Bio tech Flashcards
restriction enzyme
can be used to cut DNA fragments at specific sequences called recognition sequences
They recognize and bind to specific recognition sequences
found naturally in bacteria
where are the restricition enzymes found and used naturally
when the enzyme finds a special sequence it can remove it from the DNA to defend the bacteria from virus
how do the enzymes make genetic engineering possible
once they bind to their recognition sequence, they cut the phosphate backbones of DNA strands. EcoR1 cuts unevenly, leaving sticky ends
how is ligase
they make phospodiester bonds to join sticky ends
what is gel electrophesis
Seperates DNA fragments
uses electric current to separate different ssized molecules in porous sponge like matrix
small molecules moves faster than big ones
what gel
what solution
with pipette
negative/positive why
aragose gel
highly purified seaweed
salt, conducts electricity
DNA samples are loaded into slots made agragose gel
negative because phophates carry negative oxygen DNA moves from negative to positive
How are bands represented
fluorescent dye
ethidium bromide to stain DNA to trace it prior to procedure
glows when illumniated in UV light
photo of gel can be taken later for analysis
Gel is an obstacle course
This means short DNA fragments can move fast while big ones slowly
what is RFLP
Restriction Fragment length polymorphism
how are the fragments created
fragments of DNA cut by restriction enzymes
what chromosome pairs are commonly used as markers in a DNA profile
1
2
4
5
10
17
what is the notation used D2S44
section 44
chromosome pair 2
what is an autorad
what material is used as gel electrophesis
highly porous seaweed.
what is analyst
he made of profile of his and own family with RFLP analysis
what is RFLP
Restriction fragment length Polymorphism
What chromosome pairs are commonly used in a DNA profile
1
2
4
5
10
17
What is an autorad
photo of the gel with dark bands representing RFLP markers.
Bands are found in lanes and contain fragments from different source. Bands containing longer fragments are at top, small ones in ass
why would two different individuals have varying location od bans
DNA is stained
Different individuals have many different lengths of DNA possible at location of RFLP marker,different people will have bands at different places because no 2 guys are identical
why don’t ma and pa bands match
they are not blood relatives, they are married,
no 2 different guys have all same bands
what bands did Bob’s kids inherit from D1S7?
Top and bottom
what does a DNA analyst do?
DNA analysts prepare and analyze DNA from criminal evidence
Theyinterpret the results of their DNA analysis and often required to testify as expert witnesses on findings.
They check each other’s work and ensure accuracy
What is PCR
Polymerase Chain reaction
produces millions of copies of a specific DNA sequence in 2 hours
no need for bacteria
Describe the first phase in PCR
denature at 95 Celsius
break H bonds
the next phase in PCR
temp is raised to 50 Celsiu
primers anneal
what is 3rd phase in PCR
extend DNA chain and make more and more copies of the gene
the template shrinks and you get a lot of copies
why is PCR so useful
to make millions of copies of a DNA sequence found at a crime scen
