Q22 of 26 Page 1

Rajesh was doing gel electrophoresis to purify DNA fragments. Given below is the sketch of the observations of the experiment performed by him.


(a) At which end he would have loaded the samples and where?


(b) Analyse the reason for different positions taken up by the DNA bands.


(c) Elaborate the step he would have followed to visualize DNA bands.


(a)The samples are loaded near site A where the wells are present.


(b) The DNA bands take different positions because of the sieving effect produced by the agrose gel. Due to this effect the smaller the size of the DNA the farther it moves.


(c)


1. Firstly, DNA strands are strained with Ethidium bromide.


2. Now, these strands are exposed under UV radiations.


3. The DNA strands appear to be colored.


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20

Biotechnology has helped farmers to get pest resistant cotton crops. Explain the technique adopted along with its mode of action. (Mention six points)

OR


Draw the figure of vector pBR322 and label the following: Origin of replication, Ampicillin resistance site, Tetracycline resistance site, Bam H1 restriction site.


 21

(a) Given below is a single stranded DNA molecule. Frame and label its sense and antisense RNA molecule. 5’ ATGGGGCTC 3’ sense

(b) How the RNA molecules made from above DNA strand help in silencing of the specific RNA molecules?


 23

Mohit and Sumit want to buy a new car for their company. Mohit insisted on buying a CNG car with a better mileage but Sumit insisted on buying a diesel version of a high end car with better music system and A.C but relatively low mileage.

(a) Being a responsible citizen of Delhi, how will Mohit convince Sumit about his decision in the wake of rising pollution levels?


(b) What qualities of personality are being exhibited by Mohit in doing so?


(c) Suggest two more measures which can help in reducing vehicular pollution.


 24

Human female is not fertile after menopause whereas males can produce gametes at any age after puberty. Analyse the statement and schematically represent a comparison between gametogenesis in males and females.

OR


A village health worker was taking a session with women. She tells the women that one has to be very careful while using oral pills as method of birth control. Wrong usage can actually promote conception.


(a) Analyze the statement and compare the merits and demerits of using oral pills and surgical methods of birth control.


(b) Village women were confused as to how a thin metallic Copper loop can provide protection against pregnancy. Justify the use explaining the mode of action of IUDs.