Bacteria and Viruses

Question 1

What is the definition of bacteria?

Answer 1

• bacteria are small, single-celled prokaryotes

Question 2

What are plasmids?

Answer 2

• small, circular loops of DNA (molecule) in bacteria/ prokaryotes

Question 3

What are viruses?

Answer 3

• viruses are non-cellular infectious particles

Question 4

What are membrane-bound organelles?

Answer 4

• membrane-bound organelles are organelles that are surrounded by a phospholipid bilayer

Question 5

What does binary fission refer to?
In what type of cells does binary fission typically occur in?

Answer 5

• binary fission is a form of asexual reproduction in which a parent cell divides to form two identical daughter cells
• binary fission typically occurs in prokaryotes and a few single-celled eukaryotes

Question 6

What are mesosomes?

Question 7

What are the pili? (pilus singular)

Question 8

What is the flagellum?

Question 9

What does host refer to?

Question 10

What does the lysis refer to?

Question 11

What are antigens?

Question 12

What is a pathogen?

Question 13

What are five examples of bacteria?

Answer 13

• TB (Tuberculosis)
• E.Coli
• Salmonella
• Cholera
• Lyme disease

Question 14

What are five examples of viruses?

Answer 14

• COVID
• HIV/ AIDS
• Tobacco mosaic
• measles
• common cold

Question 15

What are three examples of fungi?

Answer 15

• athletes foot
• ringworm
• black sigatoka

Question 16

What are three examples of protoctists?

Answer 16

• tate worm
• malaria
• late tomato blight

Question 17

What are the similarities of bacteria and viruses?

Answer 17

• no nucleus
• no membrane-bound organelles
• can cause disease

Question 18

What type of cells are bacteria? What size are they? How do they reproduce?

Answer 18

• bacteria are prokaryotic cells
• They have an average diameter of 0.5-5 micrometre (um)
• they reproduce by binary fission

Question 19

Where is the genetic material of bacteria found? Does bacteria have ribosomes?

Answer 19

• genetic material found as circular DNA
• may have DNA plasmids
• Bacteria has (smaller than eukaryotes) 70s ribosomes

Question 20

How do bacteria move? What does bacteria have that allows it to attach to neighbouring cells?

Answer 20

• bacteria may have a flagellum for movement
• has protein tubes called pili (singular pilus) allowing it to attach to neighbouring cells

Question 21

Can bacteria be killed? Are bacteria living or non living cells?

Answer 21

• bacteria can be killed by antibiotics
• bacteria are living cells

Question 22

Do eukaryotes have a flagellum?

Answer 22

• not all but some do e.g. sperm - although it has a different structure to prokaryotes flagellum

Question 23

What are the organelles in bacteria? What are their functions?

Answer 23

• cell surface membrane
• (polysaccharide) cell wall
• capsule = prevents desiccation
• flagellum
• mesosome
• main circular DNA
• plasmids
• pili (pilus)
• ribosomes

Question 24

What are the two parts to a virus?

Answer 24

• protein coat
• nucleic acid

Question 25

What is the name of the cell a virus infects? What is cell lysis and when does it happen in viral reproduction?

Answer 25

• the name of the cell a virus infects is a host cell
• lysis is when host cell splits open releasing new viral particles

Question 26

What is an ‘enveloped virus’? Where is this envelope taken from? What does the envelope carry?

Answer 26

• some viruses have an outer envelope taken from the host cell’s cell surface membrane
• the envelope carries viral antigens, glycoproteins which help the virus attach to the host cell and penetrate the cell surface membrane
• as they are ‘foreign’, antigens can be recognised by host’s immune system

Question 27

Are viruses living or non-living?

Question 28

What is the general structure of a virus, prokaryote, eukaryote?

Answer 28

-

Question 29

Is the DNA looped or linear in a virus, in a prokaryote and in a eukaryote?

Question 30

What is the main genetic material?