Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

MCB 101 LEC 2 > MCB 101 Lecture 3 > Flashcards

MCB 101 Lecture 3 Flashcards

1
Q

What is a pure culture?

A

An isolate free from other organisms, containing only one species of the organism.

Important for consistent and repeatable bacterial identification results.

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

Why are aseptic techniques important?

A

They are crucial for obtaining and maintaining pure isolates.

Aseptic techniques prevent contamination in microbiological work.

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

What does studying an organism’s morphological features involve?

A

Observing microscopic characteristics in terms of size, shape, arrangement, differentiation, and identification.

Knowledge in microscopy is essential for this study.

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

How do morphological features contribute to taxonomy?

A

They provide valuable information for describing the organism.

Eukaryotic organisms typically have more stable morphological features compared to prokaryotic organisms.

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

What can cause variations in the morphological features of microorganisms?

A

Changes in temperature, pH, and medium composition.

Proper parameters must be indicated during morphological studies.

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

What are some key morphological features studied in microbiology?

A
  • Shape
  • Size
  • Arrangement
  • Colonial morphology
  • Cellular inclusions
  • Spore morphology
  • Staining behavior
  • Mode of reproduction
  • Internal structures

These features are observed using a microscope.

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

What are the three basic shapes of bacteria?

A
  • Coccus (round or spherical)
  • Bacillus (rod-shaped)
  • Spiral

Additional shapes include elongated, curved, comma form, club rod, helical, corkscrew, filamentous, and stalked.

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

What is the unique shape of the genus Stella?

A

Star-shaped morphology.

Stella includes flat, six-pronged star-shaped prosthecobacteria found in various environments.

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

What characterizes Haloarcula?

A

Box-shaped rectangular cells that grow optimally at 40–45 °C.

It is an extreme halophilic archaeon with various validly published species.

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

What defines the arrangement of bacterial cells?

A

How cells are clustered or grouped during division.

Arrangement can vary based on the planes of division.

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

Fill in the blank: The smallest bacterium is approximately _______ in size.

A

1 µm.

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

What is the size range of Thiomargarita namibiensis?

A

Can reach a diameter of 750 µm.

It is known as the largest bacterium visible to the naked eye.

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

What are inclusion bodies?

A

Granules of organic or inorganic material in the cytoplasmic matrix that are stainable and visible under light microscopy.

They serve as energy and carbon reserves.

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

What is the most common inclusion body of prokaryotes?

A

Poly-ß-hydroxybutyric acid (PHB).

PHB is formed from β-hydroxybutyric acid units and is produced during excess carbon sources.

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

What are glycogen and starch classified as?

A

Organic inclusion bodies acting as stored carbon and energy sources.

They can be stained and appear as dark-blue and brown bodies under light microscopy.

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

What is cyanophycin?

A

The only known non-protein nitrogen polymer in cyanobacteria.

It is produced during stress conditions and can be visualized through specific staining methods.

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

What is the Sakaguchi reaction used for?

A

It is a staining method visualizing cyanophycin.

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

What are carboxysomes?

A

Bacterial compartments with polyhedral protein shells that contain RuBisCO and carbonic anhydrase.

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

What is the primary function of carboxysomes?

A

To concentrate CO2 for RubisCO and restrict access to O2.

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

What is Bacillus thuringiensis (Bt) known for?

A

Producing crystal proteins that are pore-forming toxins used as insecticides.

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

What type of pests do Bt crystal proteins target?

A

Insect pests including caterpillars, beetles, black flies, and mosquitoes.

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

What are gas vesicles?

A

Conical-shaped protein structures that help maintain buoyancy in aquatic prokaryotes.

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

What are magnetosomes?

A

Magnetic storage inclusions that help bacteria orient within a magnetic field.

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

What minerals compose magnetosomes?

