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

The food component which is known as the main source of energy:
  • Fat
  • Carbohydrate
  • Protein
  • Water
Which of the following terms are correct about enzymes?
  • Proteins
  • Dinucleotides
  • Nucleic acids
  • Biocatalysts
Which of the following reaction is not an enzyme-medicated in the biological system?
  • Dissolving $$CO_2$$ in water
  • Untwining the two strands of DNA
  • Hydrolysis of sucrose
  • Formation of peptide bond
Which of the following is energy-giving nutrient? 
  • Carbohydrates
  • Proteins
  • Vitamins
  • Minerals
Which of the following food contain carbohydrates?
  • Rice
  • Pulses
  • Egg
  • Butter
Match the following.
A. Homeostasis                      1) Insulin
B. Emergency hormone         2) Structure of insulin
C. Metabolism                       3) Adrenaline
D. Peptide hormones             4) Thyroxine
E. Pancreatic islets                5) Maintenance of constant internal environment
F. Sanger                                6) Affect the properties of Plasma membrane 
  • A - 1; B - 5; C - 3; D - 4; E - 6; F - 2
  • A - 2; B - 4; C - 3; D - 1; E - 6; F - 2
  • A - 3; B - 5; C - 3; D - 4; E - 6; F - 1
  • A - 5; B - 3; C - 4; D - 1,6; E - 1; F - 2
Match the following:

Name of the sugar       Hydrolysis products
A) Sucrose            i) Glucose $$+$$ Fructose $$+$$ Galactose
B) Lactoseii) Glucose $$+$$ Fructose
C) Maltoseiii) Glucose $$+$$ Galactose
D) Raffinoseiv) Glucose $$+$$ Glucose
  • A- iii , B- ii,  C- i,  D- iv.
  • A- ii, B- iii,  C- i, D- iv.
  • A- ii,  B- iii ,C- iv, D- i.
  • A- ii,  B- iv, C- iii,  D- i.
The ratio of the number of ketonic groups in cytosine, thymine and uracil is:
  • 1: 2 : 2
  • 2 : 1 : 2
  • 2 : 2 : 1
  • 1 : 1 : 1
Which of the following carbohydrates is not a monosaccharide?
  • Glucose
  • Fructose
  • Galactose
  • Sucrose
Which of the following statement(s) is/are correct?
I. Starch is almost insoluble in cold water but relatively more soluble in boiling water.
II. Starch solution gives blue colour with $$I_2$$ solution in cold.
III. Starch is a reducing sugar.
IV. Starch forms osazone.
  • III and IV
  • I and II
  • II and III
  • I and IV

STATEMENT-1 : Sucrose is reducing sugar where as maltose is non reducing sugar.

STATEMENT-2 : In disaccharides, the reducing property depends upon the position of linkages between the two monosaccharide units.
  • STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is a correct explanation for STATEMENT-1
  • STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is NOT a correct explanation for STATEMENT-1
  • STATEMENT-1 is True, STATEMENT-2 is False
  • STATEMENT-1 is False, STATEMENT-2 is True
Reducing sugar can reduce:
  • Aldehydes to alcohols
  • Ferric salts to ferrous salts
  • Chlorates to chlorides
  • Fehling solution to cuprous oxide
A tetrapeptide has $$-COOH$$ group on alanine. This produces glycine (Gly), valine (Val), phenyl alanine (Phe) and alanine (Ala), on complete hydrolysis. For this tetrapeptide, the number of possible sequences (primary structures) with $$NH_{2}$$ group attached to a chiral centre is:
  • 4
  • 3
  • 6
  • 2
The sugar and purine rings are connected at which carbons?
  • $$1, 3$$
  • $$1, 6$$
  • $$1 , 9$$
  • $$5 , 9$$
The reagent which may be used to distinguish between cane sugar and glucose solutions is:
  • $$I_{2}$$ solution
  • Baeyer's reagent
  • Both $$A$$ and $$B$$
  • Fehling's solution
The shape of an enzyme, and consequntly its acitivity, can be reversibly altered from moment to moment by:
  • Amino acid substitutions
  • Sulphur substitutions
  • Allosteric subunits
  • High pH
Adenosine triphoshate (ATP) molecule is given above. Calculate value of $$n_{1}+n_{2}$$, where $$n_{1}$$ is the net negative charge in neutral medium and $$n_{2}$$ is number of chiral carbon atoms.

