Manipulating Genomes

What Manipulating Genomes covers

Manipulating genomes is the third section of Module 6. It covers DNA sequencing and what bioinformatics does with the result, DNA profiling and the polymerase chain reaction, gel electrophoresis, the enzymes and vectors used to move a gene between organisms, and the ethics of doing so.

The 4 subtopics

Each one has its own page.

• DNA sequencing and bioinformaticsSanger sequencing and the chain-terminating ddNTPs, high throughput sequencing, and what synthetic biology, bioinformatics and computational biology do with a sequence.Open →
• DNA profiling, PCR and gel electrophoresisWhat a DNA profile relies on and its forensic and medical uses, the three temperature steps of PCR and why Taq polymerase is used, and how electrophoresis separates fragments.Open →
• Genetic engineering: restriction enzymes and vectorsRestriction enzymes and the sticky ends they leave, plasmids as vectors, DNA ligase and recombinant DNA, and electroporation as a way into a cell.Open →
• Genetic modification, its ethics, and gene therapyGenetically modified soya, pathogens used in research and pharming, the ethical and technology transfer concerns raised, and somatic and germ line gene therapy.Open →

What you need to know

Answer each one before you reveal it.

Take Manipulating Genomes further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Restriction endonuclease vs DNA ligase

  Restriction endonuclease: an enzyme that cuts DNA at a specific recognition sequence. DNA ligase: an enzyme that joins DNA fragments by sealing the sugar-phosphate backbone.

• Polymerase chain reaction vs Gel electrophoresis

  Polymerase chain reaction: a method of amplifying a DNA sequence in vitro through repeated cycles. Gel electrophoresis: a method of separating DNA fragments by size using an electric field.

• Sanger sequencing vs DNA profiling

  Sanger sequencing: determining a base sequence using chain-terminating dideoxynucleotides. DNA profiling: comparing the lengths of repeated non-coding regions to identify an individual.

Questions from this topic

Each one with the model answer underneath.

1. 1

   What does DNA sequencing determine?

   Model answer

   The precise order of nucleotide bases (A, T, C, G) in a DNA molecule.

2. 2

   What are dideoxynucleotides (ddNTPs) and why do they cause chain termination in Sanger sequencing?

   Model answer

   Dideoxynucleotides lack a 3' hydroxyl group, so when incorporated into a growing DNA strand, no further nucleotides can be added, causing chain termination.

3. 3

   How does Sanger sequencing produce a readable DNA sequence?

   Model answer

   It produces DNA fragments of different lengths, each terminated at a specific base; these fragments are separated by size to read the sequence.

4. 4

   What advantages does high throughput sequencing offer compared to Sanger sequencing?

   Model answer

   It allows much faster and cheaper sequencing of entire genomes.

5. 5

   How can gene sequencing be used to study genetic variation within a species?

   Model answer

   It enables genome-wide comparisons between individuals of the same species to identify genetic variation.

6. 6

   How does gene sequencing help establish evolutionary relationships?

   Model answer

   It enables genome-wide comparisons between different species to search for evolutionary relationships.

What is inside Levo

Six ways to work the same material.

Manipulating Genomes revision questions

What does Manipulating Genomes cover in OCR A-Level Biology?

4 subtopics: dna sequencing and bioinformatics, dna profiling, pcr and gel electrophoresis, genetic engineering: restriction enzymes and vectors and genetic modification, its ethics, and gene therapy. Each one has its own page with questions and model answers.

How is Manipulating Genomes organised?

By the OCR H420 specification, subtopic by subtopic, so it matches the order you are taught it in.