A

Iron oxide (magnetite) and sulfur-containing minerals (greigite).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are polymetaphosphate granules also known as?
Volutin granules.
26
What do volutin granules store?
Phosphate in the form of linear chains of inorganic pyrophosphate.
27
What is the significance of sulfur granules in bacteria?
They store elemental sulfur used by bacteria that utilize hydrogen sulfide.
28
What is the purpose of studying morphological features of bacteria?
To identify and describe the organism accurately.
29
What characterizes gram positive bacteria?
They have a thicker peptidoglycan layer compared to gram negative bacteria.
30
What is the main purpose of gram staining?
To differentiate bacterial cell wall structures.
31
What does the term 'antigenic properties' refer to?
The antibody response triggered by antigens on a bacterium.
32
What are phenotypes?
Observable characteristics or traits of an organism used in species differentiation.
33
What are rapid identification kits used for?
To test nutritional and metabolic properties of bacteria for identification.
34
What does API stand for in microbiology?
Analytical Profile Index.
35
What is the function of the API 20 E kit?
To manually identify microorganisms based on metabolic reactions.
36
How is the bacterial suspension prepared for the API 20 E kit?
By adjusting the turbidity of a pure and actively growing culture.
37
What is the aim of using commercially available rapid ID kits?
To determine the identity of a bacterium with a certain level of accuracy.
38
What is the purpose of the APIWEB in bacterial identification?
To determine the identity of the bacterium based on reactions with 20 substances ## Footnote Results are used for phenotypic characterization and description purposes.
39
What types of microorganisms can Biolog kits identify?
* Aerobes (Gen III) * Anaerobes (AN) * Yeast (YT) * Filamentous fungi (FF) ## Footnote Kits can be used manually, semi-manually, or fully automated.
40
What does the Biolog microbial identification system use to provide a metabolic fingerprint?
A 96-well microplate with a patented redox tetrazolium dye ## Footnote The dye changes color as a result of cellular respiration.
41
What types of substances are contained in the Biolog microplate?
* 71 carbon sources (sugars, amino acids, etc.) * 23 chemical sensitivity assays ## Footnote Includes tests for pH, NaCl, and gram reactions.
42
What is the first step in the FAME process for bacterial identification?
Harvesting cells from a pure culture grown on a specified medium ## Footnote TSA is commonly used for most aerobic, mesophilic, and heterotrophic bacteria.
43
What is the role of gas chromatography (GC) in FAME?
To analyze fatty acid profiles for identification ## Footnote GC can identify organisms based on peak naming and profile comparison.
44
What factors can cause variation in fatty acid profiles?
* Medium used * Incubation length * Temperature * Aeration * Plate quadrant for harvesting ## Footnote These parameters must be controlled for accurate comparison.
45
What are common molecular methods used in bacterial identification?
* Gene and gene products analysis * Nucleic acid ratio determination (G+C) * DNA-DNA hybridization * Genome fingerprinting ## Footnote These methods are important in molecular taxonomy.
46
What is genome fingerprinting?
A rapid approach to evaluate genetic variation between strains ## Footnote It generates DNA fragments using restriction enzymes.
47
What is ribotyping?
A method of gene fingerprinting that uses unique DNA sequences ## Footnote It involves restriction digest and agarose gel electrophoresis.
48
What is the purpose of PCR in polyphasic taxonomy?
To amplify the 16S rRNA gene for nucleotide sequencing ## Footnote It allows for detailed genetic analysis of bacteria.
49
What is an electropherogram?
A visual chart generated during DNA analysis by electrophoresis ## Footnote It shows the quantity of fluorescence from DNA fragments.
50
What is the first step in performing a BLAST search?
Go to the NCBI website and click on BLAST ## Footnote Followed by selecting nucleotide BLAST and entering query sequences.
51
What does the mol % G+C method determine?
The DNA base composition and relatedness of organisms ## Footnote It reflects base sequence variation among organisms.
52
What does DNA-DNA hybridization compare?
The similarity of the genomes of microorganisms ## Footnote It was once considered the gold standard for delineating bacterial species.
53
What recommendation was made regarding DNA-DNA hybridization for closely related strains?
It should be performed for strains with 16S rRNA gene sequence similarities higher than 98.7–99% ## Footnote This improves efficiency in identifying genomic uniqueness.
54
What is the purpose of DNA-DNA hybridization experiments?
To test the genomic uniqueness of novel isolate(s) ## Footnote Stackebrandt and Ebers, 2006
55
What is the significance of DNA-DNA hybridization values ranging from 70-100%?
Indicates that the two strains belong to the same species ## Footnote Values below this range indicate different taxonomic relationships
56
What do DNA-DNA hybridization values below 70% but above 25% indicate?
Strains belong to the same genus ## Footnote Further breakdown includes <25-7% indicating different genera
57
What is the function of nucleic acid probes in DNA-DNA hybridization?
To detect hybridized products ## Footnote Probes can be radioactive or labeled with chemicals
58
What are the steps involved in DNA-DNA hybridization?
1. Extraction and purification of DNA 2. Denaturation of DNA strands 3. Formation of double-stranded hybrids by complementary base pairing
59
True or False: DNA molecules with very different sequences can form stable hybrids.
False ## Footnote They will not form a stable or detectable hybrid
60
What ecological properties have taxonomic significance?
1. Life cycle patterns 2. Nature of symbiotic relationships 3. Ability to cause disease 4. Preferred habitat (temperature, nutrients, pH, oxygen, osmotic concentration)
61
Fill in the blank: The ability of an organism to thrive in a particular environment has ______ value.
taxonomic
62
Who are the authors of the study discussing DNA-DNA hybridization values?
Johan Goris, Konstantinos T. Konstantinidis, Joel A. Klappenbach, Tom Coenye, Peter Vandamme, James M. Tiedje ## Footnote Published in the International Journal of Systematic and Evolutionary Microbiology
63
What is the relationship between DNA-DNA hybridization and whole-genome sequence similarities?
DNA-DNA hybridization values provide a measure of genomic similarity ## Footnote Goris et al., 2007
64
What is the main focus of Stackebrandt and Goebel's 1994 work?
The role of DNA-DNA reassociation and 16S rRNA sequence analysis in species definition in bacteriology ## Footnote Int J Syst Bacteriol

MCB 101 LEC 2 (5 decks)

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