Techniques In Modern Biotechnology 🧫 Flashcards
What is used to infect bacteria?
Virus
What is used to introduced into a plant cell ? And why?
Agrobacterium (bacterium) / gene gun
Agrobacterium contains plasmids for target gene to be inserted, can infect crop cells and transfer the genes of the plasmid to the genome of the crop cells.
Gene gun can deliver gene to any cells without limitation but it is a random process, not sure if the insertion is successful.
What is used to introduced into an animal cell?
Microinjection / virus / liposome
Virus can deliver gene to specific host cells but there are safety concerns and may induces 引起 immune response
Microinjection can deliver gene to the target cell accurately but may cause damage
What is the role of plasmids?
Act as a vector to transfer the gene of interest into host cells
What are the two types of restriction enzyme? Which one is better and why?
Sticky ends and blunt ends.
Sticky ends because it can pair up with another sticky end with a complementary base sequence and helps ligation
What should a ideal restriction enzyme have?
Create cut ends on both DNA segment and plasmid for insertion.
Doesn’t interrupt the resistance gene/selection marker gene.
Why need selection marker?
Allow for more protein production
Why only some bacteria picked up recombinant plasmids?
It is a random process, some bacteria cannot pick up plasmids during transformation.
Some plasmids join by themselves without taking up the target gene (self -ligated)
Name the three steps of PCR
DNA denaturation (breaks the hydrogen bond)
Primer annealing (primer anneal to single-stranded DNA templates by complementary base pairing)
Extension (complementary free nucleotides join to primer accordingly to extend the DNA molecule)
Benefits of VNTRs
Mutations do not affect the survival of the organisms and mutations can pass on to the next generation, leading to huge variations.
Direction of the DNA fragments during DNA fingerprinting in gel electrophoresis
Negative to positive pole
Name two applications of DNA fingerprinting
Provide evidence in forensic science
Help conserve endangered species
Identity victims in disasters
Why DNA fingerprint shows different patterns?
DNA fragments migrate to the positive pole in gel electrophoresis
The shorter the DNA fragment, the faster they migrate
The repetition of DNA fragment are different
Advantage of using plasmids
Replicate independently of the bacterial chromosome
Small in size
Carry antibiotic resistance gene to allow selection of transformed bacteria
Advantage of using bacteria as host cells
High growth rate
Products can be easily extracted and purified
Easy to manipulate
Describe the process of in vivo gene therapy
Insert a normal gene into a viral vector
Introduce the viral vector into the patient’s body.
The viral vector transfer the normal gene into patient’s cells.
Describe the process of ex vivo therapy
Remove cells from patient’s body and insert the normal gene into the viral vector.
Mix the viral vector with patient’s cells
Culture the cells and select those containing the normal gene
Transfer the cells containing normal gene back into the patient’s body
What is the problem if there’s short primers?
They have fewer combinations of base sequence and high chance of annealing primers to wrong positions of the DNA strand.
Why the bacteria need to be cultured on the Agar plate containing tetracycline/ampicillin?
To test the present of plasmid/to select the bacteria that pick up the plasmid
Hence, the bacteria can survive and divide to form colonies
