TOPIC 2: Definition & Dimension

Flashcards based on those created by @maledine

Microbiology

Branch of biology that deals with the study of microorganisms

1. Bacteriology

2. Virology

3. Mycology

4. Parasitology

5. Immunology

Branches of microbiology

Bacteriology

Study of bacteria (bacterium)

Bacteria

Minute, unicellular organisms that have all the necessary protoplasmic equipment for growth and self-multiplication at the expense of available foodstuffs

Widely distributed

Normal Flora

• Microorganisms that live on another living organism without causing a disease;

• However sometimes, they are opportunistic and adapt by undergoing mutation as they adjust to the environment, which becomes a pathogen

Pathogen

Bacteria/viruses/microorganisms that cause a disease

Virology

Study of viruses

Obligate Intracellular Parasites

Viruses are these, which are parasites that can reproduce only within a living cell (may survive for a short while outside cell, nonliving outside cells)

DNA or RNA, but NOT both

Viruses can either have _________

Capsid (protein shell)

floating shell of the virus

1. Protects nucleic acid from digestion by enzymes. 

2. Contains special sites on surface allowing viruses to attach to host cell. 

3. Provides proteins enabling viruses to penetrate the host’s cell membrane and eject infectious nucleic acid into the cell cytoplasm

3 Functions of the Capsid of a Virus

Bacteriophage

Virus may become this which is a virus that parasitizes a bacterium by infecting it and reproducing inside it.

Naked virus

Identify the type of virus shown.

Virus with capsid inside

Identify the type of virus shown.

Mycology

Study of fungi

1. Yeast (Monomorphic)

2. Yeast & mold/filamentous (dimorphic)

Fungi can either exist as either…

Monomorphic

Fungi that exists as yeast

Dimorphic

Fungi that exists as yeast and mold

Mold

What type of fungi is shown?

Malassezia furfur

What species of a fungus is naturally found on the skin surfaces of humans but may overgrows and interferes with the normal pigmentation of the skin which results to small discolored patches?

Tinea versicolor

Discolored patches on the skin caused by Malassezia furfur

Parasitology

Study of parasites

1. Flagellates

2. Amoebae

3. Sporozoans

4. Nematodes

5. Trematodes

6. Cestodes

Types of Parasites

Trichomonas vaginalis

Identify the parasite (specifically a flagellate) shown in the picture, which is causative agent of the STD trichomoniasis.

Amoeba

Identify the parasite.

Plasmodium

Identify the parasite.

Flagellates

(parasitology)

• Cells/organisms with one or more whiplike appendages (flagella)

Amoebae

(parasitology)

• Single-cell eukaryotic organism with no definite shape and move by means of pseudopodia

Nematodes

(parasitology)

• Round worms

Trematodes

(parasitology)

• Flat worms

Cestodes

(parasitology)

• Tape worms

  • Has hooks that allow it to attach to the host

Ascaris Egg

Identify the type of parasite.

Schistosomes

(parasitology)

• “Loving” flatworms

• Gonochoristic = have distinct sexes (male or female)

• Male surrounds female and encloses with gynecoforic canal and brings female along with him

• Male feeds on host’s blood and passes to the female, as well as chemicals which help females develop

• Sometimes “divorce” when female jump to another male

Elephantiasis

(parasitology)

• caused by parasitic roundworms: wuchereria bancrofti and brugia malayi

Wuchereria bancrofti and brugia malayi

(parasitology)

• parasitic roundworms that cause Elephantiasis

Immunology

Study of the immune system

Cells, molecules and mechanisms, immunity

Phagocytosis

First line of defense in immune system

1. Prokaryotes

2. Eukaryotes

2 classification of organisms based on type of cell organization and function

1. Bacteria

2. Archaea

3. Eukarya

Taxonomists have placed all microorganisms into 3 domains which are:

Prokaryotes

Unicellular organisms that lack a membrane bound nucleus, a mitochondria and other membrane bound organelles

Distinctive structural feature is not what they have but what they lack

Lack membrane surrounding their DNA and nucleus, rather have a nucleoid

What do prokaryotes lack based on light microscopy (LM)?

Nucleoid

In prokaryotes, where the single chromosomal circular double-stranded DNA molecule is located

Lack the membrane-bound organelles

What do prokaryotes lack based on electron microscopy (EM)?

1. Bacteria

2. Archaea

2 domains included in prokaryotes

Archaea (Archaeobacteria)

Domain of bacteria that appears more closely to eukaryotic cells, found in microorganisms that grow in extreme environmental conditions.

1. Nucleotide sequence of their ribosomal RNA

2. Type of lipids in cytoplasmic membranes

3. Chemistry of cell walls

What do Bacteria and Archaea differ in?

Peptidoglycan

What does the archaea cell wall lack which is a major reason why they are placed in a separated domain from bacteria?

Gram (+) Archaea

Archaea that have thick walls and stain purple

Gram (-) Archaea

Archaea that have layer of protein covering cell wall and stain pink

Eukaryotes

Organisms whose cells have a membrane surrounding their DNA forming a nucleus.

