Chapter 1 Flashcards
definition of Microbiology is ?
study of microorganism
microorganism mean
microscopic organisms that vary in term of shape,size,structure and importance.
The various categories of microorganisms include?
bacteria ,protozoa,algea and Fungi
Where we can found the microorganisms in our body ?
skin mucous membrane, nose throat gastrointestinal tract (GIT) vagina
True or false
Microorganisms are ubiquitous and the majority are harmful
False
It’s harmless
True or false
Microorganisms can live inside your body and can’t live out side
False
Microorganisms can live inside or outside your body
Full the gap
(Germs) generally can be divided into(1)…… group based on (2)…….. to
(1) -3 group
(2) -cell type
What is the Types of organisms?
Eukaryotic organisms:
1/This group of organisms have a complex cellular structure similar to human
and animals.
2/includes fungi and parasite.
3/having a nucleus and mitochondria
4/capable of independent life
#Prokaryotic organisms: 1/Those organisms are unicellular 2/not having an organised nucleus. 3/usually capable of independent life 4/such as bacteria
1/Those organisms simply have either DNA or RNA with other components such as protein.
2/Can’t capable of independent life
3/viruses are not typically considered organisms because they are incapable of autonomous reproduction growth or metabolism.
viruses are not typically considered organisms why ?
because they are incapable of autonomous reproduction growth or metabolism.
Definition of General Microbiology?
the study and classification of microorganisms and how they function
Definition of Medical microbiology?
the study of microorganisms that cause disease
Definition of Infection:
invasion of the host (our bodies) by microorganisms. Infection can be either asymptomatic or symptomatic
what the difference between Endogenous source and Exogenous source?
Endogenous source: microorganisms that originate from patient’s flora. organisms and live in the human body (skin, mouth and intestine) without causing harm to the human body
Exogenous source: microorganisms can be transmitted from other patients, animal, contaminate object, foo or water.
Definition of Opportunistic pathogen:
microorganisms that are not usually causing infection. However, it can be life-threatening if the patient is immune-compromised
Definition of Colonisation?
the presenc of bacteria at an expected site e.g large intestine and skin
What do we mean by Pathogen?
microbes that cause harm to our bodies e.g. tissue damage
What do we mean by Microbial genetics?
the study of structure and function of microbial DNA
Veterinary microbiology is ?
study of how to prevent spread and
control of infectious disease among animals
Agricultural microbiology mean ?
studies of different microorganisms that are both harmful and or beneficial in soil formation and fertility.
Sanitary microbiology mean ?
this includes processing and disposal of garbage and sewage waste as well as purification and processing of water supply
All living cell divided into two groups Are?
eukaryotic and prokaryotic.
Mention the Eukaryotic cell types?
Animals,plants, fungi, protozoans, and algae
Mention the Prokaryotic cell types?
bacteria & blue green algae
True or false
Eukaryotic cells are much smaller (microns) and simpler than Prokaryotic
cells()
False
Prokaryotic cell consists of fluid cytoplasm which is surrounded by thin, elastic and semipermeable————
Cytoplasmic membrane
The cytoplasmic membrane covered by a Rigid supporting porous is———-
Cell Wall
True or false
Prokaryotic cells have true nucleus and have mitochondria ()
False does not have true nucleus and mitochondria
True or false Bacterial cell is consists of cytoplasm packed with chromosome, ribosomes and protein ()
True
The additional structure of Bacteria Are?
plasmid, capsule, flagella, fimbriae (pili) and spores.
Describe cell wall of bacteria?
- Provide the rigidity
- Support the shape
- Protect the cytoplasm and organelles
- Outermost layer
- It is 10-25nm thick
Based on the morphology of the cell wall, bacterial cell can be classified into
four classes Are?
1-Cocci (spherical) 🔵
2-Bacilli (rods or short rods (Coccobacilli)), 🥢
3-Spiral forms (Comma shaped, S shaped, spirals) 🍤🥓
4-Pleomorphic (lack a distinct shape)
True or false
all species consists of the strengthening component which is a peptidoglycan layer
True
Peptidoglycan composed of what?
