Genes, Cell Division & Heredity — Chapter quiz · Life Science & Scientific Inquiry, Grade 7

Five focused units, a three-session investigation, chapter review, and chapter quiz.

Problem 1

Can a capital letter alone prove dominance in a real organism?
Answer and explanation

No. Dominance describes an observed relationship between allele effects in a specified model, not a property of typography.

Problem 2

A fictional trait has alleles labeled P and p, but no relationship is supplied. Can its appearance be inferred from Pp alone?
Answer and explanation

No. The genotype letters identify versions under the model, but the genotype-phenotype relationship must be specified or supported by evidence.

Response criteria

  • Explain the relevant biological process accurately.
  • Use the supplied evidence and show calculation steps with units where needed.
  • Connect a labeled model or mechanism with the claim.
  • State an assumption, evidence limitation, or useful next observation.

Problem 3

Why is mitosis not automatically gamete formation?
Answer and explanation

Mitosis normally preserves the studied chromosome set; meiosis reduces the set in the sexual reproduction model.

Problem 4

A tissue gains four cells by division and loses four in the same interval. What is its net change, and did division occur?
Answer and explanation

Net change is zero, but division occurred. Equal gains and losses can keep the total count stable.

Response criteria

  • Explain the relevant biological process accurately.
  • Use the supplied evidence and show calculation steps with units where needed.
  • Connect a labeled model or mechanism with the claim.
  • State an assumption, evidence limitation, or useful next observation.

Problem 5

Does reshuffling necessarily create a new allele sequence?
Answer and explanation

No. It can combine existing versions differently. A mutation changes genetic material; these are distinct processes.

Problem 6

A diagram gives an eight-chromosome species eight in each gamete and sixteen in the zygote. What missing process should be examined?
Answer and explanation

The diagram omitted chromosome-set reduction during meiosis in the stated diploid model. Normal gametes should have four and the zygote eight.

Response criteria

  • Explain the relevant biological process accurately.
  • Use the supplied evidence and show calculation steps with units where needed.
  • Connect a labeled model or mechanism with the claim.
  • State an assumption, evidence limitation, or useful next observation.

Problem 7

Does dominance make an Aa parent transmit A more than half the time in this model?
Answer and explanation

No. Dominance concerns phenotype expression, while the supplied gamete probabilities remain one half A and one half a.

Problem 8

In an Aa×Aa model, a sample of four has no aa offspring. Does that alone prove the probability model wrong?
Answer and explanation

No. Small independent samples can differ from expected ratios. Examine more evidence and the assumptions before choosing between sampling variation and a different model.

Response criteria

  • Explain the relevant biological process accurately.
  • Use the supplied evidence and show calculation steps with units where needed.
  • Connect a labeled model or mechanism with the claim.
  • State an assumption, evidence limitation, or useful next observation.

Problem 9

Does every body-cell mutation pass to offspring?
Answer and explanation

No. Transmission depends on contribution to reproductive genetic material, not simply occurrence anywhere in a body.

Problem 10

A mutation has no visible effect in one setting. Must it be impossible or meaningless?
Answer and explanation

No. Its effect may be small, depend on conditions, or not change the measured trait. A genetic change and a visible phenotype are different observations.

Response criteria

  • Explain the relevant biological process accurately.
  • Use the supplied evidence and show calculation steps with units where needed.
  • Connect a labeled model or mechanism with the claim.
  • State an assumption, evidence limitation, or useful next observation.

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