Careers360 Logo
NCERT Exemplar Class 11 Biology Solutions Chapter 9 Biomolecules

NCERT Exemplar Class 11 Biology Solutions Chapter 9 Biomolecules

Edited By Priyanka kumari | Updated on Aug 22, 2022 03:00 PM IST

Exams are around the corner and all the Class 11 students are looking for relevant and quality content for preparation. NCERT Exemplar Class 11 Biology solutions chapter 9 is a very important chapter from the exam point of view. And if you wish to score high then you cannot afford to leave any topic from NCERT. Students are advised to refer to this best study material for scoring high and easy understandability of concepts. NCERT exemplar Class 11 Biology solutions chapter 9 PDF download is useful if you want to access the content offline. In this article, you will find all the relevant details regarding the NCERT Exemplar Class Biology chapter 9.

Also, check NCERT Class 11 Biology Solutions of Other Chapters.

NCERT Exemplar Class 11 Biology Chapter 9 Biomolecules:

Multiple Choice Questions:

Question:1

It is said that the elemental composition of living organisms and that of inanimate objects (like earth's crust) are similar in the sense that all the major elements are present in both. Then what would be the difference between these two groups?

Choose the correct answer from among the following: -

a. Living organisms have more gold in them than inanimate objects
b. Living organisms have more water in their body than inanimate objects
c. Living organisms have more carbon, oxygen, and hydrogen per unit mass than inanimate objects.
d. Living organisms have more calcium in them than inanimate objects.

Answer:

Option (c) is the answer.
Explanation:
Carbon, oxygen, and hydrogen constitute the main component of organic compounds. So this will be the exact clue for having more amount of carbon, oxygen and hydrogen per unit mass than an inanimate object.

Question:2

Many elements are found in living organisms, either free or the form of compounds. Which of the following is not found in living organisms?
a. Silicon
b. Magnesium
c. Iron
d. Sodium

Answer:

Solution:
Option (a) is the answer.
Explanation:
Elements other than Silicon, are all important constituents of a living organism. Living organism have a significant constituent requirement of Iron, Magnesium and Sodium.

Question:3

Aminoacids have both an amino group and a carboxyl group in their structure. Which one of the following is an amino acid?
a. Formic acid
b. Glycerol
c. Glycolic Acid
d. Glycine

Answer:

Solution:
Option (d) is the answer.
Explanation:
From the list of the amino acid, most of them end with “ine.” So, Glycine is the correct answer.

Question:4

An amino acid under certain conditions has both positive and negative charges simultaneously in the same molecule. Such a form of amino acid is called

a. Acidic form
b. Basic form
c. Aromatic form
d. Zwitterionic form

Answer:
Option (d) is the answer.
Explanation:
Going through all the options, we see that the word Zwitterionic is German form which means neutral with both negative and positive charge within it.

Question:5

Which of the following sugars have the same number of carbon as present in glucose?
a. Fructose
b. Erythrose
c. Ribulose
d. Ribose

Answer:

Option (a) is the answer.
Explanation:
Among the options, it is fructose which falls in the category of monosaccharides. In fact, glucose and fructose both fall in this category, and they have 6 atoms of carbon.

Question:6

An acid-soluble compound formed by phosphorylation of nucleoside is called:
a. Nitrogen base
b. Adenine
c. Sugar phosphate
d. Nucleotide

Answer:
Option (d) is the answer.
Explanation:
When one adds a phosphate group to a nucleoside, one gets another acid-soluble biomolecule called Nucleotide.

Question:7

When we homogenise any tissue in an acid, the acid-soluble pool represents
a. Cytoplasm
b. Cell membrane
c. Nucleus
d. Mitochondria

Answer:
Option (a) is the answer.
Explanation:
When we homogenise any tissue in acid, the acid-soluble pool it represents Cytoplasm.It is because organic compounds are found in the acid-soluble pool. Cytoplasm contains various soluble compound and hence called a soluble acid pool.

