INTRO TO BACTERIOLOGY Flashcards
Bacteria are __karyotes
pro
Bacteria cells possess nuclei and organelles
T/F
F
They lack them
Bacteria range in size from about ___ to __ μm
0.2
5
Plasma membrane of prokaryotes contain sterols
T/F
Mention exceptions
F
Except mycoplasma species
Absence of nuclear membrane in prokaryotes
T/F
T
Genome of prokaryotes
Single or double
Linear or circular
Single
Circular
Prokaryotes have organelles
T/F
T
Just not membrane bound organelles
Ribosomes of prokaryotes and eukaryotes?
Pro- 70S (50+30)
Euk-80S (60+40)
Cell division of prokaryotes is by??
Binary fission
Bacteria are classified by shape into three basic groups:
*___
*_____
*___
Cocci
Bacilli
Spirochetes
Cocci (____)
Bacilli (___)
Spirochetes (_____)
round
rods
spiral-shaped
In addition to their characteristic shapes, the arrangement of bacteria is important.For example, certain cocci occur
* in pairs ( _______)
*some in chains(_______)
*some in grapelike clusters (_____)
diplococci
streptococci
staphylococci
Example of a rod shaped bacteria
Escherichia coli
3 Examples of a snake like shaped bacteria
Treponema
Borrelia
Leptospiral
Examples of a diplococci
Neisseria, moraxella
Example of a coccobacillus
Bordetella pertussis
-The bacterial “______” is a term applied to all material external to and enclosing the cytoplasm.
CELL ENVELOPE
CELL ENVELOPE
-It consists of several chemically and functionally distinct layers, the most prominent of which are the:
*_____
*______
*______
*______
Cell wall
Cytoplasmic membrane.
Capsule
Glycocalyx
CYTOPLASMIC MEMBRANE
-The cell membrane is composed of ______, the molecules of which form two parallel surfaces (called a lipid bilayer)
-The _____ groups are on the outside of the bilayer and the ______ are on the inside.
phospholipids
polar phosphate
nonpolar lipid chains
CELL WALL
-The cell wall is located (internal or external?) to the cytoplasmic membrane and is composed of _____.
External
peptidoglycan
The cell wall acts as a barrier, and protects cell contents from the external environment
T/F
T
The cell wall
Maintains cell osmotic pressure in a hypotonic environment
T/F
T
The cell wall Contributes to sensitivity to certain antimicrobial agents (penicillin) and the immune system (antibodies, phagocytes)
T/F
T
The cell wall doesn’t Determines reactivity to Gram stain
T/F
F
PEPTIDOGLYCAN
- is a complex, interwoven network that surrounds the entire cell and is composed of a single covalently linked macromolecule
T/F
-
T
PEPTIDOGLYCAN
-The basic structure consists of ______ chains with _______ or longer side chains that are cross-linked through ___ bonds.
polysaccharide (glycan)
tetrapeptide
peptide
PEPTIDOGLYCAN
The glycan chains are linear polymers of a repeating __saccharide composed of __________ and _______
di
N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM).
__________ , present in human tears and mucous secretions, cleaves glycan chains.
Lysozyme
GRAM POSITIVE CELL WALL
-Gram-positive bacteria have (thin or thick?), (single or multi?)layered, peptidoglycan cell walls that are (interior or exterior?) to the cytoplasmic membrane.
Thick
Multi
exterior
_____ and ____ acids associated with peptidoglycan are antigenic (strain differences) and may promote _______
Teichoic and lipoteichoic
adhesion to host tissue.
GRAM NEGATIVE CELL WALL
-Gram-negative bacteria have a (less or more?) complex cell wall structure composed of ___ membranes Which are separated by the _________ , which contains the (thin or thick?) peptidoglycan layer.
More
two
periplasmic space
Thin
The periplasmic space also contains ______ and ______
degradative enzymes and transport proteins.
The outer membrane of a gram negative bacteria lacks porins
T/F
F
It has it
-The outer membrane of a gram negative bacteria contains porins which allow passage of (small or?) _______ molecules.
-The outer membrane is distinguished by the presence of embedded ______
Small
hydrophilic
lipopolysaccharide (LPS)
LPS Consists of _______ and ____
antigenic o-polysaccharide and lipid A (endotoxin)
LPS also protects the cell from phagocytosis, penicillins and the antibacterial enzyme lysozyme T/F
T
GRAM STAIN PROCEDURE
Go!!!
Pour crystal violet (60 secs)
-Wash off with water and flood with iodine (60 secs)
-Wash off with water and decolorise with 95% alcohol
-Counterstain with safranin (60 secs) and wash off with water
Answer with present or absent
Gram positive vs gram negative
Outer membrane
LPS
Techoic acids
Capsule
Absent; present
Absent; present
Present in many; absent
Present in many; present in many
Who is more resistant to lysosomes and antibiotic permeability
Gram positive or negative
Negative
Which undergoes sporulation
Gram positive or negative
Positive
Which has exotoxin
Gram positive or negative
Both
CELL WALLS OF Acid-fast bacilli
-Mycobacteria (e.g._______) have an unusual cell wall, resulting in their inability to be Gram-stained.
