IGNOU BCHET-149 December 2025 Previous Year Question Paper

Q1.(a) Discuss the structure and function of mitochondria, highlighting their role in cellular energy production. 5

(b) Match the following :

Q2.. Light

(1) Energy harvesting currency of a organelles cell Gi) Peroxysomes

(2) Chloroplast

(ii) Vacuoles

(3) Powerhouse of cells

(iv) Mitochondria

(4) Hydrogen peroxide decomposition

(v) ATP

(5) Storing and transport of nutrients

Q3.(a) What are lysosomes ? Describe their function and_ significance in a eukaryotic cell. 5

(b) Write short notes on the following : 20955

(i) Cytoskeleton Gi) Insulin

Q4.(a) Write the product(s) that are obtained when D-glucose reacts with the following : 5

(i) Conc. Sulphuric acid Gi) Bromine water Gii) Nitric acid

(iv) Tollen’s reagent

(v) Three equivalents of phenyl hydrazine

(b) Write three different tests used to differentiate reducing and non-reducing sugars. Why is Sucrose classified as non-reducing sugar while Maltose and Lactose are considered reducing sugars ?

Q5.(a) Describe the stereochemistry of peptide bond. 5

(b) Describe the classification of amino acids based on the nature of R-group.

Q6.Name any five major classes of enzymes as classified by Enzyme Commission (EC).

Q7.Write one example for each class and the type of reaction they catalyse.

Q8.(a) Define the following in the context of mechanism of drug action : 5 G) Stimulation Gi) Depression Gii) Irritation

(iv) Replacement

(v) Cytotoxic action

(b) Explain the difference between competitive and non-competitive inhibition of enzymes.

Q9.(a) What are the three main roles that lipids play in the human body ? Explain. 5

(b) Describe the differences between sphingolipids and phospholipids.

Q10.Describe the steps involved in the urea cycle using a diagram. 10 2922-55

(i) seer