FDC DNA Analysis Techniques

Question 1

What is Polymerase Chain Reaction (PCR) used for in DNA analysis?

Accepted Answer

To amplify DNA segments

Answer

Polymerase Chain Reaction (PCR) is a fundamental technique in DNA analysis used to amplify specific segments of DNA, creating millions of copies from even a tiny sample. This amplification is crucial in forensic science because crime scene evidence often contains only minute amounts of DNA, which would otherwise be insufficient for further analysis. PCR enables the generation of enough material for techniques like STR profiling.

Question 2

What technique separates DNA fragments based on size?

Accepted Answer

Gel electrophoresis

Answer

Gel electrophoresis is a laboratory technique that separates DNA fragments based on their size and electrical charge. DNA fragments, being negatively charged, migrate through a gel matrix towards a positive electrode when an electric current is applied. Smaller fragments move faster and further through the gel than larger ones, allowing for their effective separation and visualization, which is crucial for DNA profiling.

Question 3

What is the purpose of DNA extraction in forensic analysis?

Accepted Answer

Isolate DNA from cells

Answer

The purpose of DNA extraction in forensic analysis is to isolate and purify DNA from other cellular components, such as proteins, lipids, and carbohydrates, found in biological samples. This crucial initial step makes the DNA accessible for subsequent analytical techniques like PCR and STR analysis. Proper extraction is essential to remove contaminants that could interfere with downstream reactions and lead to inaccurate results.

Question 4

What is Short Tandem Repeat (STR) analysis?

Accepted Answer

Examining repeated DNA sequences

Answer

Short Tandem Repeat (STR) analysis is a widely used forensic technique that examines specific regions of DNA containing short, repeating nucleotide sequences. Individuals inherit a unique number of these repeats from each parent, creating a highly variable and distinctive genetic profile. By analyzing multiple STR loci, forensic scientists can generate a unique DNA profile for individual identification, crucial for linking suspects to crime scenes.

Question 5

What is the role of a DNA sequencer?

Accepted Answer

Determine nucleotide order

Answer

The primary role of a DNA sequencer is to determine the precise order of nucleotides (adenine, guanine, cytosine, and thymine) within a DNA molecule. While other techniques amplify or separate DNA, sequencing provides the exact genetic code. This detailed information is essential for advanced genetic analysis, identifying specific mutations, or confirming the identity of a DNA sample with high precision.

(FDC) Forensic DNA Certification Practice Test

(FDC) Forensic DNA Certification Practice Test

FDC DNA Analysis Techniques