Question:8

The most abundant component of living organisms is
a. Protein
b. Water
c. Sugar
d. Nucleic acid

Answer:

Option (b) is the answer.
Explanation:
Going by constituent present in the human body, water constitutes 70% of the entire body weight.

Question:9

A homopolymer has only one type of building block called monomer repeated ‘n’ number of times. A heteropolymer has more than one type of monomer. Proteins are heteropolymers usually made of
a. 20 types of monomers
b. 40 types of monomers
c. 30 types of monomers
d. only one type of monomer

Answer:

Option (a) is the answer.
Explanation:
Going by facts, Proteins consists of 20 types of monomers

Question:10

Proteins perform many physiological functions. For example, some functions as enzymes. Which of the following represents an additional function that some proteins discharge?
a. Antibiotics
b. Pigment conferring colour to skin
c. Pigments making colours of flowers
d. Hormones

Answer:

Option (d) is the answer.
Explanation:
Antibiotics that have enzymes present do not possess any protein, but a lot of antibodies might not have protein or enzymes. Moreover, pigments are not proteins.

Question:11

Glycogen is a homopolymer made of
a. Glucose units
b. Galactose units
c. Ribose units
d. Aminoacids

Answer:
Option (a) is the answer.
Explanation:
Glycogen is a homopolymer made of Glucose units. This is because the glyo in glycose means that it is derived from glucose.

Question:12

The number of ‘ends’ in a glycogen molecule would be
a. Equal to the number of branches plus one
b. Equal to the number of branch points
c. One
d. Two, one on the left side and another on the right side

Answer:
Option (d) is the answer.
Explanation:
One should remember that the number of ‘ends’ in a glycogen molecule would be equal to the number of branches plus one.

Question:13

The primary structure of a protein molecule has
a. Two ends
b. One end
c. Three ends
d. No ends

Answer:

Option (a) is the answer.

Question:14

Which of the following reactions is not enzyme-mediated in the biological system?
a. Dissolving CO2 in water
b. Untwining the two strands of DNA
c. Hydrolysis of sucrose
d. Formation of peptide bond

Answer:
Option (a) is the answer.

Very Short Answer Type Questions:

Question:1

Medicines are either man-made (i.e., synthetic) or obtained from living organisms like plants, bacteria, animals etc. and hence the latter are called natural products. Sometimes natural products are chemically altered by man to reduce toxicity or side effects. Write against each of the following whether they were initially obtained as a natural product or as a synthetic chemical.

a. Penicillin ___________________________
b. Sulfonamide ___________________________
c. Vitamin C ___________________________
d. Growth Hormone ___________________________

Answer:
A. Penicillin - Natural product
B. Sulfonamide- Synthetic product
C. Vitamin C - Natural product
D. Growth Hormone - Natural product

Question:2

Select an appropriate chemical bond among ester bond, glycosidic bond,peptide bond and hydrogen bond and write against each of the following.
a. Polysaccharide ___________________________
b. Protein ___________________________
c. Fat ___________________________
d. Water ___________________________

Answer:
a. Polysaccharides – Glycosidic bond
b. Protein - Peptide bond
c. Fats - Ester bond
d. Water - H-bond

Question:3

Write the name of any one amino acid, sugar, nucleotide, and fatty acid.

Answer:

Nucleotide- Adenosine

  1. Amino acid- Glycine
  2. Fatty acid- Oleic acid
  3. Sugar- Glucose

Question:5

How are prosthetic groups different from co-factors?

Answer:

Enzymes are made up of a single or multiple polypeptide chains. But in several cases,there are non-protein constituents that are bound to the enzyme, they are known as co-factors, which makes the enzyme catalytically active. Co-factors can be of three types, i.e. enzymes, prosthetic groups, and metal ions.
Co-factors and prosthetic groups differ in the sense that prosthetic groups are tightly bound to the apoenzyme.

