Question

delete Dec 10, 2018 OH ps lock Он OH OL Shift What is the designation of its 30. Kojibiose (above left) is a disaccharide of two glucose monomers. What is the designa glycosidic linkage? A) ( 12) B) (1-3) C) (1-4) D) (16) 91. somaltose (above right) is a disaccharide of two glucose monomers. What is the designation or its glycosidic linkage? A) (1-2) B) (1 -- 3) C) (1.4) 32. Which of the following best describes the structural backbone of nucleic acids? A) - base - sugar - base - sugar- B) - base - phosphate-base.phosphate C) - base - phosphate - sugar - base-phosphate - sugar- D) - phosphate - sugar - phosphate - sugar- D) (1-6)

Answer 1

Answer:-

(30)-

As we know that Kojibiose is a disaccharide which composed of two $\alpha$ -D glucose monomers units, which are joined together by $\alpha$ (1$\rightarrow$ 2) glycosidic linkage. In $\alpha$ (1$\rightarrow$ 2) glycosidic linkage of Kojibiose , C-1 carbon of one $\alpha$ -D glucose unit is linked with C-2 carbon of other $\alpha$ -D glucose unit.

Therefore correct option is 'A' i.e $\alpha$ (1$\rightarrow$ 2)

(31)-

As we know that Isomaltose is a disaccharide which composed of two $\alpha$ -D glucose monomers units, which are joined together by $\alpha$ (1$\rightarrow$ 6) glycosidic linkage. In $\alpha$ (1$\rightarrow$ 6) glycosidic linkage of Isomaltose , C-1 carbon of one $\alpha$ -D glucose unit is linked with C-6 carbon of other $\alpha$ -D glucose unit.

Therefore correct option is 'D' i.e $\alpha$ (1$\rightarrow$ 6)

CHOOH Hо- oh dD Galucose Glycoyidlie Jinkage 5 OH 2 I HO CHA 2 d-D Glucore но d-D Glucase tunit unit unit 2 OH Glycondic Lininge ibioe d-D Glucoss uit Streucturce Isomaltose Shructre

(32)-

As we know that structural backbone of nucleic acid composed of sugar ( in case of DNA it is deoxy-ribose sugar and in RNA it is ribose sugar) and phosphate groups which are arranged in alternating manner. therefore option 'D' best described the structural backbone of nucleic acid i,.e phosphate ----- sugar -------- phosphate ------- sugar ------ phosphate.

Therefore correct option is 'D' i.e phosphate ----- sugar -------- phosphate ------- sugar