Year 10 Science · Unit 1 · Lesson 8

DNA Technologies, Profiling and Forensics

Foundation Worksheet

Name

Date

Class

Learning Goals

Recall the steps of DNA profiling in the correct order for a forensic case.
Use key vocabulary (STR, PCR, gel electrophoresis, DNA profile) accurately in context.
Identify real-world applications of DNA technology in Australian forensics and conservation.

Warm Up

Order the steps

Number the events from 1 to 6 to show the correct order of DNA profiling in a forensic investigation. Event 1 = what happens first.

Order	Event
	Capillary electrophoresis separates and detects the amplified STR fragments by size, producing data for the DNA profile.
	A DNA sample is collected from the crime scene (e.g. blood, hair, saliva).
	The suspect's DNA profile is compared with the evidence profile to look for a match.
	PCR is used to amplify (copy) the tiny DNA sample millions of times.
	Data analysis determines the fragment lengths at the selected STR loci and records the corresponding alleles in a DNA profile.
	The results are interpreted, and findings are reported to investigators or court.

Forensic STR workflows commonly separate and detect amplified fragments by capillary electrophoresis. A gel band diagram is a simplified classroom model of how electrophoresis separates DNA fragments by size.

Your Turn

Fill the gap

Choose the correct word from the word bank to complete each sentence.

sequencing PCR smaller identical twins gel electrophoresis highly discriminating STRs negative

DNA profiling analyses regions of DNA called , which are short repeating sequences that vary between individuals. The technique used to separate DNA fragments by size is called . In this process, DNA is in charge, so it moves toward the positive electrode. fragments travel farther through the gel. Before analysis, a tiny DNA sample is copied millions of times using . Standard STR profiling usually cannot distinguish . A profile can be , but a match needs statistical interpretation and does not alone prove identity.

Show What You Know

1. Name two applications of DNA profiling other than identifying suspects in criminal investigations. For each, explain in one sentence how DNA profiling helps.

Recall 2 marks

2. The Australian federal police use a national DNA database called the NCIDD. Describe one benefit and one limitation of storing DNA profiles in a national database.

Recall 2 marks

Wrap Up

In one sentence, what is the main idea of DNA profiling in your own words?