Biomolecules

JEE Chemistry · 116 questions · Page 1 of 12 · Click an option or "Show Solution" to reveal answer

Observation of “Rhumann’s purple” is a confirmatory test for the presence of :

A Reducing sugar

B Cupric ion

C Protein

D Starch

Correct Answer

Option C

Solution

Ruhemann’s purple is ninhydrin.

Which of the given statements is INCORRECT about glycogen?

A It is a straight chain polymer similar to amylose

B It is present in animal cells

C It is present in some yeast and fungi

D Only

\alpha

-linkages are present in the molecule

Correct Answer

Option A

Solution

Glycogen is branch chain polymer.

The water soluble protein is :

A Fibrin

B Albumin

C Myosin

D Collagen

Correct Answer

Option B

Solution

Albumin is water soluble.

Which one of the following is a water soluble vitamin, that is not excreted easily?

A Vitamin B2

B Vitamin B1

C Vitamin B6

D Vitamin B12

Correct Answer

Option D

Solution

Vitamin B12 is water soluble and not excreted easily.

Glucose on prolonged heating with HI gives

A 6-iodohexanal

B n-Hexane

C 1-Hexene

D Hexanoic acid

Correct Answer

Option B

Solution

As HI is a strong reducing agent, it reduces all the aldehydes and ketones to acohol and alcohols are further reduce to alkanes.

The incorrect statement among the following is :

\alpha

-D-glucose and

\beta

-D-glucose are anomers.

\alpha

-D-glucose and

\beta

-D-glucose are enantiomers.

C Cellulose is a straight chain polysaccharide made up of only

\beta

-D-glucose units.

D The penta acetate of glucose does not react with hydroxyl amine

Correct Answer

Option B

Solution

$\alpha$ -D-glucose and $\beta$ -D-glucose are anomers not enantiomers.

Hydrolysis of sucrose gives :

\alpha

-D-(

-

)-Glucose and

\beta

-D-(

-

)-Fructose

\alpha

-D-(+)-Glucose and

\alpha

-D-(

-

)-Fructose

\alpha

-D-(

-

)-Glucose and

\alpha

-D-(+)-Fructose

\alpha

-D-(+)-Glucose and

\beta

-D-(

-

)-Fructose

Correct Answer

Option D

Solution

Sucrose is formed by $\alpha$ -D(+). Glucose + $\beta$ -D( $-$ ) Fructose. We obtain these monomers on hydrolysis.

Which one of the following compounds contains

\beta

-C1-C4 glycosidic linkage?

A Lactose

B Sucrose

C Maltose

D Amylose

Correct Answer

Option A

Solution

In Lactose it is $\beta$ C1 - C4 glycosidic linkage. In Maltose, Amylose $\alpha$ C1 - C4 glycosidic linkage is present.

Which one of the following statements is not true?

A Lactose contains

\alpha

-glycosidic linkage between C1 of galactose and C4 of glucose

B Lactose is a reducing sugar and it gives Fehling’s test

C On acid hydrolysis, lactose gives one molecule of D(+)-glucose and one molecule of D(+)-galactose

D Lactose (C11H22O11) is a disaccharide and it contains 8 hydroxyl groups

Correct Answer

Option A

Solution

Lactose contains $\beta$ -glycosidic linkage between C1 of galactose and C4 of glucose.

Q10

Which of the following is not an essential amino acid :

A Valine

B Leucine

C Lysine

D Tyrosine

Correct Answer

Option D

Solution

Tyrosine is not an essential amino acid.

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