However, it's still a heritable mutation, and could be used to establish relationships between individuals and species.
1115828
There are many factors that affect protein folding but most importantly it is dependent on the amino acid sequence. Different amino acid side chains (R groups) have different chemical characteristics. Folding occurs spontaneously through electrostatic interactions of these side chains (H-bonding and van der waals interactions) as well as disulfide bridges between cysteine aa's. Additionally it is entropically more favorable for hydrophobic parts of the protein to be in the center and the hydrophillic parts on the surface of the protein. Molecular chaparones also assist in protein folding.
346976
The folding of proteins is inherent in its sequence of amino acids. The particular amino code sequence causes interactions among themselves due to charge difference. Chaperones only aid in folding by providing a neutral environment (safe zone) to fold away from the stressed state of the cytoplasm. Some chaperones are only expressed in times of stress, such as heat shock proteins. Chaperones themselves are folded into conformation through ATP/ enzymatic action. \nYou answer your own question...chaperonins fold themselves,due to their inherent sequence.
906132
1) Most scientists believe life on earth arose from inanimate matter. But, no scientists have any definitive mechanism by which this occurs. Look up the Miller-Urey experiement in wikipedia.\n\nhttp://en.wikipedia.org/wiki/Miller-Urey_experiment\n\nWhat is rarely mentioned is that the creation of amino acids is fairly insignificant, especially when you consider the necessary steps in protein synthesis. Also, Miller repeatedly changed the components of his "primitive" atmosphere to produce the various amino acids. Lastly, the experiment produced large amounts of formaldehyde, which reacts with the amino acids and makes them effectively unusable for protein synthesis. So, I'm not sure that the experiment really proves what it was originally thought to prove.\n\n2)\n* A homozygous dominant has two dominant alleles\n  RR\n\n* The hetrozygous has one dominant and one recessive allele\n  Rr\n\nWhen you cross them you get the following:\n\n      R     R\n------------------\nR | RR     RR\n\nr  |  Rr       Rr\n\nEach of the four resulting crosses have one dominant and one recessive allele.  So, all of the resulting offspring will have the dominant traits. In this case, all red eyes.\n\nI hope this helps. But, take the time to read and learn about this stuff. If you'll take one hour a day to actually dig into this stuff (and all the other subjects you're studying ) and learn how it works, you'll go far.
188345
There's a flaw in your analogy. In DNA, it doesn't matter what letter order you use, you still get a valid word. It's just that, in any given sentence, in any given position in the sentence, the vast majority of words don't help convey the overall meaning of the sentence.\n\nEvery codon codes for SOMETHING (an amino acid, unless it's a "start" or "stop" codon), but not all arrangements of amino acids into proteins aid the survival of any given organism (in fact, only a small percentage might, given the right circumstances)
11744
I think the question is incomplete.\nIf the question is what is the common feature of their structure, the answer is their similarity in -R group. Ornithine and lysine only differ by a single methylene(-CH2) group. Cystine has less -CH2 group where the N is replaced by less electronegative S atom. Argenine also has similar polar positively charged R group in physiological pH like ornithine and lysine.\nNone has benzene ring!!!!
271339
Concerning Amino Acid Sequences, some biologists believe that the differences in protein structure represent functional differences while others think that they occur at random because of random mutations and represent the passage of time.  The "random-tick" hypothesis states that they can be used to determine when a particular group branched off (molecular clocks).