Evidence Analysis, Recovery and QA

Question 1

When may DNA samples be rejected?

Answer 1

If they are non-compliant

Question 2

What does PPE protect?

Answer 2

Staff and exhibits

Question 3

How are exhibits separated?

Answer 3

By time and space

Question 4

What is paramount in a lab?

Answer 4

Cleanliness

Question 5

How is packaging opened?

Answer 5

In a way that protects the seals as much as possible

Question 6

How are details of an exhibit recored?

Answer 6

On a worksheet

Question 7

What is the point of examination?

Answer 7

To identify points of interest

Question 8

What can go wrong in a lab? (6)

Answer 8

Staff, equipment, tests, procedures, integrity and delivery

Question 9

How often is a method tested for quality control?

Answer 9

Constantly

Question 10

What about samples is argued in court?

Answer 10

Integrity

Question 11

How many cells are required for a DNA profile?

Answer 11

At least 3

Question 12

How are results interpreted?

Answer 12

Based on guidelines

Question 13

What happens when something goes wrong?

Answer 13

Corrective action is taken

Question 14

What ensures standards are met?

Answer 14

Accreditation

Question 15

What is removed in DNA extraction?

Answer 15

Interfering proteins and enzymes

Question 16

What are the two DNA extraction steps?

Answer 16

Breaking the matrix and lysing the cells

Question 17

How is a DNA matrix broken? (2)

Answer 17

Mechanical (Mortar and pesel) or Chemical (Protein Kinase A)

Question 18

What is the difference between organic extraction, silica kits and Chelex?

Answer 18

Organic extraction is more pure but takes longer than Chelex. Silica kits are in between.

Question 19

What is the most widely used form of DNA extraction?

Answer 19

Organic

Question 20

Why is Chelex advantageous for PCR?

Answer 20

Because it removes inhibitors

Question 21

What is quality assurance?

Answer 21

The planned, systematic practise to provide confidence in a product

Question 22

What is quality control?

Answer 22

The scrutiny of daily techniques

Question 23

Why are audits conducted?

Answer 23

To make sure standards are met

Question 24

What do positive and negative tests ensure?

Answer 24

Reagents are working properly

Question 25

What is validations purpose?

Answer 25

To show that techniques are robust

Question 26

What provides interpretation guidelines?

Answer 26

Standard Operating Procedures

Question 27

What does too much DNA result in?

Answer 27

Overblown electropherograms

Question 28

What does too little DNA result in?

Answer 28

A loss of alleles

Question 29

How many PCR cycles does it take to have 1 billion copies of DNA?

Answer 29

32

Question 30

How large is a PCR assay?

Answer 30

5-100uL

Question 31

What does a negative control test for?

Answer 31

Contamination

Question 32

Why is contamination an issue with PCR?

Answer 32

Due to how sensitive the method is, it can detect very small amounts of DNA.