Cell theory and how it was discovered
Grade 9 Science Worksheet
Circle the best answer.
Read this first
Use this
Cell theory card. Part 1: one or more cells make up all living things. Part 2: the cell is the basic living unit. Part 3: new cells arise from existing cells.
Ari reads that Schleiden looked at many plant tissues in 1838 and found cells in each. Which part of cell theory does this support, and why?
- Part 1, because the plant tissues were made of cells
- Part 2, because each tissue was one living cell
- Part 3, because the cells formed from the plant's sap
- Part 3, because Schleiden watched cells divide
Bo reads that in 1674 Leeuwenhoek saw single-celled organisms swim in lake water. Which part does this best support, and why?
- Part 3, because the organisms formed from lake water
- Part 1, because the organisms were made of many different cells
- Part 3, because the organisms were seen dividing
- Part 2, because one cell on its own can be a living thing
Esme reads that in 1852 Remak published convincing evidence that cells come from other cells by cell division. Which part does this support, and why?
- Part 3, because new cells formed from nonliving matter
- Part 3, because new cells arose from cells that divided
- Part 1, because the cells that divided made up a whole tissue
- Part 2, because a dividing cell is the unit of life
Use this
Microscope facts (real data, OpenStax Biology 2e). Columns: microscope, magnification, resolution, living cells. A light microscope magnifies up to about 400 times and has a resolution of about 200 nanometers; it can view living cells. An electron microscope magnifies up to 100,000 times and has a resolution of 50 picometers; it cannot view living cells.
Jun wants to watch a single-celled organism swim in a drop of water. Which microscope fits, and why?
- Electron microscope, because it can view living cells
- Electron microscope, because 100,000 times shows the most
- Light microscope, because it can view living cells
- Light microscope, because its resolution is 50 picometers
Use this
Microscope magnification (real data, OpenStax Biology 2e). Columns: microscope, magnification. Light microscope: up to about 400 times. Electron microscope: up to 100,000 times.
Luz compares two microscopes. About how many times greater is the electron microscope's top magnification than the light microscope's?
- 250 times
- 99,600 times
- 25 times
- 400 times
Milo finds the gap between events A and B on the timeline. How many years pass, and what did Hooke see?
- 173 years; Hooke saw only cork cell walls
- 163 years; Hooke saw only cork cell walls
- 173 years; Hooke saw living cork cells
- 173 years; Schleiden's work came first
Which two events on Pia's timeline are closest in time?
- A and C, 16 years apart
- B and C, 3 years apart
- C and D, 7 years apart
- A and B, 13 years apart
Ren says one person built cell theory. Which statement fits the timeline best?
- Virchow built it alone in 1855
- Several scientists added parts between 1665 and 1855
- Hooke finished it in 1665 after seeing living cork cells
- Schleiden finished it alone in 1838
Tala says cell theory is just a guess because it is called a theory. Which fact best answers Tala?
- A theory is another word for a hypothesis
- Theories are guesses until a scientific law replaces them one day
- Many scientists tested and confirmed its parts over the years
- It is called a theory because Virchow named it
Zee reads that Schleiden's 1838 idea began as a suggested explanation. After Schwann, Remak and Virchow added evidence, what did cell theory become?
- A guess that gained more names
- A hypothesis that still needs its first test
- A finished idea that Schleiden proved alone
- A tested and confirmed explanation
