Biomolecules Mind map PDF NEET CBSE CLASS 11

Biomolecules : All the carbon compounds that we get from living tissues are called Biomolecules.

Biomicromolecules : Molecules which have molecular weights less than one thousand dalton. They are also known as monomers. They are found acid soluble fraction.

Biomacromolecules : A biomolecule with molecular weight in the range of ten thousand daltons and above; found in acid insoluble fraction. e.g. polysaccharides, nucleic acids, proteins and lipids.

How to analyse chemical composition of living tissues?

Living tissue are treated with Trichloroacetic acid and then grinded to get Thick Slurry. Then it is filtered through cheese cloth. This gives us two parts - Filterate (Acid soluble pool) and Retentate (Acid insoluble pool).

Primary and secondary metabolites :

Primary metabolites have identifiable functions and play important roles in normal physiological process eg. Amino acids, nitrogenous bases, proteins and nucleic acid.

Secondary metabolites are product of certain metabolic pathways from primary metabolites, eg. carotenoids, drugs, alkaloids, essential oils, rubber, gum, cellulose and resins etc.

Amino acids : Organic compounds containing an amino group and one carboxyl group (acid group) and both these groups are attached to the same carbon atom called α carbon and so they are called amino acids.

Lipids :

Lipids are not strictly macromolecules as their molecular weight do not exceed 800 Da but form a part of the acid insoluble pool.

Water insoluble pool contains mainly C, H, O.

Fats on hydrolysis yield fatty acids.

Fatty acid has a carboxyl group attached to an R group (contains 1 to 19 carbons).

Fatty Acids are of two types -

Saturated : With single bonds in carbon chain, e.g., Palmitic acid, butyric acid. 

Unsaturated : With one or more double bonds, e.g., oleic acid, linoleic acid.

Phospholipids are compound lipids with phosphorus and a phosphorylated organic compound e.g., Lecithin.

Structure of Proteins

(a) Primary structure : Is found in the form of linear sequence of amino acids. First amino acid is called N-terminal amino acid and last amino acid is called C-terminal amino acid.

(b) Secondary structure : Polypeptide chain undergoes folding or coiling which is stabilized-by hydrogen bonding. Right handed helices are seen in protein e.g., fibrous protein in hair, nails.

(c) Tertiary structure : Long protein chain is folded upon itself like a hollow woollen ball. Gives a 3-dimensional view of protein, e.g., myosin.

(d) Quaternary structure : Two or more polypeptides with their foldings and coilings are arranged with respect to each other.

Ezymes : Enzymes are biocatalyst.

 Almost all enzymes are proteins.

 Ribozymes–Nucleic acid that behave like enzymes.

 Has primary, secondary and tertiary structure.

 Active site of an enzyme is a crevice or pocket into which substrate fits.

 Enzymes get damaged at high temperatures.

 Enzymes isolated from thermophilic organisms ( live in high temperatures) are thermostable.

 Enzymes accelerate the reactions many folds.

 Enzymes lower the activation energy of reactions

Co-factors : Enzymes becomes catalytically become active when it binds to non protein constituent called co-factors. Protein portion of enzyme is called apoenzyme.

 Prosthetic group : These are organic compound which tightly bound to the apoenzyme. e. g., Haem is prosthetic group in peroxidase and catalase.

 Coenzyme : These are organic compounds whose association with the apoenzyme is only transient, usually occurring during the course of catalysis. e.g., Coenzyme Nicotinamide adenine dinucleotide (NAD) and NADP contain vitamin niacin.

 Metal ions : Metal ions form coordination bond with side chains at the active site and at the same time form one or more coordination bond with substrate. e.g. zinc in enzyme carboxy peptidase.

Biomolecules are the building blocks of life, and they are essential for all organisms to survive and thrive. Biomolecules are composed of carbon, hydrogen, nitrogen, oxygen, sulphur, and phosphorus. They come in a variety of shapes and sizes and perform a wide range of functions. The four major types of biomolecules are carbohydrates, lipids, proteins, and nucleic acids. 

Carbohydrates are composed of carbon, hydrogen, and oxygen atoms. They are used by organisms as an energy source, and they can be found in plants and animals. Examples of carbohydrates include sucrose, fructose, and glucose. 

