List of top Questions asked in CBSE CLASS XII

Minimum subscription for allotment of shares as per SEBI guidelines cannot be less than 90\% of which of the following capital?
The debentures which do not carry a specific rate of interest are called:
NUK Ltd. forfeited 1,000 shares of ₹ 10 each, fully called up for non-payment of final call of ₹ 2 per share. 800 of these shares were reissued at ₹ 11 per share fully paid. The amount credited to Capital Reserve Account will be:
KLB Ltd. forfeited 3,000 shares of ₹ 10 each, ₹ 8 per share called up for non-payment of first call of ₹ 2 per share. All these shares were reissued at ₹ 7 per share, ₹ 8 paid up. The amount transferred to Capital Reserve Account will be:
Lexa Ltd. issued 50,000 equity shares of ₹ 10 each at a premium of ₹ 2 per share. The amount was payable as follows:
On application and allotment — ₹ 7 per share (including premium)
On first and final call — Balance
The issue was fully subscribed. All the money was duly received except the first and final call on 1,000 equity shares. These shares were forfeited. On forfeiture of these shares, Calls in Arrears Account will be:
Alfa Ltd. offered for public subscription 50,000 equity shares of ₹ 10 each at ₹ 110 per share. The entire amount was payable on application. Applications were received for 48,000 shares and allotment was made to all the applicants. The amount received on application will be:
Write the conclusion they arrived at the end of their experiment.
State the importance of (1) blending and (2) centrifugation in their experiment.
Why did Hershey and Chase use \(^{35}\text{S}\) and \(^{32}\text{P}\) in their experiment? Explain.
Anthropogenic action can enhance the rate of evolution. Explain with the help of an example.
In England after industrialisation, the population of dark winged moths were more favoured than white winged moths. Explain.
Natural selection operates in different ways in nature.
Identify the type of natural selection depicted in the graph above.
Endosperm development precedes embryo development. Justify.
With the help of labelled diagram only, show the different stages of embryo development in a dicot plant.
In a human female, the probability of an ovum to get fertilised by more than one sperm is impossible. Give reason.
Draw a diagram of a human sperm. Label any four parts and write their functions.
How does an anti-sense RNA function?
Name the vector that is used to introduce nematode-specific genes into the host plant (tobacco).
Name the nematode (scientific name) that infects the roots of tobacco plant and reduces its yield.
Why is insertional inactivation preferred over the use of selectable markers in cloning vectors?
A cloning vector does not have a selectable marker. How will it affect the process of cloning?
State the role of ‘rop’ gene.
Draw a schematic diagram of the cloning vector pBR 322 and label
(1) Bam HI site
(2) gene for ampicillin resistance
(3) ‘ori’
(4) ‘rop’ gene.
Read the following passage and answer the questions that follow: “Mosquitoes are drastically affecting the human health in almost all the developing tropical countries. Different species of mosquitoes cause very fatal diseases so much so that many humans lose their life and if they survive, are unable to put in productive hours to sustain their life. With the result, the health index of the country goes down.” Name a species of mosquito other than female {Anopheles} and the disease, for which it carries the pathogen.}

Read the following passage and answer the questions that follow: “Mosquitoes are drastically affecting the human health in almost all the developing tropical countries. Different species of mosquitoes cause very fatal diseases so much so that many humans lose their life and if they survive, are unable to put in productive hours to sustain their life. With the result, the health index of the country goes down.” 

Explain the events which occur within a female Anopheles mosquito after it has sucked blood from a malaria patient.