Micro: Final Exammmmm

What is microbiology? What organisms fall into this field of study?

Micro: too small to be seen with the naked eye

bio: life

ology: the study of

In general, the study of microorganisms

Why are the microorganisms in this field important to humans/ life?

\-nutrition

\-decomposition

\-biotechnology and genetic engineering

\-natural flora

What was the hypothesis of spontaneous generation?

That living things can come from nonliving things.

What is the germ theory of disease?

That sickness comes from viruses/bacteria. Opposite of Spontaneous Generation.

What are the characteristics of life?

\-heredity and reproduction

\-growth and development

\-metabolism (catabolism and anabolism)

\-movement and/ or irratibility

\-homeostasis

\-composed of cells

What is a cell?

“the structural and functional unit of living organisms”

\-tiny compartment

\-surrounded by a membrane

\-inside the membrane there are proteins and nucleic acids

\-internal “stuff” is organized

What is the difference between a prokaryote and a eukaryote? what organisms fall into what category?

prokaryotes: do not have a nucleus (bacteria)

eukaryotes: do have a nucleus (animalia, plantae, protista, fungi)

How are bacteria classified with respect to cell morphology and arrangement?

coccus: circles

Bacillus: rods

Strep: chains

Diplo: two cells

Tetrads: two on top, two on bottom

Staph: pyramid-ish shape

What is the purpose of a flagellum, fimbriae, pili, glycocalyx, and cell envelope?

flagellum: motility, self-propulsion

fimbriae: adhesion and cellular interaction

pili: (only Gram neg.) genetic transfer

glycocalyx: protection and adhesion to create biofilms

cell envelope: cell integrity, selectively permeable membrane

What are the major differences between Gram positive and Gram negative bacteria?

Gram Pos:

\-stains purple

\-95% of cell wall is peptidoglycan

\-absent outer membrane

\-small periplasmic space

\
Gram Neg:

\-Stains pink

\-

What is the difference between a chromosome and a plasmid?

Chromosome:

\-circular wad of DNA

\-found in the center of the cell

\-genes are necessary for survival

\
Plasmid:

\-little circles of DNA

\-extrachromosomal

\-often where you find genes for antibiotic resistance and toxin production

What is an endospore and when is it produced?

\-hard shell

\-protection from extreme environments

\-form when the cell is in danger

What is the theory of endosymbiosis? What is some evidence for this theory?

-Theory that eukaryotic cells originated when prokaryotic cells engulfed each other

Evidence:

1. DNA: mitochondrial DNA and chloroplasts have their own circular genomes

2. Mitochondrial membrane structure (double membrane)

3. Reproduction: mitochondria reproduce the same way bacteria do

4. Ribosomes: very structurally similar to prokaryotes

5. external appendages: eukaryotic and prokaryotic flagella and cilia are very similar

What is the function of the nucleus, ER, golgi body, ribosome, mitochondria, and chloroplast?

Nucleus: contains chromosomes (DNA) of the cell. regulates all cell activities

ER: series of tunnels used for transport (rough and smooth)

Golgi body: where proteins are modified, stored, and packaged for transport. Closely associated with the ER

Ribosome: site of protein synthesis

Mitochondria: Energy generators of the cell. Where ATP is produced.

Chloroplast: found in algae and plant cells. performs photosynthesis

Why aren’t viruses considered to be alive (by most biologists)?

\-incapable of protein synthesis

\-incapable of independent ATP production

\-can only replicate inside the living host

What are the components of a virus? What is the function of each of these components?

Capsid:

\-protection

\-aids in introducing the viral nucleic acid into the host cell.

Envelope:

\-additional external covering

\-made from the host’s membrane

Nucleic Acid:

\-can be double or single stranded DNA or RNA

What are the steps of a typical viral infection?

1. absorption (attachment)

2. penetration

3. uncoating

4. synthesis

5. assembly

6. release

what is a bacteriophage?

viruses that infect bacterial cells

\-lytic cycle: viral nucleic acid is copied, new phages are assembled, released when lysis occurs (cell dies)

\-Lysogenic cycle: viral DNA is incorporated into host DNA. lysis doesn’t occur, cell doesn’t die

What is a prion?

\-non-cellular infectious particles

\-misfolded proteins.

\-only known biologically active agent that lacks nucleic acids

What environmental factors influence bacterial growth? How do we categorize bacteria based on these factors?

What are the levels of protein structure?

primary: monomers strung together (strep formation)

secondary: twisting or folding of primary structure (alpha helix or beta-pleated sheet)

tertiary: twisting or folding of secondary structure

quaternary: combination of many tertiary molecules

Why is protein structure important?

proteins have a specific shape which is essential to their function

What are enzymes? Why are they important? How do they work?