Have internal membrane-bound compartments (organelles)

Cells of algae, protozoa, fungi, animals and plants are eukaryotic 

Larger in size and more complex than prokaryotes

Endoplasmic Reticulum

(Eukaryote Organelle)

• Process and transport proteins

Golgi Body

(Eukaryote Organelle)

• Modification of substances and transport throughout the cell, including internal delivery of molecules, and exocytosis or secretion of other molecules

Mitochondria

(Eukaryote Organelle)

• Generate energy (ATP)

Lysosomes

(Eukaryote Organelle)

• Provide an environment for controlled enzymatic degradation of intracellular substances

Nucleus

(Eukaryote Organelle)

• Provide a membrane enclosure for chromosomes

Taxonomy

Orderly classification of organisms into categories

Taxa

Organization of microorganisms that share similar morphologic, physiologic, and genetic traits into specific groups

Based on similarities and differences of genotype and phenotype

Genotype

Genetic makeup of an organism or combination of forms of one or more organisms genome

Phenotype

Observable physical and functional features of an organism expressed (i.e., Microscopy of cells)

1. Domain

2. Kingdom

3. Phylum

4. Class

5. Order

6. Family

7. Genus

8. Species

8 Taxa in order

Domain

(Taxa)

• bacteria, archaea, eukarya

1. Eukarya

2. Bacteria

3. Archaea

According to Carl Woese’s discovery, what are the three domains based on the nucleotide sequence of rRNA?

Kingdom

(Taxa)

• phyla, most inclusive taxa

Phylum

(Taxa)

• have similar classes

Class

(Taxa)

• similar orders

Order

(Taxa)

• similar families

Family

(Taxa)

• similar genera

Genus

(Taxa)

• similar species

Species

(Taxa)

• specific epithet, most exclusive taxa

• ex: areus in Staphylococcus areus

Carl Woese

Who used rRNA sequences to propose a new classification system?

rRNA (ribosomal RNA)

What molecule did Carl Woese study to classify organisms?

Domain

What new taxonomic rank did Carl Woese propose?

One or more kingdoms from the Linnaean system.

In Woese’s system, what does each domain include?

16S ribosomal RNA (rRNA)

What molecule is the 3-domain classification system based on?

Svedberg unit – a measure of sedimentation rate

What does the “S” in 16S rRNA stand for?

Prokaryotic ribosomes, mitochondria, and chloroplasts.

Which cellular structures contain 16S rRNA?

Bacteria

• environmental prokaryote

• cyanobacteria

• heterotropic medically relevant bacteria

Archaea

• environmental isolates that live in extreme environments

• high Na conc, jet fuel or extreme temp

Eukarya

• true nucleus

• contain medically relevant orgs including fungi and parasites

Nomenclature

Term for accepted labels by which organisms are universally recognized

Binomial System

scientific naming system of organisms

Carolus Linnaeus

Developed this system where each organism is given 2 names, the Genus name and the specific epithet. 2 names refer to the species

1. Family name should be capitalized and has an aceae ending

2. The genus name is capitalized and followed by the species epithet

3. Both genus and species should be italicized in print - Staphylococcus aureus but underlined when written in script - Staphylococcus aureus

4. Often the genus name is abbreviated by the use of the first letter of the genus followed by a period and the species epithet -S. aureus

5. Species are abbreviated sp (singular) and spp (plural) if species not specified

Rules for nomenclature

Genus

Comprised of different species that have several important features in common but differs sufficiently to still maintain their status as individual species

First word, example Staphylococcus is this in Staphyloccocus Aureus

Species

• Collection of bacterial strains that share many common physiologic and genetic features and as a group differ notably from other bacterial species

• most basic of the taxonomy groups

subspecies

Occassionally, taxonomic groups as ___ are recognized within a species

1. Biotype

2. Serotype

3. Phagotype

What terms are used for a group within a species that has specific, minor differences?

subspecies

What is a subgroup within a species called when officially recognized in taxonomy?

Biotype

• Same species with the same genetic makeup but displays differential physiological characteristics

• According to biochemical test results

1. Klebsiella pneumoniae

2. Klebsiella oxytoca

2 distinct species within the genus, Klebsiella

Serotype

• Differentiation is the distinct variation within species of bacteria, virus or among immune cells of different individuals classified together based on their surface antigen

Phagotype

• Strain of bacterium that is sensitive to a certain bacterialphage or set of bacteriophages

• Based on the susceptibility of to a certain bacteria

1. Genotypic Characteristics

2. Phenotypic Characteristics

How to identify bacteria?

1. DNA base composition ratio

2. Nucleic acid base sequence analysis or homology

Criteria for genotypic characteristics

Genotypic characteristics

(categories for identification)

• because of the age of genomics, organisms can now be identified by their molecular structures

• by the DNA or RNA components

DNA Base Composition Ratio

(Genotypic characteristics)

• indicates the relatedness of the organisms

• when guanine and cytosine differs by a small percentage, the organisms are not closely related

• relatedness of bacteria is reflected in the chemical makeup of their DNA molecules and they can be quantitatively measured as the mean molar percentage of G + C

Nucleic Acid Base Sequence Analysis or Homology

(Genotypic characteristics)

• Assessed by using Nucleic Acid Hybridization

Nucleic Acid Hybridization

• Refers to a molecular biology technique that measures degree of genetic similarity between pools of DNA sequences

• used to determine the genetic distance between 2 organisms

• Helps assess nucleic acid base sequence analysis or homology

Phenotypic characteristics

(categories for identification)

• expression of the genotype

1. Microscopic morphology

2. Staining characteristics

3. Environmental requirements

4. Nutritional requirements

5. Macroscopic morphology

6. Subcellular properties

7. Resistance profiles

8. Antigenic properties

Criteria for phenotypic characteristics