50,000 different strains of rice are example of:

Net primary productivity is the:

Read the following passage carefully and answer the given questions.
Restriction endonuclease on finding its specific recognition sequence, bind to the DNA and cut each of the two strands of the double helix at specific points in their sugar -phosphate backbones. Each restriction endonuclease recognises a specific palindromic nucleotide sequences in the DNA. Since the DNA is enclosed within the membranes, we have to break the cell open to release DNA along with other macromolecules such as RNA, proteins, polysaccharides and also lipids. This can be achieved by treating the bacterial cells/plant or animal tissue with enzymes such as lysozyme (bacteria), cellulase (plant cells), chitinase (fungus). Now a days the most commonly used matrix is agarose which is a natural polymer extracted from sea weeds. The DNA fragments separate (resolve) according to their size through sieving effect provided by the agarose gel. The first restriction endonuclease-Hind II, whose functioning depended on a specific DNA nucleotide sequence was isolated and characterised five years later. It was found that Hind II always cut DNA molecules at a particular point by recognising a specific sequence of six base pairs. In addition to 'ori', the vector requires a selectable marker, which helps in identifying and eliminating non-transformants and selectively permitting the growth of the transformants. Transformation is a procedure through which a piece of DNA is introduced in a host bacterium. Normally, the genes encoding resistance to antibiotics such as ampicillin, chloramphenicol, tetracycline or kanamycin, etc., are considered useful selectable markers for E. coli
Hind II always cut DNA molecules at a particular point by identifying a specific sequence of six base pairs. This specific base sequence is called _______ for Hind II.

Read the following passage carefully.
Restriction enzyme
Restriction enzymes cut the strand of DNA a little away from the center of the palindrome sites, but between the same two bases on the opposite strands. This leaves single stranded portions at the ends. There are overhanging stretches called sticky ends on each strand. These are named so because they form hydrogen bonds with their complementary cut counterparts. This stickiness of the ends facilitates the action of the enzyme DNA ligase. The word palindromes refer to group of letters that forms the same words when read both forward and backward. Restriction endonucleases are used in genetic engineering as molecular scissors.
Which one of the following enzyme helps to join DNA?

Arrange the steps involved in creating pest-resistant transgenic plants using RNA interference (RNAi).
(A) Binding of complementary RNAs to form double-stranded RNA (dsRNA).
(B) Formation of sense and antisense RNA in the host cells.
(C) Silencing of specific mRNA of the nematode.
(D) Introduction of nematode-specific genes into the host plant using Agrobacterium vectors.
Choose the correct answer from the options given below:

Following are the steps involved in Hershey and Chase experiment to prove DNA as the genetic material.
(A) Blending the cells
(B) Centrifugation of the cells was performed
(C) Growing some bacteriophages on a medium containing radioactive phosphorus and other on radioactive sulfur.
(D) Cells were infected with virus
(E) Observation and established the inference.
Choose the correct answer from the options given below:

Which one of the following infections is completely curable?

The dehydration of alcohol follows the order :

A fisherman is rowing a boat. He takes 6 hours to row 48 km upstream whereas he takes 3 hours to go to the same distance downstream.
Based on the above information, which of the following are correct?
(A) His speed of rowing in still water is 10 km/hour.
(B) The speed of the stream is 3 km/hour.
(C) The average speed of the fisherman is 32/3 km/hour.
(D) The speed of the stream is 4 km/hour.
Choose the correct answer from the options given below :

The equation of plane which cuts equal intercepts of unit length on the coordinate axes is:

Find the area of the region bounded by the two parabolas \(y=x^2\) and \(y^2=x\) :

If \(A=\left[\begin{array}{cc}2 & -3 \\ -4 & 7\end{array}\right]\) and \(2 A^{-1}=K I-A\), where \(K\) is a real number and \(I\) is the identity matrix of order 2 , then the value of \(K\) is :

If a line makes angles \(\alpha, \beta, \gamma\) with the positive directions of the coordinate axes, then the value of \(\cos 2 \alpha+\cos 2 \beta+\cos 2 \gamma\) is