Intro

Question 1

Eukaryotes vs Prokaryotes

Answer 1

Eukaryotes: linear chromosome in nucleus, more organelles, larger cells, cells divide by mitosis
Prokaryotes: no nucleus, circular chromosome, smaller cell, replicate by binary fission, may have plasmid

Question 2

Bacterial capsule

Answer 2

polysaccharide outer layer.
Functions: nutrient reserve, protection from adverse environmental conditions, facilitate adherence to host cell surface, help to evade phagocytosis

Question 3

Gram positive cell wall

Answer 3

cytoplasmic membrane, peptidoglycan layer, capsule
contains lipoteichoic acid - very antigenic
high resistance to physical disruption

Question 4

Gram negative cell wall layers

Answer 4

cytoplasmic membrane, space, peptidoglycan layer, space, outer membrane (LPS), capsule
low resistance to physical disruption

Question 5

Bacterial cell wall

Answer 5

peptidoglycan layer!
Function: rigidity, protection from mechanical damage and osmotic lysis
Different strains may have different structure - difference in pathogenicity and staining

Question 6

Mycobacteria cell wall

Answer 6

contains mycolic acids. Stain with acid fast, gram stain will not stain. mycolic acids are virulence factor

Question 7

Flagella

Answer 7

Present on the surface of (mainly) gram - bacteria, used for locomotion/motility, flagellar arrangement may be used as ID.
Endoflagella makes spiral-shaped bacteria

Question 8

Pili/Fimbrae

Answer 8

facilitate adherence to cells, may transmit plasmid, contributes to antigenicity
often species specific (ex: K99 fimbrae infect calves)

Question 9

Endospores

Answer 9

highly durable dormant state. ensures survival in adverse environmental conditions. Produced by Clostridium and Bacillus.
Sporulation (dormant state) vs germination (return to normal growth)

Question 10

Mycoplasma “exception”

Answer 10

no cell wall!

Question 11

Leptospira “exception”

Answer 11

two circular chromosomes

Question 12

Borrelia burgdorgeri “exception”

Answer 12

linear chromosome

Question 13

4 phase of bacterial growth

Answer 13

1. lag phase (increase in cell size not number)
2. exponential/log phase (cells multiply at max rate)
3. Maximal stationary phase (plateau, due to less nutrients, or accumulation of toxins)
4. decline/death phase

Question 14

what temperature class is best for the majority of bacteria?

Answer 14

Mesophiles (around human body temp)

Question 15

Exotoxins vs endotoxins

Answer 15

Exotoxin: protein toxins produced by bacteria to target specific cells. Most are heat labile
Endotoxin: cell wall components that cause inflammation by stimulating immune cells. Heat stable

Question 16

Biofilm

Answer 16

polymer matrix that adheres bacteria to one another. allows the sharing of nutrients and protection from antibiotics.

Question 17

Quorum sensing

Answer 17

small signal molecules allow bacteria to communicate and act as a colony. Some group behaviours include: symbiosis, virulence, biofilm production, etc.

Question 18

Genetic transferring in bacteria

Answer 18

via conjugation, transformation, transduction

Plasmids carry advantageous genes. capsules and fimbrae may mediate transfer

Question 19

Characteristics of fungi

Answer 19

eukaryotes, heterotrophs, plant-like cell wall with chitin, reproduce both sexually and asexually, resistant to antimicrobials, strict aerobes, most are non-pathogenic

Question 20

two major fungi forms

Answer 20

branching hyphae (molds), unicellular yeasts

Question 21

3 mechanisms of fungal disease

Answer 21

1. tissue invasion (mycosis)
2. toxin production (mycotoxicosis)
3. induction of hypersensitivity

Question 22

Infection

Answer 22

invasion and multiplication of pathogens in an individual or population

Question 23

infectious disease

Answer 23

disease caused by microorganisms