Biology Unit 4 AOS 2

Which of the following statements is false?

• Endonucleases act as molecular scissors.

• Ligases have specific recognition sites.

• Polymerases catalyse the synthesis of polynucleotides.

• Sticky-end endonucleases generate DNA fragments with overhanging nucleotides.

The following DNA strand was cut by three restriction enzymes, how many fragments will be formed?

5' A T C G A T C T T A A G C T T C G A A G G A T C C A T T3'

3' T A G C T A G A A T T C G A A G C T T C C T A G G T A A5'

Fill in the blank

___________ a protein that joins DNA fragments together

Fill in the blank

___________ the result of a staggered cut in a DNA strand by an enzyme

Fill in the blank

___________ cut fragments of DNA at known sites

Select all the following that are true about Polymerase Chain Reaction (PCR)

• Uses Taq polymerase

• Use Taq endonuclease

• Goes runs in the following order 1. Denaturation, 2. Annealing, 3. Elongation 4. Repeat

• triples the amount of DNA each cycle.

• Uses DNA primers

The following are the steps involved in setting up a gel electrophoresis experiment. Which option indicates the correct order of these steps?

1. DNA samples are loaded into wells in each lane of the agarose gel.

2. Bands can be cut from the gel and purified for use in further experiments.

3. Gel is submerged in buffer and an electric current is passed through the samples.

4. DNA is prepared using restriction enzymes or PCR.

5. DNA samples are loaded into bands of the agarose gel.

6. Bands are visualised under ultraviolet light.

7. DNA fragments migrate towards the positive electrode.

8. DNA fragments migrate towards the negative electrode.

• 4,1,3,8,6

• 4,1,3,7,6,2

• 5,3,7,4,6,2

• 1,3,8,4,6

Which option correctly labels the diagram

• A

• B

• C

• D

Which suspect is guilty?

• suspect 1

• suspect 2

• suspect 3

• suspect 4

Which DNA fragment will travel the farthest?

• A 300 BP circular fragment

• A 100 BP linear fragment

• A 100 BP circular fragment

• A 300 BP linear fragment