Gene Expression, Mutations, and Genetic Engineering. Biology honors, Lawrence, Scott

Prokaryotic cells

Turn genes on and off by controlling transcription.

Promoter

A DNA segment that allows a gene to be transcribed.

Operator

A part of DNA that turns a gene 'on' or 'off'.

Operon

Includes a promoter, an operator, and one or more structural genes that code all the proteins needed to do a job.

Lac operon

Acts like a switch; it is 'off' when lactose is not present and 'on' when lactose is present.

Eukaryotes

Regulate gene expression at many points.

Transcription

Controlled by regulatory DNA sequences and protein transcription factors.

TATA box promoter

Most eukaryotes have this type of promoter.

Enhancers and silencers

Speed up or slow down the rate of transcription.

Exons

Have the information to build the proteins.

Introns

Are used to tell you how much of a protein to produce.

mRNA processing

Includes three major steps: Introns are removed and exons are spliced together, a cap is added, and a tail is added.

Mutations

Changes in DNA that may or may not affect phenotype.

Point mutation

Where one nucleotide is substituted for another.

Frameshift mutation

Inserts or deletes a nucleotide in the DNA sequence.

Chromosomal mutations

Affect many genes and may occur during crossing over, tending to have a big effect.

Translocation

Results from the exchange of DNA segments between nonhomologous chromosomes.

Gene mutations

Some change phenotype, such as causing a premature stop codon, changing protein shape or the active site, or changing gene regulation.

Silent mutation

A mutation that may not affect phenotype.

Mutagens

Such as UV rays and chemicals, can cause mutations.

Restriction enzymes

Cut DNA and act as molecular scissors.

Restriction site

A specific nucleotide sequence where restriction enzymes cut DNA.

Restriction maps

Show the lengths of DNA fragments between restriction sites.

Gel electrophoresis

Used to separate DNA fragments by size, where smaller fragments move faster and travel farther than larger fragments.

Sticky ends

They allow complementary base pairing from what was cut to attach to new pieces.

Polymerase chain reaction (PCR)

A method that rapidly copies segments of DNA.

DNA polymerase

An enzyme used in PCR to copy DNA segments.

PCR process

A three-step process that makes many copies of a specific DNA sequence in a few hours.

Materials used in PCR

DNA to be copied, DNA polymerase, A, T, C, and G nucleotides, and two primers.

Clone

A genetically identical copy of a gene or of an organism.

Cloning in nature

Occurs through bacteria (binary fission), some plants (from roots), and some simple animals (budding and regeneration).

Nuclear transfer

The process used to clone mammals.

Benefits of cloning

Includes making organs for transplant into humans and saving endangered species.

Drawbacks of cloning

Includes low success rates, usually imperfect results, and decreased biodiversity.

Genetic engineering

Involves changing an organism's DNA to give it new traits using recombinant DNA.

Recombinant DNA

DNA based on the genes of multiple organisms.

Transgenic organism

An organism that has one or more genes from another organism inserted into its genome.

Transgenic bacteria

Bacteria used to produce human proteins by inserting a gene into a plasmid and then into bacteria.

Transgenic plants

Plants that express a foreign gene after being infected by transgenic bacteria.

Transgenic animals

Animals used to study diseases and gene functions, such as transgenic mice and gene knockout mice.

Concerns about genetic engineering

Include possible long-term health effects of eating GM foods and effects on ecosystems and biodiversity.

Genomics

The study of genomes, including sequencing and comparisons of genomes within and across species.

Gene sequencing

Determining the order of DNA nucleotides in genes or genomes.

Human Genome Project

A project that has sequenced all of the DNA base pairs of human chromosomes.

Bioinformatics

The use of computer databases to organize and analyze biological data.

DNA microarrays

Used to study the expression of many genes at once.

Proteomics

The study and comparison of proteins.

Genetic screening

Involves testing DNA to detect genetic disorders.

Gene therapy

Replaces defective or missing genes, or adds new genes, to treat a disease.

Technical challenges of gene therapy

Include inserting genes into correct cells, controlling gene expression, and determining effects on other genes.

Commonality of organisms

All organisms have a genetic code that allows genetic engineering to be possible.

Gel electrophoresis

A method that allows DNA to be separated by size.

Electricity in Gel electrophoresis

Pulls the DNA through during the separation process.

Amplifying DNA samples

Done by using PCR (Polymerase Chain Reaction).

Primers in PCR

Must be added to the DNA strand to start the PCR process.

Function of the Human Genome Project

To know the order of the bases and make a database to understand the function of all genes.

Goal achieved by scientists

Determining the order of bases.

Definition of genetic engineering

Moving genes from the chromosome of one organism to the chromosomes of another.