Microbiology Final Exam Study Guide Flashcards

Comprehensive vocabulary flashcards based on the BIO 225 Microbiology final exam study guide, covering nomenclature, history, cell structures, staining, viral replication, metabolism, genetics, immunology, and specific microbial diseases.

Binomial Nomenclature

• all names written in italics

• first name = genus

• second name = epithet

Francesco Redi

• challenge the theory of spontaneous generation

• demonstrating that maggots came from eggs of flies.

Louis Pasteur

• Performed Swan-necked flask experiments

• disprove abiogenesis and spontaneous generation.

Antonie van Leeuwenhoek

• Invented the first microscope lenses

• allowed him to observe animalcules (microorganisms).

Joseph Lister

father of aseptic surgery techniques.

Edward Jenner

• Created the first immunization

• which provided immunity against smallpox.

Paul Ehrlich

• Magic Bullet Theory

• drugs could harm infectious pathogens without damaging the host.

Robert Koch

• Developed Koch’s postulates

• steps that establish if an organism is pathogenic and which disease it caused.

Alexander Fleming

• Discovered penicillin, the first antibiotic, which destroys bacteria by targeting the cell wall.

Coccus

Sphere-shaped

Bacillus

Rod-shaped

Vibrio

Curved rod

Spirillum

Spiral-shaped

Spirochete

Spring-shaped

Staphylo- arrangement

irregular clusters.

Strepto- arrangement

chains

Sarcine

3D geometrical forms, such as cubes.

do prokaryocytes have membrane bound organelles

no

Peptidoglycan

• makes up the cell wall only in ONLY BACTERIA

• providing structural support and protection.

flagella

used for motility

Monotrichous

A flagellar arrangement consisting of a single flagellum.

Lophotrichous

A flagellar arrangement with small bunches or tufts of flagella emerging from the same site.

Amphitrichous

A flagellar arrangement with one flagellum at both poles.

Peritrichous

A flagellar arrangement where flagella are dispersed randomly on the surface of the cell.

Pilus

Tiny hollow projections that attach two bacterial cells to provide a way to exchange genetic information.

Endospore

A dormant state a bacterium enters to protect genetic material with a hard keratin coat to survive harsh conditions.

Fimbriae

Short, numerous appendages used by some bacterial cells to adhere to surfaces.

Prokaryotic Ribosome

• protein production

• two subunits: a 50S large subunit and a 30S small subunit.

Capsule

• An outer layer

• help avoid immune detection.

• used by pathogens like Neisseria meningitidis and Bacillus anthracis

Mitochondria

generates ATP (energy)

Golgi apparatus

• post office of the cell

• it tags, modifies, and ships proteins and lipids around the cell.

Eukaryotic Ribosome

• protein production

• two subunits: a 60S large subunit and a 40S small subunit.

Crystal Violet

primary stain used in the Gram Stain procedure.

Iodine

The mordant used in the Gram Stain procedure.

Safranin

The counterstain used in the Gram Stain procedure that turns gram-negative bacteria pink.

Gram Positive Bacteria

• thick cell wall

• hold on to crystal violet

• stain purple.

Gram Negative bacteria

• thin cell wall

• stripped of crystal violet

• stain pink

viruses

pathogen that must infect host in order to reproduce

nucleic acid core

• contains genetic material

• DNA/RNA (never both)

Capsid

• outer protein layer

• encases and protects the nucleic acid core of a virus.

Nucleocapsid

The combination of a virus's nucleic acid core plus its capsid.

envelope

• optional outer membrane made of phospholipids & proteins

• naked = no envelope; enveloped = has envelope

Viral Spikes

attaching a virus to host cell membrane receptors.

1. Adsorption (viral replication)

virus binds its spikes to the host’s cell membrane receptors.

host range

spectrum of hosts a virus can infect

viral specificity

specific kinds of cells/tissue a virus can infect in a specific host

2. penetration (viral replication)

entry of the virus into host

• 2 ways: endocytosis & membrane fusion

Endocytosis

host cell is tricked into engulfing the entire virus

• used by both naked and enveloped viruses.

Membrane Fusion

viral envelope merges directly with the cell membrane

• only used by enveloped viruses.

3. Uncoating (viral replication)

host cell digestive enzymes release the viral genetic material into the cytoplasm.

