Microbiology Test 1

Front 1

denaturation

Back 1

destruction of a protein's three-dimensional structure
cause by heat, unfavorable pH, high salt concentration

Front 2

nucleic acids

Back 2

3dr most abundant component of microbial cells (after water and protein)
two types: DNA and RNA

Front 3

deoxyribonucleic acid

Back 3

molecule that encodes a cell's genetic information; ensures that progeny resemble parents

Front 4

ribonucleic acid

Back 4

interprets info for protein construction encoded in DNA
much more abundant than DNA, especially in microorganisms

Front 5

ribosomes

Back 5

organelles on which proteins are manufactured, composed partly of RNA

Front 6

nucleotides

Back 6

the building blocks of nucleic acid; each contains a phosphate group and nucleoside-composed of a 5-carbon sugar and nitrogen-containing base

Front 7

pyrimidine

Back 7

single-ringed molecule
cytosine, uracil, thymine
U only occurs in ribonucleotides, T occurs only in deoxyribonucleotides

Front 8

purine

Back 8

double-ringed molecule
adenine and guanine

Front 9

type of bond that joins nucleotides

Back 9

phosphodiester bonds

Front 10

nucleoid

Back 10

irregularly shaped region occupied by the DNA of a prokaryotic cell

Front 11

peptidoglycan

Back 11

part polysaccharide part protein, makes up prokaryotic cell walls; no eukaryotic cells contain it

Front 12

cytoplasm

Back 12

lies within envelope of cell, contains DNA and metabolic machinery.

Front 13

envelope

Back 13

as many as three layers
outside-->inside
outer membrane
cell wall
cytoplasmic membrane

Front 14

gram-negative bacteria envelope

Back 14

all three layers (outer membrane, cell wall, cytoplasmic membrane)
extra-cellular component between outer and cytoplasmic membranes - periplasm

Front 15

gram-positive bacteria envelope

Back 15

lack outer membrane

Front 16

mycoplasmas envelope

Back 16

lack outer membrane and cell wall

Front 17

outer membrane of gram-negative bacteria

Back 17

bilayer. inner layer composed of phospholipid, outer layer composed of mainly lipopolysaccharide (LPS)---also contains small amount of phospholipid to which some components of capsule are attached

Front 18

lipopolysaccharide (LPS)

Back 18

found only in outer membrane of Gram- bacteria-lipid moiety at one end, polysaccharide on the other--
lipid end=Lipid A-hydrophobic
polysaccharide tail is hydrophilic
AKA endotoxin - harmful to humans/animals

Front 19

pores

Back 19

small holes in outer membrane through which nutrients a gram- cell needs pass.
formed by proteins called porins
some are selective

Front 20

how outer membrane is anchored to rest of envelope?

Back 20

molecules of lipoprotein- bonded to cell wall at one end
other end carries a lipid that inserts into the inner surface of the outer membrane

Front 21

benefits of outer membrane to gram negative bacteria

Back 21

protection - gram- bacteria generally more resistant to toxic substances because they can't get through the outer membrane.

Front 22

periplasm

Back 22

lies inside outer membrane of gram- bacteria.
important organelle - filled with gelatinous material incl. 2 types of proteins-
enzymes-most break down certain nutrients so they can pass thru cytoplasmic membrane
binding proteins - bind to certain nutrients - facilitate their passage across outer and cytoplasmic membranes

Front 23

cell wall

Back 23

all bacteria except mycoplasms have strong walls made of peptioglycan
gram- :wall lies within periplasm
gram+ :outside cytoplasmic membrane

Front 24

structure of cell wall

Back 24

made of peptioglycan - part protein, part polysaccharide
polysaccharide (glycan) part consists of long chains of alternating units of sugars NAG and NAM- chains encircle cell
held together (cross-linked) by protein part of molecule

Front 25

gram negative cell wall

Back 25

peptidoglcan mesh that is only one layer thick

Front 26

gram positive cell wall

Back 26

many layers thick
contain 2nd component - teichoic acid- adds to structural integrety

