Prokaryotic and eukaryotic cells compared
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
Three cutaways side by side (model drawing, not to scale). no nucleus. no cell wall. Ari's friend says a cell with a cell wall must be a plant cell, so a bacterium with a wall would be a plant. Which response is best?
- Disagree: a cell with a wall and no nucleus is a tiny animal cell, not a plant cell
- Agree: a wall holds a plant's shape, and no other cell needs one
- Disagree: bacteria and fungi have cell walls too, so a wall does not show a plant
- Agree: a cell wall is a plant feature, so a bacterium with one is a plant
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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.
Bo's friend says a bacterium has no DNA or ribosomes, since it has no nucleus and no organelles. Which response is best?
- Disagree: a bacterium has DNA in a nucleoid and ribosomes, but no nucleus
- Disagree: a bacterium is a tiny animal cell, so it has a nucleus and organelles
- Agree: DNA needs a nucleus to be kept in, so a bacterium has no DNA
- Agree: ribosomes are organelles, and a bacterium has no organelles
Two cutaways side by side (model drawing, not to scale). Esme's friend sees a bacterium on a slide and says a bacterium is just a tiny animal. Which response is best?
- Disagree: a bacterium is a prokaryote with no nucleus, and it is not an animal
- Agree: a bacterium is an animal cell that is simply much smaller than the others
- Disagree: a bacterium is not an animal, and it has no DNA
- Agree: a bacterium has a flagellum to move, so it is a tiny animal
Use this
Mitochondria and bacteria (real data, from OpenStax Biology), 4 rows. Columns: feature, bacterium, mitochondrion. own DNA, yes, in a nucleoid, yes, its own genome; own ribosomes, yes, yes, like those of prokaryotes; membranes around it, one plasma membrane, two; how new ones form, the cell divides, divides by a process like binary fission.
Kira reads about the idea that mitochondria came from bacteria taken into a larger cell. Which statement does the table best support?
- Mitochondria have their own DNA and ribosomes, as bacteria do
- Mitochondria make energy and bacteria make energy, so they are the same
- Mitochondria have a nucleus of their own, which shows they were cells
- Mitochondria have no DNA, since the nucleus holds the DNA of a eukaryotic cell
Chloroplasts (real data, from OpenStax Biology)
feature chloroplast own DNA a circular DNA chromosome own ribosomes similar to those of cyanobacteria membranes around it two inner membrane thought to come from the plasma membrane of a cyanobacterium taken in Luz asks why a chloroplast having two membranes fits the idea that chloroplasts came from bacteria taken into a larger cell. What is the best reason?
- Two membranes show chloroplasts came from mitochondria, which also have two
- Two membranes show that the cell built the chloroplast from scratch inside its cytoplasm
- The inner membrane is thought to come from the plasma membrane of the cyanobacterium
- Both membranes came from the nucleus, since a chloroplast has no DNA of its own
How new mitochondria form (real data, from OpenStax Biology)
observation result where new mitochondria come from previous mitochondria how they divide by pinching in two like binary fission in prokaryotes built from scratch by the cell no Milo reads the card on new mitochondria. Which conclusion fits the evidence?
- New mitochondria grow from ribosomes in the cytoplasm
- New mitochondria are built from scratch whenever the cell needs energy
- New mitochondria come from existing ones that divide, much as bacteria divide
- New mitochondria are copied from the nucleus's DNA, since they have no DNA of their own
Pia compares model cell P, a 3 µm cube, with model cell Q, a 30 µm cube. Which statement about their exchange of materials is right?
- Q exchanges better, because 27000 cubic µm of volume holds more materials
- P has 10 times the ratio of Q, so P has more membrane for each unit of volume
- Q exchanges better, because 5400 square µm is far more membrane than the 54 of cell P
- P and Q exchange equally well, because both cells are cubes
Zee doubles a model cell's side from 6 µm to 12 µm. Which statement fits the table?
- The bigger cell holds 8 times the materials, so it exchanges 8 times better than before
- Volume grew 8 times but surface area only 4 times, so the ratio fell from 1 to 0.5
- Volume and surface area both grew 8 times, so the ratio stayed at 1
- Surface area grew from 216 to 864, so the larger cell exchanges better
Cell V has a nucleus and mitochondria. Milo finds that cell V is 4 µm wide, inside the prokaryotic range, yet it has a nucleus and mitochondria. Which explanation fits?
- The measurement must be wrong, because a cell with a nucleus must be 10 µm or more across
- V is a prokaryote, because its width fits 0.1 to 5.0 µm
- V is a eukaryote: a nucleus and organelles decide the type; size ranges are typical
- V is neither kind of cell, because its size fits one and its parts fit the other
model data, not to scale. Its inside has not been checked yet. Esme thinks the soil cell is a eukaryote because it might have DNA and ribosomes. Which finding would show it is a prokaryote?
- It has no DNA of its own, because prokaryotes are cells that lack DNA
- Its DNA lies in a nucleoid, with no nucleus or organelles with membranes
- It has no ribosomes, because prokaryotes are cells that lack ribosomes
- It has a cell wall, because prokaryotes are the cells that have walls