Mci 2: Gram Negative Bacteria

Front 1

What are the two differences between gram negative and gram positive bacteria?

Back 1

Thinner peptidoglycan than gram positive.
Surrounded by an outer membrane.

Front 2

What is the outer leaflet of the outer membrane made of?

Back 2

Lipopolysaccharide

Front 3

What three components is lipopolysaccharide composed of? In to out.

Back 3

Lipid A
Core Polysaccharide
O-Polysaccharide

Front 4

What is Lipid A?

Back 4

4 to 6 3-hydroxy-fatty acids attached to dimer of glucosamine phosphate.

Front 5

What is the Core Polysaccharide?

Back 5

A fairly conserved linker. 8, 7 and 6-carbon sugars.

Front 6

What is the O-Polysaccharide? Is it strain specific?

Back 6

4 to 5 sugars repeated 10 to 20 times. Highly strain specific (somatic antigen).

Front 7

What typical disease-related symptom does LPS cause? What component causes this?

Back 7

Causes fever, caused by Lipid A.

Front 8

What holds the outer membrane to the thin peptidoglycan layer (and thus to the cell)?

Back 8

Lipoproteins

Front 9

What are the layers of of the cell membrane/wall for gram positive bacteria? In to out.

Back 9

Plasma membrane
Peptidoglycan
Teichoic Acid

Front 10

What is the function of teichoic acid?

Back 10

Improve the rigidity of the cell wall by attracting cations such as magnesium and sodium.

Front 11

What are the layers of of the cell membrane/wall for gram negative bacteria? In to out.

Back 11

Plasma Membrane
Peptidoglycan
(Lipoprotein connecting)
Outer Membrane
Lipopolysaccharide

Front 12

What is the peptidoglycan arrangement in gram negative rods? What is the orientation of the peptide cross links?

Back 12

Polysaccharide chains wrapped around circumference of the cell. Peptide cross links are parallel to cell axis.

Front 13

What is the peptidoglycan arrangement in gram positive rods?

Back 13

Wound in cables that wrap around the cell.

Front 14

What are the consequences of the lipopolysaccharide layer?

Back 14

Hydrophilic O Polysaccharide repels hydrophobic molecules that would otherwise penetrate the cell membrane.

Front 15

How can small hydrophilic molecules enter the cell?

Back 15

Can freely enter through porins.

Front 16

Enterobacteriaceae have what reaction to oxygen and what shape are they?

Back 16

Facultatively anaerobic
Gram negative rods

Front 17

Enterobacteriaceae have what type of flagella, what type of reaction to the oxidase test? Where are they found?

Back 17

Petritrichous flagella
Negative oxidase test
Found in soil and intestines

Front 18

What are the two ways Enterobacteriaceae can create energy?

Back 18

Respire with oxygen, nitrate or fumarate
Ferment sugars to butanediol or mixed acids

Front 19

What is a famous example of a gram negative rod in the Enterobacteriaceae family?

Back 19

E. Coli

Front 20

Genus Pseudomonas has what reaction to oxygen and what cell shape?

Back 20

Reaction to Oxygen: Aerobic
Shape: Gram negative rods

Front 21

Genus Pseudomonas have what type of flagellum, what is their result in the oxidase test and where are they common?

Back 21

Polar flagellum
Oxidase positive
Common in soil and water

Front 22

What are some functions of pseudomonas?

Back 22

Plant pathogens
Plant growth promoters
Degraders of toxic chemicals

Front 23

Bacteroids have what reaction to oxygen? How do they create energy.

Back 23

Die. (Anaerobic)
Fermentative

Front 24

What is the major permeability barrier?

Back 24

Cytoplasmic membrane

Front 25

Is peptidoglycan a barrier to small molecules?

Back 25

No

Front 26

What kind of resistance does the outer membrane present?

Back 26

Repels hydrophobic molecules but allows small hydrophilic molecules to enter via porins.

Front 27

What is passive transport?

Back 27

Movement of molecules down their concentration gradient, so no energy is needed to transport the molecule.

Front 28

What is active transport?

Back 28

Movement of molecules against their concentration gradient, so ATP or a proton gradient is needed to transport the molecule.

Front 29

What are the two types of passive transport?

Back 29

Simple diffusion
Facilitated diffusion

Front 30

What is simple diffusion? What molecules can do this?

Back 30

Molecule passes through membrane
Small hydrophobic molecules do this.

Front 31

What is facilitated diffusion? What molecules can do this?

Back 31

Hydrophobic channels require channels or carriers to be transported across the membrane.

Front 32

What is an example of facilitated diffusion channel protein in E. Coli?

Back 32

GlpF glycerol transporter

Front 33

Does facilitated diffusion heavy rely on high external concentration?

Back 33

Yes.

Front 34

What is the first example in the lectures of active transport?

Back 34

Proton Symport

Front 35

How is proton symport carried out?

Back 35

Substrate brought into cell by entering with a proton.

Front 36

How is proton symport driven?

Back 36

Transmembrane proton gradient.

Front 37

Do both the proton and substrate enter in the same direction with symport?

Back 37

Yes.

Front 38

What is an example of symport in E. Coli?

Back 38

LacY (Lactose Permease)

Front 39

What is the first example in the lectures of active transport?

Back 39

ATP Hydrolysis

Front 40

How is ATP hydrolysis carried out? What drives transport.

Back 40

With ABC transporters (ATP-Binding Cassettes)
Hydrolysis of ATP.

Front 41

What is the ABC Transporter often associated with in gram negative bacteria?

Back 41

Periplasmic substrate-binding protein.

Front 42

What is an example of an ABC Transporter associating with a periplasmic substrate-binding protein in gram negative bacteria?

Back 42

MalFGK, or the maltose transporter & periplasmic maltose-binding protein MalE.

Front 43

What is the third example in the lectures of active transport?

Back 43

Group Translocation

Front 44

What happens to the substrate during Group Translocation?

Back 44

The substrate is modified, typically phosphorylated.

Front 45

What is an example of Group Translocation in bacteria?

Back 45

The Phosphotransferase System

Front 46

What is the imported glucose changed into in the phosphotransferase system?

Back 46

Glucose-6-Phosphate

Front 47

Where does the phosphate come from? How

Back 47

Derived from PEP (phosphoenolpyruvate).

Front 48

How does transport happen across the outer later (excluding porins and hydrophilic molecules)?

Back 48

Some substances actively transported using energy derived from cytoplasmic membrane.

Front 49

How is energy transduced from the cytoplasmic membrane to the outer membrane?

Back 49

TonB transduces it, but in an unknown way.

Front 50

What are two of transport across the outer membrane?

Back 50

Iron-siderophore complexes and FepA transporter
Vitamin B12 complex, BtuB transporter

Front 51

What is a Nosocomial infection?

Back 51

An infection originating in a hospital.