Biotechnology Principles and Processes
Class 12 · Biology
4 ideas in Class 12 Biology, explained in plain words, with games and quizzes to practise.
Principles and First Recombinant DNA
Part of: Toolkit
Genetic engineering rewrites DNA while bioprocess engineering scales sterile production. Alien DNA survives only by joining chromosomes at origins of replication. Cohen and Boyer linked a resistance gene to a plasmid in 1972 through three steps: find genes, insert them, maintain them.
Why it matters. The ori rule plus three steps frames every vector question.
Key words
- Genetic engineering
- : Rewriting DNA and moving genes.
- Bioprocess engineering
- : Sterile scale-up of cultures.
- Origin of replication
- : The start signal copying DNA.
- Cloning
- : Copying one DNA many times.
- Recombinant DNA
- : DNA mixed from two sources.
Try it in two minutes
- Split rewriting from scaling up.
- Anchor alien DNA to ori.
- Date the first construct.
Try at home. Explain why traditional breeding drags bad genes along.
Scissors and Carriers
Part of: Toolkit
Hind II cut 6-base palindromes like GAATTC into sticky ends; over 900 enzymes from 230 strains now exist. Gels separate fragments by size for elution. Vectors need ori, markers and single sites: pBR322 loses tetracycline resistance on insertion, blue-white screening spots inserts, and disarmed Ti plasmids carry plant genes.
Why it matters. Enzyme choice plus selection logic is the most tested part.
Formulas
- Hind II recognises 6 base pairs
- Over 900 enzymes from 230 strains exist
Key words
- Restriction endonuclease
- : Enzyme cutting inside DNA.
- Exonuclease
- : Enzyme trimming DNA ends.
- Palindrome
- : Sequence reading same both ways.
- Sticky ends
- : Overhangs joining matching cuts.
- Elution
- : Extracting bands from gels.
- Selectable marker
- : Gene flagging transformants.
- Insertional inactivation
- : Insert silencing a marker gene.
Try it in two minutes
- Check GAATTC palindrome both ways.
- Run small fragments farther.
- Plate recombinants on ampicillin.
Try at home. Explain why vector and source need the same enzyme.
Delivering DNA into Cells
Part of: Into the Host
Calcium makes bacteria competent to admit plasmids after ice and 42 C heat shock. Microinjection targets animal nuclei, gold-particle bursts target plants, and disarmed pathogens deliver genes. Lysozyme, cellulase and chitinase open walls while chilled ethanol spools pure DNA threads.
Why it matters. Method-to-host matching answers application questions.
Key words
- Competent cells
- : Bacteria ready to admit DNA.
- Heat shock
- : Brief heat driving DNA entry.
- Microinjection
- : Needle delivery into nuclei.
- Biolistics
- : Particle-burst gene delivery.
- Lysozyme
- : Wall opener for bacteria.
Try it in two minutes
- Pair each method with its host.
- Chill, shock, chill the cells.
- Match each wall enzyme to walls.
Try at home. Explain why DNA cannot slip through membranes alone.
PCR, Bioreactors and Downstream
Part of: Scale Up
PCR cycles denaturation, annealing and extension with primers and heat-proof Taq to reach a billion copies. Transformants are selected on ampicillin, grown continuously in log phase, then scaled in 100 to 1000 litre stirred bioreactors. Downstream processing purifies, formulates and trials each product.
Why it matters. Cycle counting plus scale logic finishes technology questions.
Formulas
- PCR doubles DNA every cycle
- 30 cycles give about one billion copies
- Bioreactors process 100 to 1000 litres
Key words
- PCR
- : Cyclic in-vitro gene copying.
- Taq polymerase
- : Heat-proof copying enzyme.
- Primer
- : Short starter binding DNA.
- Bioreactor
- : Vessel brewing bulk cultures.
- Continuous culture
- : Fresh-fed log-phase growing.
- Downstream processing
- : Purify, formulate and test.
Try it in two minutes
- Name three PCR steps.
- Double copies per cycle.
- Stir big tanks to harvest.
Try at home. Explain why Taq survives denaturation heat.
What your child will practise
- Delivering DNA into Cells: Desert Puzzle (Clue Puzzle)
- Delivering DNA into Cells: Desert Quick Fire (Quick Fire)
- PCR, Bioreactors and Downstream: Space Puzzle (Clue Puzzle)
- Principles and First Recombinant DNA: Space Quest (Flip and Match)
- Scissors and Carriers: Jungle Quick Fire (Quick Fire)
- Quiz: Delivering DNA into Cells (8 questions)
- Quiz: PCR, Bioreactors and Downstream (8 questions)
- Quiz: Principles and First Recombinant DNA (8 questions)
- Quiz: Scissors and Carriers (8 questions)