MCQ Questions for Class 12 Engineering Chemistry Biomolecules Quiz 3

The term vitamin was introduced by

0%
Dr. Funk
0%
Dr Edwards
0%
Dr.Strepto
0%
Dr Indira Hinduja

Which of the following is true about vitamins?

0%
Vitamins in the humanbody are needed in large amounts.
0%
Vitamins are secreted by ductless glands.
0%
Vitamins are synthesized by an organisms.
0%
Vitamins A,D,E and K are fat soluble whereas vitamins of the B group and vitamin C are water soluble

Explanation

Vitamins

$A,D,E$ and

$K$ are fat soluble whereas vitamins of the

$B$ group and vitamin

$C$ are water soluble vitamins.

Fat soluble vitamins are usually absorbed in fat globules that travel through the lymphatic system of the small intestines and then circulates within the body. While water soluble vitamins are directly absorbed through the intestinal wall into the body.

Other statements are incorrect.

Option D is correct.

The vitamin which is water soluble and antioxidant is :

0%
vitamin B $_{6}$ .
0%
vitamin B $_{12}$ .
0%
vitamin C.
0%
vitamin E.

Explanation

The vitamin which is water-soluble and antioxidant is vitamin

$C$ .

It helps protect healthy cells from damage caused by free radicals. It is a water-soluble vitamin present in citrus fruits and juices, green peppers, cabbage, spinach, broccoli, kiwi and strawberries, etc.

So, option C is the correct answer.

Which amino acid is achiral?

0%
Alanine
0%
Valine
0%
Proline
0%
Glycine

STATEMENT-1: Lysine, cysteine and threonine are highly soluble in water but serine and valine are slightly soluble.

STATEMENT-2: Additional polar groups, such as $-OH, -NH_{2}$ and $COOH$ increase the solubility in water appreciably.

Select the correct option regarding given statements:

0%
STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is a correct explanation for STATEMENT-1
0%
STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is NOT a correct explanation for STATEMENT-1
0%
STATEMENT-1 is True, STATEMENT-2 is False
0%
STATEMENT-1 is False, STATEMENT-2 is True

Explanation

Lysine, cysteine and threonine contains polar groups such as

$-OH, -NH_{2} and -COOH$ .
These groups increase the solubility in water appreciably.
However such groups are not present in serine and valine.
Hence, they are slightly soluble.

Which of the following is not an amino acid?

0%
Glycine
0%
Alanine
0%
Histidine
0%
Benzidine

Explanation

Benzidine is not an amino acid but it is a aromatic amine. Its molecular formula is

$C_{12}H_{12}N_2$ .

Its IUPAC name is 4,4'-diaminobiphenyl, which is used as part of a test for cyanide and also in the synthesis of dyes.

Option D is correct.

Which of the following enzymes hydrolyse proteins to

$\alpha$ - amino acids?

0%
trypsin
0%
pepsin
0%
chymotrypsin
0%
all of the above

Explanation

Enzymes trypsin, pepsin and chymotrypsin hydrolyses proteins to

$\alpha$ - amino acids. Pepsin and trypsin hydrolyzed proteins to produce a complex mixture of peptides called proteoses and peptones. Chymotrypsin cleaves peptide amide bonds and finally breaks proteins into amino acids which is easily absorbed by the body.

N- Glycoside bond connects

0%
Sugar , base
0%
Sugar , Sugar
0%
Base , base
0%
Phosphate , ester

The chemical name of vitamin C is:

0%
citric acid
0%
acetic acid
0%
ascorbic acid
0%
oxalic acid

Explanation

The chemical name of vitamin

$C$ is ascorbic acid. The name, ascorbic acid, is derived from a (meaning no) and scorbutus (scurvy), the disease caused by a deficiency of vitamin C. The body requires ascorbic acid in order to form and maintain bones, blood vessels, and skin.

Which among the following are purine derivatives among the following bases?
Adenine Uracil Guanine Thymine

0%
1 & 4
0%
2 & 3
0%
1 & 3
0%
1, 3 & 4

Which of the following compound is not a vitamin?

0%
niacin
0%
riboflavin
0%
thiamine
0%
guanine

Explanation

Guanine is is not a vitamin but it is a nitrogenous base. Niacin is called as vitamin

$B_3$ , riboflavin is vitamin

$B_2$ and thiamine is vitamin

$B_1$ .

GC / AT ratio in E. coli is

0%
0.93 : 1
0%
1 : 0.93
0%
1 : 1.52
0%
1.52 : 1

6-amino purine is:

0%
adenine
0%
adenosine
0%
cytidine
0%
thymidine

Nucleic acids control heredity at:

0%
atomic Level
0%
ionic level
0%
complex level
0%
molecular level

Glycoside linkage is an

0%
Amide linkage
0%
Ether linkage
0%
Ester linkage
0%
None of these

Which of the following is not a disaccharide?

