Chapter 7 Flashcards
(111 cards)
1
Q
How do eukaryotic cells reproduce?
A
asexually or sexually
2
Q
Haploid
A
one
3
Q
Diploid
A
two
4
Q
Bacteria and Archaea reproduce how?
A
asexually (binary fission, budding, filamnetous)
5
Q
What do bacterial and archaeal reproduction result in?
A
haploid cells
6
Q
How do most bacteria divide?
A
binary fission
7
Q
What are the two pathways for bacterial cell cycle?
A
DNA replication and partition
Cytokinesis
8
Q
What is the shape of most bacterial chromosomes?
A
circular
9
Q
Acronym for chromosomes replication and partitioning?
A
STRO
10
Q
Where is the site at which replication begins?
A
“S”ingle origin of replication
11
Q
Where is the site at which replication is terminated?
A
“T”erminus
12
Q
What is the group of proteins needed for DNA synthesis?
A
“R”eplisome
13
Q
How do origins move during replication?
A
to opposite ends of the cell
14
Q
What is the formation of cross walls between daughter cells?
A
septation
15
Q
What are the steps to cytokinesis?
A
Selection site
assembly of Z ring
assembly of cell wall machinery
construction of cell and septum formation
16
Q
What is the Z ring composed of?
A
Protein FtsZ
17
Q
What is the shape of the protein FtsZ?
A
tubulin homologue
18
Q
How is the Z ring formed?
A
through polymerization
19
Q
How is the divisome protein formed?
A
- Z rings are anchored to p.m
- Machinery is assembled
- the z ring is constructed, invagination of the p.m. and synthesis of septal wall completes division
20
Q
How does peptidoglycan help with cellular growth and cell shape?
A
PBPs link PPG strands and catalyze degradation for new growth
21
Q
What do autolysins do?
A
PBP enzymes that degrade PPG at site where new ones are added
22
Q
Cocci divisome forms PPG only where?
A
at the septum
23
Q
What determines the site for new cell growth?
A
FtsZ rings
24
Q
What determines the shape of vibrio cells?
A
crescentin
25
What is crescentin?
intermediate filament homologue
26
What grow under harsh conditions?
Extremophiles
27
What is the osmotic concentration of hypotonic solution?
lower osmotic concentration
28
What happens in a hypotonic solution
water enters the cell, swells, and may burst
29
What is the osmotic concentration of hypertonic solutions?
higher osmotic concentration
30
What happens in a hypertonic solution?
water leaves the cell, shrinkage
31
What allows solutes to leave the cell, which reduces the osmotic concentration?
mechanosensitive channels in the plasma membrane
32
Halophiles grow optimally in the presence of what?
NaCl (0.2)
33
Extreme halophiles grow optimally in the presence of NaCl plus what?
K (2 and 6.2)
34
Why do extreme halophiles needed higher concentrations?
to maintain cell wall, proteins, and p.m
35
A lower water activity means what?
that most of it is bound
36
What is the ph for acidophiles?
0-5.5
37
What is the pH for neutrophiles?
5.5-7
38
What is the pH for alkaliphiles?
8.5-11
39
What is the internal pH of most microbes?
neutral
40
How due microbes tolerate acid?
pump protons out of the cell
41
How do many microorganisms change the pH of their habitat?
produce acidic and waste products
42
What can high temperatures inhibit?
enzyme functions
43
Temperature range for psychrophiles?
0-20 C
44
Temperature range for psychotrophs?
0-35 C
45
Temp range for mesophiles?
20-45 C
46
Temp range for thermophiles?
55-85 C
47
Temp range for hyperthermophiles?
85-113 C
48
How do thermophiles adapt to their environment?
stabilize protein structure
histones stabilize DNA
membrane stabilization
49
Obligate aerobe
requires O2
50
anaerobe
grows in the absence of O2
51
Obligate anaerobe
killed in presence of O2
52
microaerophile
requires 2-10% of O2
53
facultative anaerobe
grow better in the presence of O2
54
aerotolerant anaerobes
grow with or without O2
55
What enzymes do aerobes produce to protect themselves?
