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Gene technologies allow the study and alteration of gene function allowing a better understanding of organism function and the design of new industrial and medical processes (A-level only)

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Question 4

Short tandem repeats (STRs) are repetitive sequences of DNA used in genetic profiling. A geneticist isolates a specific locus containing an STR with a size of 14 base pairs.

a.

Describe how the target STR region can be cut and isolated from a genomic DNA sample.

[2]
b.

The PCR amplification of this STR requires knowing the specific base sequences on either side (flanking) of the target locus. Explain why knowing these flanking sequences is essential for the PCR process.

[2]
c.

A sample containing a single double-stranded DNA molecule of this 14-base-pair STR is amplified through 45 cycles of PCR. Calculate the total number of base pairs in all the generated STR molecules after 45 cycles. Show your working and give your answer in scientific notation.

[2]
d.

Explain how gel electrophoresis separates different STR fragments. State two characteristics of the DNA fragments that make this separation possible.

[2]

Gene technologies allow the study and alteration of gene function allowing a better understanding of organism function and the design of new industrial and medical processes (A-level only) Questions

  1. A Level
  2. /Biology
  3. /Gene technologies allow the study and alteration of gene function allowing a better understanding of organism function and the design of new industrial and medical processes (A-level only)