DNA probes and genetic screening Quiz
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5 questions, one answer each
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1. Which feature of a DNA probe allows it to find a specific allele?
- A. It is double-stranded
- B. Its base sequence is complementary to the allele
- C. It contains amino acids
- D. It is longer than a gene
2. What is the effect of heating the DNA before adding the probe?
- A. It joins the strands together
- B. It breaks the sugar-phosphate backbone
- C. It labels the DNA
- D. It breaks hydrogen bonds between the strands
3. A probe with a radioactive label has bound to a patient's DNA. How is this detected?
- A. By darkening of x-ray film
- B. By a change in pH
- C. By a colour change in the DNA
- D. By measuring the length of the DNA
4. Two carriers of a recessive allele have two children. What is the probability that both children are affected?
- A. 0.25
- B. 0.5
- C. 0.0625
- D. 0.125
5. A test shows a woman has an allele that increases breast cancer risk. Which statement is the most accurate?
- A. She will definitely develop breast cancer
- B. She has no risk of cancer
- C. The allele can be cured by the probe
- D. She has an increased risk and a counsellor can explain her options