SOD
Catalase
Peroxidase
56
Oxygen reduce to reactive oxygen species?
superoxide radical
hydrogen peroxide
hydroxyl radical
57
Strict anaerobic microbes lack?
superoxide dismutase
| catalase
58
Adversely affected by increased pressure?
barotolerant
59
Requires or grow more rapidly in the presence of increased pressure?
barophillic
60
X rays and gamma rays are apart of what?
ionizing radiation
61
What does ionizing radiation disrupt?
chemical structures, which can be repaired by DNA repair mechanisms
62
What microorganism is resistant to radiation?
Deinococcus radiodurans
63
What does UV radiation cause formation to?
thymine dimers
64
What is the size of the wavelength that UV radiation is most effectively absorbed?
260nm
65
UV radiation mutation to the genre can cause what?
death
66
What protects microorganisms from photooxidation?
carotenoid pigments
67
How do most microbes grow?
by being attached to surfaces
68
Microbes are apart of what complex system?
biofilms
69
Microbes attach to surfaces and release what for biofilm formation?
polysaccharides, proteins, and DNA
70
What is produced as the biofilm matures?
polymers
71
What is a mature biofilm made up of?
community of microorganisms
72
What is heterogeneity?
metabolic activities different in activity and location
73
How do interactions occur between the microbes?
among the organism through metabolism and DNA uptake and communication
74
can illness occur from biofilms?
yes
75
How do bacterial cells communicate in the biofilm?
Quorum sensing
76
Qurom sensing steps
AHL diffuses across the p.m an targets genes for regulating certain functions
77
What is AHL released by?
many gram negative organisms
78
What are the two types of culture media?
solid or liquid
79
What must a culture contain for the microorganism?
all nutrients required for growth
80
Cultures can either be blank or blank?
synthetic or complex
81
What type of media is a peptone?
protein hydrolysates from protein sources
82
What type of media is extract?
aqueous, beef or yeast
83
What type of media is agar?
solidifying agent
84
What are the different types of functional media?
Supportive
Enriched
Selective
Differential
85
What type of media favor the growth of some microorganisms and inhibits others?
Selective Media
86
What type of media distinguishes bacteria based on their biological characteristics?
Differential Media
87
What does the isolation of a pure culture do?
study for the single type of microorganism in a mixed culture (steak plate or pour plates)
88
How does a pour plate work?
a diluted bacterial sample is mixed with a liquid agar
89
Differences in the growth rate from edges to center of a dish is?
oxygen
nutrients
toxins
90
Growth in cells refers to?
increase in cell number and size
91
How does growth usually occur?
in populations
92
What are the five phases of a growth curve?
```
Lag Phase
Log Phase
Stationary Phase
Death Phase
Long term stationary term
```
93
What phase consists of cells synthesizing new components?
Lag Phase
94
What phase allows for maximal and constant rate of growth and development?
Log Phase aka Exponential Phase
95
What is the uniform of cells in the log phase?
mostly chemical and physical properties
96
During the log phase what is needed for the growth and division?
nutrients
97
What happens during the stationary phase?
growth ceases and cells stop reproducing
98
What are reasons for the stationary phase?
nutrient limitation
limited oxygen availability
toxic waste
max population
99
What are the two hypothesis for death phase?
viable cells but not culturable and programmed cell death
100
Cells alive but dormant, capable of growth under right conditions
cells are viable hypothesis
101
Suicide
programmed cell death
102
What happens in the prolonged decline in growth?
natural selection
103
What is the time required for the population to double in size?
the generation time
104
How long is the generation time?
10 minutes to days
105
What is used for direct measurements of cell numbers?
counting chambers
electronic counters
on membrane filters
106
How can you measure microbial growth?
change in number of cells in population and the mass of the population
107
What can counting chambers not distinguish between?
living and dead cells
108
How do membrane filters work?
stains them with fluorescent dyes
109
Flow Cytometry
cells forced through orifice by a laser and the cells cause an electric current that leads to a disturbance. these are then counted
110
Viable counting:alive or dead?
cells can exist between a variety of states between fully viable and actually dead
111
Spread/Pour plates (lab)
mixed, incubated, and counted expressed by CFU