\-proteins

\-they are catalysts

\-they lower the activation energy needed

What are cofactors and coenzymes?

factors: inorganic (activate the enzyme, bring the active site and substrate together)

enzymes: organic (helps alter the substrate)

What is the difference between a gene and an allele?

gene: segment of DNA which codes for a protein or an RNA molecule

Allele: version of a gene (blue eyes or brown eyes)

What does genotype describe? Phenotype?

Genotype: genetic makeup

Phenotype: physical traits resulting for the genotype

How is genetic information stored in DNA?

in the sequence of the bases (adenine, guanine, thymine, cytosine)

What type of replication does DNA undergo?

semi conservative replication

What is transcription? translation?

transcription is DNA to RNA

translation is RNA to protein

What is rRNA important? tRNA? mRNA?

rRNA:

\-ribosomal RNA.

\-molecule which, in combination with protein, makes up ribosomes

tRNA:

\-transfer RNAs

\-plays a role in translation by bringing appropriate amino acids. contains anticodon

mRNA:

\-messenger RNA

\-function in regulation of gene expression by regulating transcription and translation

How does genetic variation arise in a population?

mutations

Do mutations at the DNA level always result in a change at the protein level?

yes

Are mutations always harmful?

no

What is biotechnology? Genetic engineering?

Bio: use of microorganisms, cells, DNA, genes, or genetically altered organisms in commercial production

Engineering: the direct and deliberate modification of an organism’s genome

What are some examples of how we utilize biotechnology?

\-making food

\-chemicals

\-vitamins

\-antibiotics

With respect to killing microorganisms, which organisms exhibit the highest level of resistance? Lowest?

Highest:

\-prions

\-endospores

\
Lowest:

\-yeasts

\-most protozoans

\-fungus

\-bacterial vegetative cells

What is the difference between sterilization and disinfection?

\-sterilization destroys or removes all viable microorganisms (including viruses and endospores)

\-destroys vegetative pathogens

How is death characterized in microorganisms?

When they won’t grow anymore, even at optimum conditions

What are the modes of action for many antimicrobial agents?

\-disrupting protein synthesis

\-disrupting other vital component synthesis

\-destroying cell membrane so it loses selective permeability

\-digesting cell wall (results in lysis)

What are the physical methods we use to control microbial growth?

heat (dry and moist)

Why is moist heat more effective than dry heat?

\-causes proteins to denature

\-can achieve cell death at lower temps than dry heat

How do we achieve temperatures greater than 100C when using water?

autoclave (uses pressure as well)

What is pasteurization?

destroying pathogenic microorganisms to extend shelf-life of food

Do all chemical antimicrobials result in sterilization?

not at all

Why is resident flora important? When is resident flora initiated?

\-natural defenses/ immunity

\-at birth

What is the difference between a true pathogen and an opportunistic pathogen?

\-true pathogens can affect anyone (normal or immunocompromised)

\-opportunistic pathogens can only infect people who are immunocompromised

Does the portal of entry affect the disease sx/ progression?

Yes. S. aureus could cause a skin infection or pneumonia

What are virulence factors? Give examples

\-structures or characteristics of a microbe that contributes to the disease

\-capsules, toxins, etc.

What is a reservoir? Vector? Source?

reservoir: where you naturally find the disease

vector: when animals are the living source and reservoir

source: the individual or object where the infection is acquired

What are nosocomial infections? Why do they occur?

\-hospital acquired infections

\-surgical procedures, so many sick people

\-use of antimicrobials causes drug-resistant micros

What is the difference between a sporadic, endemic, epidemic, and pandemic?

Sporadic: random disease prevalence (tetanus)

Endemic: steady frequency over long time period n a particular geographic area (Lyme disease)

Epidemic: prevalence of a disease beyond what is expected (H1N1 in Mexico)

Pandemic: epidemic that crosses continents (H1N1 or AIDS)

What is the difference between specific and nonspecific immunity?

nonspecific:

\-present at birth

\-nonspecific resistance to infection

specific:

\-specific resistance

\-must be acquired

What is considered the 1st, 2nd, and 3rd line of defense?

1st:

\-any barrier that blocks invasion at the portal of entry

\-skin, mucus, tears, flushing actions, normal flora

\-nonspecific

2nd:

\-protective cells and fluids

\-inflammation

\-phagocytosis

\-nonspecific

3rd:

\-acquired with exposure to foreign substances

\-produces antibodies and creates memory cells

\-specific

What is blood composed of?

\-WBCs

\-RBCs

\-plasma

\-platelets

What is the role of white cells? red blood cells?

\-immune defense

\-oxygen

What cells are lymphocytes? Which line of defense are these involved in?

\-B cells and T cells

\-3rd line of defense

What role does the lymphatic system play in immunity?

filtering blood and providing immune cell presence

What are the lymphatic organs?

