1. Tardigrade
  2. Question
  3. Chemistry
  4. How many amongst the following are composed of only α -D- glucose units ? i. Maltose ii. Sucrose iii. Lactose iv. Cellulose v. Amylose

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Q. How many amongst the following are composed of only $\alpha $ $-D-$ glucose units ?
$i.$ Maltose
$ii.$ Sucrose
$iii.$ Lactose
$iv.$ Cellulose
$v.$ Amylose

NTA AbhyasNTA Abhyas 2022

Solution:

Maltose consists of two molecules of glucose that are linked by an $\alpha -\left(\right.1,4\left.\right)$ glycosidic bond. Sucrose is a glycosyl glycoside formed by glucose and fructose units joined by an acetal oxygen bridge from hemiacetal of $\alpha -D-$ glucose to the hemiketal of the $\beta -D-$ fructose. Lactose (milk sugar) is a disaccharide, obtained by the condensation of one molecule of $\beta -D-$ galactopyranose and one molecule of $\beta -D-$ glucopyranose. Cellulose is a polymer of glucose consists of $\beta -\left(\right.1,4\left.\right)$ glycosidic linkages. Amylose is a polymer of glucose consists of $\alpha -\left(\right.1,4\left.\right)$ glycosidic linkages. Hence, maltose and amylose composed of only, $\alpha -D-$ glucose units.