1. What are carbohydrates? Give their importance and

  1. Write note on monosaccharides.
  2. Write note on disaccharitles and polysaccharides.
  3. Write note on fats.
  4. What are lipids? Give their types and importance.
  5. Write note on protein.
  6. Describe structure of protein.
  7. Give types of protein.
  8. Write note on nucleic acids.
  9. Write note on DNA.
  10. Describe Watson and Crick model of DNA.
  11. Write note on RNA.
  12. Differentiate between DNA and RNA.


  1. What are carbohydrates? Why are they called hydrated carbons? –

Ans: Carbohydrates are polyhydroxy aldehydes or ketones. Carbohydrates are sugars and their polymers. They are composed of carbon, hydrogen and oxygen. The word carbohydrates literally mean hydrated carbons. The ratio of hydrogen and oxygen is the same, as in water, i.e. 2:1.

  1. Give three importances of carbohydrates.

Ans:      They form different structures, like cellulose of wood.

cotton, and papers. They are found in all organisms. They are present in all pails of the cells. They act as storage compounds like starch and glycogen.

  1. Give sources of carbohydrates.

Ans: Carbohydrates are also called isaccharides`. The word saccharide is derived from a Greek word ssakcharon’. It means sugar. Saceharide is taken as unit (monomer)

of carbohydrates.

  1. Differentiate between aldo and keto sugars. Ans: The sugars with aldehyde groups are called aldo-sugar and with the sugar with keto groups are called keto-sugars. Theexample of aldo sugar is glucose And example of keto sugar is fructose.
    1. What are monosaccharides? Write their general formula?

    Ans: Monosaccharides are simple sugars.Mono means single and sacchar means sugar. They are composed of single sugar unit. Their formula is multiple of CI-120. They generally contain carbon number from 3 to 7.

    1. Draw formula of glucose and ribose.
    2. What are Sucrose and lactose?

    Ans:     It is a disaccharide. formed tw linking a molecule of glucose

    to a molecule of fructose. Glucose molecule bonds to another monosaccharide. galactose and it forms disaccharide lactose (cornmonly called in ilk sugar).

    1. Differentiate between Amylose starch and Amylopectin.

    Ans: Amylose starch is a simple form of starch. Amylose have unbranched chain of glucose. It is soluble in hot water. Amylopectin is most complex form of starch. It has branched chains. It is insoluble in hot or cold water.

    1. What is glycogen? Give its function.

    Ans: Glycogen is a polymer of glucose. It is more extensively branched than the amylopectin of plants. It is also called animal starch. It is a chief storage compound of animals. It is found in liver and muscles. It is also found in all animal cells. It is insoluble in water. It gives red colour with iodine. It gives glucose on hydrolysis.

    1. What is chitin? Give its function.

    Ans:     Chitin is another structural polysaccharide. Chitin is found in

    cell wall of fungi. It also forms exoskeleton of Arthropods. Chitin has amino sugars in its molecules.

    1. What are lipids?

    Ans:     t.ipids are nonpolar organic molecules that are insoluble in

    polar water but soluble in nonpolar organic solvents like ether, alcohol, and chloroform.

    1. What is fatty acid? Give their importance.

    Ans: Fatty acids contain long hydrocarbon chains bonded to carboxyl (C001-1) groups. Glycerol is a three-carbon alcohol, with each carbon hearing a hydroxyl (01-1) group. Three fatty acid molecules combine with one glycerol

    molecule. They are attached to the three carbon atoms in the glycerol backbone.

    1. What are neutral fat?

    Ans: The fats with three Fatty acids are called triglyceride neutral fat or triacylglycerol. The glycerol portion of every fat molecule is the same. Rut there are many kinds of fatty acids. Therefore, there are many kinds of fats. Fatty acid molecules differ in the length of their carbon chains and in the ways the carbon atoms combine. The most common arc even-numbered chains of 14 to 20 carbons.

