Cell Theory Quiz
Cell theory is one of the great unifying ideas of biology, but it was not discovered in a single moment. It was assembled from careful microscopic observations of plant and animal tissues, from arguments about membranes and walls, and from one decisive correction about where new cells come from.
This quiz follows Lesson 2: Cell Theory and tests your understanding of:
- Matthias Schleiden and the study of plant tissues
- Theodor Schwann and the thin outer layer he called the plasma membrane
- The cell wall as a unique feature of plant cells
- The gap in the original cell theory regarding new cell formation
- Rudolf Virchow and the principle Omnis cellula-e cellula
- The modern two-part statement of cell theory
Read each question carefully. The emphasis throughout is on the logic of discovery: what was seen, what was inferred, and where the inference fell short until Virchow closed the gap.
Q1. Matthias Schleiden is best known in the history of cell theory for his careful microscopic examination of which material?
Schleiden examined plant tissues and recognised a common architecture within them, which became one half of the combined cell theory.
Q2. Theodor Schwann, who studied different types of animal cells, was described in the lesson as belonging to which profession?
Schwann (1839) is identified as a German zoologist who studied different types of animal cells.
Q3. While studying animal cells, Schwann reported that cells possessed a thin outer layer. What is this layer known as today?
Schwann reported that cells had a thin outer layer, which is today known as the plasma membrane.
Q4. According to Schwann's conclusions, the presence of a cell wall is a unique character of which type of cells?
Schwann concluded, based on his studies on plant tissues, that the presence of a cell wall is a unique character of plant cells.
Q5. Schwann proposed the hypothesis that the bodies of animals and plants are composed of what?
Schwann proposed that the bodies of animals and plants are composed of cells and products of cells.
Q6. Who together formulated the original cell theory?
The lesson states that Schleiden and Schwann together formulated the cell theory.
Q7. What important question did the original cell theory of Schleiden and Schwann fail to explain?
The theory formulated by Schleiden and Schwann did not explain how new cells were formed, which was the gap later closed by Virchow.
Q8. Rudolf Virchow, in 1855, first explained which idea?
Virchow (1855) first explained that cells divided and new cells are formed from pre-existing cells.
Q9. The Latin phrase associated with Virchow's explanation of new cell formation is:
Virchow's principle is expressed as Omnis cellula-e cellula, meaning new cells arise from pre-existing cells.
Q10. What did Virchow do to the hypothesis of Schleiden and Schwann?
Virchow modified the hypothesis of Schleiden and Schwann to give the cell theory its final shape.
Q11. Which of the following is part (i) of cell theory as understood today?
The first part of modern cell theory states that all living organisms are composed of cells and products of cells.
Q12. Which of the following is part (ii) of cell theory as understood today?
The second part of modern cell theory states that all cells arise from pre-existing cells.
Q13. A student claims that the original cell theory of Schleiden and Schwann was already complete. Which statement best corrects this claim?
The original theory did not explain how new cells were formed; Virchow supplied this missing mechanism in 1855.
Q14. Which pairing of scientist and contribution is correct according to the lesson?
Schleiden studied plant tissues and, together with Schwann, formulated the cell theory. The other pairings mix up the contributions.
Q15. Which statement best summarises the modern two-part cell theory as given in the lesson?
Modern cell theory states that all living organisms are composed of cells and products of cells, and that all cells arise from pre-existing cells.