ch 14

Chapter 14: Biotechnology

14.1 What Is Biotechnology?

Biotechnology is the manipulation or modification of living organisms or their components to produce useful products or services. It encompasses both ancient and modern techniques for improving organisms and creating new products.

• Ancient biotechnology: Includes the use of yeast to make bread and wine, and the selective breeding of plants and animals.

• Modern biotechnology: Involves genetic engineering to manipulate individual genes directly, instead of only modifying organisms through selective breeding.

• Organisms containing DNA that has been modified through genetic engineering are called genetically modified organisms (GMOs).

• Biotechnology applications include medicine, agriculture, and forensic science.

Key Terms: Biotechnology, genetic engineering, GMOs, selective breeding

14.2 What Natural Processes Recombine DNA Between Species?

DNA can be recombined between species through natural processes such as transformation and viral infection. These processes are foundational to genetic engineering and biotechnology.

• Transformation: Bacteria can pick up pieces of DNA from the environment (chromosomal or plasmid DNA).

• Plasmids: Small, circular DNA molecules found in bacteria that can carry genes useful for survival (e.g., antibiotic resistance).

• Genetic engineering: Modern biotechnology uses tools to manipulate cells or organisms by adding, deleting, or modifying genes.

• Viruses: Can transfer genetic material between species. Viral reproduction involves attachment, entry, replication, assembly, and release of new viruses.

Example: Genetically modified pig kidneys for transplantation in humans.

Table: Comparison of Natural DNA Recombination Processes

Process	Description	Application
Transformation	Uptake of DNA from environment by bacteria	Genetic engineering, cloning
Viral Infection	Virus injects genetic material into host cell	Gene therapy, transgenic organisms
Plasmid Transfer	Exchange of plasmids between bacteria	Antibiotic resistance, biotechnology

14.3 What Are Some Key Methods for Manipulating DNA?

Modern biotechnology relies on molecular tools to manipulate DNA, including PCR and CRISPR-Cas9. These methods allow scientists to amplify, edit, and analyze genetic material.

• PCR (Polymerase Chain Reaction): Amplifies DNA, making millions of copies of a specific DNA segment.

• CRISPR-Cas9: A molecular tool for editing DNA at precise locations, using guide RNA to target specific sequences.

• Restriction enzymes: Cut DNA at specific sequences, useful for cloning and genetic engineering.

PCR Steps:

1. Melting: DNA is heated to separate strands.

2. Annealing: Temperature is lowered to allow primers to bind to target DNA.

3. Extension: DNA polymerase synthesizes new DNA strands.

Equation:

$N = 2^n$ Where $N$ is the number of DNA copies after $n$ cycles of PCR.

CRISPR-Cas9 Mechanism: Guide RNA directs Cas9 enzyme to a complementary DNA sequence, where Cas9 cuts both strands, allowing for gene editing.

14.4 How Is Biotechnology Used in Forensic Science?

Biotechnology is essential in forensic science for DNA profiling, which helps identify individuals based on their genetic makeup.

• Short Tandem Repeats (STRs): Segments of DNA with repeating sequences, used to distinguish individuals.

• PCR: Used to amplify STR regions from DNA samples.

• Gel electrophoresis: Separates DNA fragments by size, allowing visualization of STR patterns.

• DNA profiles: Unique patterns of STRs used to match samples to individuals.

Table: Steps in DNA Profiling

Step	Description
Sample Collection	Obtain DNA from crime scene or individual
PCR Amplification	Amplify STR regions
Gel Electrophoresis	Separate DNA fragments by size
Profile Analysis	Compare STR patterns to database

14.5 How Are Transgenic Organisms Made?

Transgenic organisms are created by introducing foreign genes into the genome of another species, resulting in genetically modified organisms (GMOs).

• Gene isolation: Obtain the desired gene (e.g., insulin gene).

• Recombinant DNA: Insert the gene into a vector (often a plasmid).

• Transformation: Introduce recombinant DNA into host cells.

• Cloning: Host cells replicate, producing copies of the gene and its product.

Example: Bacteria engineered to produce human insulin.

Table: Steps in Creating a Transgenic Organism

Step	Purpose
Gene Isolation	Identify and extract target gene
Vector Preparation	Prepare plasmid or viral vector
Gene Insertion	Insert gene into vector
Transformation	Introduce vector into host organism
Selection and Cloning	Grow host cells and select for successful transformants

Additional info:

• Gene therapy uses viral vectors to deliver therapeutic genes to human cells.

• Ethical issues in biotechnology include concerns about GMOs, gene editing, and privacy in DNA profiling.