Which of these are essential amino acids and belong to the Positively charged polar R-groups
(a) i only
(b) iii, iv and v
(c) ii, iv and vi
2. The triple helix of collagen has many repeating units of Glycine why is that?
(a) Glycine only has a single Hydrogen atom as a side group making it fit perfectly in the small space in the interior of the chain.
(b) Glycine has optimal hydrogen bonding making it easy to be used in the triple helix.
(c)Glycine shows sterioisomerism.
(d) Glycine can bend into the small spacing in the triple helix easily.
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Enjoy……p.s this song will annoyingly stick in ur head! HAHA!
Amino acids are very important to us humans particularly because they compose proteins which are very very essential…. 😉 to us. The R-groups/ sidechains can be in various forms such as:
- Non-polar, aliphatic
- Polar, uncharged
- Positively charged
- Negatively charged
“In 1806, French chemists Louis-Nicolas Vauquelin and Pierre Jean Robiquet isolated a compound in asparagus that was subsequently named asparagine, the first amino acid to be discovered. Proteins were found to yield amino acids after enzymatic digestion or acid hydrolysis. In 1902, Emil Fischer and Franz Hofmeister proposed that proteins are the result of the formation of bonds between the amino group of one amino acid with the carboxyl group of another, in a linear structure which Fischer termed peptide.”
Essential Amino acids…..what does it mean…basically we can not make these a.a and thus we get it from foods …so lets try to eat good and stay way from d KFC…Thus conversely non-essentials does NOT mean we don not need them but we just make em ourselves. We all know there are 20 amino acids we all need but only 10 be essential and the other non-essential.
How do amino acids bond??????????
By way of a CONDENSATION REACTION (loss of a small molecule in this case good ole H2O). The bond formed is a PEPTIDE BOND a covalent bond between the amino and carboxyl group of 2 amino acids. Polypeptide is a chain of many a.a. it’s a macromolecule.
Well amino acids form protein and well there are levels of structure they are the primary, secondary, tertiary and Quaternary
Primary-linear combination of aa sequence, only posses peptide bonds
Secondary-hydrogen bonds=alpha helix( h-bonding between the oxygen in the carbonyl group to the hydrogen of the amino group on the 4th aa away) and beta pleated (anti-parallel or parallel)
Tertiary- Hydrophobic interatctions and also H-bonds, salt bridges, electrostatic bonds
Quaternary- More than one a.a chains posses all bonding
Basically it was as it always making me uneasy and nervous as heck! But with all dat still learned something,although it was in the vid in quiz atmosphere I go blank
Why are Gly and Pro destabilize the alpha helix?
Gly is the smallest, and because of the single hydrogen being it side chain it has high CONFORMATIONAL FLEXIBILTY.
Proline, has a rigid ring system, thus rotation about the N-C bond is restricted thus introducing a kink .
Why is the alpha helix more predominant in nature?
This is because there is optimal amount of H-bonding within the helix, meaning every single peptide bond is involved in H-bonding except the ones on the ends.
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Ok peeps….carbs, well nothing really new here basically what we have all been doing same monomers, bonding and levels of bonding the only thin new here for me and a lil hard was epimer mutarotaion, boat and chair formation, but all in all a good topic and understandable.
Carbohydrates composed of carbon, hydrogen and oxygen in the ratios Cn(H2O)n. Carbs play a very important role in out daily lives by most importantly functioning as our foremost energy source and in other roles as structural, storage and also as precursor molecules.
Energy Source– Respiration we burn simple carbohydrates…..glucose…. to get energy , we can metabolize monosaccharide ( the basic unit of carbs), disaccharides, polysaccharides(at decreasing metabolism rates)
Glucose + Oxygen —-> Carbon Dioxide + Water + Energy (respiration equ’n)
So carbs we eat em everyday….they are good and bad for us depending on our intake, cause they supply us with energy for daily activites also they fuction as storge, structural molecule and many others.
Monosaccharides- Glucose, Fructose
Disacchardies- Sucrose, Maltose and Lactose
Polysaccaharides- Starch, Glycogen and Cellulose.
All these except the single unit monosaccharides form by condensation reaction i.e removal of H2O and form a Glycosidic bond.The type of Glycosidic bond depends on the monomers.
But one of the new encounters for me was the Epimers, those are carbohydrates that differ only by configuration around one Carbon
e.g D-glucose and D-mannose and D-galactose
Anomers, these are special types of epimers, Lets take alha and beta glucose as examples
The hydroxyl groups on the hemiacetal of the glucose are in different positions in alpha glucose it’s below the plane and beta glucose it above the plane. Thus anomers are just sterioisomers that differ in configuration on the hemiacetal or hemiketal carbon, this is called the anomeric carbon.
2^n= no. of steriocenters in a sugar. (n=no. of chiral centers present)
Mutarotation is the change in the optical rotation that occurs by epimerization (that is the change in the equilibrium between two epimers, when the corresponding stereocenters interconvert). Thus occurs bet
Getting into the business…
Monosaccharides are simple monomers, they are classed based on the number of carbons present eg three C=trioses, then they are further grouped into aldoses containing aldehyde functional group and ketoses having the ketone group
Disaccharides made up of two monomers formed by condensation reaction and can be reversed by hydrolysis. Glycosidic bond holds em together
Polysaccharides are just many monomer joined by glyosicdic bonds
Starch-Amylose and Amylopectin- alpha (1,4 ) and alpha (1,4 and 1,6)
Cellulose- beta (1,4)
Glycogen-alpha (1,4) with more (1,6) linkages
~Song of the Day~
Wikipedia.org.a .”Mutarotation” http://en.wikipedia.org/wiki/Mutarotation