Chapter 14 Biology: Biotechnology and Genomics

biotechnology

the use of microbiological and biochemical techniques to solve practical problems and produce useful products

what applications does biotechnology have?

• production of drugs and vaccines

• increase yields of foods

• more nutritious foods

• pest resistant plants

• herbicide resistant plants

• cure diseases

recombinant DNA (rDNA) technology

moving genes from one organism to another organism and cloning it

cleave dna

cutting dna of interest at specific locations using restriction enzymes

restriction enzymes

• restriction endonucleases

• proteins that recognize and cut short sequences of DNA

sticky ends

• short, single stranded tails left behind after a restriction enzyme makes a staggered cut

  • unpaired bases that can hydrogen bond with any complementary sequence

vector

a piece of dna that acts as a carrier used to transport the DNA fragment of interest into a host cell

what allows for the vector and foreign DNA to combine?

• they are cut with the same restriction enzyme, so they produce the same sticky ends

  • they are complimentary and can bond together

what is the role of dna ligase?

after the sticky ends bond together, ligase permanently joins them by repairing the phosphodiester bond between the nucleotides where the two DNA fragments were joined.

how is the recombinant dna molecule transferred into cells?

host cells, usually a bacterium, takes up the recombinant DNA from its surrounding environment

what happens as a cell reproduces?

clones of cells form which all contain the same recombinant dna molecule

transgenic organisms

organisms which have had a foreign gene inserted into their genome

genome

the genetic information of an organism or the complete set of genetic information in a cell

genetically modified organisms (GMO)

one whos genome has been modified in some way, usually by using recombinant DNA technology

gene therapy

• uses genetic engineering techniques to treat genetic disorders

• involves the transfer of a working copy of a gene (healthy) into individuals either lacking the gene or possessing defective copies of the gene

gel electrophoresis

• a technique used to separate DNA fragments by size

  • DNA fragments are loaded into a gel and an electric current is applied

  • DNA is negatively charged, so it moves toward the positive end

  • Smaller fragments move faster and further, larger fragments move slower and not as far

  • the result is a pattern of bands that represents fragments of the same size

polymerase chain reaction (PCR)

• allows the synthesis of many copies (amplification) of a section of DNA from a small amount of DNA

  • each cycle doubles the amount of DNA, making it possible to create more then a billion copies of a given region of DNA in 4-5 hours

what is the specific DNA polymerase used in PCR?

• Taq DNA polymerase

  • short for Thermus aquaticus bacteria

why is Taq DNA polymerase used?

PCR requires high heat during the denaturation step, which would destroy a normal DNA polymerase

what ingredients are needed in DNA synthesis reactions in PCR?

• double stranded DNA containing the target sequence

• Taq DNA polymerase

• primers

• deoxynucleotides

what is the cycle of PCR?

1. Denaturation- heat separates the double stranded DNA into two single strands

2. Annealing- DNA is cooled to a lower temperature to allow annealing of primers to the target region

3. Extension- DNA is heated to 72^oC, the optimal temp for Taq DNA polymerase, which works to build a new complimentary strand from each template

what is the device used for PCR?

thermocycler

DNA probes

• short, single stranded DNA sequences that are complementary to a specific target sequence that is being looked for

  • labeled with radioactive or fluorescent marker to be detected

how do DNA probes work in prodiling?

• DNA is denatured into single strands

• probe is added and bonds to its complementary target sequence (a specific gene or sequence)

• the probe binds and lights up to reveal the location of the specific sequence

short tandem repeat (STR) analysis

• looks at specific regions of DNA where short sequences are repeated multiple times, and the number of repeats varies from person to person

• PCR is used to amplify the STR regions, then gel electrophoresis separates them by size to reveal the pattern of repeats

how are animals cloned?

• a removed nucleus of an egg cell (haploid) is inserted inside the covering of an extracted mammary cell (diploid)

• an electric shock opens cell membranes and triggers mitosis

• cells divide and form an embryo

• embryo develops in vitro

• embryo is implanted into surrogate mother

• five month pregnancy

DNA sequencing

• involves the process of determining the order of the nucleotides in a DNA molecule

  • sorts out the complete genetic makeup of an organism (all genes + junk dna)

genomics

• the study of genomes

• the study and analysis of the nucleotide sequence of DNA

• identifying genes and their locations in the DNA

• comparison of genomes of different organisms

what was found out from the Human Genome Project?

• the human genome contains 19,000 to 21,000 genes

• most are most likely protein encoding genes

• some chromosomes have few genes

• genes differ in number

• most genome DNA is noncoding DNA (junk)

• only 1% to 1.5% of the human genome is coding DNA

DNA microarrays

• chips containing thousands of known DNA probes attached to a solid surface in a grid pattern

  • allows the detection of genes and if the genes are being active (being expressed) or not

how do DNA microarrays work?

• a sample of DNA/ RNA is extracted, labeled with a fluorescent tag, and washed over the chip

• sequences in the samples that are complementary to a probe will bind to it

• wherever binding occurs, that spot fluoresces and is detected

  • the pattern of fluorescent spots reveals which sequences are present in the sample

proteomics

the study of the structure, function, and interaction of cellular proteins

bioinformatics

the application of computer technologies to the study of the genome (databases)