Count model chromosomes after fertilization

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: Zygote chromosome count equals the two supplied gamete counts added. Formula: a+b. Variable key: a = first gamete chromosomes, b = second gamete chromosomes
• Distinct worked inputs and result: A distinct fictional species has 5 chromosomes in each gamete: 5+5=10 in its modeled zygote.
• Assessment case 1: Supplied case 1: first gamete chromosomes=6; second gamete chromosomes=6, using the explicitly named quantities. Zygote chromosome count equals the two supplied gamete counts added. What result follows?
• Assessment case 2: Supplied case 2: first gamete chromosomes=8; second gamete chromosomes=8, using the explicitly named quantities. Zygote chromosome count equals the two supplied gamete counts added. What result follows?
• Assessment case 3: Supplied case 3: first gamete chromosomes=10; second gamete chromosomes=10, using the explicitly named quantities. Zygote chromosome count equals the two supplied gamete counts added. What result follows?
• Assessment case 4: Supplied case 4: first gamete chromosomes=12; second gamete chromosomes=12, using the explicitly named quantities. Zygote chromosome count equals the two supplied gamete counts added. What result follows?
• Assessment case 5: Supplied case 5: first gamete chromosomes=14; second gamete chromosomes=14, using the explicitly named quantities. Zygote chromosome count equals the two supplied gamete counts added. What result follows?
• Assessment case 6: Supplied case 6: first gamete chromosomes=16; second gamete chromosomes=16, using the explicitly named quantities. Zygote chromosome count equals the two supplied gamete counts added. What result follows?

Learn the idea

The supplied fictional species has equal-sized chromosome sets in its gametes. Adding two gamete sets gives the model zygote total. Do not transfer these counts to every species.

Zygote chromosome count equals the two supplied gamete counts added. The formula in the supplied model is a+b. Variable key: a = first gamete chromosomes, b = second gamete chromosomes. Add one count from each gamete. Counts are specific to the supplied fictional species.

A distinct fictional species has 5 chromosomes in each gamete: 5+5=10 in its modeled zygote. Fertilization differs from ordinary cell division. 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.

1. Name the measured quantities and their units before substituting values.
2. Write the stated rule and use the variable key to match each symbol to its explicitly named quantity.
3. Calculate each supplied case separately, keeping intermediate arithmetic and the result unit.
4. Explain the result in context and identify the assumption that would invalidate direct use of the rule.

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.

Take it further

Changed-input task: use the same stated model with first gamete chromosomes=7; second gamete chromosomes=7. Expected result: 14 chromosomes. Explain what changes and keep this assumption: Fertilization differs from ordinary cell division.

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.