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Biotechnology: Principles and Processes
Biology · Class 12NCERT pp. 161–1752 sets × 25 questions
Key facts and formulas for Biotechnology: Principles and Processes, three worked sample questions, and two full practice sets. Every question has a hint, a reason for every option and a step-by-step solution, with a calculator or animation where one helps. English and Hinglish.
Key facts for this chapter
| Idea | Rule or fact |
|---|
| Restriction enzyme name | EcoRI: E = Escherichia, co = coli, R = strain RY 13, I = first isolated; HindIII: d = strain Rd |
| Sites | EcoRI GAATTC; HindIII AAGCTT; BamHI GGATCC; SmaI CCCGGG; EcoRV blunt cutter |
| Palindrome | Both strands read the same 5' to 3'; EcoRI gives sticky ends by staggered cuts |
| Site frequency | Site of n bases occurs about once per 4ⁿ bp (4 bp: 256, 6 bp: 4096) |
| Fragments | Circle cut n times gives n pieces; line cut n times gives n + 1 |
| Tools | Ligase makes phosphodiester bonds; reverse transcriptase makes cDNA; probe is labelled single strand |
| Vectors | Selectable marker (ampR, tetR); ori needed to replicate; Ti plasmid disarmed; YAC carries most (about 1000 kb) |
| Transformation | Calcium, ice with DNA, 42 °C heat shock, ice; chromogenic test: recombinants colourless |
| PCR | Denature about 94 °C, anneal lower, extend about 72 °C with Taq; copies = 2ⁿ |
| Bioprocess | Stirred-tank mixes; continuous culture keeps exponential phase; downstream = separation, purification, formulation |
Three sample questions
Q1. Consider the following.
I. Setting curd can be seen as biotechnology in the broad sense.
II. In vitro fertilisation is counted as biotechnology.
III. Today the term never involves genetically modified organisms.
Which are correct?
- I and II only
- I and III only
- II and III only
- I, II and III
Hint and solution
Hint: Think of the broad definition (any use of living organisms) and then of what the word mostly means today.
- Broad sense: any use of living organisms — In the broad sense biotechnology means using living organisms or their parts to make products. Setting curd with bacteria fits this.
- IVF uses living cells (gametes, embryos) — In vitro fertilisation, which gives a test-tube baby, is also counted as biotechnology. So statement II is true.
- Modern meaning: processes with GMOs — Today the term mostly means processes that use genetically modified organisms. So saying it never involves them is false.
- I and II true, III false — Only I and II are correct, so the answer is the option 'I and II only'. Option A.
Answer: A. Today the word mostly means processes using genetically modified organisms, so III is wrong.
Q2. Match the core technique with its feature.
Column I: a. Genetic engineering; b. Bioprocess engineering
Column II: (i) Keeps the process sterile and grows only the desired cells in bulk; (ii) Alters DNA or RNA and changes the phenotype of the host
- a-(i), b-(ii)
- a-(i), b-(i)
- a-(ii), b-(i)
- a-(ii), b-(ii)
Hint and solution
Hint: One technique changes the genetic material; the other keeps conditions sterile for growth in bulk.
- Genetic engineering → alters DNA/RNA — Genetic engineering changes the DNA or RNA of an organism and so changes the phenotype of the host. That matches (ii).
- Bioprocess engineering → sterile bulk growth — Bioprocess engineering maintains sterile conditions and grows only the desired cells in large amounts. That matches (i).
- a → (ii), b → (i) — So the pairing is a-(ii), b-(i). This is the third option. Option C.
Answer: C. Genetic engineering changes the genes; bioprocess engineering is sterile, large-scale growth.
Q3. A major advantage of genetic engineering over conventional hybridisation is that it
- needs no host cell
- avoids the use of enzymes
- transfers only the chosen gene without unwanted ones
- produces only asexual progeny
Hint and solution
Hint: In hybridisation whole sets of genes mix. What can genetic engineering do instead?
- Hybridisation → unwanted genes come too — Crossing two organisms mixes thousands of genes, so unwanted traits are carried along.
- Genetic engineering → one chosen gene — In genetic engineering a specific gene is isolated and transferred, so only that trait is added.
- Eliminate wrong options — It still needs a host and enzymes, and progeny type is not the point.
- Answer: transfers only the chosen gene — So the advantage is transfer of only the desired gene without unwanted ones. Option C.
Answer: C. Hybridisation carries unwanted genes along.
How to use this chapter
Read the NCERT pages first, then attempt Set 1 without the hints. Note every wrong answer in a mistake list, read the reason for each option, and retry Set 2 two days later. A topic is solid when you can say why each wrong option is wrong.