Bacterial Cell Structure & Growth Dynamics Flashcards
1
Q
Bacterial cell structure
A
Cell wall
Structure internal to cell wall
Structures external to cell wall
Spores
2
Q
Structures internal to cell wall are 2,
Cytoplasm contain …
Cytoplasmic membrane, contain……
A
Mesosomes
Ribosome
Inclusion granules-storge-
Bacteria granuloma
cytoplasmic membrane (selective permeability)
3
Q
Structure external to cell wall and there function
A
Capsule –>antiphagocytic
Glycocalyx(cell coat)–>adherence
Flagella –> motility
Pilli—-> adherence
4
Q
Essential (basic) components in cell
A
Cell wall
Cell membrane
Ribosome
Chromosomes
5
Q
Bacterial genome [dna]
1/
2/
A
Chromosomes (nucleotid)
Plasmid
6
Q
What is cell wall?
A
The cell wall is a multilayer structure immediately external to the cytoplasmic membrane.
The outermost basic structure in all bacteria
7
Q
The main strengthening component of cell wall is
A
Peptidoglycan
8
Q
Composition of peptidoglycan
A
> alternating NAM(N-actetyl muramic acid ) & NAG (N-acetyle glucosamine)
> terapeptides : 4 amino acid attach to NAM
نام ناجي 4 ساعات بين البيبتيد
9
Q
Composition of peptidoglycan
A
> alternating NAM(N-actetyl muramic acid ) & NAG (N-acetyle glucosamine)
> terapeptides : 4 amino acid attach to NAM
> peptide crosslink
9
Q
Composition of peptidoglycan
A
> alternating NAM(N-actetyl muramic acid ) & NAG (N-acetyle glucosamine(basic)
> tetrapeptides : 4 amino acids attach to NAM
> peptide crosslinking between each 2
tetrapeptides[ gives the wall its strength ]
10
Q
Composition of peptidoglycan
A
> alternating NAM(N-actetyl muramic acid ) & NAG (N-acetyle glucosamine)
> terapeptides : 4 amino acid attach to NAM
نام ناجي ٤ ساعات بين البيبتايد
11
Q
Composition of peptidoglycan
A
> alternating NAM(N-actetyl muramic acid ) & NAG (N-acetyle glucosamine)
> terapeptides : 4 amino acid attach to NAM
12
Q
Composition of peptidoglycan
A
> alternating NAM(N-actetyl muramic acid ) & NAG (N-acetyle glucosamine)
> terapeptides : 4 amino acid attach to NAM
13
Q
من ملزمة الدكتور
Function of peptidoglycan
A
1/ rigidity or osmotic protection –> support weak cytoplasmic membrane against high internal osmotic pressure –> prevent osmotic ruption
2/structure toxic
14
Q
Name tetrapeptides
A
L-alanine
D- glutamate
Diaminopimelic acid
D- alanine
15
Q
Garm +ve cell wall contain
A
Petidoglycan
Teichoic acid, lipoteichoic acid
16
Q
Composition of gram -ve cells
A
Peptidoglycan
Outer membrane
17
Q
What is nucleoid?
A
Area of cytoplasm where dna is located
18
Q
In which type of bacteria , peptidoglycan is 40 sheet ?( 50% of wall Thickness)
A
Germ + bacteria
19
Q
Peptidoglycan in germ - is_____ about _____ sheet [ ___ % cell wall Thickness
A
Thin
1-2
5-10 %
20
Q
What dose outer membrane contain
A
LPS
Embedded protein
من الملزمة
Inner part( lipo-protein)
21
Q
What does LPS contain ?
A
Inner lipid A: endotoxin ( يطلع من بكتيريا بعد ما تموت)
Outer O-polysaccharides –>
O-somatic Ag (خارجي somatic)
22
Q
What is embedded protein ?
A
Porins and outer membrane protein OMPs
23
Q
The space between outer and inner membrane is called
A
Periplasmic space
24
What is inner membrane?
