Question

26. a. (7 pts) Match elements of a eukaryotic gene shown above, with correct statement.

1. Eukaryotic Gene ____                                A. Composed of RNA

2. Exon   ____                                                 B. Composed of DNA

3. Intron    ____                                                C. RNA Polymerase binds here for transcription initiation

4. Promoter    _____                                         D. Binding site for protein which is an activator of transcription                                                   

5. Translation initiation site   ____                    E. Three nucleotides which code for one amino acid

6. Codon ____                                                  F. Non coding region of gene; removed after transcription

7. Enhancer _____                                           G. Contains an ATG codon

        

                                                                          H. Segment of gene which codes for segment of encoded protein

b. (3 pts) Choose three of the above elements which are also present in a prokaryotic gene:

Element 1 ____          Element 2 ____     Element 3 ____

27. (2 pts) Place the following steps in cloning human insulin DNA into bacteria in correct order:

1. Use transformation to deliver new recombinant DNA to bacterial cells

2. Use restriction enzyme from step 3 to cut bacterial plasmid. Then add cut human insulin cDNA

3. Cut human insulin cDNA at each end with restriction enzyme

4. Convert human insulin mRNA to human insulin cDNA using the enzyme reverse transcriptase

5. Allow the enzyme DNA ligase to seal the new gene in to the vector (bacterial plasmid)

6. Allow bacterial cells to replicate and produce insulin.

a. 4, 3, 2, 5, 6, 1        b. 3, 2, 4, 5, 6, 1       c. 2, 3, 4, 5, 1, 6        d. 1, 3, 2, 4, 5, 6        e. 4, 3, 2, 5,1, 6   

28. (2 pts) Blue/White screening is used to screen bacterial colonies in gene cloning methods. Which bacterial colony is selected for expression of a gene?

a. A white colony. These bacteria do not have Ampicillin resistance.

b. A blue colony. These bacteria express the foreign gene inserted into the plasmid.

c. A white colony. These bacteria do not express the LacZ gene.

d. A blue colony. These bacteria do not express the LacZ gene.

Answer 1

26,

1, Eukaryotic gene- composed of DNA

A gene is composed of DNA which as acts as template for RNA which further leads to gene expression

2, Exon- segment of gene which codes of segment of encoded protein

Exons are called as the coding regions of a gene which is expressed as proteins after translation

3, Intron- Non coding regions of the gene removed after transcription

Introns are non coding regions of the gene which is spliced off during post transcriptional modification in eukaryotic gene.

4, Promoter- RNA polymerase binds here for transcription initiation

Promoters are sequences in RNA to which RNA polymerases binds to initiate transcription

5, translational initiation site- contains an ATG codon

ATG or AUG is the initiation codon which codes for methionine.

6, codon- three nucleotides which codes for an amino acid

The bases in the DNA are grouped into three bases called codons. Each codon is specific for one amino acid.

7, enhancer- binding site of a protein which is an activator of the transcription

Enhancers bind to acfivators to increase the chances of transcription of the required gene.

B, the elements comon for both prokaryotic and eukaryotic gene are.,

Element-1- promoter

Element-2- codons

Element-3- translational initiation site (AUG which codes for f-methionine)

27, 4,3,2,5,1,6 is the correct order

4,convert human insulin mRnA into c-DNA using reverse transcriptase

3, cut human insulin cDNA with restriction enzymes at both the ends

2,use the same restriction enzyme and cut the bacterial plasmid and add both together

5, allow DNA ligase to seal them both (insulin c-DNA and bacterial plasmid)

1, use transformation to deliver this gene into a host bacterial cell

6, allow bacterial cells to replicate and produce insulin