2016/17 -SAQ Flashcards by Amy Rose

List four features of bacterial cells that distinguish them from eukaryotic cells

1.No membrane bound nucleus
2.Simper cell structure
3.Lack of membrane-bound organelles
4.Presence of cell wall

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Absence of membrane bound nucleus

bacterial cells that distinguish them from eukaryotic cells

Lack true membrane bound nucleus
eukarotic cells: well defined nucleus enclosed by nuclear membrane

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Simpler cell structure

bacterial cells that distinguish them from eukaryotic cells

Bacterial cell: relatively small, simpler cell structure
Eukaryotic: larger, more complex

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Lack of membrane-bound organelles

bacterial cells that distinguish them from eukaryotic cells

Bacteria; lack this
Eukaryotic cells: Mitochondria, ER, Golgi Apparatus, lysosomes, peroxisomes

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Presence of Cell Wall

bacterial cells that distinguish them from eukaryotic cells

Most bacterial cell: Peptidoglycan
Absent in eukaryotic cells except some fungi and algae

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Major Components of biofilm extracellular matrix (ECM)

Extracellular polymeric substances (EPS)
Water
Ions and mineral
DNA
Proteins

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Extracelllarpolymeric substances

Major Components of biofilm extracellular matrix (ECM)

complex mixture: polysaccharides, proteins, nucleic acids, and lipidsmake up the bulk of the ECM
Structural integrity
Protects the resident microbial community from external stresses

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Water

Major Components of biofilm extracellular matrix (ECM)

A lot of water
Hydrated environment
For microbial growth and metabolic activity

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Ions and Minerals

Major Components of biofilm extracellular matrix (ECM)

Calcium
Magnesium
Iron
- For microbial growth and metabolic activity

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DNA

Major Components of biofilm extracellular matrix (ECM)

extracellular DNA (eDNA)
From lysed cells
Structural component
Source of nutrients and genetic material for th resident microbial community

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Protein

Major Components of biofilm extracellular matrix (ECM)

Enzymes
Adhesins
Structural proteins
Diverse roles in biofilm formation, stability and function

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Explain what thee Gram stain is used for?

Laboratory technique
Differentiates bacterial cellsinto 2 major groups based on cell wall structure
>Gram- positive
>Gram- negative

Gram stain- series of sequential steps
Application of crystal violet, iodine, alcohol, and safranin to bacterial cells

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The Gram Stain

What components of the bacterial cell membrane determines the outcome of the staining procedure?

Outcome
- depends on chemical and physcial properties of bacterial cell wall

Physical
- thickness of peptidoglycan layer

Chemical
-Composition of peptidoglycan layer

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Gram-positive bacteria

What components of the bacterial cell membrane determines the outcome of the staining procedure?

Thick layer of peptidoglycan
traps crystal violet-iodine complex
Cells appear purple/blye under light microscope

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Gram-negative bacteria

What components of the bacterial cell membrane determines the outcome of the staining procedure?

Thinner layer of peptidoglycan
Surrounded by outer membrane that contains lipopolysacchararides (LPS)
>Negatively charged

Staining procedure
- Alcohol: dissolves outer membrane, removes crystal violet-iodine complex from the thin peptidoglycan layer> cell appear pink or red after adding safranin

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Why is gram stain useful?

Identifying and classifying bacterial species
Determining antibiotic treatment
Gram negative bacteria generally more resistant to antibiotics
Why> presence of the outer membrane

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What is the regressive theory?

Q: Key aspect of the regressive theory of virus origin?

suggests virus evolved from free-living
Cellular organisms lost their cellular machinery
Became parasitic
Viruses originated from intracellular parasites that lost abbility to replicate independently
Became dependent on host cells for survival and reproduction

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Key aspect of the regressive theory of virus origin?

virus evolved from more complex cellular organisms
Rather than emerging spontaneously from non-living materials
Proposes that viruses evolved from once free-living cells that lost ability: metabolic functions
became dependent on other cells for their survival and replication
Hypothesis supported by large genome viruses: mimiviruses
> complex replicaation cycles that resemblethose of cells

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What do mamavirus, pandovirus and pithovirus have in common?

Giant viruses
1. Large genome size
2. Complex viral structure
3. Ability to infect ameoba
4. Controversial classification
5. Environmental reservoirs

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Large genome size

What do mamavirus, pandovirus and pithovirus have in common?

Larger tha typical viruses

Mamavirus - 600 kilpbases(kb)
Pandoravirus -over 2.5 megabases

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Complex viral structure

What do mamavirus, pandovirus and pithovirus have in common?

Study These Flashcards

Caspids
Nucleocaspids
Multiple Layers of membranes

Ability to infect amoeba

What do mamavirus, pandovirus and pithovirus have in common?

Study These Flashcards

Ameoba: single-celled eukaryoic organisms
Model hosts for studying viral infections

Controversial Classification

What do mamavirus, pandovirus and pithovirus have in common?

Study These Flashcards

Matter of debate
Why>
Large size
Complex genomes

Scientists
-Argue resemble those of cellular organims more thantraditional viruses

Environmental reservoirs

What do mamavirus, pandovirus and pithovirus have in common?

Study These Flashcards

Discovered in environmental samples in various locations around the world
Soil abd sedimant samples
Remote regions of melting permafrost

The 3 keys phases in the microsporidian life cycle?