74399.jpg
  • 8
  • 7
  • 9
  • None of these
What is the botanical name of sugarcane
  • Saccharum munja
  • Saccharum spontaneum
  • Saccharum berberi
  • Saccharum officinarum
Which one of the following is not an attribute of enzymes?
  • They are specific in nature
  • They are used in chemical reactions
  • They are thermolabile in nature
  • They are proteinaceous in nature

The correct statement(s) about the following sugars $$X$$ and $$Y$$ is(are):

32188_1ec29f67f2bc45aa9bf26ea79a233177.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 glucosidic linkages in $$X$$ and $$Y$$ are $$\alpha $$ and $$\beta $$, respectively
  • The glucosidic linkages in $$X$$ and $$Y$$ are $$\beta $$ and $$\alpha $$, respectively
Sugar yielding part of Beta vulgaris is
  • Leaf
  • Shoot
  • Root
  • All the above
Which one of the following enzyme is composed of simple proteins _____________.
  • Peroxidase
  • Phosphoglyceromutase
  • Proteinase
  • Amylase
Enzymes differ from inorganic catalysts in
  • not being used up in chemical reactions
  • working at high temperature
  • being proteinaceous in nature
  • working at high pH
The vitamin which helps in carbohydrate metabolism during glycolysis and TCA cycle is
  • Riboflavin
  • Thiamine
  • Folk acid
  • Pantothenic acid
Enzymes generally have:
  • Same pH and temperature optima
  • Same pH but different temperature optima
  • Different pH but same temperature optima
  • Different pH and different temperature optima
Inducer is not required in which of the following types of enzyme?
  • Allosteric
  • Inhibitory
  • Constitutive
  • All of the above
Free aldehyde group can be produced on hydrolysis of which of the following compound(s)?
  • Maltose
  • Sucrose
  • $$\alpha$$-D Glucose
  • Lactose
Which vitamin is incorporated into FAD structure?
  • Vitamine B$$_{12}$$
  • Vitamine B$$_{6}$$
  • Vitamine B$$_{2}$$
  • Vitamine C
Which among the following are compounds structurally similar to substrate and inducing enzyme synthesis?
  • Constitutive enzymes
  • Gratuitous inducer
  • Coordinated inducers
  • None of the above
The active site of an enzyme is situated in its amino acids _________ .
  • Amino groups
  • Carboxyl groups
  • R-groups
  • All the above
Which of the following statements is wrong regarding amino acids?
  • The living systems in plants can synthesise essential amino acids.
  • The living systems in animals can synthesise only essential amino acids.
  • The living systems in animals can synthesise only non essential amino acids.
  • The living systems in plants can synthesise non essential amino acids.
Compound $$A$$ has how many functional groups ?
247117_f6d2cba12b8841f98d5ff774295cbafb.png
  • $$1$$
  • $$2$$
  • $$3$$
  • $$4$$
Compound $$(D)$$ is:
247130_9dc3054ce81246d68a69f54881a29aaa.png
  • none of the above
The sequence from $$(A)$$ to $$(D+E)$$ is called:
  • Wohl's method
  • Ruff method
  • Kiliani's method
  • Ekenstein method
If a man is exposed to an environment of 100% oxygen, then the concentration of which of the following enzyme is increased in lungs?
  • Superoxide dismutase
  • Catalase
  • Carbonic anhydrase
  • All of the above
Which of the following statements are correct about $$\alpha$$-amino acids?
  • All the amino acids which constitute proteins have D-configuration
  • Isoelectric point of glycine is $$6.1$$
  • Valine is an essential amino acid
  • In $$\alpha$$-amino acids, the basic group is $$(-CO{ O }^{ \ominus })$$ and acidic group is $$(-\overset { \oplus }{ N } { H }_{ 3 })$$
Two isomer products are obtained in $$(C)$$. They are:
  • both $$\gamma$$-lactone
  • both $$\delta$$-lactones
