A - 2 - Prokaryotic Cells and Viruses

Question 1

What is a prokaryote?

Answer 1

A single celled organism

Question 2

Which organelles are found in a prokaryote?

Answer 2

• Cell surface membrane
• Cytoplasm
• Ribosomes
• Flagellum
• Free floating DNA
• Plasmids
• Slime Capsule
• Cell wall

Question 3

What is the structure and function of the flagellum?

Answer 3

• A long hair like structure that rotates to make the prokaryotic cell move
• Not all prokaryotes have a flagellum
• Some have more than one

Question 4

Describe the DNA found in a Prokaryote

Answer 4

• Floats free in the cytoplasm
• It’s circular and present as one coiled up strand
• Not attached to any histone proteins

Question 5

Describe the structure and function of a plasmid

Answer 5

• Plasmids are small loops of DNA that aren’t part of the main circular DNA molecule
• Contain genes for things such as antibiotic resistance
• Can be passed between prokaryotes
• Not always present in prokaryotes
• Some have several

Question 6

What is the function of the slime capsule?

Answer 6

Helps to protect the bacteria from attack by cells of the immune system

Question 7

What is the cell wall in a prokaryote made of?

Answer 7

• Made of a polymer called murein

- It is a glycoprotein

Question 8

What is the typical size of a prokaryotic cell?

Answer 8

less than 2 um in diameter

Question 9

What is the typical size of a Eukaryotic cell?

Answer 9

They are up to 50 times bigger than prokaryotes

Around 0.1mm

Question 10

What is Binary Fission?

Answer 10

The process by which prokaryotic cells replicate

Question 11

Describe the 4 steps of binary fission

Answer 11

1 - The circular DNA and plasmids replicate
2 - The cell gets bigger and the DNA loops move to opposite poles of the cell
3 - The cytoplasm begins to divide
4 - The cytoplasm divides and two daughter cells are produced. each daughter cell has one copy of circular DNA, but can have a variable number of copies of the plasmids

Question 12

What is a virus?

Answer 12

An acellular structure that invades and reproduces inside the cells of other organisms

Question 13

Give 3 examples of viruses

Answer 13

• HIV
• Influenza
• Rhinoviruses

Question 14

What is a host cell?

Answer 14

A cell inside which a virus replicates

Question 15

Describe the basic structure of a virus

Answer 15

• Capsid (Protein coat)
• Attachment Proteins
• Core of genetic material

Question 16

What are the 5 steps to viral replication?

Answer 16

1 - Virus attaches to host cell receptor proteins
2 - Genetic material is released into the host cell
3 - Genetic material and proteins are replicated by host cell ‘machinery’
4 - Viral components assemble
5 - Replicated viruses are released from host cell