probability questions for AP BIOLOGY. please help.?

Question

A. what is the probability that a mating between two carriers will produce an offspring with a recessively inherited disorder?


B. What is the probability that a phenotypically normal child produced by a mating of two heterozygotes will be a carrier?

Answer 1

I agree with the first responder. However, these are such easy questions that I suspect you don't understand the terminology or the basic method of working the problems.

Carriers = organisms that have the allele for a recessive trait, but do not have the trait themselves. Carriers must be heterozygous, like Bb or Rr.

Recessively inherited disorder = any disorder that only shows up when the individual has two of the recessive alleles, like bb or rr.

Phenotype = the form of the trait that the individual has; the form that shows in the individual, like normal or red.

Phenotypically normal = doesn't have the disorder, even though the individual may have a copy of the recessive allele. This individual must have at least one copy of the dominant, normal allele, like BB or Bb.

Heterozygotes = individuals with two alleles that don't match, like Bb or Rr.

A. Two carrier parents are Bb x Bb.
Possible offspring are BB, Bb, bB, bb.
Of those four possibilities, only one (bb) has the recessive disorder. One out of four is 1/4 or 25%.

B. Two heterozygous parents are Bb x Bb ... just like in part A.
Possible offspring are BB, Bb, bB, bb.
Of those four possibilities, two (Bb and bB) are carriers.
Two out of four is 2/4, or 1/2, or 50%.

Answer 2

A) 25%

B) 50%

Answer 3

A. 25%
B. 50%

Answer 4

a million/2 previous activities have no result on destiny trials. that's very such as asking: "if I turn a honest coin 6 cases and get 4 heads and a pair of tails, what's the threat of having tails on the subsequent coin toss.