Intro to bacteria

Question 1

Define bacteria

Answer 1

Single-celled – lack nucleus & other membrane-bound organelles

Some are beneficial & others pathogenic

Reproduce asexually by binary fission

Question 2

Describe basic structural components of bacteria

Answer 2

Cell wall
Cell membrane:
Ribosomes
Nucleoid
Plasmids
Flagella
Capsule
Pili/fimbriae

Question 3

What are the different shapes of bacteria

Answer 3

Rods, Staphylococcus (form bunch), Streptococcus (form chain), Spiral

Question 4

Difference in bacterial cell wall structure

Answer 4

Gram positive bacteria have thick peptidoglycan layer in cell wall

Gram negative bacteria have thinner peptidoglycan layer & an outer membrane

Mycoplasmas don’t have a cell wall

Question 5

Different oxygen requirements of bacteria

Answer 5

Aerobic (require oxygen)

Anaerobic (don’t require oxygen)

Facultative anaerobes (can grow with or without oxygen)

Question 6

What are mycobacteria

Answer 6

Similar structure to gram positive bacteria
Stain gram positive but also have acid-fast property for stains
Resist decolorisation acid-alcohol

Question 7

Types of media to grow bacteria

Answer 7

Minimal media
Nutrient media
Enriched media
Selective media
Indicator media
Selective indicator media
Transport media

Question 8

What are the 3 types of haemolysis

Answer 8

Alpha = incomplete – produces green zone

Beta = complete destruction – produces clear zone

Gamma = absence of any haemolysis