Bio Question

[d wannabe]

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Q) What is the probability that a mother who is a carrier for cystic fibrosis(an autosomal recessive disorder) will pass the diseased allele on to her child whose father is genotypically normal?

1) 50%
2) 25%
3) 100%
4) 0%

Q) If the frequency of cystic fibrosis (above) in the general population is 1/400, what is the carrier frequency?

1) 399/400
2)(19/20)^2 + 2(19/20)(1/20)
3) 2(19/20)(1/20)
4) (19/20)^2
5) (19/20)(1/20)


I don't have answerkey so I just wanna check the answer.
Can someone help me with this question?

Thanks!

 

[Tina324]

1. 50%
2. i have no idea what a carrier freq is...anyone?

 

[IWantH2O]

Q) What is the probability that a mother who is a carrier for cystic fibrosis(an autosomal recessive disorder) will pass the diseased allele on to her child whose father is genotypically normal?

1) 50%
2) 25%
3) 100%
4) 0%


Q) If the frequency of cystic fibrosis (above) in the general population is 1/400, what is the carrier frequency?

1) 399/400
2)(19/20)^2 + 2(19/20)(1/20)
3) 2(19/20)(1/20)
4) (19/20)^2
5) (19/20)(1/20)


I don't have answerkey so I just wanna check the answer.
Can someone help me with this question?

Thanks!

is that wat u got....yup it is 50 % becuase she is a carrier

 

[flycd05]

i got 50% for the first one but cant seem to get the 2nd question - anyone know how to work out the math?

 

[Mamona]

Q) What is the probability that a mother who is a carrier for cystic fibrosis(an autosomal recessive disorder) will pass the diseased allele on to her child whose father is genotypically normal?

1) 50%
2) 25%
3) 100%
4) 0%

Q) If the frequency of cystic fibrosis (above) in the general population is 1/400, what is the carrier frequency?

1) 399/400
2)(19/20)^2 + 2(19/20)(1/20)
3) 2(19/20)(1/20)
4) (19/20)^2
5) (19/20)(1/20)


I don't have answerkey so I just wanna check the answer.
Can someone help me with this question?

Thanks!

This is what I think it is!!!

 

[tisler]

I'm pretty sure that the answer to #1 is 50%
and for #2 IWantH2O is right.
1/400 = (1/20)^2 - this is the recessive allele frequency, using hardy and weinberg.
19/20 is for the dominant allele frequency (p+q = 1)
So for the heterozygote, 2pq = 2*(19/20)*(1/20)

 

[harrygt]

Q) What is the probability that a mother who is a carrier for cystic fibrosis(an autosomal recessive disorder) will pass the diseased allele on to her child whose father is genotypically normal?

1) 50%
2) 25%
3) 100%
4) 0%

The mother has one dominant and one recessive allele [because she is a carrier]. She will pass one of her alleles to the child. The chance of passing each is 50%.

Q) If the frequency of cystic fibrosis (above) in the general population is 1/400, what is the carrier frequency?

1) 399/400
2)(19/20)^2 + 2(19/20)(1/20)
3) 2(19/20)(1/20)
4) (19/20)^2
5) (19/20)(1/20)

q^2 = 1/400 ---> q = 1/20 p = 1 - 1/20 = 19/20
frequency of heterozygote [carrier] is always equal 2pq, therefore, the answer is choice 3.
These are good representatives of the types of Hardy W. problems you might get on the real thing.


I don't have answerkey so I just wanna check the answer.
Can someone help me with this question?


Thanks!

Make sure you do a lot of these and get proficient in solving them. They are not that had.