The Prokaryotic Cell Flashcards
1
Q
Chromosomes:
A
- Single (up to 3)
- haploid (1 copy)
- circular (some linear)
- supercoiled
- small & efficiently organized
~ 4.7 Mb ~ 3,000 genes
2
Q
Size of Cell:
A
Typically 0.2–2.0 mm in diameter
3
Q
Nucleus:
A
Typically no nuclear membrane or nucleoli except Gemmata
4
Q
Membrane-Enclosed Organelles:
A
Relatively few
5
Q
Flagella:
A
Consist of two protein building blocks
6
Q
Glycocalyx:
A
Present as a capsule or slime layer
7
Q
Cell Wall:
A
Usually present; chemically complex (typical bacterial cell wall includes peptidoglycan)
8
Q
Plasma Membrane:
A
Carbohydrates and generally lacks sterols
9
Q
Cytoplasm:
A
Cytoskeleton (MreB and ParM, cresetin, and FtsZ proteins); no cytoplasmic streaming
10
Q
Ribosomes:
A
Smaller size (70S)
11
Q
Chromosome (DNA):
A
Usually single circular chromosome; typically lacks histones
12
Q
Cell Division:
A
Binary fission
13
Q
Sexual Recombination:
A
None; transfer of DNA only
14
Q
Prokaryotes and eukaryotes both contain
A
- nucleic acids
- proteins
- ipids
- carbohydrates
15
Q
specialized cellular structures that have specific functions
A
organelles
16
Q
Prokaryotes from the Greek words meaning
A
prenucleus
17
Q
has a double membrane around its nucleus
A
Gemma obscuriglobus
18
Q
A bacteria that have two chromosomes
A
Vibrio cholerae
19
Q
Prokaryotes lack other membrane-enclosed organelles
A
- nuclei
- mitochondria
- chloroplast
20
Q
Prokaryotes usually divide by
A
binary fission
21
Q
Most bacteria range from ____ to ___ µm in diameter and from
___ to __ µm in length
A
- 0.2 to 2.0 µm
- 2 to 8 µm
22
Q
spherical-shaped
A
coccus
(plural: cocci, meaning berries)
23
Q
rod-shaped
A
bacillus
(plural: bacilli, meaning little rods or walking sticks)
24
Q
The shape of Cocci can be
A
- oval
- elongated
- flattened on one side
25
Cocci that remain in pairs after dividing
Diplococci
26
Cocci that divide and remain attached in chainlike patterns
Streptococci
27
Cocci that divide in two planes and remain in groups of four
Tetrads
28
Cocci that divide in three planes and remain attached in cubelike groups of eight
Sarcinae
29
Cocci that divide in multiple planes and form grapelike clusters or broad sheets
Staphylococci
30
- it divide only across their short axis
- there are fewer groupings
Bacilli
31
Single rods
Single bacilli
32
Bacilli that appear in pairs after division
Diplobacilli
33
Bacilli that occur in chains. Some bacilli look like straws. Others have tapered ends, like cigars
Streptobacilli
34
Bacilli that are oval and look so much like cocci
Coccobacilli
35
- bacteria have one or more twists
- they are never straight
Spiral
36
Bacteria that look like curved rods
Vibrios
37
- a helical shape, like a corkscrew
- fairly rigid bodies
spirilla (singular: spirillum)
38
Another group of spirals that are helical and flexible
Spirochetes
39
What does Spirilla use to move?
propeller-like external appendages called flagella
40
What does Spirochetes use to move?
