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Grade 11 · Science

Trace a stated gene-expression model

Use a supplied DNA-to-RNA-to-protein model and a small codon table without claiming that every DNA change changes a protein.

6 authored questions + worked example

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Worked example

In the model described here, a DNA segment is transcribed into RNA, then RNA is translated into a protein. Which intermediate carries the copied information?

Answer & why

Answer: RNA

The stated pathway places RNA between DNA and protein.

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All questions

All 6 authored questions for this skill.

Question 1

A supplied table says UUU → phenylalanine and UUA → leucine. What change follows when this codon changes from UUU to UUA?

  1. Leucine changes into a DNA base.
  2. The table gives no mapping for UUA.
  3. The listed amino acid changes from phenylalanine to leucine.
  4. The amino acid stays phenylalanine.
A hint

Follow the supplied information pathway and codon table; do not infer an amino acid that the table does not give.

Answer & why

Answer: The listed amino acid changes from phenylalanine to leucine.

The two provided codons have different mappings.

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Question 2

A model gives the order DNA → RNA → protein. Which process label belongs to RNA → protein? The prompt defines translation as building protein from RNA instructions.

  1. Translation
  2. Diffusion
  3. Evaporation
  4. Condensation
A hint

Follow the supplied information pathway and codon table; do not infer an amino acid that the table does not give.

Answer & why

Answer: Translation

The supplied definition directly labels the RNA-to-protein step.

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Question 3

A DNA change is observed, but no RNA or protein measurements are given. What claim needs more evidence?

  1. The change definitely altered the final protein.
  2. The record concerns a DNA sequence.
  3. More measurements could test its consequences.
  4. A DNA change was recorded.
A hint

Follow the supplied information pathway and codon table; do not infer an amino acid that the table does not give.

Answer & why

Answer: The change definitely altered the final protein.

Sequence changes can have different consequences; the final effect is not supplied.

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Question 4

Two cells contain the same gene, but measurements show its RNA is abundant in one and absent in the other. What narrow conclusion is supported?

  1. The RNA result proves every protein is identical.
  2. The gene's measured RNA expression differs between these cells.
  3. The cells must have different versions of every gene.
  4. Neither cell contains DNA.
A hint

Follow the supplied information pathway and codon table; do not infer an amino acid that the table does not give.

Answer & why

Answer: The gene's measured RNA expression differs between these cells.

The observation describes different RNA expression, not the entire genome or protein content.

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Question 5

In the model described here, a DNA segment is transcribed into RNA, then RNA is translated into a protein. Which intermediate carries the copied information?

  1. A finished protein
  2. A cell-wall brick
  3. RNA
  4. A mineral grain
A hint

Follow the supplied information pathway and codon table; do not infer an amino acid that the table does not give.

Answer & why

Answer: RNA

The stated pathway places RNA between DNA and protein.

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Question 6

The supplied RNA table says GAA → glutamate and GAG → glutamate. What happens to that amino acid if GAA changes to GAG?

  1. All protein production necessarily stops.
  2. It remains glutamate.
  3. It must become a different amino acid.
  4. The table becomes a DNA molecule.
A hint

Follow the supplied information pathway and codon table; do not infer an amino acid that the table does not give.

Answer & why

Answer: It remains glutamate.

Both listed codons map to the same amino acid.

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