Study Guide Sheet 1 (pt1)

Question 1

What is meant by “antigenic group”, and how are groups often designated?

Answer 1

Antigenic groups are for organisms possessing a major antigen that may be common to more than one species of the genus; usually designated by capital letters

Question 2

What is meant by “antigenic type”, and how are types often designated?

Answer 2

Antigenic types are for organisms possessing a specific antigen that is common to only very limited, closely related organisms; usually designated by numbers

Question 3

State and describe the major shapes of bacteria cells

Answer 3

1. Coccus - spherical
2. Bacillus – rod or cylindrical
   Variations of Bacillus:
   a) Coccobacillus – short, plump bacillus which resembles a coccus
   b) Coryneform or Diphtheroid – club shaped; resembling diphtheria bacillus
   c) Pleomorphic – a single organism or species having various distinct forms, e.g same organism being short and plump as well as long an slender, perhaps both in the same field of view
3. Spirochete or spirillum – spiral or corkscrew shape (very thin, poorly staining, not usually visible by the gram stain method)

Question 4

State and describe the arrangements of bacteria cells

Answer 4

1. Single – (by itself), no particular arrangement
2. Pairs – division on one plane; daughter cells remain paired
3. Clusters – division on three planes, (look like grapes)
4. Palisades – “picket fence”, division on one plane perpendicular to the short axis of the chain (bacilli only)
5. Chains – division on one plane, perpendicular to the long axis of the chain; cells remain attached “end-to-end”

Question 5

What are the major components of the bacterial cytoplasm?

Answer 5

1. Composition – thick, aqueous, elastic
2. Cell sap (e.g. water, nutrients, storage granules, etc…)
3. Genetic material and mechanisms (DNA, RNA, ribosomes 70S)

Question 6

What are the major functions of the bacterial cytoplasm?

Answer 6

Metabolism and replication

Question 7

What are the major components of the bacterial cytoplasmic membrane?

Answer 7

Composition (8 – 10% of dry weight of cell)

Phospholipid bilayer

Proteins: some function as porins and others as enzymes

Question 8

What are the overall functions of the bacterial cytoplasmic membrane?

Answer 8

1. Selective permeability
2. Site of energy production
3. Site of synthesis and transport of peptidoglycan, teichoic acids, and outer membrane componets
4. Site of extracellular hydrolytic enzymes

Question 9

What are the major overall functions of the bacterial cell wall?

Answer 9

1. Shape and rigidity
2. Provides protection from the environment and from some antimicrobic agents
3. Site of antibody attachment to major cell antigens

Question 10

What is the metabolically dormant, heat resistant structure within the cytoplasm of certain gram-positive bacteria?

Answer 10

The Endospore (Spore)

Question 11

What is the Endospore’s function

Answer 11

To allow the cell to survive under adverse harsh environmental conditions (heat, chemicals, and irradiation), by going from a vegetative state to a dormant state.

Question 12

What is the mucoid (slimy) material surrounding certain bacterial cells?

Answer 12

The capsule

Question 13

What are the capsules functions?

Answer 13

1. Resistant to phagocytosis
2. May “hide” surface antigens
3. Sometimes assists in attachment (dental plaque)

Question 14

What are the thread-like structures on the exterior of bacteria cells and what are they composed of?

Answer 14

Fimbriae; composed of glycoprotein

Question 15

What are the functions of Fimbraie?

Answer 15

Aid in facilitating bacterial attachment to appropriate cells

Those which lengthen and are involved in DNA transfer during conjugation, are called sex pili.

Question 16

Describe the components and structure of the gram-positive cell wall, including details of peptidoglycan.

Answer 16

1. Peptidoglycan (60 – 80%) with N-acetlyglucosamine and N-acetylmuramic acid
2. Teichoic acids
3. Protein inclusions

Question 17

Describe the components and structure of the gram-negative cell wall.

Answer 17

Outer membrane – lipopolysaccharides (O-antigen and lipid A) , lipoprotein layer and phospholipid bilayer

Peptidoglycan (10 – 20%)

Cytoplasmic membrane – phospholipid bilayer

Question 18

Which major cell bacteria is very thin, poorly staining, not usually visible by the gram stain method

Answer 18

Spirochete or spirillum

Question 19

Which bacteria cell arrangement is for bacilli only?

Answer 19

Palisades

Question 20

What are porins?

Answer 20

proteins that form channels through which large molecules can pass

Question 21

What factor controls transport of most compounds entering and leaving the cell

Answer 21

Selective permeability

Question 22

Spore may be viable for how long?

Answer 22

Years

Question 23

In the peptidoglycan of gram positive cell bacteria, how are N-acetlyglucosamine and N-acetylmuramic acid linked?

Answer 23

They are cross-linked by short peptide chains.

Question 24

What connects to the cytoplasmic membrane with long chain glycerol or ribitol connected with phospholipid bridges?

Answer 24

Teichoic acids

Question 25

Protein inclusions are _____ frequent in gram-positives than in gram-negatives.

Answer 25

Less