【PEP】Senior High Biology — Selective Compulsory Vol. 3: The Macroscopic Vision and Engineering Thinking of Genetic Engineering

Genetic engineering is not merely an accumulation of biological lab techniques; it is an engineering revolution based on the“Design-Build-Test-Verify (DBTV)”cycle. It breaks down reproductive barriers between species, treats living organisms as programmable systems, and by precisely manipulatingtarget genes(such as the gene that produces theBt insecticidal protein), achieves the precise reshaping of life traits by humans.

The Logical Framework of Engineering Thinking

Cultivating transgenic Bt cotton primarily requires four steps:screening and obtaining the target gene, constructing a gene expression vector, introducing the target gene into recipient cells, and detecting and identifying the target gene This modular thinking requires anticipating downstream compatibility at the design stage — for example, predicting the matching logic of restriction enzyme sites during the construction of the "core hub" vector.

Case Study: DBTV Closed Loop

Design:Locate the Bt gene;Build:Ligate into a plasmid;Execute:Agrobacterium-mediated transformation;Verify:PCR detection and insect resistance assays. This is not just a stack of techniques, but a systemic design. According to statistics, the global area of transgenic crops has reached $1.898 \times 10^8 \text{ hm}^2$.

QUESTION 1

Can PCR be used to amplify mRNA?

Yes, just add mRNA directly into the PCR mix as the template

No, PCR templates must be double-stranded DNA; reverse transcription is required first

Yes, but a heat-resistant RNA polymerase must be used

QUESTION 2

Section Focus: What are the applications of genetic engineering?

It is limited to agriculture and animal husbandry, e.g., transgenic cotton

It is mainly used in medicine, e.g., producing interferon

It spans multiple fields including agriculture, medicine and health, and the food industry

QUESTION 3

Which restriction enzyme can produce DNA fragments from fragment B that can be ligated to the DNA fragments produced by digesting fragment A with Spe I (5'-ACTAGT-3')?

A restriction enzyme whose recognition sequence yields compatible sticky ends

Another restriction enzyme with an identical recognition sequence

A restriction enzyme that produces blunt ends

QUESTION 4

In the process of cultivating transgenic Bt cotton, the step known as the "core hub" is:

Screening and obtaining the target gene

Constructing the gene expression vector

Introducing the target gene into recipient cells

QUESTION 5

The area of Bt cotton cultivated in China has reached approximately $1.7 \times 10^6 \text{ hm}^2$. This reflects:

The scaling effect brought about by the translation of engineering technology

The limitations of laboratory techniques

The process of natural selection in biological evolution