Question

name____ class__ date____

1. what discovery is van leeuwenhoek noted for?
2. what are the three parts of the cell theory?

read the passage below, which covers topics from your textbook. answer the questions that follow.
early evidence for the cell theory was provided by german scientists. in 1838, the botanist matthias schleiden concluded that all plants are composed of cells. a year later, the zoologist theodor schwann came to the same conclusion about animals. in 1855, rudolf virchow, a physician who had been studying how disease affects living things, reasoned that cells come only from other cells. over the years, modern scientists have gathered much additional evidence that strongly supports the cell theory.
use the two passages to complete the table below.
skill: organizing information

1. the figure below indicates events that lead up to the cell theory. complete the table by filling in the blank spaces.

date	scientist	discovery
b.	anton van leeuwenhoek	c.
1838	matthias schleiden	d.
e.	f.	stated that all animals are made of cells
1855	g.	h.

circle the letter of the phrase that best completes the sentence.

1. the cell theory was

a. first identified in 1665.
b. the end result of many scientific investigations.
c. described by rudolf virchow.
d. both (a) and (b)

Explanation:

1. Anton van Leeuwenhoek is noted for being the first to observe living cells (such as bacteria and protozoa) using a microscope.
2. The three parts of the cell - theory are: all living organisms are made up of one or more cells; the cell is the basic unit of life; all cells come from pre - existing cells.
3. a. Robert Hooke; b. 1674; c. observed living cells (bacteria, protozoa etc.); d. concluded that all plants are composed of cells; e. 1839; f. Theodor Schwann; g. Rudolf Virchow; h. stated that cells come only from other cells.
4. The cell theory was the end result of many scientific investigations. It was not first identified in 1665 (Robert Hooke just observed dead plant cell remains then) and not just described by Rudolf Virchow.

Answer:

1. Observation of living cells (such as bacteria and protozoa) using a microscope.
2. All living organisms are made up of one or more cells; the cell is the basic unit of life; all cells come from pre - existing cells.
3. a. Robert Hooke

b. 1674
c. Observed living cells (bacteria, protozoa etc.)
d. Concluded that all plants are composed of cells
e. 1839
f. Theodor Schwann
g. Rudolf Virchow
h. Stated that cells come only from other cells

1. b. the end result of many scientific investigations.