Q. No.An enzyme catalysing the removal of nucleotides from ends of DNA is:
1. DNA ligase
2. Endonuclease
3. Exonuclease
4. Protease
1. DNA ligase
2. Endonuclease
3. Exonuclease
4. Protease
Given below are four statements pertaining to the separation of DNA fragments using gel electrophoresis. Identify the incorrect statements:
| (a) | DNA is a negatively charged molecule and so it is loaded on gel towards the anode terminal. |
| (b) | DNA fragments travel along the surface of the gel, whose concentration does not affect the movement of DNA. |
| (c) | The smaller the DNA fragment, the greater the distance it travels through it. |
| (d) | Pure DNA can be visualized directly by exposing it to UV radiation. |
Choose the correct answer from the options given below:
| 1. | (a), (c) and (d) | 2. | (a), (b) and (c) |
| 3. | (b), (c) and (d) | 4. | (a), (b) and (d) |
A selectable marker is used to:
| 1. | help in eliminating the non-transformants so that the transformants can be regenerated. |
| 2. | identify the gene for the desired trait in an alien organism. |
| 3. | select a suitable vector for transformation in a specific crop. |
| 4. | mark a gene on a chromosome for isolation using a restriction enzyme. |
The two antibiotic resistance genes on vector pBR 322 are for:
1. Ampicillin and Tetracycline
2. Ampicillin and Chloramphenicol
3. Chloramphenicol and Tetracycline
4. Tetracycline and Kanamycin
Match the following enzymes with their functions:
|
Column-I |
Column-II |
||
|
(a) |
Restriction endonuclease |
(i) |
joins the DNA fragments |
|
(b) |
Exonuclease |
(ii) |
extends primers on genomic DNA template |
|
(c) |
DNA ligase |
(iii) |
cuts DNA at a specific position |
|
(d) |
Tag polymerase |
(iv) |
removes nucleotides from the ends of DNA |
Select the correct option from the following:
| Options: | (a) | (b) | (c) | (d) |
| 1. | (iii) | (i) | (iv) | (ii) |
| 2. | (iii) | (iv) | (i) | (ii) |
| 3. | (iv) | (iii) | (i) | (ii) |
| 4. | (ii) | (iv) | (i) | (iii) |
Restriction endonucleases present in bacterial cells provide an advantage to the cell because these enzymes:
| 1. | can identify the mutated sequences on the chromosomal DNA and help in their repair |
| 2. | selectively bind to particular nucleotide sequences that may appear in viral DNA preventing its replication in the cell |
| 3. | can cut the plasmid DNA of the bacterial cell that allows them to recombine foreign DNA into their plasmid DNA |
| 4. | help the bacterium take up foreign DNA from their environment and combine it into their genome |
Which one of the following represents a palindromic sequence in DNA?
1. 5' - GAATTC - 3'
3' - CTTAAG - 5'
2. 5' - CCAATG - 3'
3' - GAATCC - 5'
3. 5' - CATTAG - 3'
3' - GATAAC - 5'
4. 5' - GATACC - 3'
3' - CCTAAG - 5'
The DNA fragments separated on an agarose gel can be visualised after staining with
1. Bromophenol blue
2. Acetocarmine
3. Aniline blue
4. Ethidium bromide
Which of the following does not have the ability to replicate within bacterial cells independent of the control of chromosomal DNA?
1. Plastid
2. Bacteriophages
3. BAC
4. Plasmid
The following palindrome is recognized by the restriction enzyme:
1. BamHI
2. EcoRI
3. HindII
4. PstI
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