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: bacteria and fungi have cell walls too, so a wall does not show a plant
- Agree: a wall holds a plant's shape, and no other cell needs one
- Disagree: a cell with a wall and no nucleus is a tiny animal cell, not a plant cell
- Agree: a cell wall is a plant feature, so a bacterium with one is a plant
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?
- Agree: a bacterium has a flagellum to move, so it is a tiny animal
- Disagree: a bacterium is not an animal, and it has no DNA
- Agree: a bacterium is an animal cell that is simply much smaller than the others
- Disagree: a bacterium is a prokaryote with no nucleus, and it is not an animal
Read this first
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 a nucleus of their own, which shows they were cells
- Mitochondria make energy and bacteria make energy, so they are the same
- Mitochondria have no DNA, since the nucleus holds the DNA of a eukaryotic cell
- Mitochondria have their own DNA and ribosomes, as bacteria do
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
- Both membranes came from the nucleus, since a chloroplast has no DNA of its own
- The inner membrane is thought to come from the plasma membrane of the cyanobacterium
- Two membranes show that the cell built the chloroplast from scratch inside its cytoplasm
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 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
- New mitochondria grow from ribosomes in the cytoplasm
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
- P and Q exchange equally well, because both cells are cubes
- Q exchanges better, because 5400 square µm is far more membrane than the 54 of cell P
The side is unknown. Tala knows a model cube cell has a surface area-to-volume ratio of 0.15 per µm. Use the rule. How long is its side?
- 0.9 µm
- 0.025 µm
- 5.85 µm
- 40 µm
Use this
Cell card W (model data, not to scale), from a garden-soil sample. It has a cell wall, a plasma membrane, DNA in a central region, ribosomes and a flagellum. It has no nucleus. Width about 3 µm.
Ren expected an animal cell, since cell W moves with a flagellum, yet it shows no nucleus. Which explanation fits?
- W is a plant cell, because it has a cell wall
- W is a tiny animal cell whose nucleus is too small to see under a microscope
- W is a bacterium, a prokaryote, and bacteria can have flagella
- W is a eukaryote, because it has ribosomes and DNA
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?
- V is neither kind of cell, because its size fits one and its parts fit the other
- V is a eukaryote: a nucleus and organelles decide the type; size ranges are typical
- 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
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 a cell wall, because prokaryotes are the cells that have walls
- It has no DNA of its own, because prokaryotes are cells that lack DNA
- It has no ribosomes, because prokaryotes are cells that lack ribosomes
- Its DNA lies in a nucleoid, with no nucleus or organelles with membranes