A young couple already has three children and is expecting a fourth. Through a genetic test, the couple finds out that each of them is a carrier for cystic fibrosis. Upon counseling, they are informed that there is a 1 in 4 chance of their unborn child having cystic fibrosis and a 1 in 2 chance that he/she will be a carrier. Describe how the genetic counselor was able to determine these
probabilities. The husband deduces that the child will be born with cystic fibrosis because the other 3 children do not have it. Explain why this reasoning is faulty. How would you handle the situation?
What will be an ideal response?
The best responses will include discussions of the following ideas: Punnett square, probability, and small sample sizes. The last question is open for response but a thoughtful answer might include genetic testing of the fetus.
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The advantage of nitrogen fixation to the host plant is
A. the ability to synthesize amino acids and proteins from the ammonia produced. B. the production of nucleotides required for nucleic acid synthesis. C. the production of antibiotics that protect the plant against pathogenic soil bacteria. D. the ability to use nitrogen gas instead of oxygen gas in cellular respiration, particularly when the soil is compacted.
. If this population of butterflies is in genetic
equilibrium, the frequency of the homozygous dominant genotype in the new generation will be a. p2. b. 2pq. c. p2 + q2. d. 490 AA. e. p2 and 490 AA.
Baroreceptors detect
a. chemical substances. b. pressure changes. c. vibrational changes. d. light wavelengths. e. changes in solute concentration.
How can one justify using island biogeography theory on the tops of mountains?
A) Metapopulation dynamics are similar. B) The same species exist in the two habitats. C) Moving between mountaintops and islands is similarly challenging. D) The theory does not apply.