Is a complex of polysaccharide that composed of N acetylglucosamine (NAG) and N acetylmuramic acid (NAM)
Mention the function of peptidoglycan?
- protecting the bacterial content
- maintaining the bacterial shape,rigidity and playing a role in cell division
What is the purpose of Chemical nature in cell wall?
helps to divide bacteria into two broad groups: Gram positive and Gram negative
What is the use of Gram staining technique?
help in distinguishing the gram-positive bacteria with thick cell wall and the gram-negative bacteria with thin cell wall.
Differentiate between Gram positive bacteria and gram negative bacteria?
Gram +ve / thick cell wall(peptidoglycan) have Teichoic acids and lipoteichoic acids ,stain dark violet ,sensitive to Antibiotics and chemicals and the structure more simpler than-ve
هنا البيبتو اكثر والليبيد اقل
Gram -ve / thin cell wall mainly single layer peptidoglycan have lipoproteins,the outer membrane includes poring, have lipopolysaccharide
هنا البيبتو اقل والليبيد اكثر
Describe the Cytoplasmic(plasma) membrane ?
- Thin layer
- 5-10nm thick
- Composed of phospholipid and proteins
- Act as semipermeable
- Control the inflow and outflow of material.
What is the use of Ribosomes?
responsible for protein synthesis
What is the use of Intracytoplasmic inclusions?
to reserve of energy & phosphate for cell metabolism e.g. Metachromatic granules in diphtheria bacilli
True or false
Mesosomes mainly in gram negative bacteria ()
False in +ve
Mesosomes act as?
1-Principal sites of respiratory enzymes.
2. Coordinate nuclear & cytoplasmic division
The genetic information of bacteria is?
Bacterial nucleoid it is single circular and have double strand DNA
True or false
The DNA lies within the cytoplasm with no nuclear membrane in bacteria ()
True
——————Extranuclear genetic elements consist of DNA that can be transmitted to daughter cells via binary fission or from bacteri to another
Plasmid
Plasmid has certain properties……………&…………………
drug resistance, and toxicity
✅❌
Capsule
Viscous layer secreted around the cell wall by bacteria.It consists of protein in nature.
❌
polysaccharide/ polypeptide
Capsule protect bacterial cell from………&……………
lytic enzymes and phagocytosis
Capsule can be stained by 1……………using India Ink. Also,it can be demonstrate by 2…………………
1-negative staining
2-Quelling reaction(capsule swelling reaction).
……………………It is thinner structure similar to capsule and has fibrillar appearance Slim layer act as adhesion
Glycocalyx
Flagella is ………………
Motile bacterial possess filamentous surface appendages which is defined as flagella.
✅❌
Flagella it’s organ of locomotion
✅
Flaggella composed of proteins called ……………….
flagellins
❌✅
number and distribution of flagella on the bacterial surface are characteristic for a given species and useful in identifying and classifying bacteria
✅
Type of flagellar arrangement:
Polar/ Monotrichous: a single flagellum at one pole.
• Lophotrichous: tuft of flagella at one pole.
- Amphitrichous: flagella at both poles.
- Peritrichous: flagella all over.
- Amphilophotrichous –tuft of flagella at both ends.
…………………thin hair like appendages found on the surface of many Gram-negative bacteria.
Fimbriae
……………………… organs of adhesion(attachment) which allows bacteria to colonize environmental surfaces.
Fimbriae/Pili:
Pili consists of proteins called ……………
pilins
Pili types are
Pili could be short and abundant (common pili)
small number (one to six)
very long and process transfer of DNA (sex pili).
……………… are highly resistant resting stages formed during adverse environment
(depletion of nutrients)
Spores
If the spores formed inside the parent cell, hence called……………
Endospores
Spores are very resistant…………&……………&…………
heat
radiation
drying.
