Bacteriology Introduction

Question 1

What are the 4 phases of bacterial growth?

Answer 1

• Lag
• Logarithmic growth
• Stationary
• Death

Question 2

What are the 3 bacterial shape classifications?

Answer 2

• Coccus
• Rod
• Spirillum

Question 3

What are obligate aerobes?

Answer 3

Bacteria that require oxygen for growth

Question 4

What are obligate anaerobes?

Answer 4

Where oxygen is toxic for bacterial growth

Question 5

What are facultative anaerobes?

Answer 5

Bacteria that can use oxygen if present, but can also grow without it

Question 6

What are aerotolerant anaerobes?

Answer 6

Bacteria that do not use oxygen but it is not toxic

Question 7

What are microaerophiles?

Answer 7

Bacteria that grow best with low levels of oxygen

Question 8

What are the two general types of bacteria?

Answer 8

• Gram-positive (purple)

- Gram-negative (pink)

Question 9

What are mycobacterias?

Answer 9

A type of acid-fast bacteria

Question 10

What are mycoplasmas?

Answer 10

A type of bacteria that does not have a cell wall

Question 11

What are peptidoglycans?

Answer 11

Bacterial cell walls that is rigid and prevent osmotic lysis.

Question 12

What does the glycan backbone alternate?

Answer 12

G and M (M can form cross-linkages)

Question 13

What is lipid A?

Answer 13

A molecule that is comprised of disaccharides and fatty acid groups. They are recognized by the innate immune system which leads to septic shock.

Question 14

What is the nucleoid?

Answer 14

• not the ‘nucleus’
• does not have a surrounding membrane
• have a single, circular chromosome (most but not all bacteria)
• haploid genomes

Question 15

What are plasmids?

Answer 15

• Extrachromosomal genetic elements
• Usually not required for bacterial growth
• Often encode for ‘fitness’ factors (antibiotic resistance)
• can be transferred from bacteria to bacteria

Question 16

What are that 3 types of host-microbe relationships

Answer 16

• Commensalism
• Mutualism
• Parasitism

Question 17

What is commensalism?

Answer 17

Where one benefits without helping or hurting the other

Question 18

What is mutualism?

Answer 18

Where both benefits (the host and the microbe)

Question 19

What is parasitism?

Answer 19

Where one benefits (microbe) at the expense of the other (host)

Question 20

What makes bacterial pathogens successful?

Answer 20

• Colonization
• Invasion/toxicity
• Immune evasion
• Transmission
• Pathogens produce virulence factors (molecules produced by the pathogen that contribute to disease)

Question 21

What are the different types of virulence factors?

Answer 21

• LPS (endotoxin)
• Flagella
• Pili and adhesins
• Capsules
• Secretion system
• Exotoxins

Question 22

What are flagella?

Answer 22

Structures that allow some bacteria to be motile (chemotaxis)

Question 23

What are Pili?

Answer 23

Structures that are primarily involved in attachment to surfaces, host tissue, and other bacteria

Question 24

What are capsules?

Answer 24

• Usually made up of (exo) polysaccharides
• Attachment to host tissues
• Protection form host immune system
• Can sometimes be used in vaccines
• Formation of biofilms

Question 25

What are the 4 stages of biofilms?

Answer 25

• Attachment
• Microcolony development
• Biofilm development
• Maturation

Question 26

What are endospores?

Answer 26

• Highly differentiated cells formed within the parent cell
• Highly resistant to heat, harsh chemicals and radiation
• A “dormant” stage of the bacterial life cycle

Question 27

What are exotoxins

Answer 27

• Secreted from bacteria

- Includes hemolysins, toxins that function inside host cells, extracellular enzymes and superantigens

Question 28

What bacterial secretion may be used as a vaccine when they are inactivated?

Answer 28

Exotoxins

Question 29

How can some bacteria become intracellular pathogens?

Answer 29

• They were taken up by a macrophage and survived within it
• some ‘force’ their own uptake into epithelial cells
• allows bacteria to hide from different components of the immune system