Biomolecules MCQ Questions & Answers in Organic Chemistry | Chemistry

Thyroxine is an amine hormone.

Sucrose is non-reducing sugar because reducing part of glucose and fructose $$\left( { > C = O} \right)$$   are involved in glycosidic linkage.

While, lactose, glucose and maltose are reducing sugars.

Except alanine, all amino acids are essential amino acids which cannot be synthesised in the body and must be obtained through diet.

Zwitter ion contains both $$+ve$$  and $$-ve$$  charge. Proton of $$-COOH$$   group is transferred to the $$ - N{H_2}$$  group. $$ - NH_3^ + $$  group is acidic since it can donate a proton and $$ - CO{O^ - }$$  group is basic since it can accept a proton.

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The correct structure of thymine is

Reaction of $$D - \left( + \right) - $$  glucose with methanolic $$-HCl$$   leads to formation of methyl glucoside ( $${C_1} - OH$$   group is methylated ) which, being acetal, is not hydrolysable by base, so it will not respond Tollen’s reagent.

$$C{H_2}OH{\left( {CHOH} \right)_4}CHO$$      \[\xrightarrow[{\left[ O \right]}]{{B{r_2}/{H_2}O}}\mathop {C{H_2}OH{{\left( {CHOH} \right)}_4} \cdot COOH}\limits_{{\text{Gluconic acid}}} \]

Haemoglobin acts as oxygen carrier in the blood because four $$F{e^{2 + }}$$  $$ions$$  of each haemoglobin can bind with four molecules of $${O_2}$$  and form oxyhaemoglobin
$$4Hb + 4{O_2} \to \mathop {H{b_4}{O_8}}\limits_{{\text{Oxy - haemoglobin}}} $$

Vitamin $$C$$  is water soluble. Therefore, it is readily excreted in urine and cannot be stored in our body and is supplied regularly in diet.