The advantage of using DNA polymerases from thermophilic organisms in PCR is that:
1. | the DNA polymerases of these bacteria are much faster than those from other organisms |
2. | the DNA polymerases of these bacteria can withstand the high temperatures needed to denature the DNA strands |
3. | the DNA polymerases of these bacteria never make mistakes while replicating DNA |
4. | all of the above |
In situ hybridization is used to :
1. | Remove mutations from a chromosome |
2. | Remove plasmids from a cell |
3. | Clone a gene |
4. | Locate a gene on a chromosome |
A bacterium adds methyl group to its DNA, by a process known as modification, in order to:
1. | Clone its DNA |
2. | Turn its genes on |
3. | Transcribe many genes simultaneously |
4. | Protect DNA from its own restriction enzymes |
DNA from a eukaryotic organism is digested with a restriction endonuclease and the resulting fragments are cloned into a plasmid vector. Bacteria transformed by these plasmids collectively contain all of the genes of the organism. This culture of bacteria is referred to as :
1. | restriction map | 2. | RFLP profile |
3. | F' factor | 4. | library |
Which of the following is not part of the normal process of cloning recombinant DNA in bacteria?
1. | restriction endonuclease digestion of cellular and plasmid DNAs. |
2. | production of recombinant DNA using DNA ligase and a mixture of digested cellular and plasmid DNAs. |
3. | separation of recombinant DNAs by electrophoresis using the Southern technique to determine where the desired recombinant migrates. |
4. | transformation of bacteria by the recombinant DNA plasmids and selection using ampicillin. |
What type of probe would you use for a Western blot experiment?
1. | A known DNA sequence. | 2. | An RNA molecule. |
3. | A purified protein. | 4. | An antibody. |
In the first gene cloning experiment:
1. | Researchers successfully identified a human gene responsible for the disease. |
2. | Researchers successfully inserted a gene for kanamycin resistance into a plasmid vector. |
3. | Researchers demonstrated that many different DNA fragments could insert into a plasmid vector |
4. | Researchers produced a strain of bacteriophage with an increased ability to infect E. coli. |
Which of the following would NOT be a useful selectable marker?
1. | A gene encoding a protein that degrades the antibiotic ampicillin. |
2. | A gene encoding a protein that allows the cell to synthesize histidine. |
3. | A gene encoding a protein that is an essential structural component of the cell. |
4. | All of these are useful selectable markers. |
Consider the following statements:
I: | Asexual reproduction preserves genetic information while sexual reproduction permits variations. |
II: | Traditional hybridization often leads to the inclusion and multiplication of undesirable genes along with the desired genes. |
III: | rDNA technology allows us to isolate and introduce only one or a set of desirable genes without introducing undesirable genes in the target organism. |
Which of the above statements are true?
1. | I and II only | 2. | I and III only |
3. | II and III only | 4. | I, II, and III |
Consider the following statements:
I: | Exonucleases remove nucleotides from the ends of DNA whereas, endonucleases make cuts at specific positions within DNA. |
II: | To visualize pure DNA fragments, it is stained with ethidium bromide and seen in UV light. |
III: | Plasmids and phage DNA are used as vectors in genetic engineering as they are extrachromosomal DNA molecules. |
Which of the above statements are true?
1. | I and II only | 2. | I and III only |
3. | II and III only | 4. | I, II, and III |