Science 8 Reading Guide Page 42-45
Unicellular Organisms
1. What are two other names for unicellular organisms, and why are these names
used?
They are called microbes or microorganisms because you need a microscope to
see them.
2. Do all microorganisms cause disease?
No most are harmless and many are helpful to us.
3. What are three different specializations of bacteria?
Some can make their own food, some are parasites and some can live without
oxygen.
4. How are bacteria different from plant and animal cells? (Hint – this is why they
are called “primitive”.
They do not have a nucleus, mitochondria or ribosomes.
5. Examine Figure 2. How are pili like cilia? How are they different?
Pili look like cilia because they both resemble hairs, and they both help cells
move. Pili are different from cilia because they also help bacteria stick to
surfaces.
6. What is a capsule? How does it help bacteria that live as parasites?
It is a sticky outer coating that makes it difficult for white blood cells to destroy
them.
7. Where are protists found?
Almost anywhere there is water, even in moist soil and rotting leaves.
8. How are protists different from bacteria (and more like our cells)?
They have a nucleus, mitochondria, ribosomes and lysosomes.
9. Where are diatoms found?
They are found in either fresh or salt water.
10. How are diatoms like plant cells?
They contain chlorophyll and can make their own food.
11. Examine Figure 3. What do all diatoms have in common?
They have symmetrical grooves and pores.
12. Describe how a euglena is sometimes like a plant cell and sometimes like an
animal cell.
When there is lots of light, it makes its own food like a plant. If there is less light, it
acts like a consumer and eats smaller cells.
13. Examine Figure 4. How is a contractile vacuole different from vacuoles in plant
and animal cells?
It expels (pushes out) water that the cell does not need.
14. Examine Figure 4. How is a pellicle different from a cell wall?
It is different because it is flexible.
15. How does an amoeba move?
It stretches out a branch of cytoplasm (called a pseudopod) and then drags the
rest of the cell with it.
16. Examine Figure 5. Describe how an amoeba “eats”.
It wraps pseudopods around the food, and forms a food vacuole with its cell
membrane. The food is digested inside the vacuole.
17. What does a paramecium eat?
It mainly eats bacteria and smaller cells.
18. Examine Figure 5. Describe how a paramecium “eats”.
It uses cilia to draw food into its oral groove and creates a food vacuole to
digest it.
Science 8 Reading Guide Page 42-45
Unicellular Organisms
1. What are two other names for unicellular organisms, and why are these names
used?
2. Do all microorganisms cause disease?
3. What are three different specializations of bacteria?
4. How are bacteria different from plant and animal cells? (Hint – this is why they
are called “primitive”.
5. Examine Figure 2. How are pili like cilia? How are they different?
6. What is a capsule? How does it help bacteria that live as parasites?
7. Where are protists found?
8. How are protists different from bacteria (and more like our cells)?
9. Where are diatoms found?
10. How are diatoms like plant cells?
11. Examine Figure 3. What do all diatoms have in common?
12. Describe how a euglena is sometimes like a plant cell and sometimes like an
animal cell.
13. Examine Figure 4. How is a contractile vacuole different from vacuoles in plant
and animal cells?
14. Examine Figure 4. How is a pellicle different from a cell wall?
15. How does an amoeba move?
16. Examine Figure 5. Describe how an amoeba “eats”.
17. What does a paramecium eat?
18. Examine Figure 5. Describe how a paramecium “eats”.