Biology [Module6:Manipulating genome]

dna sequencing

-a technique that is used to read the sequence of dna bases + identify genes

-uses:diagnose and treat genetic disorders,produce dna probe to screen patients for cancer,confirm infection

gene

sequence of dna bases that codes for a protein

early dna sequencing

-used only for very short genes

-slow process

-mRNA very unstable

sangers dna replication termination method of dna sequencing

-single stranded dna

-dna polymerase

-nucleotide base

-radioactive primer (initiates dna replication)

-terminator nucleotide

-different lengths of dna were produced

-he separated thee fragments using gel electrophoresis

first dna sequencing machine

-fred sangers method

-fluorescent dyes used to label modified terminator bases

-the sequence of DNA is identified by a computer

present dna sequencing

-pyrosequencing

—fast,cheap methods to sequence a whole genome

—sequence of dna by dna replication but by termination

—as dna is added the light emitted is used to identify each base

application of gene sequencing

-to compare genes between individuals and species

-to predict the sequence of amino acids in polypeptides

-allowed the development of synthetic biology (building useful biological devices)

• bioethics:should not be about making new life but the potential of creating new systems that support life

bioinformatics

-store a huge amount of research data in a data base

-computers are used to rapidly analyse differences in sequence of dna bases +to predict the sequence of amino acids modelling of the protein structure

pcr(polymerase chain reaction)

-in vitro technique that is used to amplify the dna fragments

pcr steps

-separate the dna double helix by heating to 95C

-annealing(bind the primer to the dna strand using restriction enzyme)

-cool the temp to 68C

-dna synthesis:increase temp to 73C(opt temp for Taq dna polymerase)

-taq dna polymerase adds complementary dna nucleotides to single strands of dna in a 3 to 5 prime

pcr uses

-detect mutations

-identify viral infections

gel electrophoresis

-uses current to separate dna fragments

-used in dna profile

-test for genetic diseases

gel electrophoresis steps

-cut the dna using restriction enzyme + add a loading dye so din can be seen into wells add a buffer to keep the ph constant

-the dna fragments are loaded into the wells at the negative terminal(cathode)

-apply current + the dna fragments move to the positive terminal

-after separating the dna fragments pour away the bigger and add the staining dye to make the dna visible

separating proteins

-heat the protein to denature it and expose charges

-add charged detergent to make surface negatively charged

-so all protein molecules move to the positive terminal by length or mass

replica plating

reintroducing the plasmid

benefits and ethical issues of GMO

production of gm insulin

mode of action of restriction enzyme

-straight cut at recognition site=blunt ends

-staggered cut=sticky ends

—recombinant dna can be formed if not genes are cut with the same restriction enzyme because sotocku ends are complementary

introns

-junk dna,non coding dna bases

exons

coding dna bases

short tandem repeats(mini satellite)

-repetitive sequence of dna bases in introns+ used in dna profiling as they are different for each individual

dna probe

short single strand of dna bars that is radioactively labeled

dna profiling steps

-dna extracted from the sample

-dna cut into fragments using restriction enzymes

-fragments separated by gel electrophoresis

-fragments transferred to a nylon mem by southers blotting

-radioactive dna probes are used to bind to str by complementary base pairs

-x ray used to observe the patterns

gene therapy

replace a fault gene with healthy gene

somatic gene therapy

-cystic fibrosis

-gene introduced to body cells

-so only some of the body cells will get this gene

-cannot be passed on to offspring

-short term effect

-can treat recessive genetic conditions

gene therapy treating cystic fibrosis

germline gene therapy

-gene introduced into gamete/embryo

-all the cells get the gene

-so can be passed to offspring

-long term effects

advantages somatic and disadvantages

A:-does not alter the whole genetic makeup of people and their descendent

D:-needs to be replaced as cells constantly die and are renewed

gremlins ad+dis

A:much permanent cure

D:alters the genetic makeup +increases risk of cancer

somatic gene therapy