Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

IMED2001 UWA > Tutorial 3 > Flashcards

Tutorial 3 Flashcards

1
Q

What is the difference between bacteria and archaea?

A

Features that archaea have that bacteria don’t:

Have unique rRNA sequences

lack peptidoglycan in cell wall

Some have unusual metabolic characteristics

Many live in extreme environments

Features in bacteria that archaea lack:

Ubiquitous and some live in extreme environments

Cyanobacteria produce lots of oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are viroids and virusoids?

A

Infectious agents composed of RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are prions?

A

Infectious proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What factors affect generation times between bacterial species?

A

Environmental pH

Oxygen level

Nutrient availability

Temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the ways to measure bacterial growth?

A

Direct method

Indirect method

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the stages of the bacterial growth curve?

A

Lag phase

Exponential phase

Stationary phase

Death phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens during lag phase?

A

Hardly any reproduction while bacteria are adjusting to their environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens during exponential phase?

A

Constant growth provided nutrients are available in abundance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens during stationary phase?

A

Decreased availability of nutrients causes dying bacteria to equal bacteria reproduction rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens during death phase?

A

Inversely correlates with log phase where logarithmic decline takes place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the categories of growth requirements?

A

Physical (temp pH osmotic pressure)

Chemical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are obligate aerobes?

A

Require oxygen for growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are obligate anaerobes?

A

Cannot survive in presence of oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are facultative anaerobes?

A

Can grow with or without oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are aerotolerant microbes?

A

Grows in oxygen but doesn’t use it in metabolism

Microaerophile requires only low levels of oxygen for growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are some fastidious bacteria?

A

Mycobacterium tuberculosis (grown in vivo)

Haemophilus influenza (grown on chocolate agar)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the types of media?

A

Solid (agar)

Liquid (broth)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the difference between selective and differential media?

A

Selective medium contains ingredients that prohibit growth of some organisms

Differential medium contains ingredients that can differentiate between organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are some direct methods of measuring bacterial growth?

A

Direct cell counts

Cell-counting instruments

Viable cell counts

Plate counts

Membrane filtration

Most probable number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are some indirect methods of measuring bacterial growth?

A

Measuring biomass

Turbidity (most often used)

Total weight

Chemical constituents

Measuring cell products

Acids and gases produced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does TSB contain? Why?

A

tryptone and peptone to support growth of many fastidious organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are kings A and B used for?

A

To enhance of the fluorescein and pyocyanin pigments of pseudomonas. These broth cultures change to yellow to indicate fluorescein production and green to indicate pyocyanin production

23
Q

What is beta haemolysis?

A

Complete degradation of the red blood cells on the agar plate

24
Q

What is alpha haemolysis?