1. Infective spore stage 2. Proliferative stage 3. Sporogonial Stage

Infective spore stage ## Footnote The 3 keys phases in the microsporidian life cycle?

- Start phase of microsporidian life cycle - resistant to evironmental stresses - Persist for long periods in environment - Host organism ingest an infective spore - > spore releases its content into the host cell

Proliferative stage ## Footnote The 3 keys phases in the microsporidian life cycle?

- Replicates rapidly - Divide into small multiple uninucleate cells = **Meronts** - Meronts grow into surrounding tissues

Sporogonial stage ## Footnote The 3 keys phases in the microsporidian life cycle?

Final stage Meronts differentiate into spores Spores released from host orgnism and can infect new hosts Complete life cycle

How is microsporidian characterized? ## Footnote The 3 keys phases in the microsporidian life cycle?

High degree of host specificity Complex intracelllar parasitic strategy Allows microsporidia to evade host immune defenses Exploit host resources for own survival and reproduction

Three **main reasons** why **urinary tract infections**are more**common in women**

1. Anatomy 2. Hormones 3. Sexual Activity

Anatomy ## Footnote Q: Three **main reasons** why **urinary tract infections**are more**common in women**

Women - shorter urethra - easier for bacteria to travel up into the bladder - causes infection Urethra - tube - carries urbin from bladder to outside of the body

Hormones ## Footnote Three **main reasons** why **urinary tract infections**are more**common in women**

Hormone changes during menstruationand menopause alters pH balance of the vagina atlers pH balance of the urinary tract Favourable growth medium for bacteria - >infection

Sexual Activity ## Footnote Three **main reasons** why **urinary tract infections**are more**common in women**

Sexual activity introduce bacteria into UT Increasing risk of infection Sexually active women higher risk of developing UTIs than those who are not

Developing UTIs significance ## Footnote Three **main reasons** why **urinary tract infections**are more**common in women**

Women more susceptible Steps to UTIs how> hydration, urinating frequenty and practising good hygeine UTI suspected - antibiotic treatment - Prevent complications - Prevent recurrence

List the **receptor sites** for the**3 main mechanisms of adhesion** used by uropathogenic **Escherichia Coli** (UPEC).

UPEC main mechanism of adhesion to **attach to host cells in the urinary tract** 1. Type 1 Pili 2. P Pili 3. S Pili

S Pili ## Footnote List the **receptor sites** for the**3 main mechanisms of adhesion** used by uropathogenic **Escherichia Coli** (UPEC).

Adhesive structure used by UPEC Bind to **siaylated glycoproteins ** Present of surface: **bladder cells and urothelial cells** in the urinary tract

Type 1 Pili ## Footnote List the **receptor sites** for the**3 main mechanisms of adhesion** used by uropathogenic **Escherichia Coli** (UPEC).

UPEC express type 1 pili hair-like structures on bacterial surface binds to mannose residues on the host cell surface Receptor site=**Uroplakin Receptor** Present on surface of bladder cells

P Pili ## Footnote List the **receptor sites** for the**3 main mechanisms of adhesion** used by uropathogenic **Escherichia Coli** (UPEC).

Type of adhesive structure expressed by UPEC Binds to **globoseries glycolipid receptor** Present on the **surface of renal epihelial cells** Among other cells in urinary tract

List extremophiles (People prefer hot expresso)

1. Piezopholes 2. Psychrophiles 3. Halophiles 4. Endoliths

What **environmental conditions** to **Peizopholes** **adapt** to?

High pressures Bottom of oceans Withstand extreme pressure and oter environmental factors that exist at these depths

What environmental conditions to **Psychrophiles** adapt to?

In very low temperatures Polar regions Cold temperatures

What environmental conditions to **Halophiles** adapt to?

Thrive in high salt environments Salt flats Salt lakes

What environmental conditions to **endoliths** adapt to?

Live inside rocks and other geological structures Survive in harsh conditions High temperatures Low nutrients Limited access to water and other resources

Name **2 important diseases** of the **oral cavity**?

1.Dental Caries/tooth decay 2.Periodontitis

**Causative pathogen** of **dental caries**

Caused by interaction of acid-producing bacteria with carbohydrates in the diet Streptococcus mutans Ability produce acid and adhere to tooth surfaces

**Causative pathogen** of **Periodontitis**

Serious gum disease Result in tooth loss and other health problems Caused by complex microbial communty Porphyromonas gingivalis Tannerella forsythia Treponema denticola > ability to fom biofilms > induce infammation in gum tissue > leads to destruction of the periodontal ligament > Leads to destruction of the bone surrounding the teeth

List 2 important mycobacterial pathogens

1. Mycobacterium tuberculosis 2. Mycobacterium leprae

Disease caused by mycobacterium tuberculosis

Causative agent: M.tuberculosis of tuberculosis Serious respiratory disease Fatal if untreated Affects lungs bones and NS

Disease caused by Mycobacterium leprae

Causative agent: M. leprae of leprosy chronic infectious disease Affects skin, peripheral nerves Symptoms: skin lesions, nerve damage, muscle weakness Curable with appropriate treatment

Name 4 opportunistic pathogen associated with cystic fibrosis

1. Pseudomonas Aeruginos 2. Staphylococcus aureus 3. Burkholderia cepacia complex 4. Aspergillus fumigatus

2016/17 -SAQ Flashcards

(50 cards)