Match Column-I with Column-II and choose the correct option :
Column-I: a. Biolistic gun, b. Chitinase, c. Ti, d. Ca++
Column-II: i. Bacterial cell, ii. Tumour inducing, iii. Animal cell, iv. Fungal cell, v. Plant cell
Match Column-I with Column-II and choose the correct option :
Column-I: a. Biolistic gun, b. Chitinase, c. Ti, d. Ca++
Column-II: i. Bacterial cell, ii. Tumour inducing, iii. Animal cell, iv. Fungal cell, v. Plant cell
Options
Correct option: C — a-v, b-iv, c-ii, d-i
The correct matches are:
- a. Biolistic gun → v. Plant cell — the gene gun bombards plant cells with DNA-coated metal particles.
- b. Chitinase → iv. Fungal cell — chitinase digests chitin in the fungal cell wall to release protoplasts / DNA.
- c. Ti → ii. Tumour inducing — the Ti plasmid of Agrobacterium is literally the Tumour-inducing plasmid.
- d. Ca++ → i. Bacterial cell — calcium (CaCl₂) treatment makes bacterial cells competent to take up DNA.
Marking Scheme
- 11 mark: correct option C (a-v, b-iv, c-ii, d-i).
- 2All four pairs must be correct; no partial marks in MCQ matching.
Hint
Anchor the certain pairs: Ti = tumour-inducing; Ca²⁺ = bacterial competence; then match the rest.
Quick Oral Answer
Biolistic gun goes with plant cells, chitinase with fungal cells, Ti with tumour-inducing, and calcium with bacterial competence — so the answer is option C.
Analysis & Explanation
Concept
Each item names a method or agent used to introduce foreign DNA into, or open the cell wall of, a particular cell type.
Correct pairings
- Biolistic (gene) gun → plant cell: high-velocity tungsten/gold particles coated with DNA are fired into plant cells (particle bombardment).
- Chitinase → fungal cell: fungal walls contain chitin, so chitinase is used to break them down.
- Ti plasmid → tumour inducing: carried by Agrobacterium tumefaciens, it naturally causes crown-gall tumours and is engineered as a plant cloning vector.
- Ca²⁺ (CaCl₂) → bacterial cell: divalent calcium ions increase membrane permeability, making bacteria 'competent' to take up recombinant plasmid.
Why the distractors are wrong
- A wrongly ties chitinase to 'tumour inducing' and Ti to 'animal cell'.
- B puts biolistic gun on 'tumour inducing' and Ca²⁺ on 'animal cell' — Ca²⁺ competence is a bacterial technique.
- D correctly matches biolistic gun to plant cell but swaps b and d (chitinase↔bacterial, Ca²⁺↔fungal), which is wrong.
Exam trap
Only C gets all four pairs right; eliminate options by anchoring the two easiest facts — Ti = tumour-inducing and Ca²⁺ = bacterial competence.
Common Mistakes
- 1Matching the biolistic gun to animal or bacterial cells — it is chiefly used for plant cell transformation.
- 2Forgetting that Ca²⁺ (CaCl₂) is a bacterial competence treatment, and instead linking it to animal or fungal cells.
- 3Not realising 'Ti' stands for Tumour-inducing plasmid of Agrobacterium.
Interesting Facts
The Ti plasmid transfers a segment called T-DNA into the plant genome, which is why Agrobacterium is called nature's own genetic engineer.
The biolistic or gene gun was developed in the 1980s to transform crops like maize and rice that resist Agrobacterium infection.
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Frequently Asked Questions
Why is calcium chloride used to transform bacterial cells?
Divalent Ca²⁺ ions neutralise the negative charges on the bacterial cell membrane and DNA, increasing membrane permeability. A brief heat shock then lets the recombinant plasmid enter, making the bacterium 'competent'.
What is the Ti plasmid and why is it useful in biotechnology?
The Ti (Tumour-inducing) plasmid is found in Agrobacterium tumefaciens and naturally causes crown-gall tumours in plants by inserting its T-DNA into the host genome. Scientists disarm it and use it as a vector to deliver desired genes into plant cells.