Biotechnology Unit 4

Restriction Enzymes

Proteins that cut DNA at specific nucleotide sequences, acting like molecular scissors.

Discovery of Restriction Enzymes

First discovered in the 1950s-1960s by Werner Arber, Hamilton Smith, and Danial Nathan.

Blunt Ends

Straight cuts across both strands of DNA formed by restriction enzymes.

Sticky Ends

Staggered cuts leaving single-stranded overhangs, making recombination easier.

How Do Restriction Enzymes Work?

They bind to DNA at recognition sequences, scan the DNA, and cut at specific sites.

Applications of PCR

Used in forensics for DNA amplification from crime scenes, and in genetics for diagnosing disorders.

Polymerase Chain Reaction (PCR)

A technique to make millions of copies of a specific DNA segment.

Recombinant DNA

A DNA molecule containing genetic material from multiple sources, created in a lab.

Gene Therapy

A treatment method involving the modification of genes to replace faulty ones; first FDA approved therapy was in 2023 for sickle cell.

Applications in Genetic Engineering

Restriction enzymes are essential for creating recombinant DNA and inserting genes into plasmids.

Environmental Ethical Issues

Concerns about the potential creation of harmful organisms and unequal access to genetic engineering technology.

SV40 Virus

A virus studied using restriction enzymes that can induce brain and bone cancers.

Asilomar Conference

A landmark meeting in 1975 where scientists established guidelines for the safe use of recombinant DNA technology.

EcoRi

A specific restriction enzyme that recognizes the palindrome sequence GAATTC.

DNA Fingerprinting

A technique that utilizes restriction enzymes to create unique DNA patterns for use in forensic science.

Thermal Cycler

A machine used to perform PCR, controlling the temperature for different steps.

Denaturation

The first step in PCR, where the DNA strands are heated to separate.

Annealing

The cooling phase in PCR where primers attach to the target DNA sequences.

Extension

The step in PCR where DNA polymerase builds new DNA strands.

Danial Nathan

A scientist who used restriction enzymes as a tool for DNA analysis.

Hamilton Smith

The scientist who isolated and characterized the first type II restriction enzyme (HINDIII).

Werner Arber

The scientist who proposed the existence of restriction enzymes in bacteria.

Parental Testing

A method in forensic science that uses DNA fingerprinting based on patterns created by restriction enzymes for determining parentage.

Bacterial Transformation

The process of introducing foreign DNA into bacterial cells, foundational to recombinant DNA technology.

First Recombinant DNA Experiment

Completed by Hubert Boyer and Stanley Cohen, which involved inserting a gene from an African clawed frog into a plasmid.