Question:7

Starch, Cellulose, Glycogen, Chitin are polysaccharides found among the following. Choose the one appropriate and write against each.

a) Cotton fibre __________________________
b) Exoskeleton of cockroach __________________________
c) Liver __________________________
d) Peeled potato __________________________

Answer:

a) Cotton fibre - Cellulose
b) Exoskeleton of cockroach - Chitin
c) Liver - Glycogen
d) Peeled Potato - Starch

Short Answer Type Questions:

Question:1

Enzymes are proteins. Proteins are long chains of amino acids linked to each other by peptide bonds. Amino acids have many functional groups in their structure. These functional groups are, many of them at least, ionisable. As they are weak acids and bases in chemical nature, this ionisation is influenced by the pH of the solution. For many enzymes, activity is influenced by the surrounding pH. This is depicted in the curve below, explain.


Answer:

Explanation of this question can be summed up as below:
1. This variation triggers changes in charge of amino acid.
2. Dependence of enzyme on pH is because of the existence of charged amino acid at its active site.
3. The enzymatic activity reduces when pH is fewer than the optimal pH.

Question:2

Is rubber a primary metabolite or a secondary metabolite? Write four sentences about rubber.

Answer:

Rubber is actually a secondary metabolite because the of its unknown function in plants physiology

The following can be further said about rubber being of significance to humans: -
1. Rubber is for human commercial importance.
2. It undergoes the process of vulcanisation to be of use to humans.
3. It does not have any known function in plants, so it is called a secondary metabolite.
4. It is used for the production of various products like tyres, gloves, toys etc.

Question:4

Nucleic acids exhibit secondary structure, justify with example.

Answer:

DNA and RNA are known to exist in the form of a helix. Since a long chain of polymer is arranged as a helix. And a helix is called secondary structure.

RNA forms a single- stranded helical form while DNA forms a double helix. As a helix is regarded to be a secondary structure, therefore, nucleic acids are present in the secondary structure.

Question:5

Comment on the statement “living state is a non-equilibrium steady-state to be able to perform work”.

Answer:

Metabolic reactions in a biological system, are always going on wherein influx and efflux of metabolites take place regularly. Hence it will be appropriate to state that the living state is a non-equilibrium steady state which is able to perform work.

Long Answer Type Questions:

Question:1

Formation of the enzyme-substrate complex (ES) is the first step in catalysed reactions. Describe the other steps until the formation of the product.

Answer:

The first step in catalysed reactions is the formation of the enzyme-substrate complex (ES). The further steps are described below:

1. As described above, in the first step, the substrate binds at the active site that, in turn, results in the formation of the enzyme-substrate complex.
2. The second stage is the transient stage which is the altered structure state. In the absence of enzymes, the activation energy required would have been higher. But as the enzyme is present, the reaction takes place even with less amount of energy.
3. In the final stage, which is the product formation stage, the product is formed, and the system’s potential energy reduces drastically. Then the enzyme is free to bind with other substrate.

Question:2

What are the different classes of enzymes? Explain any two with the type of reaction they catalyse.

Answer:

There are six different enzyme classes which can be categorised as Lysates, Isomerase, Oxidoreductase, Transferase, Hydrolase, and Ligase.

a) Oxidoreductase:
These enzymes assist with the process of simultaneous oxidation as well as reduction of two substrates.
S reduced + S’reduced → S oxidised + S’ oxidised

b) Hydrolases:
Hydrolysis of a molecule is facilitated by these enzymes.
Sucrose → Glucose + Fructose

Question:3

Nucleic acids exhibit secondary structure. Describe through Watson Crick Model.

Answer:

It is known that DNA and RNA exist in the form of a helix. Since a long chain of polymer is arranged as a helix. And a helix is called secondary structure. RNA forms a single-stranded helical form while DNA forms a double helix. It is known that helix is regarded as a secondary structure; thus, in secondary structure, nucleic acids exist.

Arranged in a double helix, two polypeptide chains make up the DNA. Nitrogenous bases are present towards the inner side in the DNA while the backbone is made up of sugar-phosphate. The nitrogenous bases connect with each other through H bonds.This H bond provides stability to the helix.


