List of top Biology Questions

In Bryophytes & Pteridophytes the number of male gametes produced is several thousand times the numbe of female gametes produced.
Reason : Large number of male gametes fail to reach the female gametes during transport.
How many microsporangia are located at the corners of a typical bilobed anther of angiosperm ?
Gemmae are present in:
Following are the statements about prostomium of earthworm.
(a) It serves as a covering for mouth.
(b) It helps to open cracks in the soil into which it can crawl.
(c) It is one of the sensory structures.
(d) It is the first body segment.
Choose the correct answer from the options given below
The term used for transfer of pollen grains from anthers of one plant to stigma of a different plant which, during pollination, brings genetically different types of pollen grains to stigma, is :
Which of these is not an important component of initiation of parturition in humans
Which enzyme is responsible for the conversion of inactive fibrinogens to fibrins
The Adenosine deaminase deficiency results into
Which of the following characteristics is incorrect with respect to cockroach ?
Veneral diseases can spread through : (a) Using sterile needles (b) Transfusion of blood from infected person (c) Infected mother to fetus (d) Kissing (e) Inheritance Choose the correct answer from the options given below
A bacterial flagellum is composed of
During the process of gene amplification using PCR, if very high temperature is not maintained in the beginning, then which of the following steps of PCR will be affected first ?
For effective treatment of the disease, early diagnosis and understanding its pathophysiology is very important. Which of the following molecular diagnostic techniques is very useful for early detection
Relate Column I with Column II with regard to predatory behaviour:
 Column I Column II
1.Calotropisp.Invertebrates
2.Pisasterq.Distasteful
3.Monarch butterflyr.Cryptically colored
4.Frogss.Cardioglycoside
In an enzyme catalyzed first-order reaction, the substrate conversion follows an exponential pattern such that 80% of the substrate is converted in 10 minutes. The first-order rate constant (in min\(^{-1}\)) of the reaction, rounded off to THREE decimal places, is ............
Which of the following is(are) CORRECT?
Which of the following gas(es) function(s) as signaling molecule(s) in the human nervous system?
Protozoa are
Which of the following is(are) involved in the activation of cytotoxic T cells?
Which of the following is(are) TRUE about photosynthesis?
Determine the correctness or otherwise of the following Assertion [a] and the Reason [r].
Assertion [a]: The difference in the respective melting points of butter and coconut oil is caused by the degrees of saturation of the corresponding fatty acid chain.
Reason [r]: Unsaturated fatty acid chains in fats/lipids become solid more easily because they are relatively straight and thus able to pack together more closely than saturated chains.

Match the RNAs in Group I with their corresponding function in Group II 
Group I               Group II 
(P) snRNA          (1) rRNA processing 
(Q) piRNA          (2) RNA splicing 
(R) snoRNA        (3) Selected mRNAs degradation 
(S) siRNA            (4) Germ line protection from transposable elements 
 

Match the enzymes in Group I with the corresponding substrate in Group II 
   Group I             Group II 
(P) Amylase      (1) Protein 
(Q) Pepsin         (2) Fat 
(R) Lipase          (3) RNA 
(S) Ribozyme     (4) Starch 
 

Which of the following is(are) auxins?
Determine the correctness or otherwise of the following Assertion [a] and the Reason [r].
Assertion [a]: lac operon is an inducible operon.
Reason [r]: lac operon is not induced when the repressor protein remains bound to operator DNA sequence.