Re-Introduction

Question 1

What are the main microorganisms?

Answer 1

VIPE
V = viruses
I= infectious proteins 
P = prokaryotes (bacteria)
E = eukaryotes (fungi/ protozoa)

Question 2

What is protozoa and give an example?

What human disease is it important in?

Answer 2

Unicellular eukaryote e.g malaria, toxoplasma gondii

Malaria - often affect immunocompromised

Question 3

What is fungi and give use

What is it structure like?

Answer 3

Eukaryotic organism - many forms (filamentous or yeast) - important commercially (baking, brewing)
External rigid chitin wall

Question 4

Structure prokaryote?

Answer 4

No internal membranous compartments

Specialised cell wall

Question 5

Gram positive? - give example

Answer 5

One membrane - thick peptidoglycan later
Retain stain - purple
e.g streptococci

Question 6

Gram negative? - give example

Answer 6

Two membranes -periplasm between
Doesn’t retain stain - pink
E.g spirochete, fusobacteria

Question 7

Explain surface structure and motility of bacteria

Answer 7

1. PEPTIDOGLYCAN - polymer N-acetyl muramic acid and N-acetyl glucosamine (NAM and NAG) - cross linked via amino acid pentapeptide and anchored to cell wall
2. PILI and FIBRIAE - proteinaceous filamentous structures, often used for attachment to host cell and twitching motility

Question 8

What is a pathogen?

Answer 8

A disease causing bacteria e.g cholera

Question 9

What is an opportunistic pathogen?

Answer 9

Commensals that cause disease e.g MRSA

Mainly harmless - colonise surfaces and mucosa

Question 10

Common bacteria in GI tract?

Answer 10

E.coli - gram negative rod - some strain pathogenic

Clostridia species - gram positive anaerobic spore formers (inc. c.difficile)

Question 11

Structure mycobacteria?

How do you detect?

Answer 11

Peptidoglycan later with glycolipid sugar attached to mycolic acid
Increase resistance
Gram +ve rods - need Ziehl-Neelsen stain as impervious to gram staining

Question 12

What is a virus?

Answer 12

Obligate intracellular pathogen which is unable to reproduce w/o host factor

Question 13

Basic structure of virus?

Answer 13

Nucleic acid encapsulated to proteinaceous capsid - some can be further coated w/ lipid

Question 14

Explain retroviral replication?

Answer 14

Release mRNA into cells - form DNA via reverse transcriptase
Recombined human DNA
Integrate host genome
Transcription

Question 15

What is prion?

Answer 15

Infectious protein that is heat resistance and sticks to instruments

Question 16

How do prions cause damage?

Answer 16

Aggregte into long fibres and amyloid plaque
Transmission into brain tissue
Causes abnormal folding of proteins
E.G CJD

Question 17

What is KURU?

Answer 17

Fatal brain disorder

Papua New Guinea - ritualised canabalism