Question

QUESTION

Match the following molecular biology techniques to their correct descriptions.

Restriction Enzyme    Gel Electrophoresis Polymerase Chain Reaction . Sanger Sequencing Gene Cloning

A. Technique for separating charged molecules on the basis of molecular size or charge, or both. B. An enzyme that cuts double-stranded DNA at a specific sequence. C. Method of amplifying DNA fragments quickly in the test tube. D. A technique that makes many identical copies of a piece of DNA, by inserting the target DNA into a circular piece of DNA called a plasmid or vector. E. The selective incorporation of chain-terminating dideoxynucleotides by DNA polymerase during in vitro DNA replication.

5 points   

QUESTION 2

Which of the following DNA sequences could potentially be a recognition site for a restriction enzyme?

YES = The sequence could potentially be a recognition site for a restriction enzyme.

NO = The sequence could NOT potentially be a recognition site for a restriction enzyme.

  

(a) 5' TGCGCA 3'   YES NO

(b) 5' TGCTGC 3'      YES NO

(c) 5' ATTTTA 3'   YES NO

(d) 5' GGATCC 3'   YESNO

(e) 5' CGCG 3'   YESNO

(f) 5' AGGAGG 3'   YES NO

HINT: You will need to generate the complementary strand.

Answer 1

1) Restriction Enzyme- An enzyme that cuts double-stranded DNA at a specific sequence

Restriction enzymes are used to cut at specific sites at the DNA examples of restriction enzymes are endonucleases.

2)Gel Electrophoresis- Technique for separating charged molecules on the basis of molecular size or charge, or both.

Gel electrophoresis is a technique used to separate DNA fragments according to their size. DNA samples are loaded into wells at one end of a gel, and an electric current is applied to pull them through the gel. DNA fragments are negatively charged, so they move towards the positive electrode.

3)Polymerase chain reaction- Method of amplifying DNA fragments quickly in the test tube.

PCR is used to reproduce (amplify) selected sections of DNA or RNA. Previously, amplification of DNA involved cloning the segments of interest into vectors for expression in bacteria

4)Sanger Sequencing- The selective incorporation of chain-terminating dideoxynucleotides by DNA polymerase during in vitro DNA replication.

Sanger sequencing, also known as the chain termination method, is a technique for DNA sequencing based upon the selective incorporation of chain-terminating dideoxynucleotides (ddNTPs) by DNA polymerase during in vitro DNA replication

5)Gene Cloning- A technique that makes many identical copies of a piece of DNA, by inserting the target DNA into a circular piece of DNA called a plasmid or vector.

Gene cloning is process of developing multiple copies of identical genes which are generated by using vectors like plasmids, cosmids and phage vectors.

2)

Restriction enzymes cut at Restriction sites and produces palindromic sites which have the same bases in the both strands and which are not complementary at are not potentially Restriction sites.

a) 5' TGCGCA 3'

     3' ACGCGT 5'

Strand E is complementary producing the same complementary strand hence it produces restriction site with restriction enzyme

b) 5' TGCTGC 3'

     3'ACGACG 5'

Strand b are not complementary hence it not a potentially a restriction site

c)   5' ATTTTA 3'

         3' TAAAAT 5'

Strand C are not complementary hence it not a potentially a restriction site.

d) 5' GGATCC 3'

     3' CCTAGG 5'

Strand D is complementary which reads in the complementary strand hence it produces restriction site with restriction enzyme.

e) 5' CGCG 3'

     3'GCGC 5'

Strand E is complementary producing the same complementary strand hence it produces restriction site with restriction enzyme.

f) 5' AGGAGG 3'

    3' TCCTCC

       Strand f are not complementary hence it not a potentially a restriction site