WBJEE Biology (Descriptive) - Previous Year Paper, 2011 | WBJEE Sample Papers, Section Wise & Full Mock Tests 2025 PDF Download

Q1. What are poikilothermic animals?
A. The body temperature of poikilothermic animals (cold blooded animals) changes according to environmental temperature.
Example are invertebrates, fishes, amphibians and reptiles.

Q2. Write two functions of juxtaglomerular apparatus.
A. The Juxta glomerular apparatus (JGA) possesses  Juxta glomerular cells and Macula densa. The Juxta glomerular cells secrete renin which regulates RAAS mechanism. Macula densa responds to the change in the mineral ion concentration of glomerular filtrate.

Q3. State two differences between red and white muscles.
A.  

Q4. What is the difference between pinocytosis and phagocytosis?
A. 

Q5. State four important functions of plasma membrane.
A. Four important functions of plasma membrane are :
(i) Involved in active and passive transport
(ii) Involved in a variety of cellular processess such as cell adhesion, ion conductivity & cell signalling.
(iii) As a cell envelope it contain the protoplasm thus protective in nature.
(iv) In prokaryotes, plasma membrane is the site of E.T.S.

Q6. What is bioaccumulation?
A. Bioaccumulation is the accumulation of toxic substance at a rate greater than at which the substance is lost by an organism.
Longer the biological half life of the accumulated substance, greater is the risk of bioaccumulation.

Q7. What is a test cross? Why is it so named?
A. Test cross is a cross between F1 hybrid and homozygous recessive parent.
Test cross is so named as it determines whether the individual with dominant phenotype is homozygous dominant or heterozygous dominant.

Q8. What is ribozyme?
A. A ribozyme is a RNA molecule possessing a well defined tertiary structure that enables it to catalyse a chemical reaction eg. 23S  rRNA   (peptidyl transferase).

Q9. What are mycorrhizae?
A. Mycorrhizae is a symbiotic association between roots of higher plants and fungi.
It plays a key role in mineral absorption specially phosphate.

Q10. Write down the scientific name of China rose plant. Give its floral formula.
A. Scientific name of China rose is Hibiscus rosa - sinensis