NCERT Notes for Class 11 Biology Chapter 9 Biomolecules- Download PDF Notes

CBSE Quick Revision Notes Class 11 Biology Chapter 9: The NCERT chapter 9 Biomolecules provide you with insight into the components of living organisms. The NCERT Class 11 Biology Chapter 9 notes cover a brief outline of the chapter biomolecules. The main topics covered in Biomolecules NCERT Class 11 Biology Notes are: definition of biomolecules, how to analyse the chemical composition, primary and secondary metabolites, biomacromolecules, carbohydrates, lipids, Nucleic Acids, proteins, monomers, Metabolic process, living state, enzyme, nature of enzyme activity, factors affecting enzymes, cofactors. Class 11 biology chapter 9 notes cover all the important concepts of this chapter in easy and simple language. Having revision notes and NCERT Solutions for Class 11 Biology Chapter 9 handy is crucial to saving you time. The NCERT Class 11 Biology chapter 9 notes PDF can be downloaded through the link given below.

Biomolecules Class 11 notes Biology Chapter 9 also covers all the important headings of the NCERT Textbook that are useful in various competitive exams. Chapter 9 Biomolecules Notes help you revise these major concepts given in the NCERT Book in a short period of time during CBSE Board exam preparation. Download the CBSE Notes for Class 11 Biology Chapter 9 PDF to use them offline anywhere. They can be downloaded through the link. Students must go through each topic in Biomolecules Class 11 Notes Biology in the easiest and most effective way possible with the help of NCERT Notes for Class 11. Check the given Class 11 Biology Notes Chapter 9 Biomolecules PDF for quick revision. Biology Biomolecules notes will take you on a journey through the different types of biomolecules found on this earth.

Also, students can refer to:

• NCERT Solutions for Class 11 Biology Chapter 9 Biomolecules
• NCERT Exemplar for Class 11 Biology Chapter 9 Biomolecules

NCERT Class 11 Biology Chapter 9 Biomolecules Notes

Biomolecules

• These are elements of which living organisms are made up of. It is somewhat similar to the earth's crust components.
• The study of various organic and inorganic molecules in a cell and their role in the physiological process of the cell is called biochemistry.

This table depicts the comparison between elements present in living and nonliving matter.

How to Analyze Chemical Composition?

Trichloroacetic acid is used to fractionate Biomolecules. We get 2 fractions after treatment.

Acid soluble fraction:- In the filtrate

• Contain all micro molecules except lipids.

Acid insoluble fraction

• Contain macromolecular and lipids.

Primary and Secondary Metabolites

Primary Metabolites - These are the metabolites that have direct involvement in growth, development, and reproduction.

Example:- Amino acid

Secondary Metabolite - They are not directly involved in growth and development.

Example:- Alkaloids, Toxins, Drugs

Types of Biomolecule

Biomolecules Are of 2 types

Biomacromolecules:- Compounds having a molecular weight of less than 1000 dalton are called biomacromolecules.

Example:- Amino acid

Biomacromolecule: Compounds having a molecular weight of range of 10 thousand daltons ( except lipids ) are called biomacromolecules.

Example:- carbohydrates

Carbohydrates

• They are the biomacromolecules made up of C, H, O
• Commonly called saccharides.

• It can be monosaccharides, oligosaccharides, polysaccharides

Different Forms of Glucose

Lipids

• They are micromolecules that yield high energy.

• It is of 3 types:-

• Triglycerides are composed of Glycerol + 3 Fatty acid

Fatty Acids are Further Classified As:

Differences between Saturated and Unsaturated Fatty Acids:

Saturated	Unsaturated
CnH2nO is a general formula. n = number of carbon	CnH2n-2xO2 is a general formula. n = no of C x = no of the double bond
n= 16 Palmitic Acid n= 18 Stearic Acid n= 20 Arachidic Acid	n =18 ,x=1 ,Oleic, Also called MUFA( mono unsaturated fatty acids) n= 18, x=2. , Linoleic n= 18,x =3, Linolenic

Examples of Triglycerides are:-

Fat

• It contains saturated fatty acid.

• Remain solid at room temperature

• Tripalmitin, Tristeric are examples of fat.

Oil

• It contains unsaturated fatty acids.

• Remain liquid at Room temperature.

• Triolein , Gingelly seed are examples of oil

Amino Acid and Functions

• They are micromolecules.
• It has 3 groups- R group, COOH, NH₂ attached to the alpha carbon.

• All amino acids are optically active except glycine.

• They are small, colorless crystalline solids
  They are soluble in water, insoluble in organic solvents. There are 20 amino acids.

Function

• Glycine is the precursor of Haeme.

• Tyrosine is the precursor of Thyroxine, Melanin

• Tryptophan is the precursor of Niacin.

• Some amino acids act as neurotransmitters. Eg: GABA

Protein and Functions

• They are Heteropolymer.

• 2 Amino acids are linked by peptide bonds.

• The most abundant protein in the animal world is Collagen.

• Most abundant protein in the biosphere is - RUBISCO.

• They are classified into 4 types on the basis of folding complexity.

Functions

• Glycoprotein is present in cell membranes.
• Phloem protein is involved in the transportation of nutrients.
• Helps in storage of oxygen . example - Myoglobin
• They act as a regulatory protein in muscle.
• Streptokinase is a clot buster.
• Fibrinogen helps in blood clotting.

Nucleic Acid

• They are composed of Nitrogenous bases + pentose sugar + phosphate

Nitrogenous bases are of 2 type

• Purine:- double-ringed

  • Example- Adenine, Guanine

• Pyrimidine:- They are single-ringed.

