3.2.1.2 Prokaryotic Cells and Viruses

Question 1

What are prokaryotic cells?

Answer 1

They have no nucleus

Instead they have a single circular DNA molecule that is free in the cytoplasm and not associated with proteins

Question 2

What are the differences between prokaryotic and eukaryotic cells in terms of membranes?

Answer 2

P: few organelles bounded by a double membrane
E: have many

Question 3

What are the differences between prokaryotic and eukaryotic cells in terms of cell walls?

Answer 3

P: have rigid cell walls made of polysaccharide and protein
E: have rigid cell walls mostly made of cellulose and only found in plant cells

Question 4

What are the differences between prokaryotic and eukaryotic cells in terms of flagella?

Answer 4

P: have simple flagella
E: may have complex extension of cytoplasm to form cilia for coordinated movement

Question 5

What are the differences between prokaryotic and eukaryotic cells in terms of respiration?

Answer 5

E: have mitochondria
P: bacteria have mesosomes and algae use cytoplasmic membranes

Question 6

What are the differences between prokaryotic and eukaryotic cells in terms of photosynthesis?

Answer 6

P: no chloroplasts, only bacterial chlorophyll associated with the cell surface membrane in some bacteria
E: plant and algae cells contain chloroplasts

Question 7

What are the differences between prokaryotic and eukaryotic cells in terms of fixing nitrogen?

Answer 7

P: some have the ability to fix nitrogen
E: cannot fix nitrogen

Question 8

What are the differences between prokaryotic and eukaryotic cells in terms of a capsule?

Answer 8

P: many have an outer mucilaginous layer called a capsule
E: don’t have a capsule

Question 9

What is the structure of a bacterial cell?

Answer 9

Cell wall: made of murein
Capsule: outer mucilaginous layer, only found in some species
Cell surface membrane
Plasmid: small, circular pieces of DNA
Flagellum: can be more than one, for movement
Cytoplasm: contains enzymes and other soluble material
Ribosomes: 70S

Question 10

What is a virus?

Answer 10

Smallest structure that shows life- 20-300nm
Genetic material: DNA or RNA but not both, small number of genes
Can’t be treated with antibiotics because there are no metabolic processes for them to inhibit
Can only multiply inside a host cell

Question 11

What is the structure of viruses?

Answer 11

Lipid envelope
Attachment proteins
Matrix
Capsid
Genetic material (RNA)
Reverse transcriptase

Question 12

What is the difference between prokaryotic and eukaryotic cells in terms of nuclei?

Answer 12

P: no true nucleus, only an area where DNA is found
E: distinct nucleus with a nuclear envelope

Question 13

What is the difference between prokaryotic and eukaryotic cells in terms of DNA?

Answer 13

P: DNA is not associated with proteins, some DNA is in the form of circular strands called plasmids
E: DNA is associated with proteins called histones, there are no plasmids, and DNA is linear

Question 14

What is the difference between prokaryotic and eukaryotic cells in terms of ribosomes?

Answer 14

P: ribosomes are smaller, 70S
E: ribosomes are larger, 80S

Question 15

What is the role of the cell wall in bacterial cells?

Answer 15

Physical barrier which protects the cell against mechanical damage, certain substances and osmotic lysis

Question 16

What is the role of the capsule in bacterial cells?

Answer 16

Protects bacterium from other cells and helps to group bacteria to stick together for further protection

Question 17

What is the role of the cell-surface membrane in bacterial cells?

Answer 17

Controls the entry and exit of materials

Question 18

What is the role of circular DNA in bacterial cells?

Answer 18

Possesses the genetic information for the replication of bacterial cells

Question 19

What is the role of plasmids in bacterial cells?

Answer 19

Possesses genes that may aid the survival of bacteria in adverse conditions