List of top Questions asked in CBSE CLASS XII

Differentiate the following and give examples of each:
(a) Innate and acquired immunity
(b) Active and passive immunity

The following are some well-known abbreviations which have been used in this chapter. Expand each one to its full form:
(a) MALT
(b) CMI
(c) AIDS
(d) NACO
(e) HIV

Name the primary and secondary lymphoid organs.
Discuss with your teacher what does 'a suitable gene' means in the context of DNA vaccines.
What measure would you take to prevent water-borne diseases?

How does the transmission of each of the following diseases take place?

(a) Amoebiasis
(b) Malaria
(c) Ascariasis
(d) Pneumonia

In which way has the study of biology helped us to control infectious diseases?
What are the various public health measures which you would suggest as safeguard against infectious diseases?
Using various resources such as your school library or the internet and discussions with your teacher trace the evolutionary stages of any one animal say horse.
Can we call human evolution as adaptive radiation?
Describe one example of adaptive radiation.
Find out through internet and popular science articles whether animals other than man have self-consciousness.
Attempt giving a clear definition of the term species
Find out from newspapers and popular science articles any new fossil discoveries or controversies about evolution.
Explain antibiotic resistance observed in bacteria in light of Darwinian selection theory.
What is DNA fingerprint? Mention its application.
Why is the Human Genome project called a mega project?
Explain(in one or two lines)the function of the followings:
(a)Promoter
(b)tRNA
(c)Exons
In the medium where E.coli was growing lactose was added which induce the lac operon. Then why does lac operon shut down some time after addition of lactose in the medium?

List two essential roles of the ribosome during translation.

How did Hershey and Chase differentiate between DNA and protein in their experiment while proving that DNA is the genetic material?

Depending upon the chemical nature of the template (DNA or RNA) and the nature of nucleic acids synthesised from it (DNA or RNA), list the types of nucleic acid polymerases.

From the differential equation of the family of circles touching the y-axis at the origin.

From the differential equation of the family of parabolas having vertex at origin and axis along positive y-axis.

If the sequence of the coding strand in a transcription unit is written as follows: 

5-ATGCATGCATGCATGCATGCATGCATGC-3

 Write down the sequence of mRNA.