3.2.1.2 Structure of prokaryotic cells and of viruses

Question 1

Prokaryotic cell

Definition

Answer 1

A cell that does not contain a membrane bund nucleus or any membrane bound organelles

Question 2

Prokaryotic cell

Structure (components)

Answer 2

-cytoplasm
-cell surface membrane
-smaller (70S) ribosomes
-single circular DNA molecule
-cell wall (containing muerin)
May have:
-one or more plasmids
-a capsule surrounding the cell
-one or more flagella

Question 3

Main difference between a prokaryotic cell and eukaryotic cell

Answer 3

Prokaryotic cells

• are smaller
• do not contain a membrane bound nucleus

Question 4

Differences between a prokaryotic cell and eukaryotic cell

Answer 4

Prokaryotic cells
-are smaller than eukaryotic cells
-have a cytoplasm that lacks membrane-bound organelles
-have smaller (70S) ribosomes
-have no nucleus; instead they have a single circular DNA molecule that is free in the cytoplasm and is not associated with proteins
-have a cell wall that contains murein, a glycoprotein
May have:
-one or more plasmids
-a capsule surrounding the cell
-one or more flagella

Question 5

What is muerin

Answer 5

-a glycoprotein

Question 6

Prokaryotic DNA

Answer 6

-have no nucleus
-have a single circular DNA molecule
└free in the cytoplasm
└not associated with proteins
└no introns (non-coding DNA)
-some prokaryotic DNA may be found in the form of plasmids

Question 7

Circular DNA molecule

Function

Answer 7

-contains genetic information for replication

Question 8

Cell wall

Function

Answer 8

• acts as a physical barrier against certain substances

- protects against damage

Question 9

Plasmid

Function

Answer 9

• contains genes that may help the survival of bacteria in adverse conditions
• e.g. genes for antibiotic resistance
• can be passed between prokaryotes

Question 10

Capsule

Function

Answer 10

-protects from attack by cells of the immune system

Question 11

Flagella

Function

Answer 11

-rotates to make the cell move

Question 12

Cytoplasm

Function

Answer 12

• contains smaller 70S ribosomes

- contains no membrane bound organelles

Question 13

What are viruses

Answer 13

• acellular

- non-living

Question 14

What does acellular mean

Answer 14

-consists of only one cell

Question 15

Virus particle

Structure (components)

Answer 15

• genetic material (RNA)
• capsid
• attachment protein
• lipid envelope
• matrix
• enzyme

Question 16

Attachment proteins

Function

Answer 16

-allow the virus to identify and attach to a host cell