A Level Biology (A2) chapter 8: Genetic technology MCQs with answers
By Team Megalecture · Updated 4 Nov 2026
58 exam-style questions on Genetic technology, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.
Genetic technology applied to medicine15 questions
Genetically modified organisms in agriculture13 questions
Ten Genetic technology questions with answers
Try each one, then open the answer. These ten stay the same; the test draws new ones every time.
1. The herbicide glyphosate inhibits a plant enzyme needed to make certain amino acids. GM soybean contains a bacterial gene for a form of this enzyme that is not inhibited by glyphosate. Why does the GM soybean survive being sprayed?
A
it can still make these amino acids, and so its proteins
B
it breaks down all the glyphosate before it can enter any of its cells
C
it no longer needs these amino acids, so blocking the enzyme has no effect
D
it absorbs the amino acids from soil
Show answer
Answer: A. The bacterial enzyme keeps working in the presence of glyphosate, so the GM plant continues to make the amino acids needed for protein synthesis and survives. Weeds, with only the sensitive enzyme, die.
2. How does growing a herbicide-resistant variety of soybean help to increase the yield of the crop?
A
the soybean plants make their own herbicide, so no spraying is ever needed
B
weeds can be sprayed without harming the crop, reducing competition
C
the herbicide acts as a fertiliser
D
the herbicide-resistant soybean plants cannot be eaten by any insect pests
Show answer
Answer: B. The herbicide kills weeds, which compete with the crop for light, water and mineral ions, but not the resistant soybean. The crop therefore grows better and gives a higher yield.
3. A PCR starts with 5 molecules of double-stranded target DNA. Assuming the number of molecules doubles in every cycle, about how many molecules are present after 20 cycles?
A
1.0 × 106
B
2.6 × 106
C
2.0 × 102
D
5.2 × 106
Show answer
Answer: D. Number = 5 × 220 = 5 × 1 048 576 ≈ 5.2 × 106. Forgetting the 5 starting molecules gives 1.0 × 106, using 19 doublings gives 2.6 × 106, and 2.0 × 102 comes from multiplying 5 by 2 × 20 instead of by 220.
4. Which is an ethical concern about the screening of embryos created by IVF for alleles that cause genetic disease?
A
embryos with the allele may be discarded, which some oppose
B
the screening itself changes the alleles in the embryo, and this cannot be reversed
C
screening the embryos makes the disease more common in the next generation
D
embryos must reach adulthood to be tested
Show answer
Answer: A. Pre-implantation genetic diagnosis involves choosing which embryos to implant, and people hold different views on discarding embryos, which some regard as ending a potential life. Concerns are also raised about selecting embryos for non-medical features.
5. How has gene therapy been used to treat severe combined immunodeficiency (SCID) caused by a faulty ADA gene?
A
regular injections of recombinant ADA are given
B
the patient's stem cells are given a working ADA gene by a vector, then returned
C
the gene is put into the patient's gametes
D
the patient receives a transplant of bone marrow from a healthy and well-matched brother or sister
Show answer
Answer: B. Gene therapy adds a functional allele to the patient's own cells: bone marrow stem cells are treated outside the body with a viral vector carrying the gene and then returned, so that they produce healthy lymphocytes. Enzyme injections and transplants are not gene therapy.
6. Which of these concerns about farming GM salmon is an economic and social issue rather than an environmental one?
A
escaped GM fish might compete with wild salmon for their food
B
the transgene might spread into wild salmon if fertile fish escaped
C
waste from the fish farm might pollute the surrounding sea water
D
fishing communities might lose income if GM salmon lowers the price
Show answer
Answer: D. Loss of income and jobs among people who catch or farm non-GM salmon is an economic and social effect. Competition with wild fish, spread of the transgene and pollution are all effects on the environment.
7. In gel electrophoresis, why do DNA fragments move towards the anode (the positive electrode)?
A
the bases in DNA carry a positive charge
B
the deoxyribose sugars are attracted to the gel
C
the hydrogen bonds between strands are positively charged
D
the phosphate groups in DNA give it a negative charge
Show answer
Answer: D. Each nucleotide has a phosphate group that is negatively charged at the pH of the buffer, so DNA fragments are attracted towards the positive electrode.
8. cDNA made from the mRNA of cancer cells was labelled with a red fluorescent dye, and cDNA from normal cells of the same tissue with a green dye. Equal amounts were mixed and added to a microarray. One spot glowed bright red. What does this show about the gene on that spot?
A
it is present in the genome of the cancer cells but not in the normal cells
B
it is expressed much more in the cancer cells than in the normal cells
C
it is expressed equally in both the cancer cells and the normal cells
D
it has a mutation in the cancer cells that is not found in normal cells
Show answer
Answer: B. The cDNA comes from mRNA, so the colour shows transcription, not whether the gene is present. Red means mostly cancer-cell cDNA bound, so the gene is transcribed more in cancer cells; equal expression would give a yellow spot.
9. Which is an environmental concern about growing herbicide-resistant crops?
A
the crops produce a herbicide that kills all of the insects in the field
B
the gene could reach wild relatives in pollen, giving resistant weeds
C
the crops cannot be pollinated
D
herbicide resistance makes the crop poisonous to any animal that eats it
Show answer
Answer: B. Pollen can carry the transgene to closely related wild plants, and heavy use of one herbicide also selects for resistant weeds. Either way, weeds become harder to control.
10. Which enzyme is used to make a DNA copy of an mRNA molecule?
A
reverse transcriptase
B
DNA ligase
C
restriction endonuclease
D
RNA polymerase
Show answer
Answer: A. Reverse transcriptase makes a single strand of complementary DNA (cDNA) using mRNA as the template. RNA polymerase does the opposite, making RNA from a DNA template.
58, each with the answer and a short explanation, across 3 topics: Principles of genetic technology, Genetic technology applied to medicine, Genetically modified organisms in agriculture. Every chapter test draws ten of them, so you can take it many times.
Is the A Level Biology (A2) chapter 8 test free?
Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.
How is the chapter test marked?
The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.