Cytoplasmic membrane
Inner layer نعتبرها
25
Function of teichoic acid
Structural toxic
Adherence to host cell إلتصاق
Antigenic
26
Types of Teichoic acid
Cell wall Teichoic acid , produced from peptidoglycan
Or
Attached to cell membrane: (lipoteichoic acid) or membrane teichoic acid
27
Composition of teichoic acid
Formed of a polymer of ribitol or glycerol phosphate
28
Function of cell wall
Sot andish
Staining reaction by gram stain
Osmotic protection,Dr: supports weak cytoplasmic membrane
Toxic :Structural Toxic
--> peptidoglycan I and teichoic acid
--->lipid A:endotoxin
Antigenicity --> teichoic acid and somatic O--> identification of bacteria
Cell division
Shape of cell
Coccal عصى
Bacillary
Spiral حلزونا يما الحلزونا
29
Name the 2 forms that can occur in bacteria due to cell wall deficince (بمعنى خسارة جدار الخلية يحدث نتيجة )
Spontaneously نتيجة طفرة
Induced by laboratory manipulation
Mycoplasma (natural occurring)
29
Name the 3 forms of cell wall deficient
Protoplast
Spheroplast
L-form
29
protoplast occur in which type of cell?
Gram +
30
What causes protoplast form ?
Lyzosmes
31
What is protoplast ?
A form of bacteria caused by lysosomes in which peptidoglycan or cell wall is lost
31
Spheroplast occur in which kind of bacteria?
Gram -
32
Spheroplast is induced by
Lysozome on EDTA(مادة تسهل وصول الليزوزوم إلى طبقة جدار الخلية )treated bacteria gram - cell
Or action of Ab
33
L form is named by
Lister institutions in UK
33
What is L form
Spheroplast and protoplast that are able to grow and divide
They can revent to the normal cell wall form upon removal of the inhibitor
34
Clinical significant for L form in vivo
Resistance to Ab -->may cause chronic infection and relapse
Relapse يعني تعود الأعراض بقوى
34
Clinical significant of L form in laboratory
genetic engineering
weakened cell wall facilitate transport genetic material between cells
لولو(L form) تعود مزمنة(chronic) ومنتكسة(relapses)، استخدمها في الهندسة الوراثية
35
Function of cell wall
Sot andish
Staining reaction of gram stain
36
.
.
37
What is mycoplasma bacteria?
Natural absence of CW (without inducer)
38
Different between L form and mycoplasma
No reversion to CW state (difference from L-forms)
39
- Structures Internal To Cell Wall
Cytoplasmic membrane (CM)
Mesosomes
Cytoplasm of bacteria (Ribosome, storage granules , DNA)
40
- Cytoplasmic membrane (CM)
Composition:
Phospholipid bilayer containing proteins
No sterol(like collateral, it is a lipid)except in Mycoplasma
Osmotically sensitive(will boom due to osmotic sensitive)
41
Function of cytoplasmic membrane
Dr.sese
1- Selective permeability: Most important function of plasma membrane
2- Secretion of:
a.Exotoxins
b.Extracellular Enzymes
3- Cell division
4- Respiration & generation of energy: contains cytochrome (respiratory) enzymes
42
Invaginations of Cytoplasmic membrane into the cytoplasm
Mesosomes
43
Function of Mesosomes
1-↑ surface area →↑ active transport
2- Site of respiratory enzymes 3-Cell division
DRS mezo
44
Structure of Ribosome
RNA + proteins
45
Subunits of Ribosome
Subunits:
50S(sedimentation) & 30S: Aggregate only during protein synthesis →70S Ribosome
46
Function of Ribosome
Protein synthesis
47
Inclusion granules character
Characters: Not essential or permanent --->
Absent under certain conditions of growth
48
Functions of inclusion granules
Storage of nutrients (glycogen, lipids & polyphosphates)
49
E.g for inclusion granules
Examples: Volutin granules in Corynebacterium diphtheriae(responsible for pseudomembrane)
50
Bacterial chromosome (Nucleoid) are _______ strand with ____shap
Single
Circular
51
Length of bacteria chromosomes is ____
1 mm long
52
The bacteria size is ______ micron, so how could chromosomes in its exist in such a small space ?
0.1-5 μm
Chromosomes are Supercoiled
53
Bacterial chromosome doesn't have
Nuclear membrane, Nucleolus, or Histones
54
What dose bacteria dna carries
Carries essential genes controlling Properties & Pathogenicity
55
What is Plasmid?
