CBSE Questions for Class 12 Engineering Chemistry Biomolecules Quiz 14 - MCQExams.com

Which of the following statement is not correct?
  • All proteins are polymers of $$\alpha-$$amino acids.
  • Glycogen is the food reserve of plants.
  • Cellulose is a linear polymer of $$\beta-$$glucose.
  • Amylopection is a branched polymer of $$\alpha-$$glucose.
The vitamin that is not fat soluble is ............ 
  • Vitamin B Complex
  • Vitamin D
  • Vitamin E
  • Vitamin A
The safest and the most common alternative of sugar is
  • Glucose
  • Aspartame
  • Saccharin
  • Cyclodextrin
Which one of the following statements is incorrect ?
  • Competitive inhibitor does not affect the rate of breakdown of the enzyme-substrate complex
  • The presence of the competitive inhibitor decreases the $$K_m$$ of the enzyme for the substrate.
  • A competative inhibitor reacts reversibly with the enzyme to form an enzyme-inhibitor complex
  • In competative inhibition the inhibitor molecule is not chemically changed by the enzyme.
Which of the following test cannot be used for identifying amino acids?
  • Biuret test
  • Xanthoproteic test
  • Barfoed test
  • Ninhydrin test

Which of the following hormones is not a growth promoter ?
  • Cytokinin
  • Auxin
  • Gibberellin
  • Abscisic acid
Ninhydrin reagent react with $$\alpha$$-amino acids to give a purple colour. In the reaction of ninhydrin with pheyl alanine.Which of the following responsible for this colour? 
Which failed to form osazone with excess of $$C_{6}H_{5}NHNH_{2}$$ in strongly alkaline medium?
  • D-glucose
  • D-Mannose
  • D-Xylose
  • Sucrose
A compound with molecular mass 180is acylated. with [image] to get a compound with molecular massThe no. of amino group present per molecule of the former compound is: 
1353684_16e5b54fabf14f449ec1cc3331598ce1.PNG
  • 2
  • 5
  • 4
  • 6
Thew correct order and staement for histidine are:
1373944_1df4994752624b58a6fa5e032ea31bbd.PNG
  • q > p ......basic nature
  • r > p........ basic nature
  • Histidine has $$8\pi $$ electrons delocalized in the ring
  • All stereoisomers of Histidine have different $$p{k_{a1}}$$ values
Which of the following dissaccharide is the $$\alpha$$-anomer of $$4-O-$$($$\beta$$-D-glucopyranosyl)-D-glucopyranose? 
$$\alpha -D-$$Glucose and $$\beta -D-$$Glucose are not :-
  • Epimers
  • Anomers
  • Enantiomers
  • Diastereomers
Find out the incorrect combination of enzyme, source, substrate and product obtained :- 
Enzyme SourceSubstrateProduct
(1)pepsinStomach chief cellsProtein proteoses, peptone
(2)Amino peptidasesmall intestinepeptide dipeptide, AA
(3)Enterokinasesmall intestineTrypsinTrypsinogen
(4)$$\alpha-$$Amylasesallvary glandsstarchMaltose 
  • (1)
  • (2)
  • (3)
  • (4)
Statement-I : Lac operon explains the regulation of enzyme synthesis by the substrate.
Statement-II : In any operon, the regulatory gene must be always located very close to structural genes.
  • Both Statement I and Statement II are correct
  • Statement I is correct and Statement II is wrong
  • Statement I is wrong and Statement II is correct
  • Both Statement I and Statement II are wrong
Which can give both carbylamine test and carric ammonium nitrate test ?
  • Asn-Gln
  • Lys-Gln
  • Asp-Lys
  • Lys-Ser
Ammonia is always added in this reaction. Which of the following must be incorrect?
  • $$ NH_{3}$$ combines with $$ Ag^{+}$$ to form a complex
  • $$ Ag(NH_{3})_{2}^{+} $$ is a stronger oxidizing agent than $$ Ag^{+} $$
  • In absence of ammonia, silver salt of gluconic acid is formed
  • $$ NH_{3} $$ has affected the standard reduction potential of glucose-gluconic acid electrode
What is the gain of ATP molecules during aerobic oxidation of one glucose molecule ?
  • $$32$$
  • $$16$$
  • $$36$$
  • $$18$$
Which is odd?
  • Chitin - Carbohydrate
  • Pectin -Protein
  • Steroid - Lipid
  • Wax - Lipid
Which of the following is carbohydrate?
  • Triamine
  • Lactose
  • Glycerol
  • Insulin
Which of the following is not an appropriate source of starch?
