Biotechnology: Principles and Processes for NEET UG
Recombinant DNA technology lets us cut a gene from one organism and put it into another. Learn the tools (restriction enzymes, vectors, hosts) and the steps of the process.
BiologyClass 1274 MCQs2 lessons14 flashcards4 memory tricks
Practise Biotechnology: Principles and Processes free
What you'll learn
- Tools of recombinant DNA technology
Explain restriction enzymes, vectors and how recombinants are selected. - Steps of recombinant DNA technology
Put the steps of genetic engineering in order and explain PCR and gel electrophoresis.
Memory tricks
Restriction enzyme = scissors, DNA ligase = glue, plasmid vector = vehicle, PCR = photocopier.
Restriction sites read the same 5'→3' on both strands. EcoRI cuts between G and A, leaving sticky ends.
Denaturation (about 94 °C) separates the strands; annealing (about 55 °C) lets primers bind; extension (about 72 °C) uses Taq polymerase from Thermus aquaticus.
An insert in the lacZ gene inactivates β-galactosidase, so recombinant colonies stay white on X-gal; non-recombinant colonies turn blue.
Try 3 NEET-style questions
Q1. Restriction enzymes recognise palindromic nucleotide sequences. A palindrome in DNA is a sequence that
- reads the same forwards and backwards on one strand only
- has no complementary strand
- is made only of A and T
- reads the same on the two strands when the orientation of reading is kept the same (e.g. both 5′→3′)
Show answer
Answer: (4) reads the same on the two strands when the orientation of reading is kept the same (e.g. both 5′→3′)
A DNA palindrome reads the same on the two strands when both are read in the same orientation, for example 5′-GAATTC-3′ on both.
Q2. Recombinant DNA technology involves
- isolating DNA, cutting it, joining it into a vector, and transferring it into a host
- only sequencing DNA
- only isolating proteins
- mutating organisms with radiation
Show answer
Answer: (1) isolating DNA, cutting it, joining it into a vector, and transferring it into a host
These steps create and express recombinant DNA.
Q3. In biolistics (the gene gun method), plant cells are bombarded with
- a disarmed retrovirus
- Agrobacterium Ti plasmid
- calcium chloride and heat shock
- gold or tungsten particles coated with DNA
Show answer
Answer: (4) gold or tungsten particles coated with DNA
In biolistics, high-velocity micro-particles of gold or tungsten coated with DNA are shot into plant cells.
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