MICROBIOLOGY-BACTERIAL GENETICS, METABOLISM, AND STRUCTURE Flashcards
1
Q
hereditary information resides or is encoded
A
Nucleic acids
2
Q
Q: How many major classes of nucleic acids are there?
A
Two
3
Q
Q: What distinguishes prokaryotes from eukaryotes in terms of genetic material?
A
Prokaryotes lack membrane-bound organelles, so their genetic material is not enclosed in a nucleus, whereas eukaryotes have their genetic material enclosed in a nuclear envelope.
4
Q
Can you name the two major classes of nucleic acids?
A
DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid).
5
Q
Yes or No
Q: Do prokaryotes have DNA within a nuclear membrane?
Q: Do eukaryotes have DNA within a nuclear membrane?
A
NO
YES
6
Q
YES OR NO
Q: Do prokaryotes undergo mitotic division?
Q: Do eukaryotes undergo mitotic division?
A
NO
YES
7
Q
YES OR NO
Q: Is DNA associated with histones in prokaryotes?
Q: Is DNA associated with histones in eukaryotes?
A
NO
YES
8
Q
Q: How many chromosomes do prokaryotes typically have?
Q: How many chromosomes do eukaryotes typically have?
A
ONE
MORE THAN ONE
9
Q
YES OR NO
Q: Do prokaryotes have membrane-bound organelles?
Q: Do eukaryotes have membrane-bound organelles?
A
NO
YES
10
Q
Q: What is the size of ribosomes in prokaryotes?
Q: What is the size of ribosomes in eukaryotes?
A
70S
80S
11
Q
YES OR NO
Q: Do prokaryotes have a cell wall containing peptidoglycan?
Q: Do eukaryotes have a cell wall containing peptidoglycan?
A
YES
NO
12
Q
exist as double-stranded, closed, circular, autonomously replicating extrachromosomal genetic elements.
A
Plasmids
13
Q
The number of plasmids per bacterial cell varies.
T OR F
A
T
14
Q
Plasmids composed of few genes.
T OR F
A
F; several genes
15
Q
What are transposable elements often referred to as?
A
Jumping genes
16
Q
are pieces of DNA that move from one genetic element to another (such as from a plasmid to a chromosome or vice versa).
A
Transposable elements
17
Q
Can transposable elements replicate independently?
A
No, transposable elements are unable to replicate independently.
18
Q
Do transposable elements exist as separate entities in the bacterial cell?
A
No, transposable elements do not exist as separate entities in the bacterial cell.
19
Q
What are the two types of transposable elements?
A
simple transposon (or insertion sequence, IS) and composite transposon.
20
Q
What are episomes capable of in terms of replication?
A
Episomes are capable of replicating independently of the host chromosome.
21
Q
Are episomes considered part of the bacterial genome?
A
Yes
22
Q
How stable are episomes compared to the chromosome?
A
Episomes are not as stable as the chromosome and may be lost during replication.
23
Q
What is binary fission?
A
production of 2 daughter cells from one parent cell
24
Q
What must happen to the genome during replication in binary fission?
A
Genome must be replicated so that each daughter cell receives an identical copy of functional DNA.
25
Replication must occur quickly and accurately. T OR F
T
26
Types of genetic exchange
Transformation
Transduction
Conjugation
27
is the uptake of naked (free) DNA by a recipient cell from the environment when another bacterial cell (donor) dies and undergoes lysis.
Transformation
28
Which bacteria are examples of those that can undergo transformation?
Haemophilus, Streptococcus, and Neisseria.
29
What advantages can transformation give to recipient cells?
antibiotic resistance and the ability to cause disease.
30
Is transformation limited to organisms of the same species?
No, transformation is not limited to organisms of the same species.
31
is a process where DNA from two bacteria may come together in one cell, allowing recombination.
Transduction
32
What mediates transduction?
mediated by viruses capable of infecting bacteria, known as bacteriophages.
33
What are the two types of transduction?
generalized transduction and specialized transduction.
34
occurs between two living cells, involves cell-to-cell contact, and requires the mobilization of the donor bacterium’s chromosome.
Conjugation
35
Intercellular contact is not well characterized in bacterial species. T or F
T
36
Which bacterium's conjugation is mediated by a sex pilus?
Conjugation in E. coli is mediated by a sex pilus.
37
What must happen to plasmids during conjugation?
must be replicated
38
What is transposition in the context of conjugation?
Transposition is the process by which genetic elements, such as transposons, excise from one genomic location and integrate into another.
