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IGNOU MCH-15 (July 2025 – June 2026) Assignment Questions
1. a) What will be the sequence of separation of the organelles, ribosomes, nucleus and (5) mitochondria in a tissue homogenate when subjected to centrifugation. Explain your answer.
b) Briefly describe different modes through which cell membrane controls the transport of ingoing and outgoing molecules?
2. a) What are anomers? Explain the existence of anomers in sugars taking D-glucose as an illustrative case.
b) Discuss the classification of carbohydrates on the basis of number of saccharide units giving example of each class.
3. a) A fat has low iodine number and a high saponification number. What do you infer from that? What are essential fatty acids and why are they essential?
b) Explain the ‘fluid mosaic model’ for membrane structure.
4. a) Draw the structure of a dinucleotide of adenosine – 5′ – phosphate and uridine – 5’– phosphate. In which process of protein biosynthesis, t RNA is involved? Illustrate the gross structural features of t – RNA. Indicate the different regions.
b) Write a short note on the different forms of RNA.
5. a) What are the structural and functional differences between myoglobin and haemoglobin?
b) How is the standard free energy for chemical reactions different from the standard free energy for biochemical reactions?
6. a) With the help of an example explain the significance of coupling in biological reactions.
b) Explain homeostasis. How is the water balance maintained in the body?
7. Write short notes on the following:
a) Mitchell’s chemiosmotic hypothesis
b) ATP – the energy currency of cell
8. a) Compare the functions of RNA polymerase with DNA polymerase. How is transcription terminated?
b) Explain the mechanism of action of the enzyme aconitase on citrate in TCA cycle.
9. Compare the following:
a) Energetics of metabolic oxidation of glucose and a fatty acid
b) Biosynthesis and -oxidation of fatty acids
10. a) List different types of antibodies. What are the gross structural features of an antibody molecule? Discuss any one mechanism by which antibodies interact with antigens.
b) Discuss the “specific immunologic tolerance” theory of immune response.
IGNOU MCH-15 (January 2025 – December 2025) Assignment Questions
1. a) What is the name of the system of classification applied for the domains of life? List the common features of prokaryotes and eukaryotes.
b) Which cell organelle is called the “control centre”? Describe its composition.
2. a) Write the step wise reactions of formation of a glycoside taking glucose as an example.
b) What are hormones? Name the classes of steroid hormones along with their important functions.
3. a) Describe how the cell membrane regulates the movement of various molecules into and out of the cell.
b) Differentiate between the essential and non essential amino acids. Describe the amphoteric nature of amino acids.
4. a) Explain the geometry of the peptide backbone. Illustrate your answer.
b) Describe the tertiary structure of proteins in terms of the bonds and forces that stabilise the structure.
5. a) Why the metabolism is called the ‘intermediary metabolism’? Describe the convergent and divergent nature of metabolism.
b) Explain what is meant by high energy phosphate compounds and what their significance is in the living systems.
6. a) What is EMP pathway? Explain the isomerisation reaction of glycolysis giving the catalyst involved.
b) Explain the role of constituent enzymes of pyruvate dehydrogenase complex involved in the conversion of pyruvate into acetyl-CoA.
7. a) What are ketone bodies? Explain their significance to human beings.
b) Draw a diagrammatic sketch of the urea cycle indicating the products and enzymes involved.
8. a) Give a comparative account of purine and pyrimidine nucleotide degradation.
b) Define immunity. Differentiate between innate and acquired immunity.
9. a) What is the significance of antigen-antibody interaction? Describe in brief the mechanisms involved in antigen-antibody interaction.
b) Name the enzymes involved in DNA replication and describe their role in this process.
10. Write short notes on the following :
a) Water and electrolyte balance in living systems
b) Blood group substances
c) Nucleosides and nucleotides
d) Homeostasis
IGNOU MCH-15 (January 2024 – December 2024) Assignment Questions
1. a) What is meant by domains of life? Describe in brief the different domains of life.
b) Compare and contrast the cellular organisation in prokaryotes and eukaryotes.
2. a) Describe the method of separating the subcellular organelles. Illustrate your answer.
b) Define pH and buffer. How are the two related? Name the two important biological buffers in the human body.
3. a) Draw and explain the open chain and ring structures of monosaccharides taking a suitable example.
b) Describe the structure and classification of fatty acids giving examples.
4. a) What are zwitterions? Explain taking an amino acid as the example. How does a zwitterion relate to the isoelectric point of an amino acid?
b) Differentiate between a nucleotide and nucleoside giving their structures.
5. a) Describe the structural basis for the role of ATP as the energy carrier in biological systems. Write the reaction involved.
b) What are coupling reactions? Explain their significance in the biological systems.
6. a) Differentiate between glycolysis and gluconeogenesis writing the reactions in which these two differ from each other.
b) Describe the central role of TCA cycle in the metabolism of biomolecules in a living system.
7. a) Name the three stages of catabolism of amino acids and give a schematic representation of the same.
b) Describe the fate of uric acid during the degeneration of purine nucleotides.
8. a) What is meant by immunity? Enumerate the different levels of defense in the body.
b) Differentiate between an antigen and an antibody. Describe and illustrate the structure of an antibody.
9. a) Describe any one experiment which proved that ‘DNA is the genetic material’.
b) Explain the process of DNA replication. Illustrate your answer.
10. a) Describe the structure and role of ribosomes in protein biosynthesis.
b) Describe the oxidative degradation of acyl-CoA during the degradation of fatty acids.
