Carbohydrates
Carbohydrates are the organic compounds that are obtained in foods and living matters in the shape of sugars, cellulose, and starch. The general formula of carbohydrates is Cn(H2O)2. The ratio of H and O present in carbohydrates is identical to water.
Starch
Starch is a polysaccharide carbohydrate that belongs to the category of polysaccharide carbohydrates.
Mutarotation
The rotation of a particular structure of the chiral compound because of the epimerization is called mutarotation. It is the repercussion of the ring chain tautomerism. In terms of glucose, this can be defined as the modification in the equilibrium of the α- and β- glucose anomers upon its dissolution in the solvent water. This process is usually seen in the chemistry of carbohydrates.
L Sugar
A chemical compound that is represented with a molecular formula C6H12O6 is called L-(-) sugar. At the carbon’s 5th position, the hydroxyl group is placed to the compound’s left and therefore the sugar is represented as L(-)-sugar. It is capable of rotating the polarized light’s plane in the direction anticlockwise. L isomers are one of the 2 isomers formed by the configurational stereochemistry of the carbohydrates.
![cids and bases. Guanine is weakly acidic. It can lose a proton at higher pH, which disrupts base pairing and DNA
structure. (See section 1.3 of your textbook and the lecture slides.)
SACZALLAES
H
Guanine (G)
Biochemistry P14
Seventh Edition
2012 W. H. Freeman and Company
NH₂
pk₂=9.7
H
+H*
NH₂
1.0
0.8
0
0.6
0.4-
0.2
0
gure 1.16
8
9
pH
10
11
A) Write the Henderson-Hasselbalch equation for the acid dissociation reaction of guanine. Identify the conjugate acid
and conjugate base (HA and A-) for guanine forms.
B) If the pK₂=9.7 (see above), What is the value of the acid dissociation equilibrium Ka?
C)
At pH 7.4, calculate (1) the ratio of the protonated and deprotonated forms of guanine. (2) the fraction of
protonated guanine (i.e., HA / (HA+ A-)
D) The titration curve above shows DNA being titrated with a strong base, such as NaOH. Calculate the precise
fraction of DNA in the double helical form at three different pH values: 7.4, 8.4, and 9.4. [Hint: Note that the
double-helical form requires the protonation of guanine. Therefore, you will need to calculate the fraction in part C
(above).]](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F98f55b86-7303-4c60-8f43-d1d4ebde1187%2Fea7c94dc-148a-4fe1-8672-f34d5481ce8d%2Fq4l4aee_processed.jpeg&w=3840&q=75)
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