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Biomolecules Chemistry - Biomolecules

Bihar Board (BSEB) - STD 12 Science - Chemistry (BSEB - English Medium). 439 questions in this chapter.

Question types

Biomolecules question types

439 questions across 8 question groups — pick any mix to generate a Chemistry paper with step-by-step answer keys.

439
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8
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5
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Sample Questions

Biomolecules questions

One sample from each question group in this chapter. Select any group above to see the full set with answer keys.

Q 8Assertion (A) & Reason (B) MCQ [1M]1 Mark
Two statements are given- one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:
  1. Both Assertion (A) and Reason (R) are correct statements, and Reason (R) is the correct explanation of the Assertion (A).
  2. Both Assertion (A) and Reason (R) are correct statements, but Reason (R) is not the correct explanation of the Assertion (A).
  3. Assertion (A) is correct, but Reason (R) is incorrect statement.
  4. Assertion (A) is incorrect, but Reason (R) is correct statement.
Assertion (A): Sucrose is a non-reducing sugar.
Reason (R): Reducing groups of glucose and fructose are involved in glycosidic bond formation.
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Q 9Assertion (A) & Reason (B) MCQ [1M]1 Mark
Two statements are given- one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:
  1. Both Assertion (A) and Reason (R) are correct statements, and Reason (R) is the correct explanation of the Assertion (A).
  2. Both Assertion (A) and Reason (R) are correct statements, but Reason (R) is not the correct explanation of the Assertion (A).
  3. Assertion (A) is correct, but Reason (R) is incorrect statement.
  4. Assertion (A) is incorrect, but Reason (R) is correct statement.
Assertion (A): Sucrose is a non-reducing sugar.
Reason (R): Sucrose has glycosidic linkage.
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Q 10Assertion (A) & Reason (B) MCQ [1M]1 Mark

Note: In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.

  1. Assertion and reason both are correct statements and reason explains the assertion.
  2. Both assertion and reason are wrong statements.
  3. Assertion is correct statement and reason is wrong statement.
  4. Assertion is wrong statement and reason is correct statement.
  5. Assertion and reason both are correct statements but reason does not explain assertion.

Assertion: $\beta-$glycosidic linkage is present in maltose,

Reason: Maltose is composed of two glucose units in which C1 of one glucose unit is linked to C4 of another glucose unit.

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Q 11Assertion (A) & Reason (B) MCQ [1M]1 Mark
Note: In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
  1. Assertion and reason both are correct statements and reason explains the assertion.
  2. Both assertion and reason are wrong statements.
  3. Assertion is correct statement and reason is wrong statement.
  4. Assertion is wrong statement and reason is correct statement.
  5. Assertion and reason both are correct statements but reason does not explain assertion.
Assertion: In presence of enzyme, substrate molecule can be attacked by the reagent effectively.
Reason: Active sites of enzymes hold the substrate molecule in a suitable position.
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Q 12Assertion (A) & Reason (B) MCQ [1M]1 Mark
In these questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
  1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
  2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
  3. Assertion is correct statement but reason is wrong statement.
  4. Assertion is wrong statement but reason is correct statement.
Assertion: Nucleotides are phosphate esters of nucleosides.
Reason: The various nucleotides in nucleic acids are linked either through purine or pyrimidine bases.
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Q 233 Marks Question3 Marks
  1. Which one of the following is a disaccharide: starch, maltose, fructose, glucose
  2. What is the difference between acidic amino acid and basic amino acid?
  3. Write the name of the linkage joining two nucleotides.
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Q 263 Marks Question3 Marks
  1. Write the structural difference between starch and cellulose.
  2. What type of linkage is present in Nucleic acids?
  3. Give one example each for fibrous protein and globular protein.
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Q 28Long Answer Type Questions [5M]5 Marks
  1. What are essential and non-essential amino acids? Give two examples of each.
  2. What are the two types of photosynthesis in green plants? Give the basic equations of photosynthesis.
  3. Mention the two products of glycolysis.
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Q 32Long Answer Type Questions [5M]5 Marks
After watching a programme on TV about the presence of carcinogens (cancer causing agents) Potassium bromate and Potassium iodate in bread and other bakery products, Veena, a class XII student, decided to make others aware about the adverse effects of these carcinogens in foods. She consulted the school principal and requested him to instruct the canteen contractor to stop selling sandwiches, pizzas, burgers and other bakery products to the students. The principal took an immediate action and instructed the canteen contractor to replace the bakery products with some proteins and vitamins-rich food like fruits, salads, sprouts, etc. The decision was welcomed by the parents and students.
After reading the above passage, answer the following questions:
  1. What are the values (at least two) displayed by Veena?
  2. Which polysaccharide component of carbohydrates is commonly present in bread?
  3. Write the two types of secondary structures of proteins.
  4. Give two examples of water soluble vitamins.
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Q 33Case study (4 Marks)4 Marks

Read the passage given below and answer the following questions:

Carbohydrates can exist in either of two conformations, as determined by the orientation of the hydroxyl group about the asymmetric carbon farthest from the carbonyl.

