Bact T Exam 2

Front 1

orderly arrangement of sets of organisms into a system

Back 1

classification

Front 2

recognition of an unknown organism and placing it in a set of the scheme

Back 2

identification

Front 3

this method of classifying bacteria refers to the mole % G + C

Back 3

DNA composition

Front 4

the dna composition of Clostridium tetani vs. mycobacterium tuberculosis

Back 4

clostridium tetani 30%
mycobacterium tuberculosis 7-%

Front 5

the procedure of DNA-DNA hybridization

Back 5

way of classifying bacteria by "DNA sequence"
isolate DNA, cut it up, mix it with known DNA, heat it to separate strands, cool to reanneal, rinse away fragments, record radioactivity

Front 6

short fragment of DNA that is specific for a particular gene

Back 6

probe

Front 7

the biological analog to serological typing

Back 7

phage typing

Front 8

life cycle of a phage

Back 8

phage binds to surface receptors
phage injects its DNA into bacterial cell
DNA is transcribed and many phages are made in the cell
these lyse the cell and release phage to infect other cells

Front 9

why are phages good antibiotics

Back 9

there is no antibiotic resistance, humans have no surface receptors

Front 10

this biochemical test determines if an unknown organism is S. aureus or S epidermidis (+) OR streptococcus (-)

Back 10

catalase test

Front 11

after a positive catalase test, this can decide between S aureus (+) or S epidermidis (-)

Back 11

coagulative test

Front 12

process in which bacteria multiply by cell division

Back 12

binary fission

Front 13

enlargement in cell wall where division starts

Back 13

wall band

Front 14

inward extension of wall band where cell division will occur

Back 14

nascent septum

Front 15

in binary fission, the wall band splits into two and is known as the

Back 15

wall notch

Front 16

in binary fission these enzymes open the backbone and allow entry of wall subunit

Back 16

murein hydrolases

Front 17

binary fission without cell separation can lead to these two

Back 17

streptococcus
staphylococcus

Front 18

complex of proteins involved in cel division

Back 18

divisome

Front 19

chief protein of divisome that recruits other proteins, which bring down the membrane and stimulate septum formation

Back 19

FtsZ

Front 20

two types of cells are slowly and rapidly dividing cells

Back 20

slowly - finish replication before cell division is started
rapidly - multiple replication forks, physiologically significan in terms of gene dosage, each one expressing its product changes physiology of cell

Front 21

growth rate of gram negative rod cell division

Back 21

20-30 minutes

Front 22

growth rate of gram positive cocci cell division

Back 22

45-60 minutes

Front 23

growth rate of acid fast bacteria

Back 23

up to 24 hours

Front 24

4 ways of measuring cell growth that do not separate viable from nonviable cells

Back 24

packed cell volume - centrifuge and mass the pellet
spectrophotometry - measure optical density of culture by passing light through it
measure some component of cell like protein, DNA, ATP
microscopy - count cells

Front 25

only way to measure viable counts of cell growth

Back 25

viable counts - prepare serial dilution until you get small amount of cells, put that on a plate and incubate it, then count colonies and multiply back

Front 26

what determines length of LAG phase?

Back 26

1. if cell was just in stationary phase it is depleted and needs more time to uptake nutrients
2. composition of medium
3. organism itself, if it has efficient uptake system

Front 27

experiment with low glucose and excess lactose

Back 27

diauxie

Front 28

cell heaven; new medium added with a spout, keeps bacterial cells continuously in log phase

Back 28

chemostat

Front 29

entire bacterial cell in same phase of growth

Back 29

synchronous growth

Front 30

way of getting synchronous growth where culture passed through filter paper and then turned over, allowing cells to grow and fall onto filter paper

Back 30

age: membrane elution

Front 31

way of getting synchronous growth where culture passed through stay of filter papers, only small cells get through

Back 31

size: filtration

Front 32

way of getting synchronous growth where culture put 37 degrees then back to 25 degrees so cold sensitive enzymes shut down temorarily

Back 32

temperature

Front 33

way of getting synchronous growth by interfering with DNA replication

Back 33

thy-mutant - remove thymine, then put it back in. cell replication depends on thymine being present

Front 34

infection of bacteria when all normal flora is killed and the only thing left is antibiotic resistant bacteria

Back 34

enterocolitis

Front 35

infection in vaginal tract, isnt a problem unless normal flora wiped out

Back 35

candida infection

Front 36

penicillin only affects these cells

Back 36

growing cells

Front 37

gram negative cells take this long to kill

Back 37

seven days

Front 38

gram positive cells take this long to kill

Back 38

ten days

Front 39

acid fast organisms take this long to kill

Back 39

one year - tuberculosis

Front 40

flat, thick growth of bacteria on cell surface

Back 40

biofilm

Front 41

bacterial cells in biofilm enclosed in this

Back 41

exopolysaccharide

Front 42

refers to gene expression that is a function of number of cells present

Back 42

quorum sensing

Front 43

twitching motility done by:

Back 43

type IV pili

Front 44

how does biofilm get nutrients

Back 44

by diffusion through channels exposed to the outside

Front 45

this enzyme digests exopolysaccharide

Back 45

exopolysaccharide ligase

Front 46

growth of flagella and its synthesis

Back 46

planktonic growth

Front 47

single cells which may float or swim in a liquid medium

Back 47

planktonic cells

Front 48

how many genes are turned on or off when going from planktonic growth to biofilm growth

Back 48

800

Front 49

are cells in biofilm stage growing?

Back 49

no, they are dormant

Front 50

why are biofilms resistant to antibiotics?

Back 50

thickness, could be polysaccharide itself that neutralizes antibiotics, could be antibiotic influx pump - cells come in put are pumped out too quickly, or could be cells are dormant so antibiotics don't act

Front 51

why are biofilm cells phagocyte resistant?

Back 51

thickness makes them inaccessible

Front 52

what is different about DNA in cells in biofilm?

Back 52

cells can exchange DNA between each other because they are close

Front 53

what is the quorum sensor in gram negative

Back 53

acyl homoserine lactone

Front 54

what is the quorum sensor in gram positive

Back 54

small peptide

Front 55

is quorum sensing a property of the individual or the group

Back 55

the group because one induces others to release more sensors

Front 56

release of planktonic cells from biofilm

Back 56

swarming

Front 57

how can biofilm move from one area to another

Back 57

a clump can break off and roll somewhere new
rippling - entire biofilm moves
clumping - can get into blood and form a clot

Front 58

medical issues with where biofilm can form

Back 58

dental plaque, catheters, artificial joints, heart valves

Front 59

why is cystic fibrosis so bad

Back 59

the thick mucous is a basis for forming biofilm that causes chronic lung infections and is antibiotic resistant

Front 60

what are biofilms like multicellular organisms

Back 60

its a conglomeration of cells of different species that communicate and have different roels

Front 61

adding bacteria via ingestion for specific purposes

Back 61

probiotics

Front 62

when you take nonliving food additive for purpose of stimulating the growth of particular organisms

Back 62

prebiotics