Systemic Bacteriology 1

Question 1

What are the common bacterial shapes?

Answer 1

• Cocci
• Bacilli
• Spiral

Question 2

What are the types of divisions in Cocci?

Answer 2

Cocci- spherical bacteria.
Division in one plane to produce two coccus- diplococcus.
Division in one plane to produce chain (4-20)- Streptococcus.
Division in three planes to produce clumps- Staphylococcus.

Question 3

What are the types of Bacilli?

Answer 3

Bacilli- rod shaped bacteria.
Can forms chains of bacilli.
Can get curved rods too- known as Vibrio.

Question 4

What are the types of spiral bacteria?

Answer 4

Spiral shaped (wavy)
Can be:
Rigid- spirilium
Flexible- spirocheraete

Question 5

What is the Gram stain test?

Answer 5

Simple method that distinguishes two forms of bacteria based on their cell wall structure.
Gram + = Purple (thick PG)
Gram - = Pink (thin PG)

Question 6

State some common bacteria and their gram stain.

Answer 6

Gram -

• E.coli
• Pseudomonas Aeruginosa
• Nisseria Gonorrhoea
• Chlamydia Trachomatis.

Gram +

• Mycobacterium bovis
• Staph. Aureus
• Strep. Pneumoniae.

Question 7

What is the difference between Gram +/-

Answer 7

Gram + = Thick PG layer

Gram - = Thin PG layer.

Question 8

Role of Lipopolysaccharides?

Answer 8

Structural Role

Antigen + bacterial toxin

Question 9

Role of flagella/fimbriae?

Answer 9

Adherence + sex

Question 10

Role of pilli?

Answer 10

Attachment & biofilm formation

Question 11

What are the factors that affect prokaryotic growth?

Answer 11

• Food: C,O,H,N inorganic salts like k
• Temperature: Mesophiles (Body temp)
• pH (human pH 6-7)
• Osmotic protection: 0.85 Nacl

Question 12

Two types of aerobes?

Answer 12

1. Facultative- use o2 if available

2. Obligate- Need o2 to survive