✅❌
Spores can remain dormant for hundreds of years e.g. bacteria like Clostridia, bacillus
✅
Medically importance properties of bacteria are determined by genetic information contained within the bacterial cell. This includes information about…………&………&…………
virulence
pathogenicity
antibiotic resistance
Also, bacteria can carry extra-chromosomal materials that can replicate independently of the main chromosome which is defined as a ………………and carries supplementary materials such as …………………
plasmid
resistance toantibiotic
Mutations can be ………………&……………
point & Multisite
Multisite mutations are determined when an extensive gene rearrangement happened (inversion or deletion)
while point mutations are defined when only one or few nucleotide/s is/are affected (substitution, insertion or deletion)
………………………… change in gene expression in response to environment (induction or repression of specific enzyme)
Phenotypic variation
……………………properties of bacteria ell at a particular time
Phenotype
✅❌
Gene alteration is only caused by mutation
❌
could result from the acquisition of additional DNA from a external source
DNA may be transferred between bacteria by three mechanisms:
1) Transformation: taken up of exogenous DNAfrom the environment
2) Conjugation: transfer a fragment of DNA from one bacterium to another (from donor bacterial cell to recipient bacterial
Transduction: transfer of DNA from bacteria to another by the means of bacterial virus(phage)
Taxonomy is providing …………&…………&………… for organisms
universal names like ID
identifying
classification
………………grouping of the organisms in order.
Classification
………………… related to the naming of the organism
Nomenclature
…………………is related to clinical practice to identify the organisms correctly
identification
The taxonomic ranks used in the classification is going to be in what is the following order:
- Kingdom
- Phylum (pl. Phyla)
- SubPhylum
- Class
- Order
- Family
- Genus (Pl. Genera)
- Species (Pl. Species)
- Subspecies/Strain
1………………population of cells with similar characteristics.
2………………: population of cells derived fro a single cell.
3…………………genetically different cells within a clone.
1-Species
2-Clone
3-Strain or variety
subspecies that can show differences in ……………&……………&………………
antigenic makeup (serotype or serovar),
susceptibility to bacterial viruses (phage type)
pathogenicity (pathotype)
The main groups of bacteria are mostly distinguished
by……………………………
microscopic observation of their morphology (staining)
Bacteria can be classified based on gram stain of the cell
shape (microscopic morphology),
colony morphology (macroscopic morphology)
biochemical reactions.
biochemical (physiological) reaction
chemical analysis,
serological analysis
genetic relatedness (molecular analysis)
Bacterial system divided in to :
Phylogenetic Classification System
Phenetic Classification System
The major phylogenetic groupings of medicall significant bacteria are:
Actinobacteria
Firmicutes
Proteobacteria
Bacteroidetes
Spirochaetes
Chlamydiae
……………… which are strict intracellular parasites
Chlamydiae
……………possessing cells with a tight spiral shape and an internal
Spirochaetes
…………… is Gram-negative anaerobes.
Bacteroidetes
These characters for any kind of Phylogenetic Classification System
…………………
is very large group of Gram-negative bacteria(bacilli and
cocci) with five subdivisions(alpha, beta,gamma, delta and epsilon).
Proteobacteria
These characters for any kind of Phylogenetic Classification System
……………………
Gram-positive bacteria with low G + C content including bacilli, some of which are spore formers and cocci the group include most of the medically significant Gram-positives.
Firmicutes
These characters for any kind of Phylogenetic Classification System
………………Gram-positive bacteria with a high G + C content, many which are capable of filamentous growth with true branching and which may produce a type of mycelium.
Actinobacteria
Phenetic Classification Systemis …………………
Groups do not necessarily reflect genetic similarity or evolutionary relatedness. Instead, groups are based on convenient or observable characteristics
Phylogenetic Classification System is …………………
Groups reflect genetic similarity and evolutionary relatedness
Binomial or binary nomenclature is a formal naming system that gives the microbe two names:
- Genus (always capitalized) 2. Species (lowercase)
Media divided into 6types what are they?
1-Nutrient Media: Media used to grow most of microorganism(non fastidious)
2-Enriched media: Media used to grow the fastidious organism. This media is supplemented with various substance
3-Selective media: used to grow some microorganisms and inhibit the growth of the other. Some substance is used for microbial growth inhibition such as antibiotics
4-Non selective media: media used to enhance the growth of many organisms but it does not have antibiotic
5-Differential media: media used to differentiate between microorganisms
based on metabolic differences
6-Enrichment broth: media used to enhance the growth of some organisms and inhibit the growth of others
✅❌
Most of microorganism can be identified generally based on the gram stain and cell shape
✅
✅❌
The biochemical reactions are required to distinguish between bacterial Species.
