dna sequencing- fred sanger Flashcards
what is dna sequencing
a technique which allows genes to be isolated and WORK OUT SEQUENCE OF NUCLEOTIDE BASES (was in MS)
what was the name of the british biochemist who developed dna sequencing
fred sanger dna sequencing
why was sangers method so helpful
sped up human genome project
saved resources and money
what do we need for dna sequencing
dna sample
free nucleotides
coloured fluorescent-labelled terminator bases
dna polymerase
primers
what is dna polymerase used for
catalyses the addition of complimentary dna nucleotides to separated dna strands
process of dna sequencing
1- dna strand needs to be heated to 95 degrees to denature dna and become 2 separate strand
2- cool down to 50 degrees so primers can anneal to the
3- heat up to 60 degrees so dna polymerase can bind complimentary bases to the template strand and form phosphodiester bonds
describe the structure of a terminator base
stops the addition of any other bases.
terminator bases create varying lengths of dna
further detail- have a hydrogen atom instead of a hydroxyl group at the 3’ carbon on the ribose ring- unable to form phosphodiester bond with next nucleotide
how is this data of sequencing read
1- electrophoresis
terminator bases are fluorescently labeled, they are placed on a nylon membrane and a UV light is shone to view.
small fragments travel further down the nylon membrane, large fragments travel less.
describe the length of the dna fragments and how is affects their traveling distance across the nylon membrane
short fragments travel further
long fragments travel not as far
dna sequencing data can be read from electrophoresis, in which direction would you read dna data from the nylon membrane.
read dna data downwards, from the top of the nylon membrane downward. due to the fact smaller dna fragments travel further than large fragments.
therefore reading it top to bottom is in order of the dna sequence. so we can generate a sequence.
describe the stage of adding dna polymerase, in sequencing
heated to 60 degrees
DNA polymerase catalyses the addition of nucleotide bases to the template strand through complimentary base pairing.
if a fluorescent terminator base is added, the DNA strand can no longer be extended.
results in varied lengths of DNA ready for electrophoresis
What is the human genome project
scientist project to sequence the entire human genome to see how many genes there are
exam q- state one development, that has led to increase in speed that dna can be sequences
pyrosequencing
name 2 differences between a molecule of atp and a nucleotide base
difference 1- atp has three phosphate groups while base has one
difference 2- nucleotide base will use deoxyribose sugar, atp has a ribose sugar
what is bioinformatics
field of biology which involves the storage and analysis of data.
why is bioinformatics important
access to lots of data
acces to data on dna AND proteins
can identify vulnerable populations
