Photo AI

Ptosis is a weakness in the muscles of the eyelid - VCE - SSCE Biology - Question 2 - 2004 - Paper 1

Question icon

Question 2

Ptosis-is-a-weakness-in-the-muscles-of-the-eyelid-VCE-SSCE Biology-Question 2-2004-Paper 1.png

Ptosis is a weakness in the muscles of the eyelid. a. Using the information in the text box below, construct a pedigree to fit the description of the inheritance of... show full transcript

Worked Solution & Example Answer:Ptosis is a weakness in the muscles of the eyelid - VCE - SSCE Biology - Question 2 - 2004 - Paper 1

Step 1

a. Construct a pedigree.

96%

114 rated

Answer

To represent the inheritance of ptosis:

  1. Individuals:

    • Bill (affected, circle) married Jill (unaffected, square).
    • They have two children: Ben (unaffected, square) and Daisy (affected, circle).
    • Daisy married Bob (unaffected, square), and they have three daughters: two with ptosis (circles) and one without (circle).

  2. Pedigree: Each affected individual is depicted in a filled circle, and unaffected individuals are shown as unfilled squares/circles.

Step 2

b.i. What is the most likely mode of inheritance of ptosis?

99%

104 rated

Answer

The most likely mode of inheritance for ptosis based on the pedigree is autosomal dominant inheritance, as the trait appears in multiple generations and is passed from affected individuals to both males and females.

Step 3

b.ii. Provide two pieces of evidence from the pedigree that support this conclusion.

96%

101 rated

Answer

  1. Presence of affected individuals in every generation: The pedigree shows that affected individuals appear in each generation, suggesting a dominant trait.
  2. Both genders affected: Both males and females exhibit ptosis, supporting the conclusion that it is not sex-linked.

Join the SSCE students using SimpleStudy...

97% of Students

Report Improved Results

98% of Students

Recommend to friends

100,000+

Students Supported

1 Million+

Questions answered

;