4. synthesis (viral replication)

virus manipulates host cell to make viral DNA/RNA & proteins

5. assembly (viral replication)

• putting together all pieces to make mature virus

• capsid forms around genetic material

* if virus is enveloped, spiked are sent to cell membrane of host cell

6. release (viral replication)

2 ways:

• lysis—naked viruses

• budding—enveloped viruses (nucleocapsid binds to membrane, forms small pouch, pinches off pouch)

bacteriophage

virus that infects bacteria

anaerobes

doesnt require O2 from growth

aerobe

requires O2 for growth

how do aerobic bacteria utilize O2

using 2 enzymes:

• superoxide dismutase— converts the superoxide ion (byproduct of O2 metabolism) into normal hydrogen peroxide

• catalase—converts hydrogen peroxide into normal O2 & H2O

*anaerobic bacteria lack these enzymes (O2 is toxic to them)

Facultative anaerobes

use O2 if available but can function without it.

Microaerophiles

require a small amount of O2.

normal biota

microbes that live in/on body & dont cause harm to healthy individuals

Microbial Antagonism

• antagonistic effect “good” microbes have against intruder microbes

• 3 ways:

  • use up all the nutrients

  • use up all attachment points

  • alter environment making it hostile (usually acidic)

    • ex: lactobacillus can acidify the female reproductive tract to control the growth of yeast

antibiotics

chemicals that inhibit the growth of microbes

• only treat bacterial (not yeast)

Broad Spectrum Drugs

• effective against more than one group of bacteria

  • pro—useful in emergencies when causative agent is unknown & pt is critically ill

  • con—prone to causing superinfections & killing normal biota

Superinfection

secondary infection occurring when a drug destroys normal biota

• allows remaining pathogens to overgrow.

narrow spectrum drugs

• target specific bacterial groups

  • pro—not as harmful to normal biota

  • con—not useful in emergencies cs causative agent is unknown

horizontal gene transfer

• bacterium acquire genetic info from another source

• 3 types:

  • transformation—bacteria incorporates naked DNA into its genome

  • transduction—bacteria acquire genetic info from bacteriophage

  • conjugation—genetic info is exchanged from one bacteria to another via pili appendage

DNA Nucleotide

contains…

1. phosphate group

2. deoxyribose sugar

3. one of 4 nitrogenous bases

   1. adenine

   2. thymine

   3. cytosine

   4. guanine

DNA is antiparallel

The arrangement of DNA strands running in opposite directions

• one in the $5' \rightarrow 3'$ direction and the other in the $3' \rightarrow 5'$ direction.

RNA nucleotide

contains…

1. phosphate group

2. ribose sugar

3. one of 4 nitrogenous bases

   1. adenine

   2. uracil

   3. guanine

   4. cytosine

DNA & RNA differences

1. DNA is double stranded—RNA is single stranded

2. DNA contains deoxyribose sugar—RNA contains ribose sugar

3. DNA contains thymine—RNA contains uracil

DNA replication

• semiconservative—each strand of DNA contains one original strand & one newly synthesized strand

• replication begins at replication origin—this is at an A-T region

1. helicase breaks hydrogen bonds separating the strands of DNA

2. the single strands are kept separate by single stranded binding proteins

3. RNA primase lays down a primer so DNA polymerase III has a starting point to work from

4. DNA polymerase III reads the template strand from the primer & adds corresponding nucleotides

5. DNA polymerase II removes RNA primer & replaces it w DNA nucleotides

leading strand

synthesized continuously in the 5—3 direction

lagging strand

synthesized discontinuously backwards in the 3—5 direction

• since its made in okazaki fragments (segments) they must be fused together by the enzyme ligase

Transcription

1. DNA is separated by the RNA polymerase

2. RNA polymerase synthesizes a complimentary mRNA strand (uses DNA as template)

3. the single strand of RNA is known as mRNA & is the code for how to synthesize a specific protein

4. mRNA leaves the DNA molecule & enters the cytoplasm where it joins a ribosome to undergo translation

*in RNA…A-U & G-C

translation

1. rRNA - forms ribosomal units that together make up the ribosome (site of protein synthesis)

2. the ribosome reads mRNA transcript in 3 letter sequences (codons)

3. each codon in mRNA represents a specific amino acid

4. tRNA - transfers amino acids from the cytoplasm to the ribosomes for placement in a growing molecule

   1. tRNA has 2 components:

      1. at top of each, there is a specific amino acid bound

      2. at bottom of each, there is a specific anticodon sequence

         1. anticodon sequence is always complimentary to the codon for the amino acid

         2. ex: if tRNA is carrying amino acid TRP, the anticodon would be ACC

Incubation period

time between initial infection and the first appearance of signs or symptoms.

