Chemistry M.C.Q (1 Marks)

$(1)$ Like chemical catalysts enzymes reduce the activation energy of bio process $\Rightarrow$ This is correct statement.

$(2)$ Enzymes are polysaccharides $\Rightarrow$ This is incorrect statement because enzymes are protein in nature

$(3)$ Enzymes are very specific for a particular reaction and substrate $\Rightarrow$ This is correct statement.

$(4)$ Enzymes are biocatalyst $\Rightarrow$ This is correct statement.

It is an aldohexose.
5 -OH groups are present.
It is a reducing sugar as it contains
- CHO group.

Essential amino acid $\to$ valine, leucine, lysine

$\mathrm{DNA} \stackrel{\text { Transcription }}{\longrightarrow} \mathrm{RNA} \stackrel{\text { Translation }}{\longrightarrow}$ Protein

Glucose has two forms $\alpha$ and $\beta$. When either of these two is dissolved in water and allowed to stand, it gets converted to an equilibrium mixture of $\alpha$  and $\beta$ forms.

$HOC{H_2} - {(CHOH)_3} - CHO$

Carbohydrates gives brown red ppt. with benedict’s solution ($Alk$. $CuS{O_4} + $ Citrate ions)

$Explanation- $Ribose is a monosaccharide having five carbons, thus called pentose sugar. Ribose is the most important pentose present in living organisms. It is an aldose sugar, having an aldehydic functional group. Its molecular formula is represented as $C_5​ H_{10}​ O_5$ . The structural formula of ribose is as follow:

Starch is a polymer of glucose. It exists in two forms amylose and amylopectin. Amylose is formed by linkage of glucose by $\alpha-1,4$ glucose unit. It is a linear polymer. Amylopectin is a branched polymer of glucose where two polymeric chains of glucose of alpha 1,4 glucose unit are linked by $\alpha-1,6$ linkage.

Cellulose is linear homopolysaccharide of $\beta$ - glucose units, which are linked together by $\beta-1,4$ glycosidic bonds.

$b)$. The biuret test, also known as Piotrowski's test, is a chemical test used for detecting the presence of peptide bonds. In the presence of peptides, a copper $(II)$ ion forms mauve-colored coordination complexes in an alkaline solution.

$c)$.Fehling’s test is used for reducing sugars and non-reducing sugars, supplementary to the Tollens’ reagent test. The test was developed by German chemist Hermann von Fehling in $1849$.

$d).$ Millon's reagent is an analytical reagent used to detect the presence of soluble proteins.

$(1)$.The alpha $(\alpha)$ anomer of $D$-glucose has a specific rotation of $+112$ degrees in water.

$(2)$.The beta ( $\beta$ ) anomer of $D$-glucose has a specific rotation of $+19$ degrees. $(18.7$ actually, but rounding up to $19)$.

And when either anomer is dissolved in water, the value of the specific rotation changes over time eventually reaching the same value of $+52^{\circ}$.

The specific rotation of $\alpha$-D-glucopyranose decreases from $+112^{\circ}$ to

$+52^{\circ}$.

The specific rotation of $\beta$-D-glucopyranose increases from $+19^{\circ}$ to

$+52^{\circ}$.This behaviour is called mutarotation

$\mathop {{C_6}{H_{12}}{O_6}}\limits_{{\text{Glucose}}}  + (O)\xrightarrow{{B{r_2}/{H_2}O}}\mathop {C{H_2}OH{{(CHOH)}_4}COOH}\limits_{{\text{Gluconic acid}}} $