0%
Cane sugar
0%
Raffinose
0%
Lactose
0%
Maltose

Which of the following is least related to the other three?

0%
Galactose
0%
Glucose
0%
Mannose
0%
Arabinose

What is the minimum number of carbon atoms to be present in a carbohydrate?

0%
2
0%
3
0%
4
0%
6

Explanation

$\bf{Hint:-}$ A carbohydrate is a polyhydroxy aldehyde or ketone.

$\bf{Explanation-}$

$\bullet$ Carbohydrate is one of the three micronutrients through which a human body acquires energy. It consists of carbon, hydrogen and oxygen atoms at its chemical level.

$\bullet$ Carbohydrate is a polyhydroxy aldehyde or ketone. So, if it contains less than

$3$ carbon atoms, then, it can not have more than one hydroxyl group and a carbonyl group simultaneously. Therefore, the simplest minimum number of carbon atom carbohydrates is glyceraldehyde

$\bf{Conclusion-}$ Hence, option

$B$ is correct.

Glucose reacts with

$CH_{3}OH$ , in presence of dry

$HCl$ gas, to form:

0%
$\alpha$ -methyl glucoside
0%
$\beta$ -methyl glucoside
0%
both A and B
0%
none of these

Explanation

Glucose reacts with

$CH_{3}OH$ , in presence of dry

$HCl$ gas, to form a mixture of

$\alpha$ -methyl glucoside and

$\beta$ -methyl glucoside, depending on the approach of the two constituent molecules.

Which of the following group/linkage is absent in adenine but present in guanine?

0%
$C-N$
0%
$-NH_{2}$
0%
$C=O$
0%
$-CONH_{2}$

The sequence of bases in the nucleic acid strand is explained by:

0%
1 $^{0}$ structures
0%
2 $^{0}$ structures
0%
Both 1 $^{0}$ and 2 $^{0}$
0%
None

Explanation

The sequence of bases in the nucleic acid strand is explained by 1

$^{o}$ structures. The process of determining the precise order of nucleotides within a

$DNA$ molecule is called as

$DNA$ sequencing. It includes any method that is used to determine the order of the four bases

$(AGTC)$ .

Relation between amino acids and proteins is similar to the one between:

0%
nucleotides and nucleic acids
0%
RNA and DNA
0%
Glucose and Fructose
0%
Glucose and Mannose

Starch is converted into disaccharide in
presence of

0%
Diastase
0%
Maltose
0%
Zymose
0%
Lactose

Starch is used to test even the small amounts of:

0%
sucrose in aqueous solution
0%
glucose in aqueous solution
0%
$I_{2}$ in aqueous solution
0%
maltose in aqueous solution

In which of following cases, both the compounds are examples of reducing sugars?

0%
Glucose and Sucrose
0%
Fructose and Maltose
0%
Fructose and Sucrose
0%
Sucrose and Lactose

Combination of proteins with nucleic acids give

0%
enzymes
0%
polypeptides
0%
nucleo proteins
0%
dipeptides

The prosthetic group present in nucleoproteins is

0%
nucleic acids
0%
lipids
0%
carbohydrates
0%
phosphoric acid

Select the correct one from the following order of bonds in

$A, G, T, C$ and

$U$ .

0%
$A > G > T > C > U$
0%
$C = G > T = A = U$
0%
$G = A = T < C = U$
0%
$A < G < T < C < U$

Explanation

Order of bonds in

$A, G, T, C$ and

$U$ is

$C = G > T = A = U$ .

Within the

$DNA$ double helix,

$A$ forms 2 hydrogen bonds with

$T$ on the opposite strand, and

$G$ forms 3 hydrogen bonds with

$C$ on the opposite strand.

Option B is correct.

Which of the following is/are pyrimidine derivatives?
1.Cytosine Adenine Uracil Thymine

0%
1 and 4 only
0%
2 and 3 only
0%
1 and 3 only
0%
1, 3 and 4 only

Raffinose on hydrolysis forms_________

0%
Glucose
0%
Fructose
0%
Galactose
0%
All of these

The commonest disaccharide has the molecular formula______

0%
$C_{10}H_{18}O_{19}$
0%
$C_{10}H_{20}O_{10}$
0%
$C_{11}H_{22}O_{11}$
0%
$C _{12}H_{22}O_{11}$

Explanation

Disaccharides are the carbohydrates which on hydrolysis gives two same or different carbohydrates.

Sucrose is the most common disaccharide.