By convention, a monosaccharide is said to have D-configuration if the hydroxyl group attached to the asymmetric carbon atom adjacent to the -CH2OH group is on the right hand side irrespective of the positions of the other hydroxyl groups. On the other hand, the molecule is assigned L-configuration if the -OH group attached to the carbon adjacent to the - CH2OH group is on the left hand side.

The following questions are multiple choice questions. Choose the most appropriate answer:

  1. D-Glyceraldehyde and L-Glyceraldehyde are:
  1. Epimers.
  2. Enantiomers.
  3. Anomers.
  4. Conformational diasteriomers.
  1. Which of the following monosaccharides, is the majority found in the human body?
  1. D-type.
  2. L-type.
  3. Both of these.
  4. None of these.
  1. The two functional groups present in a typical carbohydrate are:
  1. -OH and -COOH
  2. -CHO and -COOH
  3. >C= O and -OH
  4. -OH and -CHO
  1. Monosaccharides contain:
  1. Always six carbon atoms.
  2. Always five carbon atoms.
  3. Always four carbon atoms.
  4. May contain 3 to 7 carbon atoms.
  1. The correct corresponding order of names of four aldoses with configuration given below respectively, is:

  1. L-erythrose, L-threose, L-erythrose, D-threose.
  2. D-threose, D-erythrose, L-threose, L-erythrose.
  3. L-erythrose, L-threose, D-erythrose, D-threose.
  4. D-erythrose, D-threose, L-erythrose, L-threose.
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Q 34Case study (4 Marks)4 Marks

Read the passage given below and answer the following questions:

Pentose and hexose undergo intramolecular hemiacetal or hemiketal formation due to combination of the –OH group with the carbonyl group. The actual structure is either of five or six membered ring containing an oxygen atom. In the free state all pentoses and hexoses exist in pyranose form (resembling pyran). However,inthe combined state some of them exist as five membered cyclic structures, called furanose (resembling furan).

The cyclic structure of glucose is represented by Haworth structure:

$\alpha$ and $\beta$ D-glucose have different configuration at anomeric (C-1) carbon atom, hence are called anomers and the C-1 carbon atom is called anomeric carbon (glycosidic carbon).

The six membered cyclic structure of glucose is called pyranose structure.

The following questionsare multiple choice questions. Choose the most appropriate answer:

  1. $\alpha$ D(+)-glucose and $\beta$ D(+)glucose are:
  1. Enantiomers.
  2. Conformers.
  3. Epimers.
  4. Anomers.
  1. The following carbohydrate is:

 

  1. A ketohexose.
  2. An aldohexose.
  3. An n-furanose.
  4. An $\alpha$-pyranose.
  1. In the following structure, anomeric carbon is:

  1. C-1
  2. C-2
  3. C-3
  4. C-4
  1. The term anomers of glucose refers to:
  1. Isomers of glucose that differ in configurations at carbons one and four (C-1 and C-4).
  2. A mixture of (D)-glucose and (L)-glucose.
  3. Enantiomers of glucose.
  4. Isomers of glucose that differ in configuration at carbon one (C-1).
  1. What percentage of $\beta$-D-(+) glucopyranose is found at equilibrium in the aqueous solution?
  1. 50%

  2. $\approx100%$

  3. 36%
  4. 64%
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Q 35Case study (4 Marks)4 Marks
Read the passage given below and answer the following questions:

Proteins are high molecular mass complex biomolecules of amino acids. The important proteins required for our body are enzymes, hormones, antibodies, transport proteins, structural proteins, contractile proteins etc. Except for glycine, all $\alpha$-amino acids have chiral carbon atom and most of them have L-configuration. The amino acids exists as dipolar ion called zwitter ion, in which a proton goes from the carboxyl group to the amino group. A large number of $\alpha$-amino acids are joined by peptide bonds forming polypeptides. The peptides having very large molecular mass (more than 10,000) are called proteins. The structure of proteins is described as primary structure giving sequence of linking of amino acids; secondary structure giving manner in which polypeptide chains are arranged and folded; tertiary structure giving folding, coiling or bonding polypeptide chains producing three dimensional structures and quaternary structure giving arrangement of sub-units in an aggregate protein molecule.

A statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.

  1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
  2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
  3. Assertion is correct statement but reason is wrong statement.
  4. Assertion is wrong statement but reason is correct statement.
  1. Assertion: Except glycine, all naturally occurring CL-amino acids are optically active.

Reason: All naturally occurring CL-amino acids, except glycine, has at least one asymmetric carbon.

  1. Assertion: All amino acids are optically active.

Reason: Amino acids contain asymmetric carbon atoms.

  1. Assertion: In $\alpha$-helix structure, intramolecular H-bonding takes place whereas in $\beta$-pleated structure, intermolecular H-bonding takes place.

