Biomolecules Class 11 Notes Biology Chapter 9 - CBSE
Chapter : 9
What Are Biomolecules ?
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Biomolecules
(Organic molecule produced in living cell)
Macromolecule
- Molecular Weight < 1000 Daltons
- Polysaccharide , protein , nucleic acid, lipid
Micromolecule
- Molecular Weight > 1000 Daltons
- Monosaccharide , Amino acids, nucleotides
Average composition of cells
| Component | % of the total cellular mass |
| Water | 70-90 |
| Proteins | 10-15 |
| Carbohydrates | 3 |
| Lipids | 2 |
| Nucleic acids | 5-7 |
| Ions | 1 |
Proteins
It is large, complex molecule that play very important role in our body.
Types Of Proteins
Simple
(made up of only amino acids)
Fibrous
Long, Coiled and Thread like
- Collagen
- Most abundant protein in animal body
- Present in connective tissue
- Threads of collagen known as Tendon
- Elastin
- In connective tissue
- Threads of Elastin known as Ligament
- Keratin
Globular
- Rubisco
- Present in chloroplast.
- Most abundant protein on the earth
- Albumin
- Maintain B.C.O.P
- In milk as Lactoalbumin
- In egg yolk as Ovabumin
- In blood as Serum albumin
- Globin
- Present with Haemoglobin
- Histone protein
- Present with eukaryotic DNA
- In it Lysine and Arginine amino acids are present in more amount.
- Compound
- Derived
Carbohydrate
They are sugar molecules and acts as an energy source, help to control blood glucose and insulin metabolism.
Carbohydrate (Hydrates of carbon, CnH2nOn)
Monosaccharides
(sweet in taste)
- Glucose
- Fructose
- Galactose
Disaccharides
(made by two monosaccharaides)
- Maltose= Glucose + Glucose
- Lactose= Glucose + Galactose
- Sucrose = Glucose + Fructose
Polysaccharides
Polysaccharides (made by thousands of monosaccharaides, also called glycan).
Amino Acids (General Structure, Classification, Significance)
Based on structure & chemical nature
- Aliphatic side chain Glycine, Alanine, Valine, Leucine, isoleucine
- OH group containing AA Serine, Threonine
- “S” containing AA cysteine, Methionine
- Acidic amino acids Aspartic acid, Asparagine, Glutamic acid, Glutamine
- Basic amino acids Histidine, Arginine, Tyrosine, Lysine
- Aromatic amino acids Phenylamine. Tyrosine, Tryptophan
- Imino acids Proline
Based on Polarity
- Hydrophilic (polar)
- Hydrophobic (Non-polar)
Based on Metabolic fate
- Glucogenic
- Ketogenic
- Both
Nutritional Classification
- Essential
- Phenylalanine, Valine Tryptophan PVT.
- Threonine Isoleucine Methionine TIM
- Histidine Arginine Leucine Lysine HALL
- Nonessential
- Semi essential
Lipids
They are fatty compounds that perform a variety of functions in our body. They are part of the cell membranes and help to control what goes in and out of the cells.
Nucleic Acid
Nucleic acids are polynucleotides. A nucleic acid has three chemical distinct components-heterocyclic compound (nitrogenous base), polysaccharides (ribose/ deoxyribose sugar) and phosphate or phosphoric acid.
Nitrogenous Base
Purines
- Adenine
- Guanine
Pyrimidines
- Cytosine
- Thymine
- Uracil
Nucleic Acids
RNA
Three types
- mRNA
- rRNA
- tRNA
DNA
- Genetic material in eukaryotes
- Helical chains are bonded by hydrogen bonds between the nitrogenous bases
- Double bonds between adenine and thymine
- Triple bonds between guanine and cytosine
Base in Nucleic Acids
Pyrimidine
Purine
Enzymes
Proteinaceous substances which are capable of catalyzing chemical reactions of biological origin without themselves undergoing any change. They are commonly referred as biocatalysts. Nucleic acids that behave like enzymes are called ribozymes.
$$\text{E + S} \rightleftharpoons \text{ES} \rightleftharpoons \text{EP} \rightleftharpoons \text{E + P} $$
Factor That Affect Enzyme Activity
- Temperature
- pH
- Concentration of enzymes and substrates
- Inhibitors
Types of Enzymes
- Oxidoreductases
- Transferases
- Hydrolases
- Lyases
- Isomerases
- Ligases
Co-Factor
Non- protein constituents that are bound to the enzyme and make the enzyme catalytically active.
Co-Enzyme
Compounds that bind to the enzyme transiently during the course of the reaction.
Prosthetic Groups
Organic substances that are bound very tightly to the enzyme.