• Circular Ds DNA
• In Gram +ve & -ve bacteria
• Extrachromosomal & smaller than chromosome
More in genetic
56
Carry non-essential genes
Plasmid
57
Capsule site
Firmly bound to cell wall
58
Glycocalyx (slime layer) is
Loosely attached → Covers bacteria surface like a biofilm
59
Bacterial Replication
occur by
Simple binary fission
60
Formation of Glycocalyx
inside host tissues(if in vivo)
61
Structure of capsule
Polysaccharide (mostly)
Polypeptide
Hyaluronic acid
62
Structure of Glycocalyx
Polysaccharide
63
Function of capsule
1- Virulence factor(عوامل قوة)
Antipathocytic and Adhesion to mucus membrane
2- Antigenic
vaccine preparation
(فاكرين السؤال الخازوق إلؤ نزل آخر السنة) and identification of bacteria
64
Function of Glycocalyx
Virulence factor:
firm adherence to
a) Skin, heart valves & teeth
b) Prosthetic joints & catheters
65
Stain of capsule is
Capsular Stain
(unstained halo by Gram stain)
66
Shap of Flagella
Long & thick (في الكتاب قال thin)
67
Origination of Flagella
From cytoplasm and extruded through the cell wall
68
Composition of Flagella
Flagellin protein →
Antigenic (H Ag)
69
Flagella is more common in _____ bacteria than cocci bacteria because most cocci aren't _______
Bacilli
Motile
70
Function of Flagella
1- Motility :
Toward favorable environment & nutrients
Away from adverse ones
2- Virulence factor:
Motility promotes adhesion and/or invasion
3- Antigenic: H Ag → identification of bacteria
71
Stain of Flagella is
Flagellar stain (not stained by Gram stain)
72
Shap of pili(fimbrine)
Shorter & thinner than flagela
73
Composition of pili
Pilin glycoprotein → Antigenic
74
Types of pili
Ordinary pili
Sex piliانبوبة
75
Ordinary pili function
1-Virulence factor: Firm adherence
2-Antigenic
76
Sex pili are
Conjugation (gene transfer between bacteria)
Longer than ordinary pili
77
Who have higher adherence, ordinary or sex pili
Ordinary pili
78
Spores are
Highly Resistant & Resting form
2R
79
What do you mean by resting form
Metabolic inactive (dormant) & non-reproductive
80
> Type of bacteria with ability of spores
Type of bacteria Some Gram +ve bacteria
e.g Bacillus & Clostridium
81
Antigens in bacteria
1. Cell wall --->techoic acid and somatic O
2.capsule
3.flagella H Ag
4. Pilli
82
Formation of spores
In vitro (outside the body) by exposure to unfavorable conditions
83
E.g for unfavorable conditions for bacteria to become a spore
a) Depletion of nutrients (starvation)
b) Accumulation of toxic substances
c) Unsuitable moisture (dryness) or temperature (heat)
STDH
84
H
T
85
Medical importance of spores
Highly resistant to:
a) Dryness → survive in soil for years (due to coat)
b) Chemicals: e.g disinfectantsمطهارات
c) Heat: Not killed by boiling at 100°C, but are killed at 121°C (autoclave)
Drch درش
86
Stain of spores
Spore stain (unstained by Gram stain)
87
Germination into vegetativeالشكل الأصلي form In vivo
on exposure to appropriate nutrients & H2O → Multiplies & cause disease
88
Causes of resistance in spores
1- Impermeability of outer coat (keratin-like)
2- High content of Ca dipicolinate in cytoplasm (only in spores)
89
Bacteria growth is
Definition: ↑ in size & number of bacteria
90
Bacteria growth requirements
Requirements:
Chemical: Nutrition- Gases
Physical: Temperature-pH-Osmotic press
91
What is Generation (doubling) time
Time required by bacteria to double its number.
