Pathology - Bacterial Growth

Question 1

What are the macroelements bacteria use?

Answer 1

C, O, H, N, P and S

Question 2

What microelements are used for bacteia?

Answer 2

P, Ca, Mg, Fe, Cu, Zn and V

Question 3

What is P important for?

Answer 3

ATP synthesis and NA backbone

Question 4

What is Ca important for?

Answer 4

Signal transduction pathways as well as use a second messenger molecues

Question 5

What is Mg used for?

Answer 5

Cofactor for DNAP activity

Question 6

What is Fe used for?

Answer 6

ETC redox tactions and metabolic pathways like in cyotchromes

Question 7

How do bacteria scavenge Iron from the environment?

Answer 7

Siderophores

Question 8

Siderophores

Answer 8

These are products increasing rate of transport of envrionmental iron via the cell membrane using receptors.

Question 9

What is Cu used for?

Answer 9

Cofactor for cytocrhome oxidases in aerobic respiraiton as well as Cu-Zn Superoxide Dismutase Enzyme

Question 10

Cu-Zn Superoxide Dismutase Enzyme

Answer 10

This is an antioxidant that generates hydrogen peroxide and dioxygen from highly reactive superoxide

Question 11

Culture Media

Answer 11

This is a nutrient rich solution for growth and proliferation of a microgranism

Question 12

What does a culture media contain?

Answer 12

Organic/Inorganic compounds sutable for microbial growth with antibiotics to inhibit growth of specifc bacteria

Question 13

What are the types of culture media?

Answer 13

Complex or Defined
Liquid or Solid

Question 14

Complex Media

Answer 14

This is where chemical composition is not known, made of digested material.

Question 15

What material makes up complex media?

Answer 15

Peptone, Meat/Yesat extracts and carbohydrates ources

Question 16

Peptones

Answer 16

These are mixtures of nitrogenous compoudns like AA and proteins

Question 17

Where is complex media used?

Answer 17

For bacteria with unknown nutritional requirements and growth support for bacteria difficult to culture

Question 18

Defined Media

Answer 18

Is one in which the chemical composition in precisely known allowing for highly controlled experiments for studying of particular metabolic pathways

Question 19

Liquid Media

Answer 19

This is a culture media for bacterial growth in susepnsion with required nutrients dissolved

Question 20

How is Liquid Media prepared?

Answer 20

Mixutre with required nutrients for microorganism under study, specific pH distilled then sterilization by high temperature application, then incoulation using sterile pippete and incubated

Question 21

Aseptic Technique

Answer 21

This is the procedure under controlled conditiosn to reduce contamintaiton from microbes

Question 22

How is solid media prepared?

Answer 22

Required nutrients in agar or gelation then inoculated using sterile loop across surface for individual colony formation, then with incubation

Question 23

What is the advantages of Solid Media?

Answer 23

Colonise can be isolated and studied, allowing morphological analysis for identity and behavioural analysis.

Question 24

Batch Culture

Answer 24

This is a closed system containing limited amount of nutrients with finite growth

Question 25

Binary Fission

Answer 25

This is the exponential growth of bacteria by doubling of mass of cells then division by septum formation

Question 26

What are teh steps of Binary Fission?

Answer 26

Genetic Material replication Cell elongaiton and size increase Polar segregation of replicated chromosomes Cell division by cleavage of centre with daughter cell formation

Question 27

What are the stages of the growth curve?

Answer 27

Lag Exponential Stationary Death

Question 28

Lag Phase

Answer 28

Adjustment of bacteria to a new environment when incoulated in a growth media

Question 29

What processes occur in the lag phase?

Answer 29

Ribosomal and protein synthesis with limited division in preapration for exponential phase,a djusting the specific nutriends

Question 30

Exponential Phase

Answer 30

This is the consistent doublign and maximal growth rate, influenced by assimilation and nutrients/nutrient density

Question 31

Stationary Phase

Answer 31

This occurs when nutrients have been assimilated and waste products accumulated

Question 32

How are bacteria categorise by capacity for growth?

Answer 32

Viable Cells Viable but Nonculturable Bacteria

Question 33

Viable But Nonculturable

Answer 33

This refers to bacteria in a state of low metabolic activity that do not divide, but can become resuciated and culturable.

Question 34

Legionella Pneumophilia

Answer 34

This causes legionnaires disease, being a severe form of pneumonia

Question 35

Why cant Legionella be grown on convential media?

Answer 35

Infect macrophages and amoebae in aquatic nevrionments intracellularly, requiring L-Cysteine which is unavailable to standard media, and cannot be synthesised by legionella, taken from exogenous source.

Question 36

What are the counting methods for bacteria?

Answer 36

Total Count Viable Count Culturable Count

Question 37

What are examples of total counting methods?

Answer 37

Sterile Dillution Buffer Most Probable Number Method

Question 38

What is the basic total coutn method?

Answer 38

Spreading onto an agar medium and counting of bacterial colonies to calculate total count of bacteria in original sample.

Question 39

Most Probable Number Method

Answer 39

This is a statiscal method estimating viable bacteria numbers in a sample by inoculation in a dilution series of liquid growth.

Question 40

What does total count account for?

Answer 40

Viable, VNBC, Culturbale and Dead Cells

Question 41

Viable Count

Answer 41

This utilises fluoresence activity dyes counting all cells with activity, exluding dead cells.

Question 42

How is viable count perofrmed?

Answer 42

Collecting sample, diluting by spread on solid agar medium using pippette, number of colonies counted.

Question 43

Serial Dillution

Answer 43

This is a laboratory procedure being stepwise dilution of a substance in solution

Question 44

What does viable count take into account?

Answer 44

Living viable cells, however ecludes bacteria that cannot growth within the agar

Question 45

How is Serial Dillution performed?

Answer 45

Adding poriton of sample to a volume of sterile dulent, small amount rtansferred to next dilution tube, repeated until desired dilution, spread on agar, icubated then Colony Forming Units counted

Question 46

What is an example of culturable count being used?

Answer 46

Vibrio cholera by sample of dirnking water, where presence of V-cholerae determines safety.

Question 47

How is turbidity measures?

Answer 47

Amount of bacteria inoculated in liquid growth medium and incubated, then by spectrophotometer

Question 48

Spectrophotometer

Answer 48

These are instruments measuring optical transmission characteristics of a sample over a range of wavelenghts

Question 49

Bacteriostatic

Answer 49

These are medicines whose mechanisms of action stalls bacterial cellular activity without causing death.

Question 50

Bacteriocidal

Answer 50

This is antibiotic success in bacteiral elimination

Question 51

Bacteriolytric

Answer 51

This means destruction of bacteria throguh lysis

Question 52

What are the metabolic activity classifications of bacteria?

Answer 52

Obligatory anaerobes and aerobes, facultative anaerobes, aerotoleratn anaerobes and microaerophilic

Question 53

What are the different types of bacteria by temperature?

Answer 53

Psychrophiles(Opt 15C, not above 20C can below 0C) Mesophiles(Opt between 20-40C Thermophiles(Opt betweeen 45-80C) Hyperthermophils(Best above 80)

Question 54

How are bacteria categorieed by pH and osmolarity?

Answer 54

Acidophiles, Alkaliphiles and Halophiles