39
Utilization of metabolic pathways involved in the acquisition of nutrients from the environment
Fueling
40
a passive transport mechanism where molecules like water, oxygen, and carbon dioxide move across the bacterial cell membrane
Simple diffusion
41
a process that requires energy to move nutrients such as sugars, amino acids, organic acids, and inorganic ions across the cell membrane
Active transport
42
requires energy but chemicals transported undergoes chemical modification (sugars, purines, pyrimidines, and fatty acids)
Group translocation
43
Production of metabolites
-Embden-Meyerhof-Parnas (EMP) Pathway (glycolysis)
-Tricarboxylic acid (TCA) cycle
Alternate pathways:
-Entner-Doudeoroff (degrades gluconate and glucose)
-Pentose Phosphate Pathway
44
What is the primary purpose of energy production in bacterial cells?
Energy production provides the energy required for nearly all cellular processes, including nutrient uptake and precursor production.
45
Q: How do bacteria accomplish energy production?
breaking down chemical substrates through catabolism, which is coupled with oxidation-reduction reactions
46
is a process where ATP is generated from ADP
substrate-level phosphorylation,
47
where oxygen serves as the terminal electron acceptor
Aerobic respiration
48
How does anaerobic respiration differ from aerobic respiration in bacteria?
Anaerobic respiration uses final electron acceptors other than oxygen in the electron transport chain
49
Q: What is the purpose of biosynthesis in bacterial metabolism?
uses precursor products from metabolic pathways to produce a variety of building blocks such as amino acids, fatty acids, sugars, and nucleotides.
50
Q: What are some key building blocks produced during bacterial biosynthesis?
amino acids, fatty acids, sugars, and nucleotides.
51
involves assembling building blocks into macromolecules such as lipids, lipopolysaccharides, polysaccharides, proteins, and nucleic acids.
Polymerization and Assembly
52
Q: What types of macromolecules are formed during polymerization in bacteria?
lipids, lipopolysaccharides, polysaccharides, proteins, and nucleic acids.
53
Q: What drives the synthesis of macromolecules in bacterial cells?
is driven by energy and enzymatic activity within the cell, facilitating the assembly of complex structures.
54
What type of organisms are bacteria classified as?
single-cell prokaryotic microorganisms.
55
How do fungi and parasites differ from bacteria in terms of cellular structure?
Fungi and parasites can be either single-cell or multicellular eukaryotic organisms, unlike bacteria, which are single-cell prokaryotes.
56
dependent on host cells, infectious organisms, not considered cellular organisms
Viruses
57
abnormal infectious proteins, not considered living cells
Prions
58
What is the shape of cocci bacteria?
Circular
59
What is the shape of coccobacilli bacteria?
ovoid
60
Q: What is the characteristic shape of bacilli bacteria?
rod shaped
61
Q: Describe the shape of fusiform bacteria.
have a pointed end, resembling a spindle shape.
62
What are the Bacterial morphology
* Cocci: circular
* Coccobacilli: ovoid
* Bacilli: rod shaped
* Fusiform: pointed end
* Curved
* Spiral
63
Q: What color do Gram-positive bacteria stain, and why?
Gram-positive bacteria stain deep blue or purple due to their thick peptidoglycan layer that retains the crystal violet stain.
64
What color do Gram-negative bacteria stain, and why?
Gram-negative bacteria stain pink to red because their thinner peptidoglycan layer does not retain the crystal violet stain, but they take up the counterstain (safranin).
65
Q: Who developed the Gram stain technique?
Hans Christian Gram
66
What is the primary purpose of the Gram stain in microbiology?
used for the rapid presumptive identification of microorganisms and provides important clues related to the quality of the specimen.
67
How do Gram-positive bacteria react to the Gram stain?
Gram-positive bacteria retain the basic dye (crystal violet), appearing deep blue or purple.
68
Why do Gram-negative bacteria not retain the crystal violet dye?
Gram-negative bacteria allow the crystal violet to wash out easily with the decolorizer alcohol (acetone)
69
What type of stain is the Gram stain considered, and why?
The Gram stain is considered a differential stain because it differentiates between Gram-positive and Gram-negative bacteria based on their cell wall structure and staining properties.
70
Identify: Gram negative or Gram positive
Outer lipid bilayer (dehydrated during decolorization)
Gram negative
71
Identify: Gram negative or Gram positive
Thick peptidoglycan layer
Gram positive
72
Identify: Gram negative or Gram positive
Numerous teichoic acid cross-linkages
Gram positive
73
Identify: Gram negative or Gram positive
Thinner peptidoglycan layer
Gram negative
74
are specifically designed for a subset of bacteria whose cell walls contain long-chain fatty acids (mycolic acid), making them resistant to decolorization even with acid alcohol decolorizers.
Acid-fast stains
75
How does acid-fast staining work as a differential stain?
Acid-fast staining differentiates bacteria based on their ability to retain the primary stain even after exposure to acid alcohol decolorizers, distinguishing acid-fast positive bacilli from acid-fast negative bacilli
76
Which bacteria are most commonly identified using acid-fast stains?
Mycobacteria
77
How are bacterial cell components generally divided?
