IB MYP Integrated Sciences e-Assessment : Inheritance Exam Style Practice Questions - New Syllabus
Question
Identical twins have the same genes so they are genetically identical.
(a )Select one pair of twins.(1 mark)
Pair 1: Martin Schoeller/ AUGUST
Pair 2. University Hospitals Case Medical Center, www.healthyandhandsome nl
Pair 3: Tommy Kono
Identify a feature in which this pair of twins differ.
The twins in the images are genetically identical.
(b) Suggest a factor which could account for the difference in the feature you identified in part (a).
(c )Outline a reason why the difference seen in the twins may not be seen in the children of each twin.(2 marks)
The table shows four people, identified by the letters A, B, C, and D.
(d) Use the information in the table to identify which two people are identical twins. Justify your answer using examples
from the table. (3 marks)
▶️Answer/Explanation
Ans:
(a)The hair colour
(b) The phenotype of the twins is different
(c) Because the difference might be a recessive gene, meaning it could easily be overtaken by any dominant gene
(d) \(\mathrm{A}\) and \(\mathrm{C}\) are identical twins
This is because sun tan, sex and dyed hair colour do not determine if two people are identical twins. However, eye colour, natural hair colour and tongue roll are attributes which determine if two people are twins. Since A and C have same eye colour, natural hair colour and can both do the tongue roll, it means they are identical twins.