    1. What are unsaturated fatty acids? Give their function.

    Ans: They have double bonds. Their chains bend at the double bonds. So the fat molecules cannot align closely with one another. Therefore, they hay e low. melting, points. Thus the fat may be fluid at room temperature. A liquid fat is called oil. Most plant fats are unsaterated. Fatty acids with one double bond are monounsaturated. They fatty acids yy ith numerous double bonds are poly. unsaturated.



    1. What are saturated fatty acid?

    Ans: Saturated fatty acids do not have double bonds. Animal fats are often saturated. .[hey occur as hard or solid fats. In this case, the carbon atoms join by single carbon-carbon bonds. Each carbon atom binds to many hydrogen atoms.

    1. What are phospholipids?

    Ans:     A phospholipids molecule is similar to a fat molecule. It

    contains a glycerol portion and fatty acid chains. Rut phospholipids have only two fatty acid chains. The nitrogen containing groups replace the third chain.

    1. What are waxes? Give example.

    Ans: The mixture of long chain alkalies (with odd number of carbon from C15 to (‘5). alcohols, ketones, and esters of long chain fatty acids is called waxes. e.g. cutin.

    1. Give functions of cutin.

    Ans:     Some lipids provide insulation against atmospheric heat and

    cold. They also act as water proof material. For example. waxes in the exoskeleton of insects. A wax cutin forms an additional protective layer on the cuticle of epidermis of some plant organs like leaves, fruits, seeds etc.

    1. What are proteins? Give their components.

    Ans: Proteins are polymers of amino acids. The name of proteins is derived from the Greek word called proteios. It means first place. Proteins always contain atoms of carbon, hydrogen. nitrogen. ox) gen, and sometimes sulfur. Proteins are composed of more than 50% of the dry weight of most cells.

    1. Differentiate between hydrophobic and hydrophilic amino acids.

    Ans:       Hydrophobic amino acids contain non-polar side chain.
    I lydrophilic have polar side chains.

    1. What is protein conformation?

    Ans:      A protein consists of one or more polypeptide chains. These

    chains are twisted, wound and folded upon themselves to form macromolecule. This macromolecule has definite three dimensional shapes called conformation. The function of protein depends upon its conformation.

    1. Differentiate between primary and secondary structures
      of proteins.

    Ans:      .1The linear sequence of amino acids in the polypeptide chains
    is called primary structure. The structure formed by folding or coiling of polypeptide chain with the help of hydrogen bonding is called secondary structure.

    1. Differentiate between a helix and Pleated sheet.

    Ans:       A delicate coil of polypeptide chain held together by

    hydrogen bonding between every fourth peptide bond is called alpha helix. A sheet of polypeptide chain formed by the folding back and forth of the polypeptide chain is called [3 pleated sheet.

    1. Differentiate between tertiary and quaternary structures
      of protein.

    Ans: The structure of protein formed by folding of helix or sheet into a three dimensional shape is called tertiary structure. The structure formed hy the aggregation of two or more polypeptide chains is called quaternary structure.

    1. What is Disulphide bridge?

    Ans: Disulphide bridge is formed between two cysteine amino acids of polypeptide chain. The amino acids with sulthydryl groups on their side chains are called cysteine amino acids. The sulfur of one cysteine bonds to the sulfur of second

    1. What is globular protein? How is it formed?

    Ans: Globular proteins or spheroproteins are one of the two main .protein classes. It is composed of globelike proteins that are more or less soluble in aqueous solutions. They form colloidal solutions in water. The spherical structure is induced by the proteins primary structure. The non-polar groups are bounded towards the interior of the molecule. But the polar ones are bounded outwards. It allows dipole-dipole interactions with the solvent.

    1. How do protein act as reserved compounds.

    Ans: Most part of the fruits and vegetable is composed of proteins. Thus proteins act as storage compounds. Albumin is stored in egg white. It is Major source of amino acids for developing embryo. Casein is present in milk. It is source of amino acids for baby mammals.

    1. What are exon and interon?

    Ans: the coding portions are called exons and the noncoding (junk) portions are called introns.


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