Bacterial Structure, Function, and Growth

Question 1

Bacterial Cell Wall Types

Answer 1

Gram Negative and Gram Postive

Question 2

Outer Membrane

Answer 2

Bilayer membrane

Question 3

Nucleoid

Answer 3

Where the bacterial DNA resides, specialized area that isn’t surroudned by a membrane

Question 4

Gram Negative Bacteria

Answer 4

Smaller peptidoglycan wall, space between outer and inner membrane, fewer crosslinking between peptidoglycan strands, has LPS (lipopolysaccharide)

Question 5

Flagellum

Answer 5

Structure used for motility

Question 6

Gram Positive

Answer 6

Extensive peptidoglycan network, lysine crosslinking (oligosaccharide bridges), larger cell wall, has teichoic acid (lipoteichoic acid is lipid modified teichoic acid)

Question 7

Lipopolysaccharide (LPS)

Answer 7

LPS, three portions, lipid A (endotoxin, fatty acids and hydrophobic), core polysaccharide (highly conserved in gram - bacteria), O antigen/somatic antigen (repeating unit, 4-20 repeats)

Question 8

Teichoic Acids

Answer 8

Part of gram + bacterialRibitol teichoic acids- ribitol is the repeating unit

Glycerol teichoic acids- glyerol is the repeating subunit

The repeating chain is linked by phosphate

Can be modified on their side chains and can be antigenic

Recognized as molecular patterns for TLRs

Question 9

Capsules

Answer 9

Made by polysaccharides, gelatenous, resistant to phagocytosis

Rarely, can be repeating amino acids, or d-glutinanic acids (anthrax bacterium)

Question 10

Flagellae

Answer 10

Organs of motility,

single/multiple

Unipolar/bipolar

Can tumble

Question 11

Pili/Fimbriae

Answer 11

Small portrusions on the surface of bacteria, can interact to form biofilms

Can also have sexual pili, initiated by a receptor protein which helps form a conjugation bridge

Question 12

Cell Membrane

Answer 12

generates electormotive force for ATP, has a plasma membrane ATP-ase, selective permeability, involved cell division, lipid biosynthesis

Question 13

Bacterial DNA

Answer 13

ciruclar, single stranded, not surrounded by a membrane

Polysome- multiple bound ribosomes

Translation and transcription coupled

Polycistronic- DNA can code multiple genes

Question 14

Plasmid

Answer 14

Small circular units of DNA that can confer survival benefits to bacteria (drug resistance, fitness advantages)

Can be transferred with conjugation

Question 15

Phage Conversion

Answer 15

When a given bacteria is infected with a bacteriophage and get incorporated DNA that confers a new phenotype

Question 16

Bacterial Growth Curve

Answer 16

Lag Phase- The bacterium are still trying to establish growth, adapting to their environment

Growth phase- linear on a log graph, exponentlal growth

Stationary phase- resources are starting to become limited, and toxic metabolites accumulate, growth starts to slow

Death phase- number of viable bacteria decrease over time

Question 17

Aerobic Baceria

Answer 17

need oxygen

They make catalases that can break down toxic oxygen free radicals

Question 18

Anaerobe

Answer 18

Grow by fermentative metabolism, (if obligate, oxygen can kill)

Question 19

Indifference

Answer 19

Ferments regardless of presence of oxygen

Question 20

Facultative

Answer 20

Can do either, aerobic or anaerobic

Question 21

Microaerophilic

Answer 21

Grow best at low oxygen, can grow without oxygen

Question 22

Energy currency

Answer 22

ATP- made by membrane ATPase

Proton Motive Force

Bacterial also have reducing power with NADH and NADPH

Question 23

Fermentation

Answer 23

Catabolic process in which a bacteria uses organic compound as both electon donor and receptor

Question 24

Respiration

Answer 24

Oxygen is terminal electron receptor, but sometimes other molecuels can be the final receptor (nitrate, some amino acids like arginine, but that’s anaerobic respiration)

Question 25

Sporulation

Answer 25

The formation of spores is the bacterial response to adverse conditionsCell divsion occurs but is assymetric, leaving a mother cell and a sporeDense outer coat, very dehydrated and metabolically inactive, vegtative stateReenters growth cycle via "germination"

Question 26

Explain why unique bacterial components are important as potential targets for antimicrobial therapy.

Answer 26

There are several structures that are unique to prokaryotes and not eukaryotes, so targeted drug therapies agaisnt this structures will hopefully not have a lot of side effects

Question 27

Answer 27

Coccus

Question 28

Answer 28

Bacillus

Question 29

Answer 29

Coccobacillus

Question 30

Answer 30

Fusiform Bacillus

Question 31

Answer 31

Vibrio

Question 32

Answer 32

Spirillum

Question 33

Answer 33

Spirochete

Question 34

Heterotrophic

Answer 34

The Bacteria require an enternal organic carbon source

Question 35

Autotrophic

Answer 35

Bacteria that can generate carbon from CO₂

Question 36

Cell Wall Inhibition

Answer 36

B-lactams Vancomycin Cycloserine

Question 37

Outer and cytoplasmic membrane active antimicrobials

Answer 37

Polymyxins

Question 38

Inhibitors of protein synthesis at the ribosomal leve

Answer 38

Tetracyclines Aminoglyosides Macrolides Chloramphenicols

Question 39

Inhibitors of nucleic acid synthesis

Answer 39

Quinolones Rifampicin

Question 40

Metabolic inhibitory antimicrobials

Answer 40

Sulfonamides Trimethoprim Isoniazid Metronidazole

Question 41

β-lactams

Answer 41

penicillins, cepalosporins, etc) inhibit the final transpeptidation reaction in cross-linking of peptidoglycan.

Question 42

Vancomycin

Answer 42

Inhibits elongation of the peptidoglycan chain

Question 43

Cycloserine

Answer 43

Prevents formation of muramyl pentapeptide, an earlyt intermediate in peptidoglycan synthesis

Question 44

Polymyxins

Answer 44

Cationic Disrupts bacterial outer membrane and cytoplasmic membrane

Question 45

Aminoglycosdies

Answer 45

Binds to 30S r subunit, inhibiting it

Question 46

Tetracyclins

Answer 46

Reversibly binds to 30S subunite, and inhibits tRNA binding

Question 47

Chloramphenicol

Answer 47

Reversibly binds 50S, inhibiting peptidyl transferase and bond formation

Question 48

Macrolides (like erythromycin) and lincomycins

Answer 48

bind to 23S rRNA of 50S and inhibits peptidyle transferase

Question 49

Quinolones

Answer 49

Inhibit DNA gyrase and topoisomerase

Question 50

Rifampicin

Answer 50

Inhibits RNA polymerase

Question 51

Sulfonamides

Answer 51

Inhibit formation of folic acid via competitive inhibition

Question 52

Trimethoprim

Answer 52

Inhibits dihydrofoalte reductase in folate metabolism

Question 53

Isoniazid

Answer 53

Inhibits lipid synthesis

Question 54

Metronidazole

Answer 54

Intereferes with anaerobic metabolism