-These bacteria are said to be acid-fast because ________
-This property is related to the high concentration of ___, called ______, in the cell wall of mycobacteria
Mycobacterium tuberculosis
they resist decolorization with acid–alcohol after being stained with carbolfuchsin
lipids
mycolic acids
FLAGELLA
-Flagella are polymers of ____ ( ____ )
proteins
flagellin
Flagella are strongly antigenic.
T/F
T
The flagella may be
*polar (single cell, ____)
*lophotrichous (a _____)
*amphitrichous: _________
*peritrichous (_______).
Restricted to the pole
tuft at one pole
one or more flagella at both ends of the cell
distributed over the cell surface
Capsules can be a source of nutrients and energy to microbes.
T/F
T
Capsule
Is gelatinous
T/F
T
Capsular polysaccharides are used as the antigens in certain vaccines because ________
they are capable of eliciting protective antibodies.
Streptococcus mutans, which colonizes ___, ferments the ___ in the _____ and the acid byproducts contribute to _____
teeth
sugar
Capsule
tooth decay.
Capsule Prevents cell from drying out
T/F
T
GLYCOCALYX
-aka the _____
-is a loosely bound, (amorphous or crystalline?) polysaccharide coating that is secreted by many bacteria.
slime layer
amorphous
Glycocalyx prevents the bacteria from adhering firmly to various structures (e.g., skin, heart valves, prosthetic joints, and catheters)
T/F
F
It allows it
The ____ is an important component of biofilms
glycocalyx
NUCLEOID
-Bacterial cells contain a (single or double?) chromosome composed of a (linear or circular?) DNA molecule.
Single
Circular
NUCLEOID
is not membrane bound.
T/F
T
Plasmids, which are (small or large?) , (linear or circular?) fragments of (intra or extra?) chromosomal DNA,may be present and often carry _________ genes
Small
Circular
Extra
antibiotic resistance
PLASMIDS
-(Small or large?) extrachromosomal DNA circles.
Small
Plasmids replicate dependently of the chromosome
T/F
F
Plasmids replicate independently of the chromosome
Plasmids
They carry genes that are essential for cell survival
T/F
F
Not essential
Plasmids carry genes that may give some advantage to an organism e.g they can carry genes for _______ and _____
antibiotic resistance and toxin production.
PILI
-(Short or long?) , ___-like appendages composed of protein subunits (___) and anchored in ______ of some bacteria (mostly gram ___).
Short
hair
pilins
plasma membrane
negative
Types of PILLI
______(____) pili
___ pili (____ pili)
Common; somatic
F; sex
Common (somatic) pili
_Promote ______, especially ____ cells
*F pili (sex pili)
_Promote _______
_Are encoded by a _____ (_____)
adherence of bacteria to host cells
mucosa
transfer of DNA from one bacterium to another through conjugation
Plasmid
F factor
Pili Help to prevent phagocytosis
T/F
T
Somatic pili Are a virulence factor for _______
Neisseria gonorrhoeae
RIBOSOMES
-Antibiotics inhibit protein synthesis at the subunits
-50s subunit – – e g _______,____,_____
-30s subunit — e g ____, ____
chloramphenicol
Clindamycin
macrolides
tetracyclines
aminoglycosides
β-Lactamases are an important cause of antibiotic resistance.
T/F
T
the most common site where β-lactamases are located is _____
Within the periplasmic space
the _____ of a bacteria exhibits the most antigenic
variation
Capsule
List 5 bacteria things that are antigenic and
____,___,____ also protects the cell from phagocytosis
Teichoic and lipoteichoic acids , LPS, flagella , capsule
Cell wall, LPS , pilli
OXYGEN DEPENDENCE
-Molecular O2 forms radicals lethal to them, some are armed with enzymes that break them down. (____ and ____)
-Based on this, they may be classified into a spectrum
-_____
-_____
-_____
-_____
Catalase and Superoxide dismutase
Obligate aerobes
-Facultative anaerobes
-Microaerophilic
-Obligate anaerobes
Other bases for characterizing bacteria
Colony shape or characteristics in culture
———-(α, β, non)
_________
Haemolytic patterns
Pigmentation
Other bases for characterizing bacteria
Biochemical reactions to ascertain presence of metabolic activity like
_________ of lactose or glucose (______ and ______ bacilli)
Motility (e.g ________)
Fermentation
fermentative & non-fermentative
Hanging drop
Identification of bacteria
1)Culture
2) Microscopy
Stains – e.g Gram stain
_____ - ____ or _____
3)Serology
________, _________, _______ etc
4)DNA based techniques e.g ___
Wet prep
phase contrast or dark-field microscopy
Agglutination, CFT, fluorescent antibody test
PCR
Nocardia
Gram positive or negative?
Positive but,
Weakly acid fast
CFT?
Compliment fixation test
PCR?
Polymerase chain reaction
Peptidoglycan aka ______ aka_____
Murein
Mucopeptide
Lysozymes in tears can lyse the ______ in bacteria
glycan chains
_________: only in gram+. Cell membrane +nucleic material
_______: only in gram-. Outer membrane + inner + nucleuc material
Protoplast
Spheroplast
B-lactams include ______, _______
penicillin
cephalosporins
