2.11 part 2

Biotechnology

Manipulation of organisms or their components to make useful products.

Biotechnology dates back to early civilization

Using yeast to make bread/beer and selective breeding of livestock.

Modern biotechnology = DNA technology

Modern lab techniques for studying and manipulating genetic material.

Movement of genes between organisms

Scientists can move genes between bacteria, plants, and animals.

Genetically modified organism (GMO)

Organism that has acquired one or more genes by artificial means.

Transgenic organism

Recombinant organism with a gene from another species.

Biotechnology boom (1970s)

Development of lab methods for recombinant DNA.

Recombinant DNA

Combining DNA from two different sources into one molecule.

Genetic engineering

Direct manipulation of genes for practical purposes.

Engineered bacteria use

Bacteria used to mass-produce chemicals (ex: cancer drugs, pesticides).

E. coli in biotechnology

Bacterial workhorse of modern biotechnology.

Plasmids

Small circular DNA molecules that duplicate separately; used as vectors.

Why plasmids are key

They can carry any gene and pass it to future generations → important for cloning.

DNA cloning

Production of multiple identical copies of a DNA segment.

Step 1 of cloning: Isolation of DNA

Biologist isolates plasmids and foreign DNA containing the gene of interest.

Step 2: Formation of recombinant DNA

Plasmid DNA + foreign DNA are joined → recombinant plasmids.

Step 3: Transformation

Bacteria take up recombinant plasmids.

Step 4: Bacterial cloning

Bacteria divide → clone of identical cells containing cloned gene.

Step 5: Gene cloning

Cloning specifically of a gene-carrying DNA segment.

Step 6: Protein/gene production

Bacteria produce proteins or copies of the cloned gene.

Restriction enzymes

Bacterial enzymes used as cutting tools for recombinant DNA.

Restriction site

DNA sequence recognized by a restriction enzyme.

Sticky ends

Single-stranded DNA overhangs created by staggered cuts.

DNA ligase function

Seals bonds between DNA fragments → permanent recombinant DNA.

CRISPR-Cas9

Tool that edits specific genes in living cells.

Guide RNA function

Directs Cas9 to the correct genome location.

CRISPR gene repair

Uses normal DNA as template to fix mutations → search and replace.

Protein production strategy

Insert gene into bacteria/yeast → produce protein in bulk.

Humulin

First genetically engineered pharmaceutical; human insulin made by GM bacteria.

Insulin purpose

Hormone regulating blood glucose; absence → type 1 diabetes.

Before recombinant insulin

People used cow/pig insulin.

1978 insulin breakthrough

Synthetic human insulin genes inserted into E. coli → mass production.

Yeast as expression system

Used for proteins needing eukaryotic processing (HBV vaccine, interferons).

Mammalian cell expression

Used for EPO and other proteins requiring mammalian modifications.

Transgenic animals

Used to produce drugs (example: lysozyme in milk).

Vaccines definition

Harmless derivative of pathogen used to stimulate immunity.

HBV vaccine example

Produced using genetically engineered yeast.

Why yeast instead of bacteria

Some human proteins require eukaryotic cells to be made correctly.

GM crops in the U.S.

Most corn, soybean, and cotton are genetically modified.

Examples of GM crops

Strawberries (antifreeze protein), rice/potatoes (cholera proteins).

Golden rice 2

Transgenic rice with added vitamin A precursor to prevent deficiency.

GMO definition

Organism with artificially introduced DNA.

Human gene therapy definition

Treating disease by inserting normal genes into patient cells.

Why bone marrow stem cells

They multiply for life and produce all blood cells → ideal therapy targets.

Gene therapy process summary

Insert normal gene into virus → infect patient cells → gene inserted → protein made.

DNA profiling definition

Determining whether DNA samples come from same individual.

PCR purpose

Amplify small DNA samples rapidly and precisely.

Why tiny DNA traces are enough

PCR can amplify even from ~20 cells.

Primers in PCR

Short DNA sequences marking start/end of target region.

STRs definition

Short tandem repeats: repeated DNA sequences in noncoding regions.

Why STRs are useful

Different people have different numbers of repeats.

Gel electrophoresis purpose

Separates DNA fragments by size and charge.

Gel electrophoresis movement

Shorter fragments move faster toward positive electrode.

Bioinformatics

Computational analysis of biological data.

Next-generation sequencing

Sequencing millions of DNA fragments simultaneously.

Genomics

Study of entire sets of genes.

Proteomics

Study of entire sets of proteins.

Shotgun sequencing

Genome chopped → fragments sequenced → computer assembles.

GenBank

Public DNA sequence database maintained by NCBI.

Genome medical benefits

Helps identify disease-associated genes.

Proteomics importance

Humans have ~21k genes but ~100k proteins.

Systems biology

Studies interactions between genes/proteins in whole systems.

TCGA purpose

Analyze gene and protein interactions involved in cancer.

Genomics vs proteomics

Genomics = genes; proteomics = proteins.

GM crop concerns

Herbicide-resistance genes may spread to wild plants.

Genetic privacy issue

DNA profiling could identify nearly all criminals → privacy vs safety debate.