Question

You wake up one morning to your roommate exclaiming about her sudden hair growth. She has been supplementing her diet with a strange new fungus purchased at the local farmer's market. You take samples of the fungus to your lab and you find that this fungus does indeed make a protein (the harE protein) that stimulates hair growth. You construct a fungal genomic DNA library in the hope of cloning the harЕ gene. If you succeed you will be a billionaire! You obtain DNA from the fungus, digest it with a restriction enzyme, and clone it into a vector. a) Circle the vector that has the MINIMUM features required for your library construction. - ampicillin resistance gene – site for unwinding by helicase origin of replication promoter cloning site b) You clone your digested genomic DNA into this vector. What type of cells do you need to transform to create your library? Explain your chose.

Answer 1

Answer:-

(a) For library construction, the minimum features that are required for a vector is Cloning site which is also known as restriction enzyme site, Origin of replication and a Selectable marker like ampicillin resistance gene. Apart from these features, there are other features too which could be required depending upon the aim of setting up the library. Hence, the second vector in the below row would be the correct option.

(b) We clone our digested genomic DNA into the above vector we choose. We actually need bacterial cells which are sensitive to ampicillin. Before the process of transformation, the bacterial cells which are needed to be transformed will be sensitive to antibiotic present in the vector i.e ampicillin. This results in selecting the cells that are acquired by the plasmid.

(c) The bacterial cells that carry a vector would be able to grow in the presence of ampicillin as there cells have selectable marker for antibiotic ampicillin whereas, other bacterial cells without vector would not be able to survive in the presence of ampicillin.

(d) In order to construct intact genomic DNA library, we would need Restriction enzyme (for cleaving the DNA molecules at specific sites), Ligase (for joining the two strands of DNA), Cloning vector (in order to insert foreign DNA into it for the process of cloning) and Size separation gel ( used to separate the molecules on the basis of size).

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