Bio chapter 14

PCR Steps•

A DNA sample is mixed with nucleotides, the DNA replication enzyme DNA polymerase, and a few other ingredients • The solution is then exposed to cycles of heating (to separate the DNA strands) and cooling (to allow double-stranded DNA to re-form) • During these cycles, specific regions of each molecule of DNA are replicated, doubling the amount of that DNA The result of this chain reaction is an exponentially growing population of identical DNA molecules

vaccine

A ______________ is a harmless variant or derivative of a disease-causing microbe — such as a bacterium or virus — that is used to prevent an infectious disease • When a person is inoculated, the vaccine stimulates the immune system to develop lasting defenses against the microbe

Cutting and Pasting DNA with Restriction Enzymes

After a restriction enzyme binds to its restriction site, it cuts the two strands of the DNA by breaking chemical bonds at specific points within the sequence, like a pair of highly specific molecular scissors

particular short DNA sequence

Biologists have identified hundreds of restriction enzymes, each recognizing a _____________________, usually four to eight nucleotides long

forensics

DNA profiling has rapidly transformed the field of _____________, the scientific analysis of evidence for crime scene investigations and other legal proceedings To produce a DNA profile, scientists compare DNA sequences that vary from person to person

Vaccines

DNA technology helps medical researchers develop ________

staining, radiolabeling, or fluorescence labeling

Once the gel is done running; a series of bands is left in each column of the gelEach band is a collection of DNA fragments of the same lengthThe bands can be made visible by __________________________________

Safety and Ethical Issues

Early concerns about DNA technology focused on the possibility of creating hazardous new disease-causing organisms • To address such concerns, scientists developed a set of guidelines that have become formal government regulations in the United States and some other countries • One safety measure in place is a set of strict laboratory procedures to protect researchers from infection by engineered microbes and to prevent microbes from accidentally leaving the laboratory• Certain obviously dangerous experiments have also been banned

DNA Profiling Steps•

First, DNA samples are isolated from the crime scene, suspects, victims, or other evidence • Next, selected sequences from each DNA sample are amplified (copied many times) to produce a large sample of DNA fragments • Finally, the amplified DNA fragments are compared• All together, these steps provide data about which samples are from the same individual and which samples are unique

vaccine

For many viral diseases, the only way to prevent serious harm from the illness is to use vaccination to prevent the illness in the first place for example, the vaccine against hepatitis B, a disabling and sometimes fatal liver disease, is produced by genetically engineered yeast cells that secrete a protein found on the microbe's outer surface

Human Gene Therapy

Ideally, the non-mutant version of the gene would be inserted into cells that multiply throughout a person's life.Bone marrow cells, which include the stem cells that give rise to all the types of blood cells, are prime candidates.If the procedure succeeds, the cells will multiply permanently and produce a steady supply of the missing protein, thus curing the patient

transgenic organism

If the newly acquired gene is from another organism, typically of another species, the recombinant organism is called a ____________________

1978

In ________, scientists working at a biotechnology company chemically synthesized DNA fragments and linked them to form the two genes that code for the two polypeptides that make up human insulin • They then inserted these artificial genes into E. coli host cells• Under proper growing conditions, the transgenic bacteria cranked out large quantities of the human protein

1982

In _________, Humulin hit the market as the world's first genetically engineered pharmaceutical product • Today, it is produced around the clock in gigantic fermentation vats filled with a liquid culture of bacteria • Each day, more than 4 million people with diabetes use the insulin collected, purified, and packaged at such facilities

insulin

In humans, __________is a protein normally made by the pancreas

next-generation sequencing

In one standard procedure, the DNA is first cut into fragments, and then each fragment is sequenced • In the past decade, "___________________________" techniques have been developed that can simultaneously sequence thousands or hundreds of thousands of fragments, each of which can be 400-1,000 nucleotides long

bioinformatics

In the past decade, new experimental techniques have generated enormous volumes of data related to DNA sequences• The need to make sense of an ever-increasing flood of information has spawned the field of ___________, the application of computational methods to the storage and analysis of biological data

type 1 diabetes

Insulin functions as a hormone and helps regulate the level of glucose in the blood• If the body fails to produce enough insulin, the result is ___________________

sickle-cell disease, hemophilia, cystic fibrosis, Huntington's disease, and Duchenne muscular dystrophy

