Differentiation, Growth & Cell-Cycle Control — Practice · Grade 10 Science

Chapter: Cell Division, Reproduction & Development

What this practice covers

By the end of Differentiation, Growth & Cell-Cycle Control you should be able to:

8 questions, multiple choice and written answer, each with a worked explanation.

Vocabulary used: differentiation, gene expression, checkpoint.

Problem 1

Different cell functions commonly reflect…
  1. different gene-expression patterns
  2. complete removal of all shared DNA
  3. lack of proteins in most tissues
  4. only cell color
Answer and explanation

different gene-expression patterns

Expression determines which products are made.

Problem 2

Why can a checkpoint delay division after DNA damage?
Answer and explanation

A delay permits repair or other responses before damaged information is passed on.

Problem 3

Distinguish healthy growth from uncontrolled proliferation.
Answer and explanation

Healthy growth is coordinated with tissue needs and regulation; uncontrolled proliferation bypasses important controls.

Problem 4

Why can a neuron and a muscle cell have different functions despite sharing much of the same DNA? Explain the reasoning in your own words.
Answer and explanation

Differential gene expression helps create functional differences without requiring different basic genomes.

Different gene-expression patterns produce different proteins.

Those proteins support distinct structures and activities.

Response criteria

  • Use the stated conditions.
  • Show the evidence or calculation.
  • Explain the conclusion and any stated limitation.

Problem 5

What distinguishes controlled cell division from uncontrolled proliferation? Show the reasoning, not just the conclusion.
Hints

Compare gene presence with gene use.

Answer and explanation

Regulatory signals and checkpoints normally constrain division; disrupted controls can allow excessive proliferation.

Problem 6

Why can a DNA change in a cell-cycle regulator matter to tissue organization?
Hints

State what the supplied observations or conditions establish, and separate that from any assumption.

Answer and explanation

It may alter growth or division control, depending on the change and biological context.

Problem 7

A cell count combines division, loss and changes in stateA cell count combines division, loss and changes in stateCell count in a supplied culture model1001201401601800123DaysPopulation APopulation B
Original illustrative culture-count records, not a tissue-specific clinical growth curve.
Interpret the supplied visual. Can a nearly steady count mean no cells divided or died?
Answer and explanation

No. Birth and loss can nearly balance; direct tracking or separate rate measurements are needed.

Turnover combines production and removal of cells within a defined population. A rising culture count can reflect division exceeding loss; it does not directly show the rate of one cell or whether descendants have specialized. Different tissues maintain different renewal patterns, and many cells can pause division. Migration, death and measurement boundaries matter when comparing counts. A useful explanation links signals, checkpoint conditions and measured state rather than assuming every slowly growing sample has the same defect.

No. Birth and loss can nearly balance; direct tracking or separate rate measurements are needed.

Response criteria

  • Read the structures, axes, directions and units correctly.
  • Connect the evidence with the biological mechanism.
  • Respect stated model assumptions and distinguish an observation from a further inference.

Problem 8

Two samples share the same DNA sequence at a tested gene but show different RNA amounts and cell functions. Explain a possible mechanism and one limit of the evidence.
Answer and explanation

Different regulation can change expression without changing that tested sequence. Other genes, processing and cellular conditions can contribute; matching one gene does not establish complete genome identity or a unique cause.

Different regulation can change expression without changing that tested sequence. Other genes, processing and cellular conditions can contribute; matching one gene does not establish complete genome identity or a unique cause.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the biological mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

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