Lipids are composed of carbon, hydrogen, and oxygen atoms, but they also contain additional elements such as phosphorus, sulfur, and nitrogen. They are used by organisms as energy storage molecules and are important components of cell membranes. Examples of lipids include triglycerides, phospholipids, and sterols. 

Proteins are composed of amino acid monomers and are essential for the structure and function of cells and tissues. They can be found in all living organisms and can be divided into two categories: structural proteins, which provide physical support and strength, and functional proteins, which are involved in cell signaling and other activities. Examples of proteins include enzymes, hormones, and antibodies. 

Nucleic acids are composed of nucleotides and are the genetic material of all living organisms. DNA and RNA are the two types of nucleic acids, and they are responsible for the transmission of genetic information from one generation to the next. 

Biomolecules are essential for all cellular functions and processes, and understanding the structure and function of these molecules is key to unlocking the mystery of life. In this article, we have discussed the four major types of biomolecules – carbohydrates, lipids, proteins, and nucleic acids – and their roles in living organisms. We have also discussed the structure and function of each type of biomolecule, as well as the importance of understanding their role in the body.

Previous year questions (PYQs) of Chapter Biomolecules -

1. A phosphoglyceride is always made up of

(a) a saturated or unsaturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached

(b) a saturated or unsaturated fatty acid esterified to a phosphate group which is also attached to a glycerol molecule

(c) only a saturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached

(d) only an unsaturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached.

2. Which one of the following biomolecules is correctly characterized?

(a) Lecithin-a phosphorylated glyceride  found in cell membrane.

(b) Palmitic acid - an unsaturated fatty acid with 18 carbon atoms.

(c) Adenylic acid - adenosine with a glucose phosphate molecule.

(d) Alanine amino acid - contains an amino group and an acidic group anywhere in the molecule.

3. Enzymes, vitamins and hormones can be classified into a single category of biological chemicals, because all of these

(a) help in regulating metabolism

(b) are exclusively synthesized in the body of a living organism as at present

(c) are conjugated proteins

(d) enhance oxidative metabolism.

4. Role of an enzyme in reactions is to/as

(a) decrease activation energy

(b) increase activation energy

(c) inorganic catalyst

(d) none of the above.

5. Which one of the following statements regarding enzyme inhibition is correct?

(a) Competitive inhibition is seen when a substrate competes with an enzyme for binding to an inhibitor protein.

(b) Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme.

(c) Non-competitive inhibition of an enzyme can be overcome by adding large amount of substrate.

(d) Non-competitive inhibitors often bind to the enzyme irreversibly.

6. Which one of the following statements is incorrect?

(a) The competitive inhibitor does not affect the rate of breakdown of the enzyme-substrate complex.

(b) The presence of the competitive inhibitor decreases the Km of the enzyme for the substrate.

(c) A competitive inhibitor reacts reversibly with the enzyme to form an enzyme-inhibitor complex.

(d) In competitive inhibition, the inhibitor molecule is not chemically changed by the enzyme.

7. Three of the following statements about enzymes are correct and one is wrong. Which one is wrong?

(a) Enzymes require optimum pH for maximal activity.

(b) Enzymes are denatured at high temperature but in certain exceptional organisms they are effective even at temperatures 80° - 90°C.

(c) Enzymes are highly specific.

(d) Most enzymes are proteins but some are lipids.

8. Consider the following statements.

(A) Coenzyme or metal ion that is tightly bound to enzyme protein is called prosthetic group.

(B) A complete catalytic active enzyme with its bound prosthetic group is called apoenzyme.

Select the correct option.

(a) (A) is false but (B) is true.

(b) Both (A) and (B) are true.

(c) (A) is true but (B) is false.

(d) Both (A) and (B) are false.

9. Which of the following glucose transporters is insulin-dependent?

(a) GLUT IV             (b) GLUT I

(c) GLUT II               (d) GLUT III

10. Which of the following nucleotide sequences contains 4 pyrimidine bases?

(a) GATCAATGC           (b) GCUAGACAA

(c) UAGCGGUAA          (d) Both (b) and (c)

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