DNA testing - PCR and electrophoresis

name the technique known as PCR

Polymerase chain reaction

outline the process of PCR

95 → Depuration / strand separation / Breaking of H bonds

68 → annealing / primers are added to DNA

72→ Synthesis of new strands / addition of nucleotides ( to new DNA)

why a temp of 72 - 75 at final steps for PCR

To keep the optimum temperature for enzymes

why PCR step is usually necessary when creating a DNA profile from a crime scene ?

initial sample is small, not enough DNA to begin with

why some loci have 2 peaks but some only have one peaks ?

2 peaks → different alleles / heterozygous

1 peak → same allele / homozygous

difference in process of TLC and electrophoresis used for sequence DNA

TLC → Dye used in TLC/ separate non charged particles / not automated / no electricity used / separates by solubility with the stationary phase

Electrophoresis → no dyes used / separated only charged particles / automated / uses electricity / separates by size in electrophoresis / fluorescent tags used in electrophoresis.

why only selected of non coding DNA are used when a profiles a human

Genome are similar / same

coding sequence not provide unique profile

parts of non coding DNA contains variable numbers of short tandem repeats

why DNA polymerase used ?

Thermostable around 93*c

2 solutions that should be added before electrophoresis

Buffer solution : maintain optimum pH

Dye or stains : see and monitor the process of the bands/ DNA / fragments