A

Partial degradation of red blood cells

25
What is rogosa agar?
Selective medium for isolation of lactobacilli used to isolate lactobacilli in faeces, saliva, mouth rinsis and dairy products. It contains acetate which lowers pH and allows lactic bacteria to grow alone. Low magnesium, manganese and iron ensure optimal growth of lactobacilli. Glucose is used as carbon source
26
What is Cysteine Lactose Electrolyte Deficient Agar?
Fermentation of lactose results in yellow colonies and L-cysteine causes alkaine reaction that results in blue colonies
27
What kind of zone does alpha haemolysis produce?
Greenish coloured zones
28
What is mannitol salt agar?
a selective-differential medium. It uses a nutrition medium containing 7.5% salt a single major carbon source and an acid base indicator. Result is growth of salt tolerant, mannitol fermentors of different kinds that show up in different colours
29
What is CHROMagar Candida?
Selective/differential media for identification of yeasts. Selective medium for isolation and presumptive isolation of yeasts and filamentous fungi
30
What is CHROMagar Candida used to detect?
Yeasts and filamentous fungi
31
What do yeasts look like in CHROMagar Candida culture?
Produce different colours based on species: Candida albicans green Candida tropicalis small smooth metallic blue Candid krusei large rough pale pink to mauve with white colony borders Candida parapsilosis large smooth white to pale pink colonies Candida guilliermondii large smooth dark purple with white colony borders Candida stellatoidea small smooth deep greeny-blue colonies
32
What is HEKTOEN ENTERIC AGAR?
Selective-differential medium for isolation of food poisoning organisms. Different bacteria produce different colored colonies
33
How does Hektoen Enteric Agar work?
Contains various sugars as carbon sources which cannot be used by salmonella or shigella. Peptone metabolism by salmonella and shigella results in an increase in pH turning the indicator blue. Medium contains thiosulphate which forms black precipitate in presence of hydrogen sulphide and appears black/brown Shigella does not produce hydrogen sulphide and so it looks green
34
What is Xylose Lysine Deoxycholate Agar?
XLD agar is another selective+differential medium to isolate pathogens from enteric specimens
35
How does XLD work?
Xylose is present which can be fermented by salmonella and decarboxylated to keep medium red however hydrogen sulphides make colonies have black center. Shigella cannot ferment xylose and remains red. E.coli ferment lactose and sucrose acidifying the medium resulting in yellow colonies
36
What is MEGA (Membrane Enriched Enterococcus Glucoside Azide Agar)?
Medium used in the membrane filtration analysis of water samples to select for faecal streptococci.
37
What does MEGA contain?
Sodium azide at a concentration inhivitory to coliform organisms and most other gram negative bacteria. 2, 3, 5 - triphenyl tetrazolium chloride which can be reduced by faecal streptococci to form formazan.
38
What is MESLS?
Medium used in membrane filtration analysis of water samples to select for faecal coliforms.
39
How does MESLS work?
Sodium lauryl sulfate acts to inhibit growth of non-coliform bacteria. Lactose is the sole carbohydrate available and phenol red is the indicator of acidity
40
How do bacteria selected for look like on MESLS agar?
Lactose fermenting colonies appear yellow while other non-coliform bacteria are pink
41
What is E.coli used for?
indicator organism for monitoring faecal contamination of water sources.
42
What are the features of ideal indicator organisms?
Present when pathogens are present Present only when there is danger of pathogens Occue in greater numbers than pathogens Survive in the environment as long as the pathogens are present Easy to detect Should not multiply in water and thus distort numbers
43
What are the limitations of using E.coli for monitoring pollution?
It does not reflect possible presence of protozoa and is not linked with possible viral contaminants such as enteroviruses
44
What are slope cultures?
agar cultures that are liquid but not broths
45
What are urea slopes?
slopes used for detection of organisms that can hydrolyse urea by producing urease. All proteus species have urease which can be differentiated from other members of enterobacteraceae
46
How does a capsule appear when stained with india ink?
Like a halo around bacteria
47
What bacteria are detected using ZIEHL NEESON ACID-FAST stain?
Mycobacterium species such as M.tubercolosis or M.leprae
48
What makes cell wall difficult to penetrate and how is that fixed with ZIEHL-NEELSON ACID-FAST stain?
Mycolic acid in cell walls make cell wall difficult to penetrate. Heat is used to permit entry of the stain. Acid-fast because positive cells retain colour after being washed with acid
49
How does kinyoun's stain work?
Waxy mycolic acid in cell envelope is resistant to drying which improves survival in environment. Mycolic acid binds with the stain carbol fuchsin and cannot be removed with acid-alcohol during decolourisation step.
50
How is tuberculosis diagnosed?
Kinyoun's stain on sample from sputum
51
What are the staining reagents of kinyoun's stain?
Kinyoun's carbol fuchsin 3% acid alcohol 0.3% aqueous methylene blue counterstain
52
What do acid fast bacteria look like on kinyoun's stain?
Red against blue background Non-acid fast bacteria stain blue/purple
53
Endospore staining
find info

IMED2001 UWA (44 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions