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Module 4 Week 3 > Growth and Physiology of Bacteria > Flashcards

Growth and Physiology of Bacteria Flashcards

1
Q

Bacteria have:
-High or low metabolic rate
-Long or short gen time
-Ability to use…

A

-high metabolic rate ; grow very quickly
-short generation time
-ability to use a vast array of energy sources both chemical (i.e. inorganic as well as organic) and physical (e.g. radiant energy) e.g can grow in disinfectants; will always outcompete mammalian cell as grow so rapidly

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2
Q

Bacteria replicate by…

A

Binary Fission

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3
Q

Bacterial growth is increase in no. or increase in size of cells?

A

^ in number of cells

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4
Q

-Bacterial cell daughter cells are of equal size true or false
-Do cells separate after division?

A

-True
-may or may no

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5
Q

Cocci gram positive or gram negative bacteria?

A

Gram +ve

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6
Q

2 types of cocci and their differences in growth

A

Streptococci- grow in chains
Staphylococci- grow in clumps/clusters

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7
Q

Chromosome replication in bacteria initiates…

A

Cell division; then proceeds in both directions until it reaches terminus

(Diagram of chromosome replication, don’t need to understand all of it, just the concept of movement of direction to terminus)

https://www.google.co.uk/imgres?imgurl=https%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2F7%2F7c%2FOrigins_of_DNA_replication_Figure_1.jpg&imgrefurl=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FOrigin_of_replication&tbnid=ovZBCN-TbJtR9M&vet=12ahUKEwit_eLrmev8AhXnvicCHdpmC6wQMygAegUIARC5AQ..i&docid=4xazyyziHBhhJM&w=4945&h=4649&q=origin%20DNA%20replication%20and%20terminus%20in%20bacteria%20diagram&hl=en-gb&client=safari&ved=2ahUKEwit_eLrmev8AhXnvicCHdpmC6wQMygAegUIARC5AQ

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8
Q

2 ways of measuring bacterial growth in lab

A

In liquid or solid media

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9
Q

-Types of liquid media measurement of bacterial growth
-Types of solid media measurement of bacterial growth

A

-Turbidity
-Count particles
-Viable counts

-serial dilution

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10
Q

-What is turbidity type of measurement of bacterial growth
-What is Count particles type of measurement of bacteria growth

A

Use of absorbance of light on spectrophotometer or light scatter on nephelometer; start off with clear fluid and as bacteria grows it gets more cloudy so you can see the visible changes

Counting the number of cells of bacteria either microscopically or using an electronic particle counter

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11
Q

What is the generation/doubling time

A

Time it takes for population to divide and double
Under optimum conditions the doubling time is characteristic of each bacteria

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12
Q

Doubling time of bacteria greatly affected by… and is…

A

Culture conditions and is species specific

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13
Q

Name the Bacterial growth rates of these microorganisms
(Their doubling time in min)

-Vibrio natriegens
-Bacillus sterothermophilus
*-Escherichia coli
-Bacillus subtilis
*-Pseudomonas putidia
-Mycobacterium tuberculosis

A
  1. 9.6
  2. 8.4
  3. 22.8
  4. 25.8
  5. 45
  6. 360
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14
Q

Microorganisms grow slower in vivo or vitro?

A

In vivo

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15
Q

Name the bacterial growth curve phases

A

Lag phage
Log phase
Stationary phase

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16
Q

Describe each phase of bacterial growth curve
-lag phase
-log phase
-stationary phase

A
  1. Bacteria adjusting to environment and producing enzymes to allow it to use substrate
  2. Doubling rapidly
  3. Run out of nutrients to grow
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17
Q

Requirements for bacteria to grow

A

Physical requirements
-temp
-pH
-osmotic pressure

Gaseous requierments

Nutrients

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18
Q

What are mesophiles

A

Bacteria with optimum temp of 37C

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19
Q

What are neutrophiles

A

Pathogenic bacteria with an optimum pH of around 7

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20
Q

Products of bacterial metabolism are usually ________. Therefore pH for their growth can be ________.

A

Acidic
Lower

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21
Q

4 Types of growth of bacteria in semi solid media (relating to effect of oxygen on them)

A
  1. Obligate aerobe
  2. Facultative anaerobe
  3. Microaerophile
  4. Obligate anaerobe
22
Q

What is the obligate aerobe type bacteria in semi solid media
-examples

A

Bacteria which in semi solid media gravitates to the surface where there is most oxygen; like to grow in oxygen
Microbacterium bovis, microbacteriumtberculosis

23
Q

What is the facultative anaerobe type bacteria in semi solid media

A

Bacteria that grow aerobically and anaerobically (in absence of O2)

24
Q

What is the microaerophile type bacteria in semi solid media

A

Bacteria that grow below surface of liquid as they prefer less O2 and more CO2

25
Q

What is the obligate anaerobe type bacteria in semi solid media
-examples

A

Grow in absence of O2; it is toxic/fatal to them
-clostridium prefringes

26
Q

Too much oxygen is ________ to bacteria

A

Toxic

27
Q

How does oxygen intoxicate bacteria

A

By forming reactive oxygen intermediates (ROI)

28
Q

Name the 3 types of ROI

A

superoxide

peroxide

hydroxyl radical

29
Q

Which enzymes detoxify the ROIs

A

Superoxide dismutase
Catalase

30
Q

Pathogenic bacteria are chemoheterotrophs. What does this mean?

