A bacterial cell was transformed with a recombinant DNA molecule that was generated using a human gene. However, the transformed cells did not produce the desired protein. The reasons could be:
1. | Human genes may have intron which bacteria cannot process |
2. | Amino acid codons for humans and bacteria are different |
3. | Human protein is formed but degraded by bacteria |
4. | All of the above |
In agarose gel electrophoresis, DNA molecules are separated on the basis of their:
1. | Charge only | 2. | Size only |
3. | Charge-to-size ratio | 4. | All of the above |
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 |
Which of the following cannot be used as a vector in rDNA technology?
1. | Plasmid | 2. | Phage DNA |
3. | Bacterium | 4. | YAC |
It is useful to use restriction enzymes in rDNA experiments that produce sticky ends in the resultant fragments because:
1. | it allows a cell to recognize fragments produced by the enzyme |
2. | the single-stranded ends serve as starting points for DNA replication |
3. | the fragments will bond to other fragments with complementary single-stranded ends |
4. | only single-stranded DNA segments can code for proteins |
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 |
A DNA library is:
1. | information in a computer database about all the genes sequenced so far |
2. | a collection of vectors in a molecular biology lab |
3. | a collection of fragments of DNA that make up the entire genome of an organism |
4. | all the restriction sites put together on a DNA fragment |
Consider the following statements:
I: | Ori is responsible for the copy number of the linked DNA. |
II: | Transformation is a process through which a piece of DNA is introduced into a host bacterium. |
III: | Bacteriophages have very high copy numbers of their genome within the bacterial cell. |
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 |