Cell Theory & the Discovery of Cells — Drills · Grade 10 Science

Chapter: Cells, Membranes & Exchange

What these drills covers

By the end of Cell Theory & the Discovery of Cells you should be able to:

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

Vocabulary used: cell, cell theory, magnification, resolution, spontaneous generation, organism.

Problem 1

Which statement is part of the cell theory?
  1. All cells contain a nucleus
  2. All living things are made of one or more cells
  3. All cells are the same size
  4. Cells arise spontaneously from non-living matter
Answer and explanation

All living things are made of one or more cells

The three classical statements are that living things are made of cells, that the cell is the basic unit of structure and function, and that cells come from pre-existing cells. Bacteria have no nucleus, so the first choice is false.

Problem 2

A microscope has a 10× eyepiece and a 40× objective in place. What is the total magnification?
Answer and explanation

400 ×

Total magnification is the product: 10 × 40 = 400×.

Problem 3

A cell appears 2.0 mm wide under 400× total magnification. What is its actual width in micrometres?
Answer and explanation

5 µm

Actual size = image size / magnification = 2.0 mm / 400 = 0.005 mm = 5 µm.

Problem 4

Redi's and Pasteur's sealed-flask experiments mattered to cell theory because they
  1. showed cells contain organelles
  2. measured cell size accurately
  3. undermined spontaneous generation, supporting the claim that cells come from cells
  4. proved all cells have membranes
Answer and explanation

undermined spontaneous generation, supporting the claim that cells come from cells

Their controls showed that growth appeared only when existing organisms could enter, supporting the third statement of cell theory.

Problem 5

A field of view is 400 µm across and 8 identical cells fit end to end across it. What is the mean cell length in micrometres?
Answer and explanation

50 µm

400 µm / 8 = 50 µm per cell. Counting across a known field is how sizes are estimated without a stage micrometer.

Problem 6

Explain why the invention of better lenses was necessary before cell theory could be proposed, and what that says about instruments in biology.
Answer and explanation

Cells are a few micrometres to tens of micrometres across, below what the unaided eye resolves, so they could not be observed at all until lenses magnified them adequately. Hooke saw cork compartments and Leeuwenhoek saw living single cells only because their instruments resolved that scale. Biological claims are limited by what instruments can detect, so a new instrument often precedes a new theory rather than following it.

Response criteria

  • State a biologically accurate conclusion.
  • Show the data, mechanism, or calculation that supports it.
  • Include units, conditions, or limits where relevant.

Browse all courses