Bacterial cell components are divided into the outer cell structure (cell envelope and its appendages) and the cell's interior.
78
What is the primary structural component of the cell wall in bacteria?
peptidoglycan macromolecules, also known as the murein layer.
79
Where periplasm usually found?
Gram-negative bacteria
80
Which type of bacteria has an outer membrane
Gram-negative bacteria
81
encloses the cytoplasm
cytoplasmic or cell membrane
82
What is the structural composition of the outer membrane in Gram-negative bacteria?
bilayer structure composed of lipopolysaccharides and proteins
83
protein structures that form water-filled channels, allowing controlled passage of nutrients and solutes, such as antibiotics, through the outer membrane.
Porins
84
Essential enzymes and proteins are located in the periplasmic space?
T or F
T
85
facilitate the attachment of the outer membrane to the peptidoglycan layer, serving as adhesins for host cell attachment or acting as transporters.
Murein lipoproteins
86
What is the main structural component of the bacterial cell wall?
peptidoglycan or murein layer.
87
What is the composition of the peptidoglycan layer in the bacterial cell wall?
composed of disaccharide-pentapeptide units, specifically N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM).
88
Is cell wall thicker in gram-positive bacteria?
T or F
T
89
What are teichoic acids composed of?
composed of glycerol or ribitol phosphate polymers combined with various sugars, amino acids, and amino sugars.
90
In which type of bacteria are teichoic acids primarily found?
found in Gram-positive bacteria.
91
What is the difference between teichoic acids and lipoteichoic acids in terms of their linkage?
Teichoic acids are sometimes linked to N-acetylmuramic acid in the cell wall, while lipoteichoic acids are linked to the underlying cellular or cytoplasmic membrane.
92
What type of bacteria primarily contains mycolic acids?
Mycobacteria
93
What are mycolic acids and where does it located
waxy substances within the murein layer
94
95
How do mycolic acids affect the bacterial cell wall of mycobacteria?
Mycolic acids make the cell wall more refractory to toxic substances
96
Where is the periplasmic space typically found in bacteria?
gram-negative bacteria
97
The periplasmic space is bounded by?
the internal surface of the outer membrane and the external surface of the cellular membrane.
98
The periplasmic space contains?
murein layer
99
What type of substances are found in the periplasmic space?
consists of gel-like substances that assist in the capture of nutrients from the environment.
100
What enzymes are present in the periplasmic space, and what is their function?
contains enzymes involved in the degradation of macromolecules and the detoxification of environmental solutes such as antibiotics.
101
In which types of bacteria is the cytoplasmic (inner) membrane found?
The cytoplasmic (inner) membrane is present in both gram-negative and gram-positive bacteria.
101
Where does cytoplasmic (inner) membrane located?
deepest layer of the cell envelope
102
the cytoplasmic membrane is heavily laced with
various proteins and enzymes that are vital to cellular metabolism.
103
what additional function does the cytoplasmic (inner) membrane serve?
osmotic barrier
104
Where is the capsule located in gram-positive and gram-negative bacteria?
In gram-positive bacteria
105
What is the primary composition of bacterial capsules?
composed of high molecular weight polysaccharides.
106
What is the primary function of the capsule regarding the immune system?
The capsule protects bacteria from attack by components of the human immune system
107
The capsule facilitates and maintains bacterial colonization on?
biologic and inanimate surfaces
108
What are fimbriae or pili made of?
are hairlike, proteinaceous structures.
109
Where do fimbriae or pili extend from and to?
They extend from the cell membrane into the external environment.
110
What is the specific function of the sex pilus in E. coli?
serves as a conduit for the passage of DNA during conjugation
110
What is the primary function of fimbriae or pili in bacteria?
serve as adhesins to help bacteria attach to animal host cell surfaces.
111
composed of flagellin and are responsible for bacterial motility
Flagella
112
single flagellum is present at one end of the bacterium.
Monotrichous
113
flagella at both ends of the bacterium.
Lophotrichous
114
flagella cover the entire surface of the bacterial cell.
Peritrichous
114
What gives the cytosol its granular appearance?
due to polysomes and inclusions (storage or reserve granules).
115
single flagellum located at both ends of the bacterial cell.
Amphitrichous
115
is the fluid component of the cell interior where nearly all cellular functions, except those conducted by the cell membrane, occur. It contains enzymes and is the site of protein synthesis.
Cytosol
116
What is the storage form of glucose in bacterial cells?
Glycogen
117
function of polyphosphate granules in bacteria?
storage form of inorganic phosphates.
118
highly coiled DNA intermixed with RNA, polyamines, and various proteins
Nucleoid
119
Other genetic element that exist independently in the cytosol
Plasmids
120
are highly resistant structures formed by some bacteria to survive extreme environmental conditions, such as heat, chemical exposure and etc
Endospores
