chap14: molecular genetics Flashcards
what is DNA
a molecule that contains genetic information
how is DNA organised inside a cell
a small segment of the DNA carries a gene which contains genetic information to produce a protein. the protein is responsible for determining the characteristics of an organism
each DNA structure consists of 2 strands that twists around each other to form a double helix
DNA wraps itself around a protein to form a chromosome
relationship between chromosome, DNA and genes
basic unit of a DNA is called a nucleotide which consists of a sugar, a phosphate group and a nitrogenous base (A,T,C,G)
nucleotides can be joined together to form a polynucleotide
each gene is made up of a sequence of nucleotides
what is a gene
a gene is a sequence of a nucleotide , a section of a DNA that codes for one polyp[eptides
a unit of inheritance
it is used to carry the genetic code that is used to synthesise specific polypeptides
what is genetic engineering
a technique used to transfer a gene from one organism to another by cutting off individual genes of one organism and inserting it into the cell of a another organism of the same organism different species
the transferred gene can express itself in the recipient organism
what is a vector
a vector is used to transfer genes
eg plasmid
how is an insulin gene inserted into a bacterium
the insulin gene from the human cell and the plasmid from the bacterium are both cut with the same restriction enzyme to form complementary sticky ends. when mixed together, the insulin gene and bacterium plasmid binds together by complementary base pairings between sticky ends. DNA ligase enzyme seals the both insulin gene and plasmid together to form a recombinant plasmid. mix recombinant plasmid with bacterium and heat shock it to allow the cell membrane to open up for recombinant plasmid to enter, forming a transgenic bacterium. the bacteria is cultured large scale in a fermenter. transgenic bacteria expresses insulin gene and produces insulin which s then extracted and purified for use.
benefits of genetic engineering
low cost of production: makes drugs more affordable for patients
improve crops: drought-resistant, allows farmers to cultivate crops even when environmental conditions are not suitable
development of food to meet specific nutritional goals: improve nutritional quality of food
ethical considerations of genetic engineering
genetically modified food may cause allergies that have not been studied
biotech companies may engineer crop plants that do not produce seeds that can be germinated. farmers have to buy new seeds for every year. farmers cannot afford, struggle to make a living
animal testing