Front 27

spherical

Back 27

cocci (sing)
coccus

Front 28

rod-shaped

Back 28

bacilli (sing)
bacillus

Front 29

spiral shaped

Back 29

spirilla
spirillum

Front 30

short rod shaped

Back 30

coccobacillus

Front 31

mycoplasmas envelope

Back 31

lack outer membrane and cell wall

Front 32

outer membrane of gram-negative bacteria

Back 32

bilayer. inner layer composed of phospholipid, outer layer composed of mainly lipopolysaccharide (LPS)---also contains small amount of phospholipid to which some components of capsule are attached

Front 33

lipopolysaccharide (LPS)

Back 33

found only in outer membrane of Gram- bacteria-lipid moiety at one end, polysaccharide on the other--
lipid end=Lipid A-hydrophobic
polysaccharide tail is hydrophilic
AKA endotoxin - harmful to humans/animals

Front 34

pores

Back 34

small holes in outer membrane through which nutrients a gram- cell needs pass.
formed by proteins called porins
some are selective

Front 35

how outer membrane is anchored to rest of envelope?

Back 35

molecules of lipoprotein- bonded to cell wall at one end
other end carries a lipid that inserts into the inner surface of the outer membrane

Front 36

benefits of outer membrane to gram negative bacteria

Back 36

protection - gram- bacteria generally more resistant to toxic substances because they can't get through the outer membrane.

Front 37

periplasm

Back 37

lies inside outer membrane of gram- bacteria.
important organelle - filled with gelatinous material incl. 2 types of proteins-
enzymes-most break down certain nutrients so they can pass thru cytoplasmic membrane
binding proteins - bind to certain nutrients - facilitate their passage across outer and cytoplasmic membranes

Front 38

cell wall

Back 38

all bacteria except mycoplasms have strong walls made of peptioglycan
gram- :wall lies within periplasm
gram+ :outside cytoplasmic membrane

Front 39

structure of cell wall

Back 39

made of peptioglycan - part protein, part polysaccharide
polysaccharide (glycan) part consists of long chains of alternating units of sugars NAG and NAM- chains encircle cell
held together (cross-linked) by protein part of molecule

Front 40

gram negative cell wall

Back 40

peptidoglcan mesh that is only one layer thick

Front 41

gram positive cell wall

Back 41

many layers thick
contain 2nd component - teichoic acid- adds to structural integrety

Front 42

spherical

Back 42

cocci (sing)
coccus

Front 43

rod-shaped

Back 43

bacilli (sing)
bacillus

Front 44

spiral shaped

Back 44

spirilla
spirillum

Front 45

short rod shaped

Back 45

coccobacillus

Front 46

vibrio

Back 46

short, comma shaped spirillum

Front 47

turgor

Back 47

osmotic pressure within cell
high in bacterial cell because contents are concentrated

Front 48

how bacterial cells grow within rigid peptidoglycan wall

Back 48

to enlarge peptioglycan shell bacteria produces enzymes that break cross-linking bonds in peptioglycan and others that reseal the breaks by adding new peptidoglycan monomers

Front 49

transpeptidases

Back 49

reseal breaks in peptidoglycan walls by adding new peptidoglycan monomers

Front 50

autolysins

Back 50

enzymes that break cross-linking bonds in peptidoglycan

Front 51

penicillin-binding proteins

Back 51

another name for transpeptidase enzymes; penicillin kills growing bacteria b/c inactivated transpeptidases cant close the breaks in the cell wall that autolysins make to enlarge. cell lyses (bursts) b/c wall becomes too weakened to hold turgor pressure

Front 52

mycoplasmas

Back 52

lack cell wall but dont lyse b/c they dont have sig. turgor pressure. maintain= [] of solutes inside cytoplasm and external environment by pumping out sodium ions
cytoplasmic membrane strengthened by sterols

Front 53

L-forms

Back 53

wall-less strain of bacteria
can be made artificially by treating normal bacteria with lysozome (removes walls) or penicillin (prevents synthesis)

Front 54

unit membranes

Back 54

cytoplasmic membranes of eukaryotes and bacteria
lipid component composed of phospholipids
form membranes spontaneously
hydrophilic head: glycerol + phosphate group
hydrophobic tail: 2 fatty acid chains