Question:4

What is the difference between a nucleotide and nucleoside? Give two examples of each with their structure.

Answer:

The difference between a nucleotide and nucleoside can be described as below:
Talking about Nucleotides, they are formed of nucleoside and phosphate group and are the monomers of nucleic acid. As a matter of fact, nucleosides are the constituent of nucleotides. Some examples of nucleosides are guanosine, thymidine, adenosine, uridine and cytidine. Some examples of nucleotides are guanylic acid, uridylic acid adenylic acid, thymidylic acid, and cacodylic acid.


Question:5

Describe various forms of lipid with a few examples.

Answer:

Lipids are classified into three categories:
1. Simple lipids: - Simple lipids are the esters of fatty acids and can be further divided into: -

- Waxes: - Esters of high fatty acids with alcohol.
- Fats: - Eaters of higher fatty acids with glycerol.
For example Triglycerol etc.
2. Compound lipids: - Compound lipids are those lipids that contain other groups as well in addition to alcohol and glycerol. They can be further categorised into: -

  1. Sphingo Lipids
  2. Glycerophospholids
  3. Glycolipids

For example: Cephalin, Gangliosides etc.

3. Derivatives lipids: - When lipids consist of hydrocarbon ring and the long chain of hydrocarbons they are called derivatives
For Examples: Steroids, Cholesterol etc.

Introduction of NCERT Exemplar Class 11 Biology Solutions Chapter 9:

Class 11 Biology NCERT exemplar solutions chapter 9 is about ‘biomolecules’. Biomolecule refers to the molecule which is produced by a living organism. Biomolecules include lipids, carbohydrates, proteins, and nucleic acids. They further consist of large macromolecules and small molecules. This chapter explains the concept of Biomolecules in detail. The students from this chapter will learn how to analyze chemical composition. The chapter is an important topic so understanding the chapter is really important.

Major Subtopics in NCERT Exemplar Class 11 Biology Solutions Chapter 9:

Following are the major subtopics in NCERT exemplar class 11 Biology chapter 9 solutions

  • How to Analyze Chemical Composition?
  • Primary and Secondary Metabolites
  • Biomacromolecules
  • Proteins
  • Polysaccharides
  • Nucleic Acids
  • Structure of Proteins
  • Nature of Bond Linking Monomers in a Polymer
  • Dynamic State of Body Constituents-Concept of Metabolism
  • Metabolic Basis for Living
  • The Living State
  • Enzymes

NCERT Exemplar Class 11 Biology Solutions Chapter 9 - Learning Outcome:

This chapter is important for those who wish to pursue a career in the field of medicine. Biomolecules is used in medicine. And also, this chapter is important for biology, biotechnology, chemistry, etc and particularly important for scientific research. So, you will be learning a lot from Class 11 Biology NCERT exemplar solutions chapter 9 so it is advisable to not to skip any topic from the chapter.

NCERT Exemplar Class 11 Biology Solutions Chapter Wise:

Important Topics in NCERT Exemplar Class 11 Biology Solutions Chapter 9:

In order to know the important topics of Chapter 9 the students can check the previous year question papers. Previous year question papers can be really helpful. Previous year question papers will let you know the important questions and topics that are constantly being asked in the exam.

NCERT Exemplar Class 11 Solutions:

Check Chapter-Wise Solutions of Questions Given in Book:

Also, Read NCERT Solution subject wise

NEET Highest Scoring Chapters & Topics
Most Scoring concepts For NEET (Based On Previous Year Analysis)
Download EBook

Must Read NCERT Notes subject wise

Also Check NCERT Books and NCERT Syllabus here

Frequently Asked Question (FAQs)

1. What are the properties of enzymes covered in the Chapter 9 of NCERT Solutions for Class 11 Biology?

The properties of enzymes that are covered in the Chapter 9 of NCERT Solutions for Class 11 Biology are as following  –

  • The enzymes have higher molecular weight and are complex macromolecules.
  • The biochemical reactions which are involved in the cell are catalyzed by the enzymes, assisting in breaking down larger molecules into simpler molecules.
  • Enzymes only accelerate the reaction.
  • The rate of biochemical reaction gets affected by the enzymes and does not influence the direction of the reaction.
  • Enzymes are action specific.
  • The maximum activity of enzymes is observed at 6-8 pH level.
2. From where can I download NCERT biology book for class 11 and 12

You can download the book directly from the NCERT eBook website.

