These eight original questions follow the genetic technology lessons in SPM Biology. All scenarios are invented. Write your own answer first, then open the model answer.
Questions
1. State the job of a restriction enzyme and of DNA ligase in genetic engineering.
Answer
A restriction enzyme cuts DNA at a specific sequence. DNA ligase joins pieces of DNA together, such as a gene into a plasmid.
2. Explain how a recombinant plasmid is formed.
Answer
A restriction enzyme cuts the plasmid open and cuts the gene from its source DNA, leaving matching ends. The gene is placed in the opened plasmid, and DNA ligase joins them, forming a recombinant plasmid.
3. Why are the host cells grown in large numbers after the recombinant plasmid is inserted?
Answer
Each host cell carries the gene and makes the protein. Many cells produce a larger amount of the protein.
4. Sort into application or limitation: (a) a crop gains a trait that helps it resist a pest, (b) the long-term effects on other organisms are uncertain.
Answer
(a) Application, because it describes a use and a gain. (b) Limitation, because it describes an uncertain risk.
5. A student asked for a limitation of genetic engineering writes that it makes crops grow faster. Explain the error.
Answer
Faster growth is a benefit, so it is an application. A limitation would be something such as high cost, long testing time, uncertain effects on other organisms, or ethical concerns.
6. In an invented trial, an ordinary crop yields 2.5 tonnes per hectare and a modified crop yields 3.0 tonnes per hectare. Calculate the percentage increase.
Answer
Increase = 3.0 − 2.5 = 0.5 tonnes. Percentage = 0.5 ÷ 2.5 × 100 = 20%.
7. Write a two-sentence evaluation of the trial in question 6, given that it covered one season at one site.
Answer
The modified crop gave a 20% higher yield, from 2.5 to 3.0 tonnes per hectare. However, the data comes from one season at one site, so more trials are needed before a firm conclusion.
8. A diagram shows the arrow “recombinant plasmid → bacterium”. Name the process, the input and the output.
Answer
The process is placing the recombinant plasmid into the bacterium. The input is the recombinant plasmid and the bacterium. The output is a modified bacterium carrying the new gene.
If you got these wrong
For questions 1 to 3, revisit explaining biotechnology processes at syllabus level. For questions 4 and 5, see distinguishing applications from limitations.
For questions 6 and 7, see evaluating benefits and risks using evidence. For question 8, see interpreting a genetic-technology diagram.
Log each slip in the mistake log and paper-error review, then build a timed set with the timed original practice session builder.
If you want a teacher to go through your answers, see online one-to-one Biology tuition.