Final Exam Flashcards
(126 cards)
1
Q
a genome contains?
A
genetic information in a cell
2
Q
a genotype is?
A
the genetic makeup containing potential properties
3
Q
what is DNA gyrase?
A
bacteria have a singular circular chromosome, supercoiled and attached to the plasma membrane
4
Q
ecoli DNA has____ base pairs?
A
46 million
5
Q
what is genomics?
A
sequencing and molecular characterization of genomes
6
Q
how is supercoiled DNA made?
A
relaxed circle of dna folded over each other, result in the contact between the helix in two places, dna gyrase action, twisting introduces
7
Q
what are the 3 stages of molecular information flow?
A
replication(duplication of dna), transcription (dna participation in protein synthesis through rna) and translation (determination of amino acid sequence)
8
Q
Dna gyrase activity is inhibited by?
A
quinolones, fluoroquinolones, novobiocin
9
Q
Archaea uses _______ gyrase?
A
reverse
10
Q
does cellular dna replicate before or after division?
A
before cell division
11
Q
what is semiconservative replication?
A
each new double stranded dna molecule contains one original strand and one new strand
12
Q
DNA is replicated from the ____ end?
A
3’
13
Q
Dna in some bacteria is________?
A
biderctional
14
Q
what are the steps to transcription?
A
- enzymes unwind from double helix
- proteins stabilize the unwound parental dna
- leading stand synthesized continuously by dna polymerase
- lagging strand synthesized discontinuously
- dna polymerase digests rna primer and replaces it with dna
- dna ligase joins the discontinuous fragments of the lagging strand
15
Q
rapid amplification of Dna in vitro is?
A
polymerase chain reaction
16
Q
PCR uses DNA _____?
A
polymerase
17
Q
what are used to run through repeated cycles of heating and cooling in the PCR?
A
thermocyclers
18
Q
transcription synthesizes _____ from _____?
A
dna from rna
19
Q
what are the 3 types of rna used in transcription?
A
mrna, rrna, trna
20
Q
what is used in the rna nucleotide instead of thymine?
A
uracil
21
Q
what enzyme does transcription use?
A
rna polymerase
22
Q
translation includes sense condons that?
A
code for amino acids
23
Q
in bacteria what does the start codon AUG code for?
A
formulmethione
24
Q
what are nonsense codons?
A
stop codons that signal the end of protein molecule
25
during translation what asists the transport of required amino acids during protein synthesis?
trna
26
why can translation of mrna into proteins begin before transcription is complete in prokaryotes?
since mrna is produced in the cytoplasm
27
what is repression?
regulatory mechanism that inhibits gene expression and decreases synthesis
28
what is repression response of?
overabundance of end product mediated by repression proteins
29
what is induction?
process that turns on transcription of a gene induced by an inducer (ex. lactose metabolism in ecoli)
30
what is used for the regulation of bacterial gene expression?
operon model of expression
31
francis jacob and jaques monod are responsible for ?
model for regulation of protein synthesis
32
what is the main idea of the operon model of suppression?
structured genes are regulated together
33
what is an operon?
set of operator and promoter sites and structural genes
34
what is a mutation?
change in the base sequence of dna
35
a silent mutation is?
may not be affected by actual function of encoded protein
36
a mutation where a single base is replaced is?
point mutation
37
a missenese mutation is?
base substitution results in amino acid substitution
38
a mutation where a stop codon is created is?
nonsense
39
a mutation where there is deletion insertion to cause a shift is?
frameshift
40
a spontaneous mutation is?
occurs in the apparent absence of mutation
41
mutagens are?
environmental agents that directs or indirectly bring out mutations
42
chemical mutatgens consist of ?
nitrous acid
43
what creats thymine dimmers during radiation?
uv light
44
what are light repair enzymes?
photolysases use visible light energy to separate dimer
45
what is dark repair?
nucleotide excision repair
46
what is the muattion rate?
probability that a gene will mutate when a cell divides
47
spontaneous mutation rates are usually high or low?
low
48
how do mutagens affect the frequency of mutation?
increase the spontaneous rate of mutation usually by 10-1000 times
49
how is identifying mutations easier in prokaryotes?
effects of mutated gene are not masked by normal versions as in most eukaryotes
50
what is positive or direct selection?
detection of mutant cells by rejection of unmutated parent cells
51
what is negative or indirect selection?
indifies cells that cannot preform a certain function
52
what is an auxotroph?
any mutant microorganism with a nutritional requirement that is absent in the parent
53
a carcinogen is?
mutagens that cause cancer
54
what is an ames test?
use bacteria as carcinogen indictaters based on back mutations or reversions
55
the removal or destruction of all forms of microbial life?
sterilization
56
commercial sterilization?
limited heat treatment sufficient to destroy spores of clostridium
57
disinfection is?
control directed at destroying harmful microorganisms
58
antisepsis is?
disinfection applied to living tissue
59
mechanical removal is?
degerming
60
sanitization is?
lowering microbial counts to safe public health levels
61
bacteriostasis is?
does not kill but stops or stays further growth
62
asepsis is?
absence of significant contamination
63
biocide or germicide is?
cide to kill, death occurs at constant rate
64
what are 3 affects of antimicrobial treatments?
number of microbes, environmental influences, exposure time
65
alteration of membrane permeability causes?
leaky cells ,lots of cellular contents
66
heat kills primarily through?