Reason: An egg contains a soluble globular protein called albumin which is present in the white part.

  1. Assertion: Secondary structure of protein refers to regular folding patterns of continuos portions of the polypeptide chain.

Reason: Out of 20 amino acids, only 12 amino acids can be synthesised by human body.

  1. Assertion: The helical structure of protein is stabilised by intramolecular hydrogen bond between -NH and carbonyl oxygen.

Reason: Sanger's reagent is used for the identification of N-tenninal amino acid of peptide chain.

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Q 36Case study (4 Marks)4 Marks
Read the passage given below and answer the following questions:

The sequence of bases along the DNA and RNA chain establishes its primary structure which controls the specific properties of the nucleic acid. An RNA molecule is usually a single chain ofribose-containing nucleotide. On the basis of X-ray analysis of DNA, J.D., Watson and EH.C. crick (shared noble prize in 1962) proposed a three dimensional secondary structure for DNA. DNA molecule is a long and highly complex, spirally twisted, double helix, ladder like structure. The two polynucleotide chains or strands are linked up by hydrogen bonding between the nitrogeneous base molecules of their nucleotide monomers. Adenine (purine) always links with thymine (pyrimidine) with the help of two hydrogen bonds and guanine (purine) with cytosine (pyrimidine) with the help of three hydrogen bonds. Hence, the two strands extend in opposite directions, i.e., are antiparallel and complimentary.

  1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
  2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
  3. Assertion is correct statement but reason is wrong statement.
  4. Assertion is wrong statement but reason is correct statement.
  1. Assertion: DNA molecules and RNA molecules are found in the nucleus of a cell.

Reason: There are two types of nitrogenous bases, purines and pyrimidines. Adenine (A) and guanine (G) are substituted purines; cytosine (C), thymine (T) and uracil (U) are substituted pyrimidines.

  1. Assertion: In both DNA and RNA, heterocyclic base and phosphate ester linkages are at C-1' and C-5' respectively of the sugar molecule.

Reason: Nucleotides and nucleosides mainly differ from each other in presence of phosphate units.

  1. Assertion: The backbone of RNA molecule is a linear chain consisting of an alternating units of a heterocylic base, D-ribose and a phosphate.

Reason: The segment of DNA which acts as the instruction manual for the synthesis of protein is ribose.

  1. Assertion: The double helical structure of DNA was proposed by Emil Fischer.

Reason: A nucleoside is an N-glycoside of heterocyclic base.

  1. Assertion: In DNA, the complementary bases are, adenine and guanine; thymine and cytosine.

Reason: The phenomenon of mutation is chemical change in DNA molecule.

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Q 37Case study (4 Marks)4 Marks
Read the passage given below and answer the following questions:

Glucose is known as dextrose because it occurs in nature as the optically active dextrorotatory isomer. lt is essential constituent of human blood. The blood normally contains 65 to 110mg of glucose per 100mL (hence named Blood sugar). The level may be much higher in diabetic persons. The urine of diabetic persons also contain considerable amount of glucose. ln combined form, it occurs in cane sugar and polysaccharides such as starch and cellulose.

Glucose has an aldehyde group (-CHO), one primary alcoholic group (-CH2OH) and four secondary alcoholic groups (-CHOH) in their structure. Due to the presence five hydroxyl groups (-OH). glucose undergoes acetylation. Glucose also undergoes oxidation with mild oxidising agents like bromine water as well as with strong oxidising agents like nitric acid. Since glucose is readily oxidised, it acts as a strong reducing agent and reduces Tollen's reagent and Fehling solution. Glucose exists in two crystalline forms: $\alpha$-D-glucose and $\beta$-D-glucose. If either of the two forms is dissolved in water and allowed to stand, the specific rotation of the solution changes gradually, until a constant value is obtained. This change is called mutarotation.

A statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.

  1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
  2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
  3. Assertion is correct statement but reason is wrong statement.
  4. Assertion is wrong statement but reason is correct statement.
  1. Assertion: A diabetic person carries a packet of glucose with him always.

Reason: Glucose increases the blood sugar level almost instantaneously.

  1. Assertion: On oxidation with nitric acid, glucose as well as gluconic acid both yield saccharic acid.

Reason: The pentaacetate of glucose does not react with hydroxylamine indicating the absence of free -CHO group.

  1. Assertion: Glucose reacts with acetyl chloride to form pentaacetyl glucose.

Reason: The formation of pentaacetyl derivative confirms the presence of five -OH groups in glucose.

  1. Assertion: A certain compound gives negative test with ninhydrin and positive test with Benedict's solution, the compound is an amino acid.

Reason: Glucose is a monosaccharide.

  1. Assertion: The rapid interconversion of $\alpha$-D-glucose and $\beta$-D-glucose in solution is known as racemisation.

Reason: Hydrolysis reaction will take place when a mineral acid is treated with sugar.

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