move by means of axial filaments
41
- it resemble flagella
- contained within a flexible external sheath
Axial Filaments
42
Bacteria that maintains a single shape
Monomorphic
43
Bacteria that can have many shapes
Pleomorphic
44
Example of Bacteria (Pleomorphic)
Rhizobium and Corynebacterium
45
Structures External to the Prokaryotic Cell Wall
- Glycocalyx
- Flagella
- Axial Filaments
- Fimbriae
- Pili
46
It is a substance that may prokaryotes secrete on their surface
Glycocalyx
47
Glycocalyx
- meaning sugar coat
- a general term used for substance that surround cells
48
Characteristic of Glycocalyx
- viscous (sticky)
- gelatinous polymer
49
Glycocalyx is composed of
polysaccharide and polypeptide
50
It plays a role in bacterial virulence
Capsule
51
It plays a role in bacterial identification
Cell wall or Flagella
52
It plays a role in targets of antimicrobial agents
Cell wall
53
- it encode information such as genes for resistance to antibiotics or the production of toxins
- it may be exchanged between bacteria
Plasmids
54
Glycocalyx is described as ____ if the substance is organized and is firmly attached to the cell wall
Capsule
55
Glycocalyx is described as ____ if the substance is unorganized and only loosely attached to the cell wall
Slime layer
56
A glycocalyx that helps cells in a biofilm attach to their target environment and to each other
Extracellular polymeric substance (EPS)
57
What does EPS do to the cells?
- protects the cells within it
- facilitates communication among them
- enables the cells to survive by attaching to various surfaces in their natural environment
58
A glycocalyx also can protect a cell against ________, and its viscosity may inhibit the movement of nutrients out of the cell
Dehydration
59
- present in some bacterial cell
- which are long filamentous appendages that propel bacteria
Flagella (singular: flagellum)
60
Bacteria that lack flagella
atrichous (without projections)
61
Flagella may be __________ (distributed over the entire
cell)
peritrichous
62
Flagella may be _____ (at one or both poles or ends of the cell)
polar
63
If polar, flagella may be _________ (a single flagellum at one pole)
monotrichous
64
If polar, flagella may be _________ (a tuft of flagella coming from one pole)
lophotrichous
65
If polar, flagella may be __________ (flagella at both poles of the cell)
amphitrichous
66
Three basic parts of a Flagellum
- Filament
- Hook
- Basal body
67
- the long outermost region
- contant in diameter
- contains globular (roughly spherical) protein
Filament
68
It is a protein arranged in several chains that intertwine and form a helix around a hollow core
Flagellin
69
- it is where the filament is attached
- consists of different protein
Hook
70
- third portion of a flagellum
- anchors the flagellum to the cell wall and plasma membrane
Basa body
71
The basal body is composed of a _____ _____ ___ inserted into a series of rings
small central rod
72
Two pairs of rings of a Gram-negative bacteria
- outer pair of rings
- inner pair of rings
73
It is anchored to various portions
of the cell wall
Outer pair of rings
74
It is anchored to the plasma membrane
Inner pair of rings
75
What pair of rings is present in Gram-positive bacteria?
Only the inner pair of rings
76
Rotation of a Flagellum in Prokaryotic cells
Either clockwise or counterclockwise
77
Motion of a Flagellum in Prokaryotic cells
Undulate in a wavelike motion
78
It is the ability of an organism to move by itself
Motility
79
Term for the movement of a bacterium in one direction fro a length of time
Run or Swim
80
It is called when "runs" are interrupted by periodic, abrupt,random changes in direction
Tumbles
81
What is the cause of "tumbles"?
a reversal of flagellar rotation
82
Some species of bacteria endowed with many flagella
Proteus
83
Proteus can _______, or show rapid wavelike movement across a solid culture medium
Swarm
84
One advantage of motility
enables a bacterium to move toward a favorable environment or away from an adverse one
85
The movement of a bacterium toward or away from a particular stimulus
Taxis
86
Stimuli include light
Phototaxis
87
Stimuli include chemicals
Chemotaxi
88
What are the chemical stimuli?
