Chapter 1.1 Bacterial Taxonomy

Question 1

What color does a gram-positive organism stain?

Answer 1

Blue

Question 2

What color does a gram-negative organism stain?

Answer 2

Red

Question 3

What is the peptidoglycan layer?

Answer 3

Cell wall that is outside the bacterial cytoplasmic membrane

Question 4

What organisms is the peptidoglycan layer present?

Answer 4

Gram-positive and gram-negative

Question 5

What is the function of transpeptidase?

Answer 5

An enzyme that catalyzes the formation of the links of amino acids of peptidoglycan

Question 6

What are the characteristics of the gram-positive cell wall?

Answer 6

Very thick and have extensive cross linking of amino acid side chains

Question 7

What are the characteristics of a gram-negative cell wall?

Answer 7

Very thin with simple cross-linking pattern

Question 8

What important polysaccharide is present in gram-positive cell walls?

Answer 8

Teichoic acid

*teichoic acid is not present in gram-negative cell walls

Question 9

What lipoprotein is present in gram-negative cell walls?

Answer 9

Murein lipoprotein

Question 10

What does the outermost portion of the bilayer contain in gram-negative organisms?

Answer 10

Lipopolysaccharide (LPS)

Question 11

What are the components of LPS?

Answer 11

Outer carbohydrate of oligosaccharides, center part called core polysaccharide, and interior to the core is lipid component

Question 12

What is lipid A?

Answer 12

The gram-negative endotoxin that is toxic to humans

Question 13

What manifestations occur when lipid A is released into the circulation from lysis of bacterial gram-negative cells?

Answer 13

Fever, diarrhea, possible fatal endotoxin shock (septic shock)

Question 14

What allows for passage of nutrients in only gram-negative cells?

Answer 14

Porin proteins

Question 15

What is the importance of the structure of gram-positive cells vs gram-negative cells?

Answer 15

The thick peptidoglycan of a gram-positive cell does not block diffusion of low molecular weight compounds allowing substances that damage the cytoplasmic membrane to pass through (antibiotics, dyes, and detergents).
The gram-negative LPS blocks the passage of these substances.

Question 16

Can antibiotics and chemicals attack gram-negative bacteria?

Answer 16

No, because the LPS is blocking access to the peptidoglycan later

Question 17

Examples of chemicals that can attack the peptidoglycan layer?

Answer 17

Penicillin and lysosomes

Question 18

What are the 4 major shapes of bacteria?

Answer 18

Cocci, bacilli, spiral forms, and pleomorphic

Question 19

What is the shape of cocci bacteria?

Answer 19

Spherical

Question 20

What is the shape of bacilli bacteria?

Answer 20

Rod shaped

Question 21

What are short bacilli called?

Answer 21

Cocobacilli

Question 22

What is the shape of spiral formed bacteria?

Answer 22

Comma-shaped, S-shaped, or spiral-shaped

Question 23

What is the shape of pleomorphic bacteria?

Answer 23

Lack a distinct shape (like jello)

Question 24

What are diplococci?

Answer 24

Pairs of different shapes that organize together into a more complex pattern

Question 25

What are the shapes of the 6 classic gram-positive cells?

Answer 25

2 cocci and 4 bacilli

Question 26

What are the 2 gram-positive cocci?

Answer 26

Streptococcus- form strips of cocci Staphylococcus- form clusters of cocci *both have cocci in the name

Question 27

What are the 2 spore forming gram-positive bacilli?

Answer 27

Bacillus | Clostridium

Question 28

What does spore mean?

Answer 28

Spheres that protect a dormant bacterium from the harsh environment

Question 29

What 2 gram-positive bacilli do not form spores?

Answer 29

Corynebacterium | Listeria

Question 30

What is unique about Listeria?

Answer 30

It's the only gram-positive organism that has endotoxin

Question 31

What is the only gram-negative cocci?

Answer 31

Neisseria which is a diplococcus

Question 32

What is the 1 group of spiral-shaped organisms?

Answer 32

Spirochetes

Question 33

What is the syphillis causing spirochete?

Answer 33

Treponema pallidum

Question 34

What are the 2 shapes of all gram-negative organisms other than Spirochetes?

Answer 34

Rods or pleomorphic

Question 35

What organisms are exceptions to bacterial morphology?

Answer 35

Mycobacteria, Spirochetes, and Mycoplasma

Question 36

What is the morphology of mycobateria?

Answer 36

Weakly gram-positive but stain with a special acid-fast stain Includes tuberculosis and leprosy organisms

Question 37

What is the morphology of Spirochetes?

Answer 37

Gram-negative cell wall but are too small to be seen with a microscope so have to use darkfield microscope

Question 38

What is the morphology of mycoplasma?

Answer 38

Do not have a cell wall Only have a simple cell membrane They are neither gram-positive or gram-negative

Question 39

What are the 3 enzymes that some bacteria have to breakdown oxygen products?

Answer 39

Catalase, Peroxidase, and Superoxide dismutase

Question 40

What is the function of catalase?

Answer 40

Breaks down hydrogen peroxide

Question 41

What is an obligate aerobe?

Answer 41

Bacteria that use glycolysis, the Krebs TCA cycle, and the electron transport chain with oxygen as the final electron acceptor

Question 42

What are facultative anaerobes?

Answer 42

Aerobic bacteria that use oxygen as electron transfer chain but they can grow in the absence of oxygen using fermentation for energy *faculty to be anaerobic but prefer aerobic conditions

Question 43

What are aero-tolerant anaerobe (microaerophilic) bacteria?

Answer 43

Bacteria that use fermentation and have no electron transport system but can tolerate low amounts of oxygen

Question 44

What are obligate anaerobes?

Answer 44

Bacteria that have no enzymes to defend against oxygen | Can't survive with oxygen

Question 45

What do all medically important bacteria use for energy?

Answer 45

Chemical and organic compounds such as glucose | *called chemoheterotrophs

Question 46

What is the most common fermentation pathway?

Answer 46

Embden-Meyerhof pathway

Question 47

What happens in the Embden-Meyerhof pathway?

Answer 47

Glucose breakdown into lactic acid, ethanol, propionic acid, butyric acid, and acetone for bacteria to use for oxygen metabolism

Question 48

How do obligate intracellular organisms obtain ATP?

Answer 48

Stealing from their host because they are not capable of metabolic pathways for ATP synthesis