Micro: Flora Flashcards by Rylee Sybert

Prokaryote vs. Eukaryote: Chromosome

Prokaryote: single circular
Eukaryote: multiple chromosomes

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Prokaryote vs. Eukaryote: Nucleus

Prokaryote: no nucleus
Eukaryote: Nucleus

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Prokaryote vs. Eukaryote: Membrane bound organelles

Prokaryote: no membrane bound organelles
Eukaryote: membrane bound organelles

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Prokaryote vs. Eukaryote: cell wall

Prokaryote: PPG cell wall
Eukaryote: cell walls in plant but no ppg

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Prokaryote vs. Eukaryote: Ribosomes

Prokaryote: 70S
Eukaryote: 80S

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Normal Flora are what?

Microorganisms that are normally present in a specific site

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Are normal flora harmful?

Usually harmless, even beneficial

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4 main functions of normal flora

Help block pathogenic invaders
Production of antimicrobial substances
Aid in vitamin absorption
Stimulates development of the immune system

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How is the pH of the urogenital tract?

Low pH

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Urogenital tract is maintained by ___________

Lactobacillus

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What flora/bacteria are present in the eye?

Staphylococcus epidermidis (+ cocci)
Staphylococcus aureus (+ cocci)
Strep Pneumo (+ cocci)
Corynebacterium species (+ rods)

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Tears contain the antimicrobial enzyme ____________ which help limit what?

Lysozyme

Help limit the bacterial population of the conjunctiva

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How does bacteria number change along the alimentary canal in the GI tract?

Increasing number along the alimentary canal

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Transient flora of skin help keep it _______ and _______ pH

Dry
Acidic pH

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Resident flora of the skin

Cause regeneration
Staph epi
Coagulase
Anaerobes

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Bacteria species that inhabit the mouth and nose

Coryne (+ rods)
Strep viridans
Strep mutants

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In what situations can normal flora produce disease?

If displaced from normal site
If potential pathogen gains competitive advantage
Immuno-compromised individuals

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Normal flora, if in their normal location are often _________, however when overgrown or removed from their normal location can result in __________

Helpful
Disease

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The plasma membrane of the bacterial cell functions in what way?

Controls what enters and leaves the cell

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Cell wall (bacterial cell) has what function?

Provides shape to the cell

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Glycocalyx is the external surface of a plasma membrane that is important for _________________

cell-to-cell communication

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Why can the glycocalyx aid in identification?

Because it varies from species to species

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Flagella aid in _____________

Movement

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Flagella are highly _______

Antigenic (produce an immune response)

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Pili (aka fimbriae) aid in ____________ and ___________

Attachment and conjugation

5 stages of bacterial growth

1. Binary fission 2. Lag phase 3. Log phase 4. Stationary phase 5. Death phase

Do temperature and pH contribute to growth of bacteria?

Yes

Heterotrophs require ________ for growth

Organic carbon

Do autotrophs require organic carbon for growth? Why or why not?

No, because they reduce carbon dioxide

What type of organism requires a large number of growth factors or very specific ones?

Fastidious organism

Obligate aerobes must have __________ and only get energy from ______________ respiration

Oxygen Aerobic respiration

Facultative aerobes can convert ____________ when there is no oxygen

Fermentation

Microaerophilic aerobes survive with a small amount of ___________

Oxygen

True anaerobes get energy from ___________

Fermentation

Bacterial genome consists of:

Single chromosome Plasmid Transposons

The single chromosome in the bacterial genome contains _________ genes

Essential

Plasmid contains ____________ genes

Nonessential

Transposons are ________ DNA sequences

Mobile

What is a bacteriophage?

Virus that replicates inside a bacterial cell

Two types of bacteriophages

virulent and temperate

Virulent bacteriophage will ______ the bacteria

Lyse

Virulent bacteriophage produces hundreds of ___________

Progeny

What are the two scenarios in which a temperate bacteriophage can impact a cell?

A - lyses cell, no progeny, cell dies B - no progeny, no cell lysis, phage incorporated into the bacteria

What happens when the temperate phage is activated from within the bacterial genome?

