Prokaryotic and eukaryotic cells compared

Grade 9 Science Worksheet

Circle the best answer.

1. Read this first

   Use this

   Cell card X (model data, not to scale), from a pond-water sample. It has no nucleus and no other membrane-bound organelle.

2. 1.

   Ari and a teacher read card X. What kind of cell is X, and why?

   • An animal cell, because it uses a flagellum to move about
   • A prokaryote, because it has no nucleus or membrane-bound organelles
   • A plant cell, because it has a cell wall around its membrane
   • A eukaryote, because ribosomes are found in eukaryotes
3. 2.

   “(model data, not to scale),” Bo reads card Y, from a mushroom. What kind of cell is Y, and why?

   • A eukaryote, because it has a nucleus, and a wall does not decide
   • A plant cell, because a cell wall means a plant cell
   • A prokaryote, because a cell wall is a feature of bacteria
   • A prokaryote, because it has ribosomes and a plasma membrane
4. 3.

   It has no cell wall. Esme compares card U with a bacterium. Which parts does cell U share with a bacterium?

   • Plasma membrane, cytoplasm and DNA, since bacteria lack ribosomes
   • Nucleus, ribosomes and DNA, since a bacterium has a nucleus too
   • Plasma membrane, cytoplasm and ribosomes, since bacteria lack DNA
   • Plasma membrane, cytoplasm, ribosomes and DNA

5. Use this

   Two cell cutaways side by side (model drawing, not to scale) above a Venn diagram. Left cutaway: a prokaryotic cell. Right cutaway: a eukaryotic (animal) cell. Venn diagram, left circle, prokaryotic cell only: DNA in a nucleoid; no membrane-bound organelles. Right circle, eukaryotic cell only: DNA inside a nucleus; membrane-bound organelles. Overlap, both cells: plasma membrane; cytoplasm; ribosomes; DNA.

6. 4.

   Kira reads the Venn diagram. Which statement about building proteins is right?

   • Eukaryotic cells have ribosomes, and prokaryotic cells use the nucleoid instead
   • Prokaryotic cells lack ribosomes, so they cannot build proteins
   • Prokaryotic cells are tiny animal cells, so they build proteins in a nucleus
   • Both kinds of cell use their ribosomes to build proteins
7. 5.

   model drawing, not to scale. Tala labels two cutaways. Letters B and F point to the same kind of part: small dots that build proteins. What are they, and where are they found?

   • Ribosomes, found in both the bacterium and the animal cell
   • Ribosomes, found in the animal cell but not the bacterium
   • Mitochondria, found in both the bacterium and the animal cell
   • Nucleoids, found in the bacterium but not the animal cell

8. Cell diameters (real data, from OpenStax Biology)

   kind of cell	smallest diameter in µm	largest diameter in µm
   prokaryotic cell	0.1	5.0
   eukaryotic cell	10	100

9. 6.

   Esme uses the table. How many times wider is the smallest eukaryotic cell than the largest prokaryotic cell?

   • 50 times
   • 20 times
   • 5 times
   • 2 times

10. Two model cells (model data, widths inside the real ranges)

    cell	width in µm
    model bacterium	2
    model eukaryotic cell	20

11. 7.

    Ren lines up model bacteria end to end across the model eukaryotic cell. How many bacteria fit across its width?

    • 22 bacteria
    • 10 bacteria
    • 40 bacteria
    • 18 bacteria
12. 8.

    Pia compares model cells. A cube cell has surface area 6 × side × side and volume side × side × side. Which cell has more membrane for each unit of volume?

    • The 2 µm cell, with a ratio of 3 against 1.5
    • The 4 µm cell, because its volume of 64 holds more materials
    • The 4 µm cell, because 96 is more surface area than 24
    • Neither cell, because both cells are cubes

13. Model cube cell (model data)

    quantity	value
    side in µm	5
    surface area formula	6 × side × side
    volume formula	side × side × side

14. 9.

    Zee uses the formulas. What is the surface area-to-volume ratio of this model cube cell?

    • 1.2 per µm
    • 10 per µm
    • 0.24 per µm
    • 0.83 per µm
15. 10.

    A model cell grows from a 10 µm cube to a 20 µm cube. Jun says the larger cell exchanges materials better. What does the table show?

    • The ratio stayed the same, because the shape is still a cube
    • The ratio rose, because the surface area grew from 600 to 2400
    • The ratio fell from 0.6 to 0.3, so the larger cell has less membrane per unit of volume
    • The larger cell is better, because 2400 is far more membrane than 600