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Released STAAR Biology EOC · 2025 · Item 6 · 1 point

Walkthrough: Biology 2025, Item 6

B.7B · Protein Synthesis · unscored study

A large two-part structure labeled X sits on a horizontal strand running from 5′ to 3′. A chain of circles extends from the structure, representing a growing chain of amino acids.
Protein synthesis with structure XOriginal visual from the released STAAR test.

Proteins serve numerous roles in the human body. Part of the biological process for making proteins is shown in the image. Based on the image, which of these BEST describes the structure and function of the organelle identified as X?

  1. Endoplasmic reticulum, which carries nucleotides as a DNA strand is being transcribed
  2. Endoplasmic reticulum, which carries nucleotides as a DNA strand is being translated
  3. Ribosome, which holds the mRNA in place as amino acids are transported by tRNA
  4. Ribosome, which holds the tRNA in place as amino acids are transported by mRNA

1. Understand the question

Identify structure X in the diagram of protein synthesis, then describe its job correctly.

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.