Question

Cell theory was proposed by: ____.

• A. Watson and Crick
• B. Schleiden and Schwann
• C. Darwin
• D. Mendel

Hint:

To connect the names to their fields: Schleiden sounds like "slide" (which you use to look at plant tissues under a microscope), and Schwann sounds like "swan" (an animal, fitting the zoologist).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Cell theory is a foundational principle of biology that defines the cellular nature of all living structures and organisms.

Step 2: Detailed Explanation:
The Cell Theory was jointly formulated by two German scientists:
• Matthias Schleiden (1838): A German botanist who concluded that all plants are composed of different kinds of cells.
• Theodore Schwann (1839): A German zoologist who studied different types of animal cells and concluded that all animals are made of cells. He also noted that the presence of a cell wall is a unique character of plant cells. Rudolf Virchow later expanded the theory in 1855 by adding the concept of “Omnis cellula-e cellula” (all cells arise from pre-existing cells).

Step 3: Final Answer:
Cell theory was proposed by Schleiden and Schwann.

Answer 2

The question asks who proposed cell theory, the idea that all living organisms are composed of cells. Each option names scientist(s) tied to a different, well-known biological milestone, so identifying which milestone matches "cell theory" narrows the answer.

1. Watson and Crick: This duo is remembered for working out the double-helix structure of DNA in 1953, a discovery in molecular genetics that came roughly a century after cell theory was proposed, so it does not match.
2. Schleiden and Schwann: Matthias Schleiden studied plant tissue and concluded all plants are made of cells, while Theodor Schwann extended the same conclusion to animal tissue. Together their combined findings gave rise to the principle that all living things are built from cells, which is the definition of cell theory itself.
3. Darwin: is known for the theory of evolution by natural selection, an explanation of how species change over time, unrelated to the structural composition of organisms.
4. Mendel: is remembered for laws of inheritance derived from pea plant experiments, a topic in genetics rather than cell biology's foundational structure.

Matching each name to its actual scientific legacy leaves only one pair credited with establishing that all organisms are made of cells.

Therefore, the correct answer is Schleiden and Schwann.