- oxygen
- ribose
- galactose
89
Positive chemotactic signal
Attractant
90
Negative chemotactic signal
Repellent
91
- flagellar protein
- useful for distinguishing among serovars
H antigen
92
variations within a species of gram-negative bacteria
Serovars
93
Motile archaeal cells have ______
archaella (singular: archaellum)
94
Archaella share similarities with bacterial _______ and ____
flagella and pili
95
It anchors archaella to the cell
A knoblike structure
96
No _______ type anchor has been found for ____
- bsal-body
- pili
97
Archaella rotate like _______
flagella
98
Archaella use ATP for energy and lack a cytoplasmic core like ____
pili
99
Archaella consist of ___________ called _______
- glycoproteins
- archaellins
100
_________ are a group of bacteria that have unique structure and motility
Spirochetes
101
One of the best-known spirochetes
Treponema pallidum
102
Treponema pallidum
the causative agent of syphilis
103
Another example of spirochete
Borrelia burgdorferi
104
Borrelia burgdorferi
the causative agent of Lyme disease
105
Spirochetes move by means of
axial filaments, or endoflagella
106
bundles of fibrils that arise at the ends of the cell beneath an outer
sheath and spiral around the cell
axial filaments, or endoflagella
107
Bacteria that contain hairlike appendages
Gram-negative bacteria
108
Hairlike appendages in many gram-negative bacteria
- shorter
- straighter
- thinner
(than flagella)
109
These hairlike appendages consist of a protein called
pilin
110
The arangement of the protein pilin
arranged helically around a central core
111
Two types of pilin
- fimbrae
- pili
112
- can occur at the poles of the bacterial cell
- can be evenly distributed over the entire surface of the cell
Fimbriae (singular: fimbria)
113
Fimbrae are involved in forming ________ and other aggretions on the surfaces of _____, _____, and _____
- biofilms
- liquids, glass, and rocks
114
Example of a bacteria help
the microbe colonize mucous membranes
Neisseria gonorrhoeae
115
Neisseria gonorrhoeae
the causative agent of gonorrhea
116
- usually longer than fimbriae
- number only one or two per cell
- involved in motility and DNA transfer
Pili (singular: pilus)
117
One type of motility where a pilus extends by the addition of subunits of pilin makes contact with a surface or another cell, and then retracts (powerstroke) as the pilin subunits are disassembled
Twitching motility
118
- kind of twitching motility (dko sure kung kind ba ni sya basta tung "model")
- results in short, jerky, intermittent movements
Grappling Hook Model
119
- the smooth gliding movement of
myxobacteria
- provides a means for microbes to travel in environments with a low water content, such as biofilms and soil
Gliding motility
120
- is a complex, semirigid structure responsible for the shape of the cell
- fragile plasma (cytoplasmic) membrane
- protects it and the interior of the cell from adverse changes in the outside environment
Cell wall
121
What macromolecular network a bacterial cell wall has?
peptidoglycan (also known as murein)
122
Cell wall of a Gram-positive bacteria
- consists of many layers of peptidoglycan
- forming a thick, rigid structure
123
The space between the cell wall and plasma membrane of gram-positive bacteria
Periplasmic space
124
Two classes of teichoic acids
1. lipoteichoic acid
2. wall teichoic acid
125
lipoteichoic acid
- spans the peptidoglycan layer
- linked to the plasma membrane
126
wall teichoic acid
linked to the peptidoglycan layer
127
Cell wall of a Gram-negative bacteria
consist of one or a very few layers of peptidoglycan and an outer membrane
128
a gel-like fluid in the periplasmic space of gram negative bacteria
periplasm
129
- proteins in the membrane
- permeable
porins
130
a large, complex molecule that contains lipids and carbohydrates
lipopolysaccharide (LPS)
131
Three components of lipopolysaccharide (LPS):
1. lipid A
2. a core polysaccharide
3. O polysaccharide
132
- lipid portion of the LPS
- embedded in the top layer of the outer membrane.
Lipid A
133
When gram-negative bacteria ____, they release lipid A, which functions as an _________
- die
- endotoxin
134
Lipid A role
responsible for the symptoms associated with infections by gram-negative bacteria such as fever, dilation of blood vessels, shock, and blood clotting
135
- attached to lipid A
- contains unusual sugars
Core polysaccharide
136
Core polysaccharide role
structural, provide stability
137
- extends outward from the core polysaccharide
- composed of sugar molecules
O polysaccharide
138
O polysaccharide function
- antigen
- useful for distinguishing serovars of gram-negative bacteria