  • one is $$\gamma$$-lactone and another is $$\delta$$-lactone
  • none
Compound $$(B)$$ is:
247120_595a6ab79b27477593fbe85b38955674.png
..................... enzymes have heme as a prosthetic group.
(i) Catalase
(ii) Carboxypeptidase
(iii) Succinic dehydrogenase
(iv) Peroxidase
  • (i) only
  • (i) and (ii) only
  • (ii) and (iii) only
  • (iii) and (iv) only
  • (i) and (iv) only
$$K_m$$ value of enzyme is substrate concentration at 
  • 10 V$$_{max}$$
  • 0.5/1 V$$_{max}$$
  • 1/2 V$$_{max}$$
  • 4/5 V$$_{max}$$
Which of the following statements are correct about $$\alpha$$-amino acids:
  • All the amino acids which constitute proteins have D-configuration
  • Isoelectric point of glycine is $$6.1$$
  • Valine is an essential amino acid
  • In $$\alpha$$-amino acids the basic group is $$(-CO{ O }^{ \ominus })$$ and acidic groups is $$(-\overset { \oplus }{ N } { H }_{ 3 })$$
The function of an enzyme is to ?
  • Cause chemical reactions that would not otherwise take place
  • Change the rates of chemical reactions
  • Change the directions of reactions
  • Control the equilibrium points of reactions
An enzyme may be rendered inoperative by?
  • Adding apoenzyme
  • Doubling its concentration
  • Blocking its active site
  • Removing byproducts as soon as they are formed
Thymine is
  • 5-Methyluracil
  • 4-Methyluracil
  • 3-Methyluracil
  • 1-Methyluracil
Starch molecules are polymer with repeating glucose units. Select the correct statement.
  • Glucose units are joined through $$\beta$$-glycosidic linkage
  • The branches of amylopectin are linked to the chain with $$\alpha$$-1,4'-glycosidic linkages
  • The linear linkages of amylopectin are formed by $$\alpha$$-1,4'-glycosidic bond
  • Amylose has an unbranched skeleton of glucose molecules with $$\alpha$$-1,6'-glycosidic linkages
The shape of an enzyme, and consequently its activity, can be reversibly altered from moment to moment by ?
  • Amino acid substitutions
  • Allosteric subunits
  • Sulphur substitutions
  • High pH
Which of the statements are correct about D.L of sugars and amino acids.
  • In sugars, symbols D and L refer to the relative configuration of the OH groups at the penultimate C atom w.r.t to glyceraldehyde taken as standard. D refers to $$(-OH)$$ group on R.H.S and L refers to $$OH$$ group on L.H.S
  • In amino acids, symbols D and L refer to the relative configuration of $$({NH}_{2})$$ group w.r.t D(+) serine taken as standard (figure) [D(+) Serine] D refers to $${NH}_{2}$$ group on R.H.S and L refers to $$(-{NH}_{2})$$ group on L.H.S
  • In sugars, D refers to dextrorotatory and L refers to laevoratory
  • In amino acids, D refers to positive and L refers to negative optical rotation
Enzymes are?
  • Substances which are broken into simpler substances during digestion.
  • Substances which are made by the combination of carbohydrates.
  • Substances which break complex food molecules into simpler food molecules.
  • Substances which break complex substances and they themselves undergo dissociation reactions.
Base treatment of an amino acid usually result in the conversion of the acid to a derivative via the amino carboxylate salt.The above procedure -
264702_3484081d94f14075a6b3cb6bf215ad2a.png
  • Decrease the rate of electrophilic reaction of the free amino group.
  • Decrease the rate of nucleophilic reaction of the free amino group.
  • Enhances the rate of nucleophilic reaction of the free amino group.
  • Enhances the rate of electrophilic reaction of the free amino group.
Which of the following does not represent a disaccharide? 
  • Maltose
  • Sucrose
  • Lactose
  • Dextrose
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