​Quizzes

 Answers of Quiz #1

1.   a) Anaphase       

      b) 4     

2.  ACTAGT

     TGATCA

     or the like sequences

3.   a) Lane 2

       b) 77+175 resulting in the 252 bp band

            97+45 resulting in the 142 bp band

4.  a) P20

     b) P20

     c) P10

     d) P200

5. Heavy fragments run slowly, whereas light fragments run fast

6. To precipitate the DNA

7.  G2: 0.36x2=0.72 pg

     Metaphase: 0.36x2=0.72 pg

     Each daughter cell: 0.36 pg

8. DNA bands on the EcoRI lane:  9 (two 9-kb bands overlap), 3, 1

    DNA bands on the HindIII lane: 12, 7, 3

    DNA bands on the EcoRI+HindIII lane: 7, 5, 4, 3, 2, 1

         

 Answers of Quiz #2

1. The order from top: 11, 8, 4, 10, 1, 2, 9, 5, 7, 3, 6

 

2. The DNA polymerase must withstand high temperatures because PCR amplification requires temperatures as high as 92 degrees, or even higher

 

3. Step 3;  annealing temperature must be about 5 degrees lower than the melting temperature 

 

4. To eliminate (kill) non-transformed E. coli cells

 

5. Ligation; the amplified DNA failed to be taken up by the vector, thus all transformed E. coli cells carried non-recombinant (empty) vector

 

6. Forward primer 5' GTCGA 3'; anneals to the 3' end of the first five bases of the target region on the lower sequence

    Reverse primer 5' AGGTA 3'; anneals to the 3' end of the first five bases of the target region on the upper sequence

 

7. The 1 kb fragment between B and H

 

8. The last HindIII lane:  the band underneath the vector should not be visible, also the three smaller bands (542, 256, and 83 bp) are missing

Possible cause: human error resulting from carelessness, playing with cellphone while doing the experiment, etc.