Bacterial Structure 2&3. 2

Question 1

The major function of the cytoplasmic membrane is to act as?

*Other two big function?

Answer 1

a permeability barrier, preventing leakage of cytoplasmic metabolites into the environment
*protein anchor and energy conservation

Question 2

Selective permeability also prevents the diffusion of?

Answer 2

most solutes

Question 3

The cytoplasmic membrane is constructed of

Answer 3

lipids and proteins that form a bilayer with hydrophilic exteriors and a hydrophobic interior

Question 4

Phospho-Lipids have both ________ and ________ properties. They play a crucial role in?

Answer 4

hydrophobic (nonpolar) and hydrophilic (polar) properties

* crucial role in membrane

Question 5

cytoplasmic membrane as permeability barrier? Reason for this barrier?

Answer 5

prevents leakage and function as a gateway for transport of nutrients into and out of cell
*Polar and charged molecules must be transported

Question 6

cytoplasmic membrane as protein anchor?

Answer 6

site of many proteins involved in transport, bioenergetics, and chemotaxis

Question 7

cytoplasmic membrane as energy conservation?

Answer 7

site of generation and use of the proton motive force

Question 8

cytoplasmic membrane anchors protieins such as?

Answer 8

 enzymes for catabolic degradation of large macromolecules
 electron transport system
 proteins for transport of nutrients
 structures for chemotaxis (flagella)
 structures for attachment (pili)

Question 9

cytoplasmic membrane is composed of ___% and ___%?

Answer 9

75% protein and 25% phospholipid

Question 10

Transport proteins accumulate molecules into or out of the cell against the?

Answer 10

concentration gradient

*Molecule inside of cell is at a higher concentration than outside cell or vice versa

Question 11

Simple transporter- are often driven by the? Examples

Answer 11

proton motive force: uniporter, symporter, antiporter

Question 12

uniporter

Answer 12

one molecule is transported from outside to inside

Question 13

symporter

Answer 13

two molecules are transported from outside to inside

Question 14

antiporter

Answer 14

one molecule transported in/another is

transported out

Question 15

Prokaryotes have at least these 3 types of transporters?

Answer 15

• simple transporters
• phosphotransferase-type transporters
• ABC (ATP-binding cassette) transporters

Question 16

simple transport

Answer 16

driven by the energy in the proton motive

Question 17

group translocation

Answer 17

chemical modification of the transported substance driven by phosphoenolpyruvate

Question 18

ABC transporter (general definition)

Answer 18

periplasmic binding proteins are involved and energy comes from ATP

Question 19

Phosphotransferase group translocation requires? occurs where?
What happens to nutrients transported in?

Answer 19

*requires energy and phosphate
*occurs at cytoplasmic membrane
*nutrient transported in is modified by phosphorylation, thus a high energy
phosphate group is used

Question 20

The Phosphotransferase System in E. coli

Answer 20

• A type of group translocation
• The best studied system
• Responsible for transporting glucose, fructose, and mannose
• Five proteins are required
• Energy derived from phosphoenolpyruvate

Question 21

ABC (ATP-Binding Cassette) transporters contain 3 ______ components

Answer 21

interacting

Question 22

ABC transporters requires?

Answer 22

energy from either the proton motive force, ATP, or other energy-rich substance

Question 23

how many different systems identified in prokaryotes for ABC transporters? they display?
contains?

Answer 23

200

• display high substrate specificity
• contain periplasmic binding proteins

Question 24

what do ABC transporters uptake?

Answer 24

organic compounds (sugars, amino acids)
inorganic nutrients (sulfate, phosphate)
trace metals

Question 25

Proteins are exported out of prokaryotic cells through the actions of proteins called ________, which are specific in the types of proteins exported.

Answer 25

translocases
2 systems:
1) Sec translocase system
2) Type III secretion system

Question 26

translocases are responible for?

Answer 26

exporting proteins through and inserting into prokaryotic membranes

Question 27

Sec translocase system

Answer 27

exports proteins and inserts integral membrane proteins into the membrane; consists of 7 proteins

Question 28

Type III secretion system

*Is often a ___ factor?

Answer 28

common in pathogenic bacteria; secreted protein translocated directly into host
•Often a virulence factor

Question 29

what are the penicillin-binding proteins (PBPs)? They are targets for?

Answer 29

•transpeptidases and carboxypeptidases

* targets for penicillin and other β-lactam antibiotics

Question 30

Transpeptidation is joining of two?

Answer 30

layers of peptidoglycan via peptides of each layer

Question 31

Transpeptidation starts with a _________ of one layer and a ______ of the other layer *whereby a diaminopimelic acid is joint to?

Answer 31

starts with a pentapeptide of one layer and a tetra peptide of other layer *diaminopimelic acid is joint to the pentultimate D-alanine and
on D-alanine is lost from the pentapeptide to yield a tetrapeptide on each layer

Question 32

Peptidoglycan synthesis concludes at

Answer 32

Transpeptidation

Question 33

what is one of the few remaining drugs for the treatment of multi-resistant G+ infections?

Answer 33

Vancomycin

Question 34

Vancomycin predominantly binds?

Answer 34

the D-alanyl-Dalanine (D-ala-D-ala) part of the pentapeptide

Question 35

**penicillin inhibits? ONLY works on growing or dormat bacteria?

Answer 35

transpeptidation aka prevents crosslinkage of cell wall peptidoglycan
*growing bacteria, if dormat than transpeptidation has already happened

Question 36

what is the first microbial enzyme discovered capable of destroying beta lactam penicillin

Answer 36

Beta-lactamases

Question 37

Beta-lactamases discovery required the development of? UNFORTUNATLY what happened?

Answer 37

antibiotics resistant to betalactamases such as cephalosporins or compounds capable of inactivating betalactamase or inhibitors
*unfortunatly, new beta-lactamases have evolved that inactivate these second generation antibiotics (so far 890 have been discovered)

Question 38

what is the new beta-lactamase of mahor concern? (recently discovered, inactivate all generations of antibiotics)

Answer 38

NDM-1, which stands for New Delhi metallo-beta-lactamase-1

Question 39

Describe NDM-1, which stands for New Delhi metallo-beta-lactamase-1?
encoded on?
hydrolyzes?
what is found on same plasmid?

Answer 39

*A new Beta-Lactamase that has evolved to inactive penicillin antibiotics
 encoded on a 180 kb plasmid encoding multiple resistance genes
 NDM-1 beta lactamase hydrolyzes penicillins and cephalosporins
 Another beta lactamase on the same plasmid inactivates erythromycin,
ciprofloxacin, and chloramphenicol