Biology 30 question. (Im stuck on it :( )

    • Thread Starter

    ********PLEASE NOTE THERE IS A PICTURE IN AN ATTATCHMENT. If anyone is able to help me with this question it would be awesome, I do not understand it and cant decide on an answer.

    Porphyrias are genetic disorders in which the hemoglobin component of red blood cells is abnormally assembled. Individuals with one type of porphyria called variegate porphyria are unable to synthesize an enzyme that is necessary for the production of the heme component of hemoglobin. Symptoms of variegate porphyria include sensitivity to light, abdominal pain, digestive disorders, and, in some cases, paralysis. This type of porphyria is inherited in an autosomal dominant mode.

    - adapted from Huskey, 2002
    Diagram by Robert J. Huskey, 1996. Variegate Porphyria Pedigree. Adapted and reprinted with permission.

    1. If individuals II-4 and II-5 have another child, the probability that this child will have variegate porphyria is
    A. 0.00 C. 0.50
    B. 0.25 D. 0.75
    Attached Images

    I think it's C - 0.5

    because one parent has the condition and as it's dominant, the child only needs one copy of the faulty allele to get the condition. The parent with the condition has one faulty allele and one 'normal' allele (you can tell that from their parents) so there is a 50:50 chance that the faulty allele will be inherited from this parent.

    Sorry I'm not very good at explaining, ask me any questions you need to make it clearer
    • Thread Starter

    Thank you !! I understand your explaination !! Again, thank you soo much !
Write a reply… Reply
Submit reply


Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. Oops, you need to agree to our Ts&Cs to register
  2. Slide to join now Processing…

Updated: April 17, 2012
TSR Support Team
How often do you buy stationery?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.