Medical scientists can now diagnose hundreds of human genetic disorders by using PCR with primers that target the genes associated with these disorders: ______________________

genetically modified organisms (GMOs)

Organisms that have acquired one or more genes by artificial means are called __________________

gene cloning

Plasmids are key tools for _______________ the production of multiple identical copies of a gene-carrying piece of DNA

genetic engineering

Recombinant DNA technology is widely used in ________________, the direct manipulation of genes for practical purposes Scientists have genetically engineered bacteria to mass-produce a variety of useful chemicals, from cancer drugs to pesticides • Scientists have also transferred genes from bacteria to plants and from one animal species to another

DNA sequencing

Researchers can exploit the principle of complementary base pairing to determine the complete nucleotide sequence of a DNA molecule• This process is called ____________

recombinant DNA

Scientists can construct ________________ by combining pieces of DNA from two different sources — often from different species — to form a single DNA molecule

DNA profiling

Such evidence can be examined by ___________, the analysis of DNA samples to determine whether they come from the same individual

restriction site

The DNA sequence recognized by a particular restriction enzyme is called a _________________

restriction enzymes

The cutting tools used for making recombinant DNA are bacterial enzymes called ______________

primers

The key to amplifying one particular segment of DNA and no others is the use of ____________, short (usually 15-20 nucleotides long), chemically synthesized single-stranded DNA molecules • For each experiment, specific primers are chosen that are complementary to sequences found only at each end of the target sequence

DNA amplification by PCR

The polymerase chain reaction (PCR) is a method for making many copies of a specific segment of DNA. Each round of PCR, performed on a tabletop thermal cycler (shown at top), doubles the total quantity of DNA.

Primers

The primers thus bind to sequences that flank the target sequence, marking the start and end points for the segment of DNA to be amplified • Beginning with a single DNA molecule and the appropriate primers, automated PCR can generate hundreds of billions of copies of the desired sequence in a few hours

(1)a restriction enzyme, which cuts the original DNA molecules into pieces, and (2)DNA ligase, which pastes the pieces together

The production of recombinant DNA requires two enzymes:

1990

The project began in ________ as an effort by government-funded researchers from six countries At the completion of the project, more than 99% of the genome had been determined to 99.999% accuracy • This ambitious project has provided a wealth of data that may illuminate the genetic basis of what it means to be human

restriction fragments

The restriction enzyme cuts the DNA strands within the recognition sequence, producing pieces of DNA called ___________________

"sticky ends"

The staggered cuts yield two double-stranded DNA fragments with single-stranded ends, called _________________ ___________ are the key to joining DNA restriction fragments originating from different sources

proteomics

The successes in genomics have encouraged scientists to begin similar systematic studies of the full protein sets that genomes encode (proteomes), an approach called _____________

bacterial plasmids

To manipulate genes in the laboratory, biologists often use _______________, which are small, circular DNA molecules that duplicate separately from the larger bacterial chromosome

gel electrophoresis

To separate and visualize DNA fragments of different lengths, researchers carry out a technique called __________________, a method for sorting macromolecules — usually proteins or nucleic acids — primarily by their electrical charge and size

1. Bacterial plasmids that will serve as vectors and 2. DNA from another organism that includes the gene of interest

To start, the biologist isolates two kinds of DNA:

DNA technology methods

Using ______________, scientists can modify specific genes and move them between organisms as different as bacteria, plants, and animals

DNA Profiling and Forensic Science

When a crime is committed, body fluids (blood, semen) or small pieces of tissue (skin beneath a victim's fingernails) may be left at the scene or on the victim or assailant

Humulin

_______________ is human insulin produced by genetically modified bacteria

The Human Genome Project

________________ was a massive scientific endeavor to determine the nucleotide sequence of all the DNA in the human genome and to identify the location and sequence of every gene

Human gene therapy

__________________ is intended to treat disease by introducing new genes into an afflicted person

The polymerase chain reaction (PCR)

____________________________is a technique by which a specific segment of DNA can be amplified: targeted and copied quickly and precisely • Through PCR, a scientist can obtain enough DNA from even minute amounts of blood or other tissue to allow a DNA profile to be constructed

Biotechnology

_______________is the manipulation of organisms or their components to make useful products