1. NCERT Solutions for Class 12 Chemistry Chapter 14
  2. NCERT Solutions Class 12 Chemistry Chapter 14 Biomolecules - Free Download
  3. Biomolecules..Ncert
  4. CBSE Class 11 Biology NCERT Solutions: Chapter 9, Biomolecules

systems are made up of various complex biomolecules like carbohydrates, proteins, nucleic acids, lipids, etc. Proteins and carbohydrates are essential. BIOMOLECULES. In higher classes you will learn about how to analyse a living tissue sample and identify a particular organic compound. It will suffice to. Biomolecules: All the carbon compounds that we get from living tissues. Micromolecules: Molecules which have molecular weights less than one thou- sand.

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Biomolecules Ncert Pdf

NCERT Solutions Class 12 Chemistry Chapter 14 Environmental Chemistry Download in Pdf. (Visit for all ncert solutions in text and videos, CBSE Biomolecules are the organic compounds which form the basis of life, i.e., they build. NCERT Class 12 Chemistry Biomolecules. Download NCERT Chapters and Books in pdf format. Easy to print and read. Copies of these textbooks may be.

Pentaacetyl glucose does not react with hydroxyl amine. This shows the absence of —CHO group and hence the presence of ring structure. Cyclic structure of glucose: Cyclic structure of fructose: Haworth representation of fructose Glycosidic linkage: The oxide linkage formed by the loss of a water molecule when two monosaccharides are joined together through oxygen atom is called glycosidic linkage. Since the reducing groups of glucose and fructose are involved in glycosidic bond formation, sucrose is a non-reducing sugar. The free aldehyde group can be produced at C1 of second glucose in solution and it shows reducing properties so it is a reducing sugar. The linkage is between C1 of galactose and C4 of glucose. Hence it is also a reducing sugar. Haworth projection of lactose: Starch: It is a polymer of -glucose and consists of two components — Amylose and Amylopectin. It is a straight chain polysaccharide composed only of -D-glucose units which are joined by glycosidic linkage between C1 of one glucose unit and C4 of the next glucose unit. Glycogen: The carbohydrates are stored in animal body as glycogen. It is also known as animal starch because its structure is similar to Amylopectin.

Similarly, a ketone group is denoted by the prefix keto-. Consumed fructose and glucose have different rates of gastric emptying, are differentially absorbed and have different metabolic fates, providing multiple opportunities for 2 different saccharides to differentially affect food intake.

Disaccharides are formed when two monosaccharides, or two single simple sugars, form a bond with removal of water. They can be hydrolyzed to yield their saccharin building blocks by boiling with dilute acid or reacting them with appropriate enzymes. Polysaccharides are polymerized monosaccharides, or complex carbohydrates. They have multiple simple sugars.

Examples are starch , cellulose , and glycogen. They are generally large and often have a complex branched connectivity.

Because of their size, polysaccharides are not water-soluble, but their many hydroxy groups become hydrated individually when exposed to water, and some polysaccharides form thick colloidal dispersions when heated in water. It successfully discriminated three brands of orange juice beverage.

After cellulose, lignin is the second most abundant biopolymer and is one of the primary structural components of most plants. It contains subunits derived from p-coumaryl alcohol , coniferyl alcohol , and sinapyl alcohol [13] and is unusual among biomolecules in that it is racemic.

The lack of optical activity is due to the polymerization of lignin which occurs via free radical coupling reactions in which there is no preference for either configuration at a chiral center. Lipids[ edit ] Lipids oleaginous are chiefly fatty acid esters , and are the basic building blocks of biological membranes.

NCERT Solutions for Class 12 Chemistry Chapter 14

Another biological role is energy storage e. Most lipids consist of a polar or hydrophilic head typically glycerol and one to three nonpolar or hydrophobic fatty acid tails, and therefore they are amphiphilic. Fatty acids consist of unbranched chains of carbon atoms that are connected by single bonds alone saturated fatty acids or by both single and double bonds unsaturated fatty acids.

The chains are usually carbon groups long, but it is always an even number. For lipids present in biological membranes, the hydrophilic head is from one of three classes: Glycolipids , whose heads contain an oligosaccharide with saccharide residues.

Phospholipids , whose heads contain a positively charged group that is linked to the tail by a negatively charged phosphate group. Sterols , whose heads contain a planar steroid ring, for example, cholesterol. Other lipids include prostaglandins and leukotrienes which are both carbon fatty acyl units synthesized from arachidonic acid. They are also known as fatty acids Amino acids[ edit ] Amino acids contain both amino and carboxylic acid functional groups.

In biochemistry , the term amino acid is used when referring to those amino acids in which the amino and carboxylate functionalities are attached to the same carbon, plus proline which is not actually an amino acid. Modified amino acids are sometimes observed in proteins; this is usually the result of enzymatic modification after translation protein synthesis. For example, phosphorylation of serine by kinases and dephosphorylation by phosphatases is an important control mechanism in the cell cycle.

