Count complete codons
Count complete codons using supplied evidence and a solved model.
About 25 minutes, plus any extended practice
Supplied materials
- All measurements and observations below are supplied classroom examples. They are not data from actual learners or a claim about a particular real site.
- Paper or browser document; an ordinary calculator is optional.
- Rule: Complete codon count equals coding-segment bases divided by three for these divisible-by-three cases. Formula: a/3. Variable key: a = coding-segment RNA bases
- Distinct worked inputs and result: A distinct supplied segment has 15 bases: 15/3=5 complete codons.
- Assessment case 1: Supplied case 1: coding-segment RNA bases=12, using the explicitly named quantities. Complete codon count equals coding-segment bases divided by three for these divisible-by-three cases. What result follows?
- Assessment case 2: Supplied case 2: coding-segment RNA bases=18, using the explicitly named quantities. Complete codon count equals coding-segment bases divided by three for these divisible-by-three cases. What result follows?
- Assessment case 3: Supplied case 3: coding-segment RNA bases=24, using the explicitly named quantities. Complete codon count equals coding-segment bases divided by three for these divisible-by-three cases. What result follows?
- Assessment case 4: Supplied case 4: coding-segment RNA bases=30, using the explicitly named quantities. Complete codon count equals coding-segment bases divided by three for these divisible-by-three cases. What result follows?
- Assessment case 5: Supplied case 5: coding-segment RNA bases=36, using the explicitly named quantities. Complete codon count equals coding-segment bases divided by three for these divisible-by-three cases. What result follows?
- Assessment case 6: Supplied case 6: coding-segment RNA bases=45, using the explicitly named quantities. Complete codon count equals coding-segment bases divided by three for these divisible-by-three cases. What result follows?
Learn the idea
In a supplied coding segment, each complete codon contains three RNA bases. The count here excludes incomplete endings and says nothing about untranslated regions or stop-codon effects unless separately specified.
Complete codon count equals coding-segment bases divided by three for these divisible-by-three cases. The formula in the supplied model is a/3. Variable key: a = coding-segment RNA bases. Group bases in threes from the stated reading frame. The task concerns a supplied coding segment, not all RNA.
A distinct supplied segment has 15 bases: 15/3=5 complete codons. Stop codons do not add an amino acid. Track the quantity and unit before calculating. Explain the meaning of a positive, negative or fractional result when relevant. A numerical answer supports the stated model calculation; broader claims require the additional measurements and assumptions described here.
- Name the measured quantities and their units before substituting values.
- Write the stated rule and use the variable key to match each symbol to its explicitly named quantity.
- Calculate each supplied case separately, keeping intermediate arithmetic and the result unit.
- Explain the result in context and identify the assumption that would invalidate direct use of the rule.
See the method in action
Worked distinct example: A distinct supplied segment has 15 bases: 15/3=5 complete codons. Method: identify the quantities in the stated rule, substitute using compatible units, and perform the operations in the correct order. Group bases in threes from the stated reading frame. The task concerns a supplied coding segment, not all RNA. Interpret the final unit and keep the model assumption visible; this calculation is not a measurement of a real learner or site.
Check your reasoning
Your answer is temporary and is not saved to an account. Download your current answer before leaving or reloading. Written work on paper or in another app stays in your own file.
Helpful tips
- Group bases in threes from the stated reading frame.
- The task concerns a supplied coding segment, not all RNA.
See the answer and explanation
4 codons
Substitute the supplied values: (12)/3 = 4 codons. Group bases in threes from the stated reading frame. Stop codons do not add an amino acid.
Take it further
Changed-input task: use the same stated model with coding-segment RNA bases=18. Expected result: 6 codons. Explain what changes and keep this assumption: Stop codons do not add an amino acid.
Nothing here is saved to an account or sent to a teacher. The answer download includes your current choice and any checked feedback. It does not include choices from the separate More practice section. Download that section separately.
More practice: try new cases
Choose an answer for each problem. Explain your method on paper, then use the feedback to decide what to revisit.
Your choices are temporary. Feedback appears after you check all the answers.
Nothing here is saved to an account or sent to a teacher. Keep your own notes or download them before leaving. The score describes these questions; it does not certify subject mastery.
Check the subject sources
These LifeStarter passages, scenarios and exercises are authored for this Academy with AI assistance and review. External resources keep their publishers’ terms. A grade label suggests a starting level; it does not establish alignment with your school’s complete requirements.