Released STAAR Biology EOC · 2026 · Item 9 · 1 point

Walkthrough: Biology 2026, Item 9

B.7C · Mutations · unscored study

Two panels. Normal chromosomes: a long light chromosome 9 and a short dark chromosome 22. Mutated chromosomes: chromosome 9 now ends in a short dark section, and the shortened chromosome 22, labeled Ph, ends in a light section, showing the two chromosomes exchanged pieces. — Normal and mutated chromosomes 9 and 22Original visual from the released STAAR test.

The Philadelphia chromosome (Ph) is a chromosomal abnormality that results in cancer in humans. This occurs when portions of chromosome 9 and chromosome 22 are switched, as shown in the image. Which type of chromosomal mutation must occur in order to form the Philadelphia chromosome?

Translocation
Deletion
Insertion
Nondisjunction

1. Understand the question

Compare the normal and mutated chromosomes. Ask what happened to the pieces: lost, added, or exchanged?

Try the question on your own first, then reveal one step at a time.

2. Solve it step by step

Practice released items for this skill Back to the lesson

Question, artwork, answer key and rationale: Texas Education Agency released STAAR test. Walkthrough steps written by TEKSForge. Studying here does not change your mastery or scores.