Primary:

\-thymus gland

\-bone marrow

Secondary:

\-lymph nodes

\-spleen

\-MALT

\-SALT

\-GALT

What is the inflammatory response? Why is it important?

\-vascular changes

\-edema

\-fever

serves as a warning sign, blocks further invasion, attracts immune cells to the site of injury

What is phagocytosis? What immune cells perform it?

eating other cells

\-neutrophils

\-macrophages

what is an antibody? antigen?

antibody: large protein evoked in response to a specific antigen

antigen: molecules that stimulate a response by T and B cells

What do B cells do?

they produce antibodies \*\*\*

What do T cells do?

activate other cells \*\*\*

What is hypersensitivity?

what we think of as allergies (hay fever, asthma, anaphylaxis, food allergies)

What is the difference between autoimmune diseases and immunodeficiency diseases?

\-autoimmune diseases are your body being over-reactive

\-immunodeficiency is an under-active immune response

What is chemotherapy

“using chemicals in therapy”

what are antibiotics

a medicine that inhibits the growth of or destroys microorganisms

For which microorganisms is selective toxicity easiest to achieve? hardest?

easiest:

\-bacteria

hardest:

\-viruses (whole other conversation)

\-helminths (they are animalia)

How is antibiotic resistance acquired

\-spontaneous mutatations

\-acquiring new genes via transfer from another species

Why is antibiotic resistance on the rise

broad-spectrum antibiotic usage

What is the difference between impetigo, cellulitis, and gas gangrene

impetigo: superficial bacterial infection causing skin to flake

cellulitis: fast-spreading bacterial or fungal infection of the dermis and subcutaneous tissues (pain, swelling, warmth, fever)

gangrene: serious skin infection caused by G+ endospore forming bacteria

Where do staphylococci normally inhabit?

skin and mucus membranes

What types of localized and systemic diseases does S. aureus cause?

localized:

\-folliculitis

\-boils

\-carbuncle

\-impetigo

\
systemic:

\-osteomyelitis

\-pneumonia (low proportion, high fatality)

\-bacteremia (endocarditis, arthritis, meningitis)

\--scalded skin syndrome

\-toxic shock syndrome

how do you differentiate S. aureus from other staphs

coagulase test

What is MRSA

Methicillin-Resistant Staph Aureus

\-antibiotic- resistant strain of s. aureus

\-vancomycin is the only treatment available (but there have been some resistant strains over the last decade as well)

what virus has been eradicated from the earth through vaccination? which other one are we close with?

Smallpox (1978)

\*\*\*

What virus causes chickenpox and shingles

Varicella zoster

What are the typical sx of measles

\-full body rash

\-serious secondary infections

\-oral lesions

\-pneumonia or encephalitis

What forms do fungi take on? which form is the most invasive?

\-Hyphae, spores, and yeast

\-yeast phase most invasive and more likely to spread

what kinds of disease does Neisseria cause? what is the gram reaction and morphology?

\-meningitis

\-gram negative cocci

what diseases are caused by clostridium species? Bacillus species?

Clostridium:

\-tetanus

\-CDIF

\-botulism

\
bacillus:

\-anthrax

What are the vectors of arboviruses (generally, not specifically?)

insects

What type of microorganism causes rabies?

a virus

What microorganisms cause african sleeping sickness? Chagas disease?

protozoans

what are the insect vectors for African sleeping sickness and chagas disease?

\-tsetse flies

\-kissing bugs

what is meningitis? encephalitis? Endocarditis? Septicemia?

Meningitis: infection/ inflammation of the brain

Encephalitis: inflammation of the brain (can happen in conjunction w meningitis

Endocarditis: inflammation of the endocardium (acute or subacute)

\

What bacterium causes the Black Plague?

Yersinia pestis

What diseases are caused by the Borrelia species?

relapsing fever and Lyme disease

How is Lyme disease transmitted?

ticks

What diseases are caused by the Rickettsia family?

\-typhus

\-rocky mountain spotted fever

What are the insect vectors for typhus and rocky mountain spotted fever?

louse

What disease does plasmodium cause?

malaria

What is the insect vector carrying plasmodium?

mosquitoes

What tissues are infected with HIV

white blood cells (T cells)

Which strep species is the most serious pathogen?

S. pyogenes

What types of localized and systemic diseases does S. pyogenes cause?

Localized:

\-impetigo

\-strep throat

\-tonsillitis

\
Systemic:

\-scarlet fever

\-septicemia

\-pneumonia (only 5%)

\-toxic shock syndrome

what type of microorganism causes diptheria?

bacteria

What causes the sx of diptheria?

\-pseudomembrane on the pharynx (can cause suffocation)

\-toxemia

\-can be respiratory or cutaneous

What disease does Bordetella pertussis cause?

pertussis (whooping cough)

Which bacteria genus is considered acid fast? what does this mean?

mycobacterium leprae