A

They require a source of nutrients

31
Q

List the nutrient requirements bacteria require

A

– Organiccarbon
– Nitrogen
– Sulphur
– Phosphorus
– Potassium
– Magnesium
– Calcium
– Trace elements
• Iron,Zinc,Copper,Molybdenum

32
Q

What extra organic growth factors do some bacteria require?

A

NAD or NAD

33
Q

Solid media
-is solidified by…

A

-Agar (1-3%) put into a petri dish (plate)

34
Q

Bacteria grow as colonies. Each colony arises from…

A

Growth of a single bacterial cell or clump of cells

35
Q

What is streaking of bacteria on agar plate

A

Movement of bacterial colonies across plate to dilute bacteria to grow individual colonies and identify them

36
Q

When making a bacterial sample in the lab, some bacteria need an enriched media. Name substances used to help the bacteria grow

A

Blood, serum, chocolate agar (heated blood agar)

37
Q

What is horse blood agar used to grow and why
What is sheep blood agar used for

A

Anaerobic bacteria because it gives better haemolysis than other blood
Aerobic bacteria

38
Q

Agar that we use to grow bacteria is differential and selective. What does this mean

A

Selective; contains inhibitory substances to prevent some bacteria from growin
Differential; contains a sugar (lactose). If the organism metabolises lactose it produces acid and the colonies become pink. This allows us to identify the colony being grown

39
Q

Which bacteria; gram +ve or gram -ve ferment lactose and therefore colones will turn pink in an agr

A

Gram positive!

40
Q

Cultivation of fungi
-fungi are chemoheterotrophs true/false
-require complex substances such as…
-optimum growth temp and pH
-common agar media used
-yeast grown as colonies however filamentous fungi grown as a ___________

A

• Fungi are chemoheterotrophs
• Growth requirements similar to bacteria some require complex substances such as keratin
• Optimum growth temperature for many fungi much lower than for pathogenic bacteria
• Most fungi grow at lower pH than bacteria
• Media
– Sabouraudsagar
– Dextrose and peptone, pH5.6
• Yeast grow as colonies
• Filamentous fungi grow as a mycelium

41
Q

What is mycelium

A

root-like structure of a fungus consisting of a mass of branching, thread-like hyphae

42
Q

What is sterilisation

A

Killing or removal of all living organisms in or on a substance or object, usually by denaturing proteins, nucleic acids and membrane permeability

43
Q

What is disinfection

A

Killing of most microorganisms on a substance or object (kill may not be complete – removes a high % of organisms to numbers too low to cause disease)

44
Q

What are sterile techniques

A

Procedure carried out in absence of living things
Used in surgery

45
Q

What are aseptic techniques

A

Procedures performed in a way to prevent contamination with infectious microorganisms
Used in laboratory

46
Q

Methods of sterilisation

A

• Irradiation
• Heat
– Moist
–boiling, autoclave
– Dry– hot air oven
• Filtration
• Chemicals
– Ethyleneoxide
– Formaldehyde and Gluteraldehyde
– Hydrogen peroxide
– Chlorinedioxide
– Peraceticacid

•
Ionising radiation – disposable plastics, surgical materials, unsuitable for glass and metal

47
Q

Describe how heat works as a method of sterilisation
-what methods of heating would you use

A

Denatures enzymes- coagulation of proteins and breakage of H bonds
-boiling, autoclave

48
Q

REMEMBER TO KILL THE BACTERIA U MUST KILL THE BACTERIAL SPORES OR ELSE IT IS NOT A STERILISING METHOD

A

Yuh

49
Q

What is autoclave

A

Steam under pressure

50
Q

Materials and objects that require sterilisation

A

Microbiological and tissue culture.
Medicines.
Surgical, optical and electrical instruments.
Reagents.
Equipment or containers in which any of the above are to be handled.
Infected material.

51
Q

Factors affecting the action of a disinfectant

A

Period of exposure
Concentration (there is an optimum dilution for disinfectant)
Temperature
pH
Organic matter
Number of bacteria present

Module 4 Week 3 (8 decks)

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