It can be found in many fruits and is naturally occuring.

It has molecular formula

$C_{12}H_{22}O_{11}$ .

Option D is correct.

Match the following.

List-I	List-II (Monomer)
A) Sucrose	i) $\beta$ -D-Galactose and $\beta$ -D-Glucose
B) Cellulose	ii) $\alpha$ -D-Glucose and $\beta$ -D-Fructose
C) Starch	iii) $\beta$ -D-Glucose
D) Lactose	iv) $\alpha$ -D-Glucose

0%
A-i; B-ii; C-iii; D-iv
0%
A-ii; B-i; C-iii; D-iv
0%
A-ii; B-iii; C-iv; D-i
0%
A-iv; B-iii; C-i; D-ii

Explanation

Sucrose is made up of two monomers

$\alpha$ -D-Glucose and

$\beta$ -D-Fructose.
Cellulose is made up of

$\beta$ -D-Glucose.
Starch is made up of

$\alpha$ -D-Glucose.
Lactose is made up of two monomers

$\beta$ -D-Galactose and

$\beta$ -D-Glucose.

Which of the following is not optically active?

0%
Glycine
0%
Lysine
0%
Aspartic acid
0%
Isoleucine

Which of the following amino acids does not correspond to the general formula:

$R - CH(NH_{2}) - COOH$ ?

0%
Cysteine
0%
Proline
0%
Argenine
0%
Glutamic acid

Explanation

Among the given amino acids, cysteine, arginine and glutamic acid correspond to the general formula

$R - CH(NH_2) - COOH$ .

However, proline does not correspond to the general formula

$R - CH(NH_2) - COO$ , as N is a part of a ring.

Option B is correct.

A sulfur containing amino acid is

0%
Glycine
0%
Cysteine
0%
Alanine
0%
Leucine

Explanation

$\bf{Hint:-}$ An amino acid contains

$-COOH$ and

$-NH_{2}$ functional group.

$\bf{Correct \ Aption-}$ Option

$B$

$\bf{Explanation\ for \ correct \ option-}$

A sulfur-containing amino acid is a cysteine.
Cysteine is an $\alpha$ -amino acid with the chemical formula $C_3H_7NO_2S$ . It is a semi-essential amino acid, which means that it can be biosynthesized in humans.

$\bf{Explanation\ for \ incorrect \ options-}$

All other given amino acids do not contain

$S$ atom, as shown below:

IUPAC name of glycine is:

0%
2-Aminopropanoic acid
0%
2-Aminobutanoic acid
0%
2-Aminoethanoic acid
0%
2-Aminopent-1,5-dioic acid

Explanation

IUPAC name of glycine is 2-Aminoethanoic acid.

Its molecular formula is

$NH_2CH_2COOH$ .

Hence,Option C is the correct answer.

The most common reagent for qualitative and quantitative analysis of amino acids is:

0%
Ninhydrin reagent
0%
Millon's reagent
0%
Sangars reagent
0%
Edmanns reagent

Starch undergoes hydrolysis in presence of mineral acids to form:

0%
glucose
0%
fructose
0%
maltose
0%
sucrose

Explanation

Starch undergoes hydrolysis in presence of mineral acids to form glucose.

$\underset{\begin{matrix}starch\, or\\cellulose\end{matrix}}{(C_6H_{12}O_5)_n} + nH_2O \xrightarrow[\begin{matrix} 393K\\2-3 \,bars\end{matrix}]{H^+} \underset{glu\,cose}{nC_6H_{12}O_6}$

Which one of the following statements about starch is correct?

0%
It occurs in the cell walls of plants
0%
It is a disaccharide
0%
It is present in roots and seeds of plants
0%
It gives a red orange precipitate on boiling with Fehlings solution

Number of

$C=O$ groups in thymine and X are equal. Now, X is

0%
cytosine
0%
uracil
0%
adenine
0%
guanine

Explanation

Number of

$C=O$ groups in thymine is same as in uracil. Both contains 2

$C=O$ groups.

On hydrolysis of starch, we finally get:

0%
glucose and fructose
0%
glucose
0%
fructose
0%
sucrose

Explanation

On hydrolysis of starch, we finally get glucose. This is because starch is the polymer of glucose. The reaction takes place in presence of amylase enzymes.

