| Date | May 2015 | Marks available | 1 | Reference code | 15M.1.HL.TZ2.8 |
| Level | Higher level | Paper | Paper 1 | Time zone | Time zone 2 |
| Command term | Deduce | Question number | 8 | Adapted from | N/A |
Question
What is a characteristic of the human Y chromosome?
A. It is made of DNA and histones covered by phospholipids.
B. It contains some genes that are not present on the X chromosome.
C. It is the largest chromosome in the human karyotype.
D. It has a condensed length of approximately 100 µm.
Markscheme
B
Examiners report
Although the fact that Y-chromosomes contain genes not present in the X chromosome is not part of the guide, in 4.3.5 and 4.3.6 candidates are expected to explain how the sex chromosomes determine sex, therefore they should be able to answer the question correctly. All the other answers are obviously wrong, so could easily be discarded.