Prodromal phase

A short period during which nonspecific, mild symptoms occur.

invasive phase

when the individual experiences typical signs & symptoms of the disease

decline phase

when host defenses & effects of tx overcome the pathogen

convalescence period

pathogen is completely cleared from body, tissue is healing

virulence

the severity of disease caused by the microbe

exotoxins (virulence factor)

produced by gram positive bacteria; toxins secreted into host tissue

• hemolysins - lyse RBC

  • alpha hemolysins - partially break down hgb & produce greenish ring around colonies

  • beta hemolysins - completely break down hgb & leave clear ring around colonies

• leukocidins - damage WBC

• neurotoxins - prevent muscle contraction or relaxation

• enterotoxins - act on tissue of the gut

Endotoxins (virulence factors)

• Lipopolysaccharides that are part of the outer membrane of gram-negative bacteria

• released when the cells die or divide.

true pathogen

microbe that can cause disease in healthy ppl

Opportunistic pathogen

microbe that only causes disease in immunocompromised patients or when a specific opportunity arises.

• often doesnt cause disease in health ppl

skin (innate 1st line—physical barrier)

• tough, closely packed keratinized layers of skin; prevent microbes from entering

• acidity & high salt prevent microbes from growing

  • main reason why staphlococcus makes up 90% of normal skin biota

respiratory tract (innate 1st line—physical barrier)

• nose hairs - trap microbes

• mucous - trap microbes

• ciliary escalator - sweeps microbes out

• coughing/sneezing - remove irritants/clear out junk

fever (innate 2nd line)

• rise in body temp

• temp is controlled by hypothalamus

• pyrogens released by immune system stimulate hypothalamus to raise temp

• benefits of fever:

  • body temp is greater than optimal growth temp for pathogen

  • high temp can inactivate microbial enzymes/toxins

  • phagocytosis & other immune reactions are enhances

Interferons (innate 2nd line)

• Molecules produced by the immune system that interfere with viral replication in 3 ways:

  • bind to receptors on nearby uninfected cells inducing an antiviral state

  • activate immune cells

  • bind to receptors on nearby infected cells to trigger apoptosis (cell death)

phagocytes (innate 2nd line)

cells that ingest invaders

• PRRs (pattern recognition receptors) - receptors present of phagocytes that adhere them to foreign cells

• PAMPs (pathogen associated molecular patterns) - molecules present on pathogens that allow immune system to distinguish them as foreign

include:

• monocytes - phagocytes in blood

• macrophages - monocytes that migrate out of blood into tissue

• neutrophil - general purpose phagocytes; react early in inflammatory processs

  • form pus upon death

inflammation (innate 2nd line)

process of recruiting fluid, immune cells, etc to side of infection/damage to clean site & initiate repair

• histamine - jump starts inflammation process; released by mast cells or damaged cells

antigen

any molecule that activates an immune response; often a pathogen

T cells (adaptive 3rd line)

• CD4 helper T cells - recognize antigen present in MHC II receptor of antigen presenting cells (APC) to become activated

  • function:

    • acticate B cells

    • activate other T cells

• CD8 cytotoxic T cells - recognize antigen present in MHC I receptor of any nucleated cell

  • function:

    • kill infected cells

    • kill cancerous cells

B cells (adaptive 3rd line)

• must be activated by both:

  • binding to antigen

  • binding to activated CD4 helper T cell

• once activated, differentiate into:

  • plasma cells - create antibodies specific to pathogen

  • memory B cell - remember pathogen incase it invades 2nd time

skin infections

have high concentration of normal biota, mostly staphlococcal species due to high salt concentration on skin

measles (skin infection)

• causative agent: measles virus

• transmission: respiratory droplets

• s/s:

  • maculopapular rash (red rash)

  • koplik spots inside mouth

  • severe cases lead to subacute sclerosing panencephalitis (inflammation of brain)

• tx: monitor s/s

• prevention: MMR vaccine

rubella (skin infection)

• causative agent: rubella virus

• transmission: respiratory droplets

• s/s:

  • postnatal: maculopapular rash (flat pink rash)

  • prenatal (congenital rubella): birth defects, deafness

• tx/prevention: MMR vaccine

Smallpox (skin infection)

• causative agent: variola virus

• transmission: respiratory droplets & fomites

• s/s: systemic puss filled lesions

• tx: none

• prevention: vaccine

*ONLY DISEASE TO BE ERADICATED

chicken pox (skin infection)

• causative agent: initial infection with varicella zoster

• transmission: respiratory droplets & fluid from active lesions

• s/s: clear fluid filled lesion lasting several days

• tx:

  • monitor s/s

  • watch for secondary infection

• prevention: MMR vaccine

Shingles (skin infection)

• causative agent: reactivation of varicella zoster virus hiding in spinal ganglia

• transmission: occurs sometime after initial chickenpox infection during dip in immune system effectiveness (stress)

• s/s: localized, painful, red lesions associated w nerves (can last for weeks)

• tx/prevention:

  • antiviral meds (lessen progression)

  • shingles vaccine (ppl over 50 & immunocomprimised)