Prokaryotic Cell Morphology

Question 1

What are the different shapes of prokaryotic cells?

Answer 1

1. Coccus: spherical
2. Bacillus: rod-shaped
3. Spirillum: spiral-shaped
4. Spirochetes: tight corkscrew
5. Budding: appendages
6. Filamentous: strand-like
7. Vibrios: comma-shaped

Question 2

What are the different arrangements of prokaryotic cells?

Answer 2

1. Staph-: clusters
2. Strep-: chains
3. Diplo-: pairs
4. Sarcina: 3D formations
5. Palisades: upright

Question 3

What are the components of the cell wall?

Answer 3

1. Peptidoglycan layer
2. Teichoic acids
3. Lipids
4. Outer membrane
5. Periplasmic space

Question 4

Differentiate G+ and G- organisms based on the cell wall

Answer 4

G+ organisms have a thick peptidoglycan layer, usually has teichoic acids, small amounts of lipids, no outer membrane, and no periplasmic space

G- organisms have a thin peptidoglycan layer, no teichoic acids, lipids in the lipopolysaccharide layer, an outer membrane, and periplasmic space

Question 5

What are the components of the peptidoglycan layer for G+ organisms?

Answer 5

N-acetylmuramic acid
N-acetylglucosamine

L-Alanine, D-Glutamic acid, Lysine, D-Alanine

beta-1,4-glycosidic bonds
pentaglycine cross-links

Question 6

What is the structure of pseudomurein?

Answer 6

N-acetylglucosamine
N-acetyltalosaminuronic acid

beta-1,3-glycosidic bonds

L-Ala, L-Glu, L-Lys

Question 7

What are the linkages present in the phospholipid bilayer?

Answer 7

Ester linkages

Question 8

What are the linkages found in the Archael plasma membrane?

Answer 8

Ether linkages

Question 9

Differentiate between the Bacterial plasma membrane and the Archaeal plasma membrane?

Answer 9

Bacteria: phospholipid bilayer, ester linkages, true fatty acids and glycerol heads

Archaeal: lipid monolayer, ether linkages, repeating isoprene units

Question 10

What are the functions of the plasma membrane?

Answer 10

Permeability barrier
Protein anchor
Attachment site of bacteriophages
Energy conservation 
Biosynthesis of other cells

Question 11

What are the G+ organisms associated with endospore formation?

Answer 11

Bacillus anthracis

Clostridium botulinum

Question 12

What are axial filaments?

Answer 12

Endoflagella

Question 13

Give two examples of organisms with axial filaments?

Answer 13

Treponema sp.

Pallidum sp.

Question 14

What are the two types of microbial taxes?

Answer 14

Chemotaxis: response to chemical signals
Phototaxis: response to light

Question 15

What is glycan tetrapeptide?

Answer 15

Repeating unit of the peptidoglycan layer

Question 16

Differentiate the peptido linkages in the peptidoglycan layer of G+ and G- organisms

Answer 16

G+: Lysine connects to D-Alanine via a pentaglycine cross-link

G-: DAP connects to straight to D-Alanine

Question 17

Which sugar is the tetrapeptide linked to in the peptidoglycan layer?

Answer 17

N-acetylmuramic acid

Question 18

Which sugar is the tetrapeptide linked to in the archael cell wall pseudomurein layer?

Answer 18

N-acetyltalosaminuronic acid

Question 19

What is the function of the outer membrane?

Answer 19

Helps the passage of Ca2+ and Mg2+ ions

Question 20

What are the components of the periplasmic space?

Answer 20

Hydrolytic enzymes
Binding proteins
Chemoreceptors

Question 21

What are the 3 lipids found in the lipopolysaccharide layer found in G- organisms?

Answer 21

Lipid A
Core polysaccharide
O-polysaccharide

Question 22

Give 3 organisms that have fimbriae

Answer 22

Salmonella sp.
Neisseria gonorrhoeae
Bordetella pertussis