Viruses compared with cells, and how viruses spread

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   Ari compares a bacterium with a virus in a model drawing. Letter B points to the protein layer around the virus's genetic material. What is B called?

   • A ribosome, a structure that builds proteins
   • The envelope, a membrane around the coat
   • The capsid, a coat made of protein
   • A cell wall, as on the bacterium
2. 2.

   Model drawing, not to scale: an animal cell cutaway beside an enveloped virus. Bo studies a model drawing of an enveloped virus beside a host cell. Letter C points to the outer layer, made from host-cell membrane. What is C called?

   • The envelope, a layer of host-cell membrane
   • The plasma membrane, which the virus makes itself
   • The nucleus, which holds the viral DNA
   • The capsid, the coat made of protein
3. 3.

   Model drawing, not to scale: a plant cell cutaway beside a virus. Esme reads a model drawing of a virus beside a plant cell. Letter A points to the part with the instructions for making new virus particles. What is A?

   • The nucleus, which holds the viral DNA
   • The capsid, which holds a plan for each protein
   • A ribosome, which reads the instructions
   • The genetic material, which is DNA or RNA
5. 4.

   Jun reads a Venn diagram that compares a virus with a cell. In which part is the word ribosomes written?

   • In the virus circle only, so cells have none
   • In the cell circle only, so a virus has none
   • Outside both circles, so neither has ribosomes
   • In the overlap, so a virus has ribosomes too
6. 5.

   Kira uses the Venn diagram to place a fact about copying. Which sentence agrees with the diagram?

   Use the picture in question 4.

   • A virus copies itself in a host cell, so this fact is in the cell circle
   • A virus copies itself on its own, so this fact is in the overlap with cells
   • A virus divides in two the way a bacterium does, so this fact is in the overlap
   • A virus copies itself only in a host cell, so this fact is in the virus circle

7. Read this first

   Use this

   Word card (model). The word to define is bacteriophage. Examples named on the card: a phage with a head and a tail. Not to scale.

8. 6.

   Noah meets the word bacteriophage on a word card. Which meaning is right?

   • A bacterium that makes copies of itself inside a virus
   • A tiny bacterium that is covered by a protein coat
   • A virus that infects plant cells and animal cells
   • A virus that infects bacteria as its host cells

9. Use this

   Word card (model). The word to define is virion. Examples named on the card: one virus particle sitting outside any host cell. Not to scale.

10. 7.

    Pia meets the word virion on a word card. Which meaning is right?

    • A virus that has copied itself many times
    • A small cell with a protein coat and genetic material
    • The protein coat of a virus, with nothing inside
    • A single virus particle outside a host cell

11. Widths table (real data, from OpenStax Biology 2e; 1 µm = 1,000 nm)

    particle	width in nm	width in µm
    most virions	20 to 250	0.02 to 0.25
    prokaryotic cell	100 to 5,000	0.1 to 5.0
    eukaryotic cell	10,000 to 100,000	10 to 100

12. 8.

    Ren reads the table of widths. What is the width range of most virions?

    • 0.1 to 5.0 µm
    • 20 to 250 µm
    • 20 to 250 nm
    • 10 to 100 µm
13. 9.

    1 µm = 1,000 nm. Tala measures three model particles, P, Q and R. Using the table, which one is most likely a virion?

    • R, because a virus is larger than a cell
    • P, because 80 nm is inside the virion range
    • Q, because 3 µm is inside the virion range
    • P and Q, because both are smaller than a eukaryotic cell

14. Widths table (real data, from OpenStax Biology 2e; 1 µm = 1,000 nm)

    particle	width in nm	width in µm
    most virions	20 to 250	0.02 to 0.25
    prokaryotic cell	100 to 5,000	0.1 to 5.0
    eukaryotic cell	10,000 to 100,000	10 to 100

15. 10.

    Zee compares the widest virion in the table with the narrowest eukaryotic cell. Which statement agrees with the table?

    • A virion and a eukaryotic cell overlap in width, between 20 and 100
    • The widest virion in the table, 0.25 µm, is narrower than the narrowest eukaryotic cell, 10 µm
    • A virion is wider than a eukaryotic cell, because 250 is more than 100
    • The widest prokaryotic cell, 5.0 µm, is narrower than the widest virion, 250 nm