$\underset{\begin{matrix}starch\, or\\cellulose\end{matrix}}{(C_6H_{10}O_5)_n} + nH_2O \xrightarrow[\begin{matrix} 393K\\2-3 \,bars\end{matrix}]{H^+} \underset{glu\,cose}{nC_6H_{12}O_6}$

The functional group which is found in amino acid is

0%
$COOH$
0%
$NH_{3}$
0%
$CH_{3}$
0%
both A & B

Explanation

Option (D) is correct. The functional group which is found in amino acid are

$COOH$ and

$NH_3$ (amine group). So every amino acid has a central carbon with a

$H$ ,

$R$ group (varies for each amino acid), a carboxylic group and an amine group. These groups are joined to a single (aliphatic) carbon. The carbon directly attached to a carboxyl group is the alpha position, so the amino acids in proteins are all alpha-amino acids.

$H_2N - \underset{R}{\underset{|}{\overset{H}{\overset{|}{C}}}} - COOH$

Match the following

Set A	Set B
Adenine	a. $C_5N_5H_5O$
Guanine	b. $C_4N_2H_4O_2$
Uracil	c. $C_5N_5H_5$
Thymine	d. $C_5N_2H_6O_2$

0%
1-c; 2- a; 3-d; 4-b
0%
1-c; 2-b; 3-d; 4-e
0%
1-b; 2-c; 3-d; 4-a
0%
1-c; 2- a; 3- b; 4-d

Explanation

Option (D) is correct.
(1) Adenine has molecular formula of

$C_5N_5H_5$ .
(2) Guanine has molecular formula of

$C_5N_5H_5O$ .
(3) Uracil has molecular formula of

$C_4N_2H_4O_2$ .
(4) Thymine has molecular formula of

$C_5N_2H_6O_2$ .

If the amino group of glycine and carboxylic acid group of alanine undergo elimination of water molecule, the name of the compound thus formed is

0%
alanylglycide (dipeptide)
0%
glycylalanide (tripeptide)
0%
glycylalanine (dipeptide)
0%
alanylglycine (dipeptide)

The functional groups present in cytosine are:

0%
Keto and amino
0%
Keto only
0%
Amino only
0%
methyl

Which of the following statements is not correct?

0%
Proteins are poly amides formed from aminoacids
0%
Except glycine, all other amino acids show optical activity
0%
Natural proteins are made up of L isomers of amino acids
0%
In amino acids NH $_{2}$ and COOH groups are attached to different carbon atoms

Explanation

(A) Proteins are poly amides formed from alpha amino acids. Thus, the option A is correct.
(B) Except glycine, all other amino acids show optical activity as they contain chiral carbon atom. Glycine is achiral. Thus, option B is correct.
(C) Natural proteins are made up of L isomers of amino acids. Thus, statement C is correct.
(D) In amino acids

$NH_2$ and COOH groups are attached to same carbon atom.
Thus, the statement D is incorrect.

The non-proteinaceous substance, which certain enzymes require for their activity are called

0%
catalysts
0%
inhibitors
0%
co-enzymes
0%
epimers

Explanation

The non-proteinaceous substance, which certain enzymes require for their activity are called coenzymes. Coenzymes are organic molecules that are required by certain enzymes to carry out catalysis. They bind to the active site of the enzyme and participate in catalysis but are not considered substrates of the reaction. They function as intermediate carriers of electrons, specific atoms or functional groups that are transferred in the overall reaction. Example:

$FAD$ ,

$NAD^+$ ,

$TPP$ .

The number of tripeptides possible from three different amino acids is:

0%
81
0%
27
0%
9
0%
6

Explanation

The number of tripeptides possible from three different amino acids is 27. The protein can have 3

$^3=$ 27 different tripeptide sequences (by permutations).

Among Valine, Leucine, Isoleucine, Lysine and Phenyl alanine, odd member is:

0%
Leucine, since others are acidic
0%
Valine, since others are basic
0%
Isoleucine, since others are optically active
0%
Leucine, since others are neutral

Assertion:

$\alpha$ -amino acids are the building blocks of proteins.
Reason: Natural amino acids are mostly

$\alpha$ -amino acids.

0%
Both A and R are true and R is the correct explanation of A
0%
Both A and R are true but R is not correct explanation of A
0%
A is true but R is false
0%
A is false but R is true

Explanation

$\alpha$ -amino acids are the building blocks of proteins.
Proteins on hydrolysis exclusively give

$\alpha$ -amino acids.
Amino acids can be classified into

$\alpha, \beta, \gamma$ , etc.
Natural amino acids are mostly

$\alpha$ -amino acids.

CBSE Questions for Class 12 Engineering Chemistry Biomolecules Quiz 3 - MCQExams.com

0:0:1

Practice Class 12 Engineering Chemistry Quiz Questions and Answers

CBSE Questions for Class 12 Engineering Chemistry Biomolecules Quiz 3 - MCQExams.com

0:0:1

Practice Class 12 Engineering Chemistry Quiz Questions and Answers

Support mcqexams.com by disabling your adblocker.