Micro Intro

Question 1

Viruses

Answer 1

(0.03 - 0.3 micron)
Intracellular
DNA or RNA
Most: 
-Protein Coat
-Sometimes a lipid surface membrane

Direct the metabolic activities of the cell.

Some viruses integrate into genome.

Question 2

Bacteria

Answer 2

Are the smallest living cells (0.1 - 10 micron)
(about 1 micron)

Have Cell Membrane and
Cell Wall made of Peptidoglycan

No organelles

No nucleus

Question 3

Fungi

Answer 3

Yeast or Mold forms

Most are 2-12 micron

Multiply by Budding

Tubular extensions called Hyphae.
–Form hyphae at Body demp (37 C), not at room temp; part of virulence.

Eukaryotic

Rigid external cell wall

Diploid or Haploid genome

Meiosis or Mitosis

Free-living

Grow more slowly than bacteria.

Question 4

Parasites

Answer 4

Most diverse

Unicellular Amoebas of
10-12 micron

Multicellular Tapeworms:
1 meter long

Eukaryotic

Worms have their own organ systems.

Worms: Microscopic egg stage, Multiple hosts.

Free-living, but some depend on hosts.

Question 5

Skin Normal Flora

Answer 5

@ Skin:

• Staphylococci,
• Propionibacterium

@ Subsurface Sebum:

• Propionibacteria,
• Gram-positive rods

Skin flora, Resistant to skin lipids and fatty acids.

Conjunctivae:

• -Have few flora
• -High Lysozyme content of lachrymal (bactericidal)

Question 6

Intestinal Tract Normal Flora

Answer 6

• Mouth, Pharynx: Anaerobes:
• Streptococci @ Buccal, Tongue mucosa

Neisseria and Moraxella (Branhamella), facultative organisms (can live with/without oxygen).

Throat 5-40% healthy ppl:

• -Streptococcus pneumoniae
• -Neisseria meningitidis

Stomach:

• Few microbes
• Gastric Hydrochloric acid

Small Intestine:

• -Few
• -Some in lower ileum

Colon:
-Prolific Flora

Feces:
–25% Bacteria

90% Anaerobes:

• Bacteroides,
• Fusobacterium,
• Eubacterium,
• Clostridium

Facultative Organisms:

• E. coli,
• Enterococci,
• Yeasts.

Diet of host influences flora:
-Meat has more Bacteroides.

Question 7

Respiratory Tract Normal Flora

Answer 7

Nares:

• -Staphylococcus aureus
• -25-30% healthy ppl

Nasopharynx:

• -Pneumococci
• -Meningococci
• -Haemophilus

Respiratory tract below larynx protects movement of the mucociliary blanket.

Sterile:

• The accessory sinuses
• Middle ear
• Lungs

Question 8

Genitourinary Tract Normal Flora

Answer 8

Urinary Tract:
–Sterile above the Distal 1 cm of the Urethra

Sterile:

• -Urine in Bladder
• -Ureters
• -Renal Pelvis

Vagina:

• -Flora that varies:
• -Lactobacillus (in Childbearing years)