3. What are the fundamental concepts that I can learn from the Chapter 9 of NCERT Exemplar Solutions for Class 11 Biology?

Some of the fundamental concepts which you can learn from the Chapter 9 of NCERT Solutions for Class 11 Biology are as following –

  • Primary And Secondary Metabolites, 
  • Biomacromolecules, 
  • Proteins, 
  • Polysaccharides, 
  • Nucleic AcidsStructure Of Proteins, 
  • Nature Of Bond Linking Monomers In A Polymer, etc.
4. Why should you refer to the NCERT Exemplar Solutions for Class 11 Biology Chapter 9?

The NCERT Solutions are prepared by the subject matter experts with utmost care and perfection. The solutions are concept focused, so as to increase the conceptual knowledge of the students.

Articles

Upcoming School Exams

View All School Exams
Get answers from students and experts

A block of mass 0.50 kg is moving with a speed of 2.00 ms-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

Option 1)

0.34\; J

Option 2)

0.16\; J

Option 3)

1.00\; J

Option 4)

0.67\; J

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times.  Assume that the potential energy lost each time he lowers the mass is dissipated.  How much fat will he use up considering the work done only when the weight is lifted up ?  Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate.  Take g = 9.8 ms−2 :

Option 1)

2.45×10−3 kg

Option 2)

 6.45×10−3 kg

Option 3)

 9.89×10−3 kg

Option 4)

12.89×10−3 kg

 

An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

Option 1)

2,000 \; J - 5,000\; J

Option 2)

200 \, \, J - 500 \, \, J

Option 3)

2\times 10^{5}J-3\times 10^{5}J

Option 4)

20,000 \, \, J - 50,000 \, \, J

A particle is projected at 600   to the horizontal with a kinetic energy K. The kinetic energy at the highest point

Option 1)

K/2\,

Option 2)

\; K\;

Option 3)

zero\;

Option 4)

K/4

In the reaction,

2Al_{(s)}+6HCL_{(aq)}\rightarrow 2Al^{3+}\, _{(aq)}+6Cl^{-}\, _{(aq)}+3H_{2(g)}

Option 1)

11.2\, L\, H_{2(g)}  at STP  is produced for every mole HCL_{(aq)}  consumed

Option 2)

6L\, HCl_{(aq)}  is consumed for ever 3L\, H_{2(g)}      produced

Option 3)

33.6 L\, H_{2(g)} is produced regardless of temperature and pressure for every mole Al that reacts

Option 4)

67.2\, L\, H_{2(g)} at STP is produced for every mole Al that reacts .

How many moles of magnesium phosphate, Mg_{3}(PO_{4})_{2} will contain 0.25 mole of oxygen atoms?

Option 1)

0.02

Option 2)

3.125 × 10-2

Option 3)

1.25 × 10-2

Option 4)

2.5 × 10-2

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Option 1)

decrease twice

Option 2)

increase two fold

Option 3)

remain unchanged

Option 4)

be a function of the molecular mass of the substance.

With increase of temperature, which of these changes?

Option 1)

Molality

Option 2)

Weight fraction of solute

Option 3)

Fraction of solute present in water

Option 4)

Mole fraction.

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

Option 1)

twice that in 60 g carbon

Option 2)

6.023 × 1022

Option 3)

half that in 8 g He

Option 4)

558.5 × 6.023 × 1023

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

Option 1)

less than 3

Option 2)

more than 3 but less than 6

Option 3)

more than 6 but less than 9

Option 4)

more than 9

Back to top