Understanding Cell Theory and Development

Using a classroom microscope, Nancy observes a small single-celled bacterium become two. She explains this by saying: All living organisms are made up of only one cell. New cells are made from nonliving things. Rewrite Nancy’s explanation, changing any words to make it correct.

• All living organisms are made up of one or more cells. New cells are made from pre-existing cells.

• All living organisms are made up of multiple cells. New cells are made from nonliving things.

• All living organisms are made up of one or more cells. New cells are made from nonliving things.

• All living organisms are made up of only one cell. New cells are made from pre-existing cells.

Answer explanation

Nancy's explanation is incorrect because all living organisms are made up of one or more cells, not just one. Additionally, new cells arise from pre-existing cells, not from nonliving things.

Tags

NGSS.MS-LS1-1

Who was the first scientist to observe and describe cells in a piece of cork?

• Louis Pasteur

• Robert Hooke

• Anton van Leeuwenhoek

• Rudolf Virchow

Answer explanation

Robert Hooke was the first scientist to observe and describe cells in cork in 1665. He used a microscope to examine the cork and coined the term 'cell' based on the small, box-like structures he observed.

Which scientist is credited with the statement that all plants are made of cells?

• Theodor Schwann

• Matthias Schleiden

• Rudolf Virchow

• Louis Pasteur

Answer explanation

Matthias Schleiden, a German botanist, is credited with stating that all plants are made of cells, forming a key part of the cell theory. This theory was later expanded by Theodor Schwann, who applied it to animals.

Tags

NGSS.MS-LS1-1

What was Rudolf Virchow's contribution to the cell theory?

• He discovered the nucleus in plant cells.

• He stated that all cells arise from pre-existing cells.

• He was the first to observe living cells.

• He developed the first microscope.

Answer explanation

Rudolf Virchow's key contribution to cell theory was stating that all cells arise from pre-existing cells, which emphasized the continuity of life and contradicted the idea of spontaneous generation.

Which of the following statements is NOT part of the modern cell theory?

• All living things are composed of one or more cells.

• Cells are the basic unit of structure and function in living things.

• All cells arise from nonliving matter.

• All cells come from pre-existing cells.

Answer explanation

The statement 'All cells arise from nonliving matter' is incorrect. Modern cell theory states that all cells come from pre-existing cells, not from nonliving matter.