A catalyst

• changes the equilibrium constant

• lowers the activation energy

• increases the forward and backward reactions at different speeds

• follows same mechanism for the reaction

Which of the following test is not used for testing of proteins ?

• Millon's test

• Molisch's test

• Biuret test

• Ninhydrin test

The pair in which both species have iron is

• nitrogenase, cytochromes

• carboxypeptidase, haemoglobin

• haemocyanin, nitrogenase

• haemoglobin, cytochromes

Assertion : Alpha ($\mathrm{\alpha }$)-amino acids exist as internal salt in solution as they have amino and carboxylic acid groups in near vicinity.

Reason: H⁺ ion given by carboxylic group (-COOH) is captured by amino group (-NH₂) having lone pair of electrons.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Thymine is

• 5-methyluracil

• 4-methyluracil

• 3-methyluracil

• 1-methyluracil

Lysine is least soluble in water in the pH range

• 3 to 4

• 5 to 6

• 6 to 7

• 8 to 9.

Methyl-$\mathrm{\alpha }-\mathrm{D}$-glucoside and methyl-$\mathrm{\beta }$-D-glucoside are

• epimers

• anomers

• enantiomers

• conformational diastereomers.

Assertion : In the iodometric titration starch is used as an indicator.

Reason : Starch is a polysaccharide.

• If both assertion and reason are true and reason is the correct explanation of the assertion.

• If both assertion and reason are true but reason is not the correct explanation of the assertion.

• If assertion is true, but reason is false.

• Both assertion and reason are false statements.

The safest and the most common alternative of sugar is :

• glucose

• aspartame

• saccharin

• cyclodextrin

Which one of these elements is found in vitamin B₁₂ ?

• Fe

• Zn

• Mg

• Co