Ch 3

Question 1

Cell envelope refers to the chemical structure ______ to the inner membrane

Answer 1

external

Question 2

Molecular composition of a bacterial cell E. coli

Answer 2

proteins/DNA/RNA - 24%
cell envelope - 5%
other - 1.5%

Question 3

components found in the cytoplasm

Answer 3

-proteins, RNA, macromolecules
-water
-inorganic ions
-small organic molecules
-nucleoid: DNA
-ribosomes
-plasmid
-inclusions

Question 4

external structures of a bacterial cell

Answer 4

-pili/fimbriae
-flagellum/flagella
-capsule - surrounding cell wall

Question 5

“inner” cell membrane of bacterial cell

Answer 5

-phospholipids
-proteins (transport, enzymes)
-maintain gradients

Question 6

cell wall is composed of

Answer 6

peptidoglycan
(sugar peptide polymer)

Question 7

gram positive bacteria is a _______ cell wall

Answer 7

thick

Question 8

gram negative bacteria is a ______ cell wall

Answer 8

thin

Question 9

structure of bacterial cell membrane

Answer 9

phospholipid bilayer containing proteins

Question 10

function of bacterial cell membrane

Answer 10

-separates cytoplasm from the external medium
-contains many proteins w specific functions

Question 11

membrane protein functions

Answer 11

-structural support
-detect environmental signals
-ion transport/energy storage
-secrete communication & virulence factors

Question 12

_____ reinforce the cell membrane

Answer 12

hopanoids (look like cholesterol

Question 13

environmental conditions can induce variation in membrane lipid structure

Answer 13

-phospholipid head group; fatty acid type & length
-saturation/unsaturation of fatty acid
-cyclization of fatty acid chain (cyclopropane)

Question 14

in archaebacterial membrane lipids, hydrocarbon chains are made of

Answer 14

terpenoids; from isoprene

Question 15

hydrocarbons are connected to glycerol via

Answer 15

ether link [-C-O-C-]

Question 16

bacterial phospholipids utilize which linkage

Answer 16

ester linkage

Question 17

group translocation definition

Answer 17

modification of substrate during transport; the source substrate is continually moving down its gradient; a form of active transport

Question 18

bacteria maintain a _____ cell interior

Answer 18

hypertonic; water diffuses in creating osmotic pressure -> cell wall protects vs. pressure

Question 19

ion gradients serve to

Answer 19

store energy for metabolism or drive transport of other molecules

Question 20

ABC transporters expend energy to transport ______

Answer 20

amino acids and carbohydrates

Question 21

the cell envelopes of firmicutes are _____

Answer 21

gram positive; staphylococcus, bacillus

Question 22

what is the name of the taxonomic group which has gram negative cell envelope

Answer 22

proteobacteria; E. coli, pseudomonas

Question 23

the composition of peptidoglycan is

Answer 23

a polymer of disaccharides, glycan, cross-linked with peptide tetramers

Question 24

effect of penicillin on bacterial cells

Answer 24

targeting of peptide cross-link enzyme

Question 25

factor which binds to terminal alanine dipeptide, preventing cross bridging

Answer 25

vancomycin

Question 26

beta-lactamase

Answer 26

cleaves penicillin, inactivating it

Question 27

peptidoglycan synthesis complex functions to

Answer 27

extend the chain of amino-sugars: NAG, NAM

Question 28

In rod-shaped cells, MreB functions to

Answer 28

help protein complex synthesize cell wall in helical direction

Question 29

what is MreB

Answer 29

a cytoskeletal component that polymerizes an arc beneath the PM

Question 30

cell wall growth of E.coli and bacillus

Answer 30

synthesis in dispersed zones

Question 31

staphylococcus and streptococcus cell wall synthesis

Answer 31

only at midpoint of fission

Question 32

are S layers found in firmicutes or proteobacteria

Answer 32

firmicutes

Question 33

properties of gram positive bacteria cell wall

Answer 33

-thick -multiple peptidoglycan layers w/ teichoic acids -S layer

Question 34

properties of gram-negative bacteria cell wall

Answer 34

-thin -1-2 peptidoglycan layers -cell wall bridged to outer membrane via murein lipoprotein -outer LPS

Question 35

what bacteria lacks a cell wall

Answer 35

mycoplasma

Question 36

archaea has a cell wall composed of

Answer 36

pseudomurein

Question 37

mycobacteria have _____ in addition to peptidoglycan

Answer 37

mycolic acids; 50-60 C atoms in length to provide protection against host defenses

Question 38

capsule lies _____ the cell envelope

Answer 38

outside

Question 39

are capsules found in gram positive or gram negative bacteria

Answer 39

both

Question 40

can capsules have different material

Answer 40

yes; protein

Question 41

which is tighter to the cell: capsules or slime layers

Answer 41

capsules; slime layers are looser assemblages

Question 42

Biofilms are

Answer 42

multi-cell populations surrounded by an exopolysaccharide matrix