Only two amino acids other than the standard twenty are known to be incorporated into proteins during translation, in certain organisms: Selenocysteine is incorporated into some proteins at a UGA codon , which is normally a stop codon.

Pyrrolysine is incorporated into some proteins at a UAG codon. For instance, in some methanogens in enzymes that are used to produce methane.

Besides those used in protein synthesis , other biologically important amino acids include carnitine used in lipid transport within a cell , ornithine , GABA and taurine.

NCERT Solutions Class 12 Chemistry Chapter 14 Biomolecules - Free Download

Main articles: Protein structure , Protein primary structure , Protein secondary structure , Protein tertiary structure , and Protein quaternary structure The particular series of amino acids that form a protein is known as that protein's primary structure. This sequence is determined by the genetic makeup of the individual. It specifies the order of side-chain groups along the linear polypeptide "backbone". Thus, glucose contains an aldehydic group.

Since the penta acetate of1 glucose does not contain a free -OH group at C-l, it cannot get hydrolysed in aqueous solution to produce open chain aldehydic form and hence glucose pentaacetate does not react with NH2OH to form glucose oxime. The reactions are shown as: Due to this dipolar salt like character, they have strong dipole-dipole attractions.

Therefore, their melting points are higher than corresponding haloacids which do not have salt like character. Due to salt like character, amino acids intereact strongly with water. As a result, their solubility in water is higher than corresponding haloacids which do not have salt like character. When egg is boiled, proteins first undergo denaturation and then coagulation and the water present in the egg gets absorbed in coagulated protein, probably through H- bonding Vitamin C cannot be stored in the body because it is water soluble and is, therefore, easily excreted in urine.

The products obtained are 2-deoxy-D-ribose,. What does this fact suggest about the structure of RNA? A DNA molecule has two strands in which the four complementary bases pair each other, i. Thus, when a DNA molecule is hydrolysed, the molar amounts of cytosine is always equal to that of guanine and that of adenine is always equal to thymine.

In RNA, there is no relationship between the quantities of four bases C, G, A and U obtained, therefore, the base pairing principle, i.

A pairs with U and C pairs with G is not followed.

Monosaccharides are carbohydrates Which cannot be hydrolysed to smaller molecules. They are further classified as trioses , tetroses ,pentoses , hexoses and heptoses according as they contain 3,4,5,6, and 7 carbon atoms respectively. For example. All monosaccharides both aldoses and ketoses and disaccharides except sucrose are reducing sugars.

Two major functions of carbohydrates in plants are following a Structural material for plant cell walls: The polysaccharide cellulose acts as the chief structural material of the plant cell walls. It is stored in seeds and act as the reserve food material for the tiny plant till it is capable of making its own food by photosynthesis. Ribose, 2-deoxyribose, maltose, galactose, fructose and lactose.


Monosaccharides: Ribose, 2-deoxyribose, galactose and fructose. Disaccharides: Maltose and lactose. The ethereal or oxide linkage through which two monosaccharide units are joined together by the loss of a water molecule to form a molecule of disaccharide is called the glycosidic linkage. The glycosidic linkage in maltpse molecule is shown below: How is it different from starch? Both sucrose and lactose are disaccharides. Sucrose on hydrolysis gives one molecule each of glucose and fructose but lactose on hydrolysis gives one molecule each of glucose and galactose.

Starch consists of amylose and amylopectin. Amylopectin on the other hand has highly branched structure. This implies that the aldehydic group is absent in glucose pentaacetate.

Give two examples of each type. For example, valine, leucine, phenylalanine, etc. For example, glycine, alanine, aspartic acid etc. For example, ii Primary structure: Proteins may contain one or more polypeptide chains.

CBSE Class 11 Biology NCERT Solutions: Chapter 9, Biomolecules

The specific sequence in which the various amino acids present in a protein linked to one another is called its primary structure.

This is called native form of a protein. When a protein in its native form is subjected to a physical change such as change in temperature or a chemical change like change in pH, etc. As a result, soluble forms of proteins such as globular proteins undergo coagulation or precipitation to give fibrous proteins which are insoluble in water.

This coagulation also results in loss of biological activity of the proteins and this loss in biological activity, is called denaturation. The most common example of denaturation of proteins is the coagulation of albumin present in the white of an egg. When the egg is boiled hard, the soluble globular protein present in it is denatured and is converted into insoluble fibrous protein.

The conformation which the polypeptide chains assume as a result of hydrogen bonding is called secondary structure of the proteins.

The polypeptide chains in them are held together usually at many points by hydrogen bonds and some disulphide bonds. Further, these proteins are stable to moderate changes in temperature and pH.

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