Structure of prokaryotic cells and viruses

Question 1

What is a prokaryotic cell?

Answer 1

Prokaryotic cells are unicellular that lack a nucleus and membrane-bound organelles

Question 2

Where are prokaryotic cells found?

Answer 2

• Bacteria
• Archaea

Question 3

Are prokaryotic cells smaller or bigger than eukaryotic cells?

Answer 3

Smaller

Question 4

What is the structure of prokaryotic cells?

Answer 4

• Cell-surface membrane
• Cytoplasm
• Cell wall made of murein
• 70S ribosomes
• Circular DNA
• Plasmids
• Some have a capsule
• Some have flagella
• Some have pili

Question 5

Do prokaryotic cells have membrane-bound organelles?

Answer 5

No

Question 6

What type of ribosomes do prokaryotic cells have?

Answer 6

70S ribosomes

Question 7

Do prokaryotic cells have a nucleus?

Answer 7

No
- They have a single circular DNA molecule that is free in the cytoplasm and is not associated with proteins

Question 8

Do prokaryotic cells have a cell wall?

Answer 8

Yes
- Made of murein which is a glycoprotein

Question 9

Do prokaryotic cells contain plasmids?

Answer 9

Yes but not always
- Can contain one or more

Question 10

Describe the function of plasmids

Answer 10

Plasmids carry genes that can be passed between prokaryotes

Question 11

Some prokaryotic cells may have an extra layer around the cell wall. What is this called?

Answer 11

A capsule

Question 12

Describe the function of a capsule around the cell wall

Answer 12

Protective slimey layer which helps the cell to retain moisture

Question 13

Do prokaryotic cells have flagella?

Answer 13

Yes but not always
- Can contain one or more

Question 14

Describe the function of flagella

Answer 14

It rotates to enable the cell to move

Question 15

What are the similarities between eukaryotic and prokaryotic cells?

Answer 15

• Both have DNA
• Both have a cell membrane
• Both contain cytoplasm
• Both have ribosomes

Question 16

What are differences between eukaryotic and prokaryotic cells?

Answer 16

• Eukaryotic cells have a nucleus, prokaryotic cells don’t
• Eukaryotic cells have linear DNA, prokaryotic cells have circular DNA
• Prokaryotic cells don’t have membrane-bound organelles, eukaryotic cells do
• Eukaryotic cells have 80S ribosomes, prokaryotic cells have 70S ribosomes
• Prokaryotic cells have cell wall made of murein, eukaryotic cells have cell walls made of either cellulose (plants) or chitin (fungi)
• Prokaryotic cells may have a capsule, eukaryotic cells don’t

Question 17

How do prokaryotic cells replicate?

Answer 17

Binary fission

Question 18

Describe the process of binary fission

Answer 18

• Circular DNA and plasmids replicate (circular DNA replicates once, plasmids can replicate many times)
• Cell gets bigger and DNA loops move to opposite poles
• Cytoplasm begins to divide and a new cell wall begins to form
• Cytoplasm divides and 2 daughter cells are produced

Question 19

What is a virus?

Answer 19

An acellular non-living particle

Question 20

Describe the structure of a virus

Answer 20

• Protein capsid
• Attachment proteins on capsid
• DNA or RNA core

Question 21

How do viruses replicate?

Answer 21

By infecting host cells

Question 22

Describe the process of viral replication

Answer 22

• Virus uses attachment proteins on its surface to attach to complementary receptor proteins of a host cell
• Virus inject their DNA or RNA into host cell
• Host cell uses its nucleic acid and protein-building machinery to produce new viral particles