  • Example:- Thymine, Uracil, cytosine

Pentose Sugar

• Ribose

• Deoxyribose

Nucleoside= Sugar + Base

Nucleotide = Sugar + Base + phosphate

Examples of nucleic Acids are DNA, RNA

DNA( Deoxyribose Nucleic Acid)

• Double Helix Structure of DNA cis described by Watson and Crick.

• Bases are attached to sugar N- glycosidic bond in 3' to 5' direction.( 3' C of nucleotide to 5'C of sugar)

• Phosphates are attached to sugar by phosphodiester bonds.

RNA (Ribonucleic Acid)

• RNA is the genetic material of viruses.
• In cellular organization, it helps in protein synthesis.
• In RNA, uracil is found instead of cytosine.

Metabolic Basis for Living

Metabolism = Catabolism + Anabolism

• Catabolic pathway - Pathways that lead to degradation of compounds.

• Anabolic pathway - pathway which leads to the formation of compounds.

Enzyme

• Term enzyme was given by Kuhne.

• Enzymes are bio catalysts made up of protein ( exception -Ribozyme).

• Enzymes are thermolabile..ie..they degrade at high temperature.

Chemical Reactions

• Enzymes are used to catalyse inorganic reactions.

Example:- Carbonic amylase accelerate the reaction by 10 million times

How do Enzymes Bring About Such a High Rate of Chemical Conversations.?

• Enzymes have active sites..ie..sites for holding the substrate.

• Then convert that substrate into a product by different transition states.

S - P

S ...> ES ....> P+ E Action of enzyme

S= substrate P= product

• Enzymes lower the activation energy.

• Maximum Binding energy is released due to maximum interaction between enzyme and substrate, which ultimately lowers the activation energy.

Nature of Enzyme Action

E = enzyme P = product

S = substrate

• Substrate get bind to the active site of an enzyme to form ES complex

ES = enzyme-substrate complex

• This binding leads to shape alteration of active sites.

E + S forms ES COMPLEX..and then EP complex

• Then, enzymes get separated out leaving the product.

Factors Affecting Enzyme Activity

Temperature:

• At optimum temperature, the enzyme shows maximum binding.

• The optimum temperature of enzymes is 25°C - 40°C.

• Enzyme activity varies with temperature as shown in the graph.

PH:

• Each enzyme has its optimum ph for its maximum functioning.

• Example:- pepsin has an optimum ph of 1.5 - 2.5

• Trypsin has an optimum ph of 7.5 - 8.5

Substrate Concentration:

• With the fixed molecules of an enzyme, the rate of reaction or velocity increases with the increase of substrate up to a particular limit.

• Km value - It is the substrate concentration at which enzymes attain half of their max velocity.

• Km is inversely proportional to the affinity of the enzyme with its substrate.

Inhibitors:

• They are the structure resembling the substrate

• Enzymes are sensitive to these inhibitors, thus they affect binding.

• They are of many kinds: Example; Competitive inhibitors, non-competitive inhibitors, Allosteric inhibitors

Classification and Nomenclature of Enzyme

• Enzyme commission has developed a rule for naming enzymes.

• Enzymes are classified according to the chemical reaction it catalyses.

EC numbers are 4-digit numbers given to each enzyme.

• 1st no. denote - major class

• 2 nd number denote- sub class

• 3 rd no. denote - sub sub class

• 4 th no. denotes - the serial number in sub sub class .

• The first number, denoting class can be classified into 6 groups

EC1

• OXIDOREDUCTASE

• Example- oxidases, oxygenases

EC2

• TRANSFERASES

• Example:- Kinases

EC3

• HYDROLASES

• Example - Peptidases

EC4

• LYASES

• Example - Aldolases

EC5

• ISOMERASES

• Example - Mutase

EC-6

• LIGASES

• Example- Carboxylases

Co- Factors

Enzymes are of 2 type

• Simple

• Conjugate

The Conjugate Enzyme Has 2 Parts:

• Protein part called Apoenzyme

• Non-protein part called Cofactors. These cofactors can be organic and loosely bound called Coenzyme.

Example- NAD has vitamin niacin

• Cofactors that are organic and tightly bound are called a prosthetic group.

Eg- Haeme in peroxidase.

Key

NCERT Class 11 chapter 9 Biomolecules contains the overview of element founds in different living organisms and their function. Also what is the availability of that elements in non livings and their functions.

Chapter-Wise NCERT Class 11 Notes Biology

Subject Wise NCERT Exemplar Solutions

• NCERT Exemplar Class 11 Solutions
• NCERT Exemplar Class 11 Maths
• NCERT Exemplar Class 11 Physics
• NCERT Exemplar Class 11 Chemistry
• NCERT Exemplar Class 11 Biology

Significance of NCERT Class 11 Biology Chapter 9 Notes

• NCERT Class 11 Biology chapter 9 notes pdf download focus on the important points regarding the different biomolecules in the earth. It is a very basic topic of biology subject.
• Class 11 Biology chapter 9 notes pdf download will help students in getting good marks in their exams.
• Class 11 Biomolecules notes help students in getting a revision for cracking the exams NEET and JEE Main exams.
• The notes for Class 11 Biology chapter 9 will help students to study in the offline mode.
• The comparative analysis of different biomolecules is also covered in the CBSE Class 11 Biology chapter 9 notes NCERT Class 11 chapter 9.

Subject Wise NCERT Solutions

• NCERT Solutions for Class 11 Mathematics
• NCERT Solutions for Class 11 Chemistry
• NCERT Solutions for Class 11 Physics

• NCERT Solutions for Class 11 Biology