✅
Indirect identification methods are ……………&…………&…………
- Gene targeted analysis
- Antibody reaction
- Latex agglutination
- Enzyme linked immunosobent assay
- Haemagglutination and haemadsorption
- Fluoresence microscopy and immunofluorescence
- Immuno polymerase chain reaction
- Biotyping
- Serotyping
- Phage typing
Bacteria grow by ?
binary fission(cell enlarge and divide into two cells).
Bacterial growth is defined as the ability of the bacterial cell to propagate when placed in suitable condition what are these conditions?
nutritious environment and under appropriate physically and chemical conditions
Bacterial growths are indicated by increasing ………&…………
the size of the organism and
increase the cell number
Bacterial growth is measured by 2 methods
by viable counts(colonies count: macroscopic product of 20- 30 cell division) and nonviable counts (Turbidity: when a clear media transformed to turbid(107- 109 cell per ml)) (2).
The time required for the bacterial cell to divide into two cells is defined as ………………
generation time
There are four phases for bacterial growth:
Lag phase
Log (exponential)phase:
Stationary phase:
Decline phase:
What happens in Lag phase?
When the growth is initiated in the presence of appropriate media. There is no increase in cell number. The increase is only in cell size(The growth factor, The cell number N=N0).Bacteria have the maximum cell size towards the end of this phase).
The duration of the lag phase varies with the size of inoculum, nature of culture medium & environmental factors such as temperatur
What happens in Log(exponential)phase:
At this stage, the cells start to divide and the number is increased.A straight line is obtained in this phase (µ =µmax= constant,N increases)
What happens in Stationary phase:
In this phase, cell division stops dueto depletion of nutrients & accumulation of toxic products and sporulation could occur at this stage. The viable count remains stationary:N=Nmax =constant, µ=0.
What happens in Decline phase:
Population decreases due to cell death. Nutritional
exhaustion&toxic accumulation occurs Involution forms are common in this phase and N decreases and µ<0.
Bacterial physiology is defined as the process that enables an organism to live in a particular environment. This includes?
chemical(energy source)
and physical(temperature and pH)
In general, bacteria requires an energy source, carbon source,proper pH,water and minerals to grow
What the difference between chemotrophs & heterotrophs
Bacteria are chemotrophs that’s because their ability to oxidise chemicals and used them as a source of energy. Regard the carbon requirements, bacteria are
heterotrophs that’s because bacteria use organic carbon as the sole carbon source
Physical requirement for bacteria is 3 what are they?
Growth atmosphere:
Growth temperature:
pH
Explain PH in Bacteria?
Bacteriain general prefer the neutral pH (7.2). However, there are some exceptions such as: Lactobacillus spp prefer the acidic medium (pH4) to grow and Vibrio cholerae prefers the alkaline medium (pH8.5)Further, mold and yeast grow between pH 5and6.
————————The inactivation of all self-propagating biological entities (e.g. bacteria, viruses, prions) associated with the materials or areas under consideration
Sterilization
Disinfection is …………………
The reduction of pathogenic organisms to a level at which they no longer constitute a risk
—————-Term used to describe disinfection applied to living tissue such as a wound
Antisepsis
Degerming is —————-
Remova of microbes from a limited area
………………Lower microbial counts on eating utensils(spoon,knife,etc)
Sanitization
Bacteriostasis is —————
Inhibiting (not killing) bacterial growth
………………the process that Kills bacteria
Bacteriocidal
✅❌
Microbial killing can be achieved by two varied approaches and classified into physical and chemical approaches.
❌
Five varied approaches
يعني عندنا ٥طرق لقتل القتل المايكروب صنفوهم ل٢ رئيسيات هم طرق فيزيائية وكيميائية
What’s the Physical methods that used in sterilization and disinfection?
Heat (Moist &Dry) Pasteurisation RadiationFiltration Cold Desiccation Osmotic pressure
What’s the chemical Methods that used in sterilization and disinfection?
Phenol Halogens Alcohols Heavy metals Surface active agents Organic acid Aldehydes Gas Oxidizing agents