  • Rice
  • Corn
  • Potato
  • Molasses
The glycosidic linkage involved in linking the glucose units in amylose part of starch is:
  • $$C_{1} - C_{4}\beta - linkage$$
  • $$C_{1} - C_{6}\alpha - linkage$$
  • $$C_{1} - C_{6}\beta - linkage$$
  • $$C_{1} - C_{4}\alpha - linkage$$
Protein enzyme are
  • Carbohydrates
  • amino acids
  • both (a) and (b)
  • none of these
Ribose and deoxyribose differ in structure around a single carbon, namely: 
  • $$C-1$$
  • $$C-2$$
  • $$C-3$$
  • $$C-4$$
Prosthetic group of glycoprotein is: 
  • lipids
  • carbohydrate
  • metal ions
  • nucleic acid
One per cent composition of an organic compound $$A$$ is carbon $$= 85.71\%$$ and $$hydrogen = 14.29\%$$. Its vapour density is $$14$$. Consider the following reaction sequence:
$$A \xrightarrow {Cl_{2}/H_{2}O}$$  $$B \xrightarrow {(ii)H_{3}O^{+}}{{\xrightarrow {(i)KCN/ EtOH}}}$$ C; 
Identify C.
  • $$CH_{3} - \underset {\underset {OH}{|}}{C}H - CO_{2}H$$
  • $$HO - CH_{2} - CH_{2} - CO_{2}H$$
  • $$HO - CH_{2} - CO_{2}H$$
  • $$CH_{3}CH_{2} - CO_{2}H$$
Functionally active form of vitamin D is:
  • cholecalciferol
  • ergocalciferol
  • dehydro cholesterol
  • calcitriol
Which one of-the following polysaccharides is composed of $$\beta-$$ glycosidic link?
  • Starch
  • Glycogen
  • Dextrin
  • Cellulose
The change is optical rotation with time of freshly prepared solutions of sugar, is known as
  • Specific rotation
  • inversion
  • rotatory motion
  • mutaroatation
The cogulation of protein is called
  • dehydration
  • decay
  • deamination
  • denaturing
The total number of basic groups in the following form of lysine 
1720879_c357c05480e248ab8c6cc681d2d673bf.png
  • 0
  • 1
  • 2
  • 3
Which of the following is found cod-liver oil
  • Vitamin C
  • Vitamin E
  • Vitamin A
  • Vitamin $$ B_{1} $$
The aqueous solution of carbohydrate gave dark blue colour with iodine,
the carbohydrate is
  • starch
  • sucrose
  • fructose
  • glucose
Which of the following do not undergo hydrolysis?
  • Glucose
  • Fructose
  • galactose
  • sucrose
The enzyme pepsin hydrolyses
  • protein to amino acid
  • fats to fatty acid
  • glucose to ethyl alcohol
  • polusachharides to monosaccharides
Select the carbohydrate which gives only glucose on hydrolysis: 
  • sucrose
  • lactose
  • maltose
  • galactose
Select the correct statements about enzymes.
  • Enzymes are bio-catalyst found in organism
  • all enzymes are protiens
  • enzymes can catalyse any reaction
  • enzyme's activity is optimum at $$27^o C$$
Fructose is present in sperm.
  • True
  • False
Biuret test is not given by
  • proteins
  • urea
  • polypeptide
  • carbohydrates
Which of the following is not present in a nucleotide?
  • Cytosine
  • Guanine
  • Adenine
  • Tyrosine
Carbohydrates have been classified on the basis of:
  • sugars and non-sugars
  • reducing character
  • optical activity
  • hydrolysis (complexity of structure)
Which of the following acts as a biological catalyst?
  • Carbohydrates
  • Lipids
  • Vitamins
  • proteins
Complete hydrolysis of cellulose gives:
  • D-fructose
  • D-ribose
  • D-glucose
  • L-glucose
The purine base present in RNA is:
  • adenine
  • cytosine
  • uracil
  • thymine
Which of the following is not a disaccharide?
  • cane sugar
  • raffinose
  • lactose
  • maltose
The correct statement about the following disaccharide is: 
1721499_3df128be29054a83bbccc858fb9122ab.JPG
  • ring (I) is pyranose with $$\alpha$$ - glycosidic link
  • ring (I) is furanose with $$\alpha$$ - glycosidic link
  • ring (II) is furanose with $$\alpha$$ - glycosidic link
  • ring (II) is pyranose with $$\beta$$ - glycosidic link
Raffinose on hydrolysis gives:
  • mannose
  • fructose
  • glucose
  • galactose
Starch is made up of:
  • $$\alpha -$$ glucose pyranose
  • $$\alpha -$$glucose furanose
  • $$\beta -$$ fructose pyranose
  • $$\beta -$$ fructose furanose
Parkinson's disease is linked to abnormalities in the levels of dopamine in the body. The structure of dopamine is.
The correct statement (s) about the following sugars X and Y is (are):
1722116_1621395f41a14aacac3e77c5efb5a12a.png
  • X is a reducing sugar and Y is a non-reducing sugar
  • X is a non-reducing sugar and Y is a reducing sugar
  • the glycosidic linkages in X and Y are $$\alpha-$$ and $$\beta-$$ respectively
  • the glycosidic linkage in X and Y are $$\beta-$$ and $$\alpha -$$ respectively
State whether the following statements are True or False:
Vitamins A, D, E and K are water soluble.
  • True
  • False
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