Phage becomes virulent Bacteria ultimately die and phages will be released

3 mechanisms of bacterial gene transfer

Conjugation Transduction Transformation

Conjugation is _______ to ______ transfer

Cell to cell

Conjugation mechanism

Via donor cells sex pili and formation of cytoplasmic bridge

Two forms of transduction

generalized and specialized

Generalized transduction produces a ____________ phage

Bacterial-DNA-only

Specialized transduction produces a new phage that has what DNA?

Both phage and bacterial DNA

In specialized transduction, when this DNA is transferred to another host, it is all incorporated into the genome creating a ____________

Prophage

Transformation is the transfer of genes by ______ DNA

Naked

What is the process of transformation

DNA crosses membrane and one strand is destroyed, remaining single strand finds a spot and cuts and pastes itself into the genome

Transformation is useful in introducing _________ genes

Cloned

DNA segments with the ability to move from place to place on the chromosome

Transposons

Transposons are responsible for much of the spread of ______________

Antibiotic resistance

Staining characteristics that help identify microbes

Gram reaction Acid fast Fungal

Gram + have a _________ cell wall

thick peptidoglycan

How do gram (+) bacteria stain?

*DEEP PURPLE* - crystal violet stain adheres to the thick peptidoglycan layer

Gram - bacteria have a ________ cell wall

Thin PPG

How do gram (-) bacteria stain?

*PINK* - crystal violet washes off, safranin binds to cell wall

Definitive microbial diagnosis involves ____________

Culturing the organism

Enriched media promotes ____________ growth

Non-selective

Enriched media is good for what organism?

Fastidious organisms

Enriched media examples

blood agar and chocolate agar

Growth conditions of enriched media

Mimic growth conditions by controlling O2 and CO2

Examples of selective media

MacConkey's agar Hektoen Enteric agar Thayer Martin

What is the most common selective media?

MacConkey agar

What does MacConkey agar select for?

gram negative rods

Disk diffusion method

An agar-diffusion test to determine microbial susceptibility to chemotherapeutic agents.

Minimum inhibitory concentration (MIC)

A laboratory measure of the lowest concentration of a drug needed to kill a certain standardized amount of bacteria.

4 single enzyme tests

catalase, coagulase, oxidase and urease

Catalase test is used to differentiate between what?

Staph vs. Strep

The oxidase test is used to differentiate what bacteria?

Gram (-)

Urease test differentiates ___________________

Enterobacteriaceae

Coagulase Test

Separates Staph aureus from other staph spp.

Direct hybridization uses a ________

Probe

PCR benefits

Fast Quick Allows amplification millions of times

PCR disadvantages

Cross-contamination can lead to false + Expensive

Bacterial Pathogenesis 5 steps

1. Entry into host 2. Adhesion to host cells 3. Propagation 4. Damage to host cells via toxin or inflammatory response 5. Evasion of host defenses

An isolated pathogen from a sick patient should create the same disease in a susceptible patient, if it is truly the etiologic agent. What postulate is this?

Koch's postulates

Person to person spread of an infectious disease

Communicable disease

Non-communicable infectious disease is?

Not spread by person to person contact

What is a highly communicable disease under everyday circumstances?

Contagious disease

An epidemic occurs when what occurs?

Unusually high disease frequency

A pandemic occurs when what occurs?

The incidence of disease is unusually high for population or world

How does transmissibility contribute to virulence?

How easy the pathogen can be transferred

How does adherence contribute to virulence?

How well does the pathogen adhere

How does invasion enzymes and invasins contribute to virulence?

Allow the pathogen to get in

Exotoxin is very __________

Poisonous

Strongest known exotoxin

Botulinum toxin

Are exotoxins broken down by heat?

Yes

Exotoxin is carried on __________ or ____________

Plasmids or bacteriophages

Endotoxin is heat _______

stable

Endotoxin causes a variety of systemic effects, including ______.

Fever Shock Thrombosis

Spore structure

1. Exosporium: outer layer (protein) 2. Spore coat: PPG 3. Cortex: PPG 4. Wall: PPG 5. Core: DNA

Micro: Flora Flashcards

(96 cards)