chapter 14 - molecular genetics Flashcards
function and structure of DNA
DNA is made up of two strands of anti-parallel polynucleotides twisted around each other to form a double helix. the two strands are held together by hydrogen bonding. each nucleotide form the basic unit of DNA. it is made up of deoxyribose sugar, a phosphate group and a nitrogenous base. there are four types of bases, adenine, thymine, guanine and cytosine. by complementary base pairing, adenine pairs with thymine and cytosine pairs with guanine. dna is a molecule that contains many genes that carries genetic information in the form of genes, which is made up of a specific sequence of nucleotides that codes for a specific polypeptide.
complimentary base pairing
DNA molecules made up of two antiparallel polynucleotide strands (strands run in opposite directions). the base on one strand form hydrogen bonds with the bases on the other strand according to the rule of complementary base pairing (A and T, G and C are complementary bases)
gene
sequence of nucleotides of DNA that codes for a specific polypeptide
gene
sequence of nucleotides of DNA that codes for a specific polypeptide
gene expression
- gene expression : process of decoding information from genes (in DNA form) to the final synthesis of proteins
transcription : DNA to mRNA, translation : mRNA to polypeptide chain
significance of order of bases
different order of bases result in different genes which codes for a different sequence of amino acids which codes for a particular polypeptide which determines a specific characteristic.
genetic engineering
transfer of foreign genes from one organism to another via human intervention or artificial means (can be diff species)
inserting gene into bacteria DNA
the desired gene is isolated from the cell and cut using a restriction enzyme to produce 2 sticky ends. the same restriction enzyme is used to cut a bacterial plasmid isolated from a bacterial cell to produce 2 complementary sticky ends. mix the gene and the bacterial plasmid and anneal using DNA ligase to form a recombinant plasmid. apply temporary heat or electric shock to open up the pores of the bacteria to allow the recombinant plasmid to enter. transgenic bacteria is cultured in large-scaled fermenters for mass production.
advantages of genetic engineering
1) low cost production of medicines : drugs like human insulin become more affordable
2) production of crops that grow in extreme conditions : farmers are able to increase crop yield
3) development of poultry that grow fast : farmers are able to increase meat production to meet market demand
4) development of foods designed to meet specific nutritional goals : nutritional quality of foods are improved
hazards of genetic engineering
- environemental : GM crop plants that produce insect toxins may result in deaths of insects that feed on them and may result in loss of biodiversity. the insects that on the GM plants might also adapt and develop resistance to the toxins.
- economical : the company that first engineered the GM seed can patent their GM food and obtain economic monopoly to prevent others from profiting. some companies produce GM plants that produce non-germinating seeds, making farmers spend more money to buy new plants
- health : GE could introduce allergens in food, causing reactions within the immune system. modifying a single gene in plants could result in the alteration of some metabolic processes, resulting in the formation of toxins not usually found and could be harmful when consumed.
- social : GE may lead to class distinctions as only those with sufficient financial means can afford certain gene technologies. lack of approval from certain religions regarding GE as it might go against some of their beliefs
hazards of genetic engineering
- environemental : GM crop plants that produce insect toxins may result in deaths of insects that feed on them and may result in loss of biodiversity. the insects that on the GM plants might also adapt and develop resistance to the toxins.
- economical : the company that first engineered the GM seed can patent their GM food and obtain economic monopoly to prevent others from profiting. some companies produce GM plants that produce non-germinating seeds, making farmers spend more money to buy new plants
- health : GE could introduce allergens in food, causing reactions within the immune system. modifying a single gene in plants could result in the alteration of some metabolic processes, resulting in the formation of toxins not usually found and could be harmful when consumed.
- social : GE may lead to class distinctions as only those with sufficient financial means can afford certain gene technologies. lack of approval from certain religions regarding GE as it might go against some of their beliefs
