Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Microbial world > Lecture 7 and 8 > Flashcards

Lecture 7 and 8 Flashcards

1
Q

What are the 5 shapes of colonies?

A

Circular, rhizoid, irregular, filamentous, spindle

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

What are the 6 possible margins of a colony?

A

Entire, undulate, lovate, cruled, rhizoid, filamentous

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

What 4 elevations can a colony have?

A

Flat
Raised
Convex
Umbonate

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

What is the smallest colony size?

A

Punctiform

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

Bacteria within a colony can be genetically identical but, they can be…

A

Metabolically different

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

Define binary fission

A

Division into 2 equally sized daughter cells

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

What happens during binary fission?

A

Cell elongates/replicates DNA
Cell wall/plasma mebrane constrict
Cross wall forms
Cells separate

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

Define generation time

A

Time required for cell to divide

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

What is generation time for E.coli in nutrient rich medium at 37?

A

30 minutes

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

What is the generation time for Mycobacterium tuberculosis?

A

15-20 hours

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

What is the advantage of using logarithmic scale over non-logarithmic scale when representing bacterial populations?

A

Possible to predict the number of cells that will be produced over a certain time period

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

Why is there a lag phase?

A

New cultures usually come from cultures in stationary phase/ death phase (not adjusted to new environmnet)

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

What phase comes after lag phase?

A

Log phase

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

What happens during log phase?

A

High metabolic activity: cells divide, exponential growth

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

What phase comes after log phase?

A

Stationary phase

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

Why stationary phase?

A

Cells run out of nutrients, metabolic changes pH, waste products accumulate (equilibrium)

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

What phase comes after the stationary phase?

A

Death phase

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

Name three indirect methods of measuring microbial growth.

A

Turbidity
Metabolic activity
Dry weight

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

Name 4 direct methods of measuring microbial growth.

A

Plate counts
FIltration
Microscopic count
Most probable number (MPN)

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

What is turbidity as an indirect method for measuring microbial growth?

A

The use of a spectrophotometer to measure percentage transmission in suspended cells

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

What is a disadvantage to turbidity?

A

If bacteria change morphology in growth phases, turbidity changes
Cells may aggregate

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

What is metabolic activity as an indirect method for measuring microbial growth?

A

The amount of certain metabolic products is directly proportional to number of bacteria (e.g. acid or CO2 production)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is dry weight as an indirect method of measuring microbial growth?

A

Cells removed from media, filtered, dried, weighted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is a plate count?

A

Serial dilution of population, the number of cells is expressed as colony forming units (CFU)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
How is the amount of bacteria in the original sample calculated using plate counts?
Count colonies on plate, multiply by dilution factor
26
What are the two types of plate count?
Pour plate method | Spread plate method
27
What type of bacteria can be grown using the pour plate method?
Facultative anaerobic bacteria (problematic if bacteria are temperature sensitive)
28
What is the filtration method of measuring microbial growth?
Bacteria are filtered and the filter is placed on a growth medium
29
When is filtration used to measure microbial growth?
When quantity of bacteria is very small (e.g. samples from lakes/ streams)
30
How does the MPN (most probable method) measure microbial growth?
Dilute to reduce density to which no bacteria are left to grow in tubes
31
When is MPN useful?
When microbes will not grow on solid media
32
What is MPN?
The statistical estimation of number of cells
33
What are the two main requirement catagories for bacterial growth?
Physical requirements | Chemical requirements
34
What name is given to bacteria that grow between ~-10-20 degrees C?
Psychrophiles
35
What name is given to bacteria that grows between 0 and 30 degrees C?
Psychrotrophs
36
Between which temperatures do mesophiles grow?
10 and 50 degrees
37
Between which temperatures do thermophiles grow?
40 and 70
38
What name is given to bacteria that grows between 65 and 110 degrees?
Hyperthermophiles
39
How do psychrophiles keep their fatty acids remaining fluid?
Proeinaceous antifreeze
40
Name a psychrotroph that grows in fridges.
Listeria monocytogenes
41
Name a mesophile.
E.coli
42
Name a thermophile
Sulfolobus (e.g. Yellowstone national park hotsprings)
43
What are the red/brown bacteria in Grand pismatic spring?
Pigmented bacteria (carotenoid) gives protection from light
44
Name a hyperthermophile.
Thermothoga maritima (lives in hydrothermal vents)
45
What is the temperature growth record?
121C
46
What pH do acidophiles grow at?
pH below 7
47
What pH do moderate acidophiles grow between?
3-5
48
What name is given to acidophiles that grow below pH 3?
Extreme acidophiles
49
What bacteria grow between pH 6.5 and 7.5?
Most bacteria | Neutrophiles
50
What type of bacteria grows at pH 9-12?
Alkaliphiles
51
What does hypertonic environments cause?
Plasmolysis
52
What name is given to bacteria that require high external solute concentration?
Extreme/obligate halophiles
53
What name is given to bacteria that can tolerate high external solute concentrations?
Facultative halophiles
54
Why do bacteria require nitrogen?
Protein synthesis DNA RNA ATP
55
Where do bacteria obtain nitrogen from?
Amino acids NH4+ NO3- Gaseous N2
56
Why do bacteria require sulfur?
Protein synthesis, vitamins
57
Where do bacteria obtain sulfur from?
Amino acids SO4^2- Hydrogen sulfide
58
Why do bacteria require phosphorus?
DNA, RNA, ATP
59
Where do bacteria obtain phosphorus from?
PO4^3-
60
What are trace elements?
Inorganic elements require in small amounts for co-factors in enzymes
61
Name some trace elements
Iron, copper, zinc
62
What are organic growth factors?
Organic compounds obtained from the environment
63
Name some organic growth factors
Vitamins Amino acids Purines Pyrimidines
64
What bacteria have only aerobic growth (oxygen required)?
Obligate aerobes
65
What bacteria have both anaerobic and aerobic growth?
Facultative anaerobes
66
What bacteria only grows anaerobically?
Obligate anaerobes
67
What name is given to bacteria that only grows anaerobically, but continues in the presence of oxygen?
Aerotolerant anaerobes
68
What name is given to bacteria that only grow in aerobic conditions, but oxygen is required in low concentration?
Microaerophiles
69
Why can oxygen be toxic?
``` Singlet oxygen (O2-) Higher energy state Peroxide anion (O2^2-) contained in H2O2 ```
70
What enzyme detoxifies peroixide anions?
Superoxide dismutase (SOD) turns it back to H2O2
71
What enzyme turns H2O2 into water and oxygen?
Catalase
72
What enzyme turns H2O2 into water in the presence of hydrogen?
Peroxidase
73
How do bacteria communicate in biofilms?
Quorum sensing
74
What do nutrient agar's typically contain?
``` Peptone Beef extract Sodium chloride Agar Water ```
75
What is peptone? Why is it added?
Partially digested protein | Energy, carbon, nitrogen, sulfur
76
Why is beef extract in agar?
Vitamins, organic growth factors
77
What are two types of medium?
Selective medium, differential medium
78
What is an enrichment culture?
Similar to selective medium, but increases number of desired microbes to detectable levels

Microbial world (12 decks)

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