Aseptic Technique

Question 0

Defference between a Mixed Culture and a Pure Culture

Answer 0

• A mixed culture is a culture with many different species of bacteria.
• A pure culture is a culture with only one specie of bacteria.

Question 1

Definition of Aseptic Technique

Answer 1

Is a way of working with microbial cultures that insures the environment, personnel, and microbial cultures are Not contaminated.

Question 2

Definition of Colony

Answer 2

Consists of identical cells, which are called Clones, because they are all descended from a single, original cell.
The separated cells reproduce and form a colony separated from other colonies.

Question 3

Tryptic Soy Broth (TSB) mixed culture with three different bacteria:
~Chromobacterium volacium + TSB
~Serratia marcescens + TSB
~Escherichia coli + TSB
Give a color and cause in body

Answer 3

Chromobacterium volacium: Purple; Pus-forming infections.
Serratia marcescens: Red; Bladder infection.
Escherichia coli: White; Colon infection.

Question 4

Structure of bacteria

Answer 4

They are unicellular and much smaller than eurakyotic cells.

Question 5

Basic Shape of bacteria:

• Coccus; Coccobacillus; Bacillus; Vibrio; Spirillum; Spirochete; Pleomorphic
• Diplococci; Streptococci; Tetrads; Sarcina; Staphylococci
• Single bacillus; Diplobacilli; Streptobacilli; Palisade

Answer 5

• Spherical or oval; Rod Shape; shape like Comma; Curved shape; loose spiral; tight spiral; no shape
• 2 spheres; Chain of spheres; 4 spheres; 8 spheres cube shape; Clusters like grapes
• 1Rod; 2 Rod; Chain of Rods; V-shape Rods

Question 6

Why are Negative stains used for?

Answer 6

They are useful in observing Morphology, size, and arrangement of bacteria cells.

Question 7

Why do the Negative staining technique use a dye solution?

Answer 7

Because a dye solution contains the chromogen (nigrosin) that is acidic ( give up a hydrogen ion) and carries a negative charge. Since bacteria are negatively charged as well (due to Teichoic acid on gram positive bacteria, and the lipopolysaccharide on the gram negative bacteria), they will repel the negative charged chromogen. As a result, the bacterial cells will not take up the dye remain unstained. However, the background will be colored with the dye.