enzyme denaturation
67
what is thermal death point?
lowest temperature at which microorgansims in a liquid will be killed in 10 minutes
68
thermal death time?
minimum length of time for all bacteria in a liquid culture to be killed at a certain temperature
69
decimal reduction time is?
in which 90% of a population of bacteria at a given temp
70
______ kills microrganisms through coagulation of proteins ?
moist heat
71
what lowers microbial numbers and eliminates pathogenic microorganisms?
pasteurization
72
what is hist?
high temperature short time pasteurization
73
what is filtration used for?
sterilize heat sensitive materials
74
what bacteria grows slowly at refrigerator temperatures?
pychotrophs
75
what is desiccation?
viability retained but reproduction and growth ceases
76
osmotic pressure is used in?
food preservation
77
what have high electron beams?
gamma rays, x rays
78
what does the target theory of damage do?
creates sufficient mutations to import lethality
79
what wavelength has little affect of microorgansims?
microwaves
80
how many bacteria is the disinfectant solution tested with?
3 bacteria (salmonella cholerasus, staphlococcus aureus, pseudomonos aeruginosa)
81
what is the disk diffusion method?
disks of filter paper containing agents or antibiotics are placed on an agar plate and monitored for zones of inhibition
82
what are 6 types of disinfectants?
phenol and phendics, bisphenols, biguanides, halogens, alkohols, heavy metals.
83
who established the magic bullet theory?
paul enrlich
84
who first found penicillin?
alexander flemming
85
how does narrow spectrum differ from broad spectrum?
broad (inhibit gram negative and positive)
| narrow (primarily gram positive)
86
inhibition of cell wall synthesis can react with which subunits?
30s or 50s
87
disruption of the plasma membrane results in ?
metabolite loss
88
what inhibits cell wall synthesis?
penicillin, carabaperems
89
what do semi synthetic penicillins do?
remove and replace side chains from the neutral molecule
90
what are carabaperems?
class of b-lactam antibiotics
91
monobactams have ______ toxicity?
low
92
what time of ring structure do monobactams have and what bacteria do they affect?
single, and affects only gram negative bacteria
93
what are cephalosporins?
inhibit cell wall structure, resistant to penicillin, affective against gram negative
94
what inhibits protein synthesis, has a broad spectrum and can be toxi to the host?
chlaramphenicol and aminogycosides
95
what are tetracyclines?
broad specrum, inhibit protein synthesis, penetrate body tissues, affective against stds
96
what are macroslides?
contain macrocyclic lactone ring, most affective against strepto cocci
97
what is polymyxin B ?
effective against gram negative bacteria, injures plasma membrane, used against infections caused by pseudomonas
98
what inhibits rna synthesis?
rifamycins
99
what do quinolones do?
selectively inhibit dna gyrase required in dna replication?
100
what are sulfonamidas?
sulfa drug, among first synthetic drugs to treat microbial disease
101
what is an antifugal drug?
used against athletes foot, and yeast infections
102
what are 4 types of drug resistance?
1) destruction or inactivation of the drug
2) prevention
3) altertion of target site
4) rapid efflux
103
what do nitrogen fixing bacteria do?
fix nitrogen , obligately aerobic, members of alpha or gamma proteobacteria
104
what are enteric bacteria?
homegenous group of gram negative non spoulating bacteria, facuulatively aerobic
105
vibrio and photobacterium are?
mostly aquatic and fermentive metabolism
106
what are rickettsias?
obligate intacellular parasites, significant human pathogens
107
what are spirillia?
motile and spiral shaped, nitrogen fixers
108
what are sheathed proteobacteria?
filamentous beta with unique life cycle, formation of flagellated swarmer cells with long tube or sheath
109
organisms that form varous cytoplasmic extrusions are?
stalked bacteria
110
what ar gliding myxobacteria?
specialized form of motility, members of delta proteobacteria,
111
what functions as electron acceptors under anoxic conditions?
sulphate and sulfur
112
phylum 2 consists of?
gram positive bacteria
113
phylum 2 is divided into 2 subdivisions which are?
high gc and low gc
114
low gc gram positive bacteria are ?
sporeformers
115
what are two characteristics staphlococci?
nonspore, common parasite of humans, found on skin and mucous membranes, produce toxins
116
what are lacto bacilli?
includes lactic acid bacteria, produces lactic acid as byproduct, grow anaerobically
117
what are two properties of streptococci?
produce acidic byproducts, classified according to reactions on blood sugar
118
what are listeria enterococcus?
gram positive cocco bacilli, survives refrigeration temps
119
what are mycoplasms?
no walls, highly peomorphic, smallest self replicating organisms
120
what are cryneform bacteria?
rod shaped, irregular cell arrangements, include animal and plant pathogens
121
what are propiohic acid bacteria?
discovered in swiss cheese, ferment glucose to propiohic acid
122
what are mycobacterium
distinctive cell wall (acid fast stain), seperated into slow and fast growing groups
123
what are actinomycetes?
group of filamentous bacteria, soil organisms
124
phylum 3 consists of?
cyanobacteria, blue green pigment, oxygenic photosynthesis, n fixing cells
125
what are prochlorophytes?
oxygenic phototrophs containing chlorophyll
126
what are the assorted phyla ?
chlamydia
spirochates
bacteriodetes
fusobacteria
