List of top Questions asked in CBSE CLASS XII

Name one commonly occurring genetic disorder in humans which is caused due to monosomy (one chromosome less than the normal number of chromosomes) of sex chromosome. Give its two symptoms.

Answer the following questions:

  • Explain how the process of RNA interference technology is used effectively to prevent infestation of the roots of tobacco plant by the nematode Meloidogyne incognita.
    OR
  • Explain how more than a billion copies of a fragment of DNA are formed using the technique of PCR.
AGGTATCGCAT is a sequence from the coding strand of a gene. What will be the corresponding sequence of the transcribed mRNA?
Removal of RNA polymerase-III from nucleoplasm of a eukaryotic cell will affect the transcription of which of the following?
Large scale industrial production of streptokinase for human welfare is done using the microbe:
Isolation of DNA from a plant cell can be achieved by using:
In a pea plant (Pisum sativum), green pod colour is dominant over yellow pod colour. The expected ratio of the phenotypes of the offsprings (F$_1$) in a cross between parents with heterozygous green pod colour and homozygous yellow pod will be:
Given below are few statements with reference to the major events in the menstrual cycle of a human female:
  • During the follicular phase, the primary follicles grow to become a Graafian follicle.
  • Gonadotropins FSH and progesterone stimulate follicular development during the follicular phase.
  • LH surge induces rupture of Graafian follicle thereby releasing the corpus luteum.
  • Progesterone released by corpus luteum is essential for maintenance of endometrium.
  • Both LH and progesterone attain a peak level in the middle of the cycle.
Choose the option with all true statements from the given options:
The approach used in HGP of identifying all the genes that are expressed as RNA is referred to as:

Study the pedigree chart of a family showing the inheritance of myotonic dystrophy:

The trait under study is:

The large bean-shaped organ acting as a filter of the blood in humans is:
Select the following statements that are true for insect pollinated flowers from the given options.
  • Majority of these flowers are large, colourful and rich in nectar.
  • Nectars and seeds are usual floral rewards to attract insects for pollination.
  • Pollen grains of these flowers are generally mucilaginous so as to stick to the body of the insects.
  • A foul odour is emitted by some flowers to attract flies and beetles.
Choose the correct answer:
In E. coli, a DNA sequence that specifies where RNA polymerase will bind and initiate transcription of a gene is:
As the Banker to the Bank, Reserve Bank of India performs all functions except ___.
Define Nominal Gross Domestic Product. How is it different from Real Gross Domestic Product?
Differentiate between positive externalities and negative externalities.
"In a two-sector economy, National Income is always equal to Domestic income " Defend or refute the given statement with valid reasons.
Define Real Gross Domestic Product. How is it different from Nominal Gross Domestic Product?
Differentiate between factor income and transfer income.
Briefly explain the dual pricing policy adopted by China.
Explain the volume and direction of foreign trade during the British rule.
Value Addition = __ Value of Intermediate Consumption. (Choose the correct option(s) to complete the stated formula.)

On the basis of the data given below, estimate the value of National Income (NNPFC)

Regulation of lac operon by repressor is referred to as:

Explain how the addition of lactose in the medium regulates the switching on of the lac operon in bacteria.