Varies according to type of organism & environmental conditions
92
E.coli doubling time is
20 minutes (short) in E.coli
93
TB generation time is
18 hours (long) in M. TB
94
-- Chemical Requirements are
A-Nutritional Requirements
B- Gaseous Reguirements
95
Nutritional Requirements
1- Carbon & Nitrogen source
2- Mineral elements
96
According to Carbon, bacteria may be:
Autotrophic ذاتية التغذية
Heterotrophic غير ذاتية التغذية
97
Carbon of Autotrophic is
Inorganic
98
E.g for inorganic carbon sources
Co, & inorganic salts
They are utilized by autotrophic
99
What type of bacteria is autotrophic bacteria
Free living (saprophytes) --->
Non-pathogenic
تحس السؤال فيه غزل 😅
وطبعا يدرسونا تبعين كلية الزراعة
100
Hetrotrophic bacteria carbon is
Organic
101
Sources of organic carbon
Protein, CHO & lipids from living host
102
Heterotrophic according to Nitrogen requirements
Exacting كثيرة المطالب
Non-exacring
103
Name bacteria Utilize organic source of N
Exacting bacteria
104
Utilize inorganic source of N
Non exacting
105
E.g for non exacting bacteria
e.g nitrates
106
Exacting bacteria Grow only in ______ containing specific growth factors
Culture
Like fluid or solid Culture
107
specific growth factors of exacting bacteria
Amino acids, purines, pyrimidines & blood
108
Fastidious bacteria are
Requiring large number of growth factors
OR complex nutrition
109
E.g Fastidious bacteria
Mycoplasma
110
Types of Heterotrophic bacteria
Pathogenic OR commensals (flora)
الممرضة أو المتعايشات (النباتات)
111
- Mineral elements:
Bacteria require small amounts of Phosphorus, sulfur, Ca & Mg
Dr: كل دي تشتغل كco-enzyme , اكيد اخذتها في البايو
112
-Gaseous Requirements are
O2 requirements:
CO2 requirements:
113
Toxic O2, metabolites (ROS) produced by O2, consumption are degraded by 2 enzymes :
Superoxide dismutase (degrades O2 سامة للخلية ) &
Catalase (degrades H2O2 برضوا سامة للخلية)
114
If Toxic O2 metabolites (ROS) are not degrades, this will cause
Death cell
115
O2 requirements are
Facultative anaerobes
Microaerophilic
Obligate aerobes
Obligate anaerobes
116
Obligate aerobes Growth only in
presence of high concentration of O2
117
Obligate anaerobes growth environment
Only in absence of O2
118
In presence (better) or absence of O2
Facultative anaerobes
119
Microaerophilic bacteria growth environment
In presence of low concentration (tension) of O2
هي تحتاج اوكسجين ولكن بكميات قليلة
120
Name bacteria that Contain these ROSand who does not contain them too, SOD(Superoxide dismutase)& Catalase
Obligate anaerobes(no)
Microaerophilic
Facultative anaerobes
Obligate aerobes
121
Generation of energy bu obligate aerobes
Aerobic respiration
122
Generation of obligate anaerobes
Anaerobic respiration
Fermentation التخمر
123
Generation of energy by Facultative anaerobes
Aerobic respiration (better)
Anaerobic respiration & fermentation
124
E.g for obligate anaerobe
Clostridia
125
E.g for obligate aerobes
Mycobacterium TB
126
E.g for Facultative bacteria
Most pathogenic bacteria
127
E.g for Microaerophilic
Campylobacter
128
CO2 requirements are
most bacteria need only CO2 in air (0.03%)
Some are Capnophilic: need a higher con. of CO2 (5-10%)
129
E.g for bacteria need high concentration of CO2
Pathogenic Neisseria
نايسيريا
130
Physical requirements:
Temperature -->bacteria that can live in -5 to 25 °C range are called
Psychro(برودة)philic
Non pathogenic
131
Bacteria live in range of 25 to 45 °C
Mesophilic دي بتاعتنا احنا
Pathogenic
132
Range of Thermophilic
45 to 75 °C
Non pathogenic
133
Optimum temp of psychrophilic
15
134
Optimum temp of Mesophilic is
37°C
135
Optimum temp of Thermophilic is
60°C
136
Hydrogen ion concentration (pH) of most bacteria
6.5-7.5
137
Hydrogen ion concentration (pH) of
Lactobacillus
pH= <4
Acid
138
Hydrogen ion concentration (pH) of Vibrio cholera is
Alkaline pH= 8
139
Name bacteria grow in high salt
Halophilic (very few)
140
E.g for halophilic
Marine (تنتقل عبر sea food)
141
Most bacteria Grow in ______ medium (1% NaCl)
Isotonic
142
Isotonic media is
Same salt concentration in cytoplasm & environment
143
[Bacterial Growth curve measure
the number of viable cells in a fluid culture medium over time مستنبتات
144
[Bacterial Growth curve phases are
1- Lag phase تأخر
2- Exponential (logarithmic) phase نمو متسارع
3- Stationary phase ثبات
4- Decline (death) phase هبوط
145
What happens to bacteria in the Lag phase
Adaptation by forming new enzymes
146
Number remains constant but (↑ in size) in which phase
Lag phase
147
Length of lag phase is
(1 hour to days)
148
Length of lag phase(1 hour to days) depends on:
a) Type of organism
b) Type of medium
c) Size of inoculum(التلقيح)
149
Clinically of lag phase is
Incubation period الحضانة
150
Most active phase is
Exponential (logarithmic) phase
151
Why is the Exponential phase the most active
Rapid ↑ in number
Highly susceptible to antibiotics
152
Exponential phase Continues until:
a) dec. nutrients
b) ↑ toxic metabolites
153
•Clinically Exponential phase
Clinical signs & symptoms الأعراض
154
Name bacteria species that grow in pH = 8
Vibreo cholera
