INTRO TO BACTERIOLOGY Flashcards by Iseoluwa Ojo

Bacteria are __karyotes

pro

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Bacteria cells possess nuclei and organelles

T/F

They lack them

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Bacteria range in size from about ___ to __ μm

0.2

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Plasma membrane of prokaryotes contain sterols

T/F

Mention exceptions

Except mycoplasma species

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Absence of nuclear membrane in prokaryotes

T/F

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Genome of prokaryotes

Single or double
Linear or circular

Single

Circular

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Prokaryotes have organelles

T/F

Just not membrane bound organelles

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Ribosomes of prokaryotes and eukaryotes?

Pro- 70S (50+30)

Euk-80S (60+40)

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Cell division of prokaryotes is by??

Binary fission

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Bacteria are classified by shape into three basic groups:

*___
*_____
*___

Cocci

Bacilli

Spirochetes

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Cocci (____)

Bacilli (___)

Spirochetes (_____)

round

rods

spiral-shaped

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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

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Example of a rod shaped bacteria

Escherichia coli

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3 Examples of a snake like shaped bacteria

Treponema
Borrelia
Leptospiral

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Examples of a diplococci

Neisseria, moraxella

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Example of a coccobacillus

Bordetella pertussis

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-The bacterial “______” is a term applied to all material external to and enclosing the cytoplasm.

CELL ENVELOPE

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CELL ENVELOPE

-It consists of several chemically and functionally distinct layers, the most prominent of which are the:
*_____
*______
*______
*______

Cell wall

Cytoplasmic membrane.

Capsule

Glycocalyx

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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

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CELL WALL
-The cell wall is located (internal or external?) to the cytoplasmic membrane and is composed of _____.

External

peptidoglycan

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The cell wall acts as a barrier, and protects cell contents from the external environment

T/F

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The cell wall

Maintains cell osmotic pressure in a hypotonic environment

T/F

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The cell wall Contributes to sensitivity to certain antimicrobial agents (penicillin) and the immune system (antibodies, phagocytes)

T/F

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The cell wall doesn’t Determines reactivity to Gram stain
T/F

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PEPTIDOGLYCAN - is a complex, interwoven network that surrounds the entire cell and is composed of a single covalently linked macromolecule T/F -

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

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

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

Capsule Is gelatinous T/F

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

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

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

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

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