Conjugated Molecules

Biology 3 minutes read

Two different molecules, belonging to different categories, usually combine together to form conjugated molecules. Carbohydrates may combine with proteins to from glycoprotein or with lipids to form glycolipids. Most of the cellular secretions are glycoprotein in nature. Both glycoprotein’s and glycolipids are integral structural components of plasma membranes. Lipoprotein formed by combination of lipids and proteins are basic structural framework of all types of membranes in the cells.

Nucleic acids have special affinity for basic proteins. They are combined together to form nucleoproteins. The nucleohistones are present in chromosomes. These conjugated proteins are not only of structural, but also are of functional significance. They play an important role in regulation of gene expression.

Conjugated_Molecules

Exercise

1. Fill in the blanks.

  1. The sum of all the chemical reactions taking place within a cell is called ………………..
  2. ……………is the basic element of organic compounds.
  3. All the amino acids have an amino group and a carboxyl group attached to the same …………….atom.
  4. ………….is the most abundant carbohydrate in nature.
  5. Adenine ad guanine are double ringed bases and are called………………..

2. Write whether the statement is ‘true’ or ‘false’ and writes the correct statement if it is false.

    1. A small proportion of water molecules are in ionized from.

The covalent bond among two monosaccharides is called a peptide bond.

  • Glycogen is also called plant starch.
  • Adenine is always opposite to guanine; cytosine and thymine are opposite to each other in DNA molecule.
  • DNA molecule is made of two polynucleotide strands.

3. Each question has four options. Encircle the correct answer.

(i) Animals obtain carbohydrates mainly from:

a) Glucose                           (b) Starch

© Sucrose                           (d) Glycogen

(ii) Peptide bond is a:

               (a)     C – N link                   (b)  C – O link

©         N – H link                (d) C – H link

(iii) Globular proteins differ from fibrous proteins in:

  1. Having amino acids
  2. Their repeating units joined by peptide bond
  3. Being soluble in aqueous medium
  4. Being non-crystalline

(iv) Which of the following kinds of atom do not occur in carbohydrates?

  1. Carbon
  2. Hydrogen
  3. Nitrogen
  4. Oxygen

(v) Amino acids are arranged in proper sequence during protein systhesis according to the instructions transcribed on.

(a) Transfer RNA                                              (b) ribosomal RNA

© Messenger RNA                                          (d) DNA

4. Sort questions.

  1. Name the carbohydrates suitable as food for man.
  2. Why are fats considered as high energy compounds?
  3. What is the function of mRNA?
  4. What is the
    general formula for amino acids?i>
  5. What a short note on amino acids.

5. Extensive questions.

i. describe

ii. Describe what you know about polysaccharides.

iii. Write a short note on amino acids.