The History of Cell and Cell Theory (Worksheet)

Fill in the blanks to complete the three main principles of cell theory. All ______________ are composed of one or more cells.

• organisms

• molecules

• atoms

• particles

Answer explanation

The correct choice is 'organisms' because cell theory states that all living organisms are made up of one or more cells, distinguishing them from molecules, atoms, and particles, which are not living entities.

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Fill in the blanks to complete the three main principles of cell theory. The smallest structural and functional unit of organisms is ______________.

• cell

• atom

• molecule

• tissue

Answer explanation

The smallest structural and functional unit of organisms is a 'cell'. Cells are the basic building blocks of life, making 'cell' the correct choice over 'atom', 'molecule', or 'tissue', which represent different levels of biological organization.

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NGSS.MS-LS1-1

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Fill in the blanks to complete the three main principles of cell theory. Cells arise from ______________.

• pre-existing cells

• spontaneous generation

• non-living matter

• chemical reactions

Answer explanation

Cells arise from pre-existing cells is a fundamental principle of cell theory, emphasizing that new cells are produced by the division of existing cells, not from spontaneous generation or non-living matter.

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NGSS.MS-LS1-1

Who discovered the existence of cells in 1665?

• Anton van Leeuwenhoek

• Theodor Schwann

• Robert Hooke

• Matthias Schleiden

Answer explanation

Robert Hooke discovered the existence of cells in 1665 while examining cork under a microscope. He coined the term 'cell' to describe the small, box-like structures he observed.

The person in the following picture was the first scientist to observe living cells in 1674. Who is this scientist?

• Anton van Leeuwenhoek

• Theodor Schwann

• Robert Hooke

• Matthias Schleiden

Answer explanation

The correct answer is Anton van Leeuwenhoek, who was the first to observe living cells in 1674 using a microscope he designed. Robert Hooke observed cells in cork but not living ones, while Schwann and Schleiden contributed later.

What invention made the discovery of the cell possible?

• Telescope

• Microscope

• Stethoscope

• Thermometer

Answer explanation

The microscope was the key invention that allowed scientists to observe cells for the first time, revealing the complex structures within living organisms. Other options like the telescope and stethoscope do not provide the necessary magnification for this discovery.

Which of the following scientists discovered the cell nucleus?

• Charles Darwin

• Rudolf Virchow

• Louis Pasteur

• Robert Brown

Answer explanation

Robert Brown discovered the cell nucleus in 1831 while studying plant cells. His observations led to the identification of the nucleus as a key component of cells, distinguishing him from the other scientists listed.

Which of the following scientists concluded that all plants are made of cells in 1838?

• Anton van Leeuwenhoek

• Theodor Schwann

• Robert Hooke

• Matthias Schleiden

Answer explanation

Matthias Schleiden concluded in 1838 that all plants are made of cells, contributing to the cell theory. Anton van Leeuwenhoek and Robert Hooke made earlier discoveries about cells, but Schleiden specifically focused on plants.

Which of the following scientists concluded that all animals are made of cells in 1839?

• Anton van Leeuwenhoek

• Theodor Schwann

• Robert Hooke

• Matthias Schleiden

Answer explanation

Theodor Schwann, in 1839, concluded that all animals are made of cells, contributing to the cell theory. Anton van Leeuwenhoek and Robert Hooke made earlier discoveries about cells, but Schwann was the one who focused on animals.

Which of the following scientists reported that all cells come from preexisting cells through division in 1855?

• Rudolf Virchow

• Robert Brown

• Robert Hooke

• Matthias Schleiden

Answer explanation

Rudolf Virchow is credited with the statement "Omnis cellula e cellula" in 1855, meaning all cells arise from preexisting cells through division, which is a fundamental concept in cell theory.