Microbio Exam 2- Eukaryotic comparison and Antibacterials

what is the microbe of the day

clostridium botulinum

clostridium botulinum

• gram positive

• obligate anaerobes

• bacillus

• produce heat resistant endospores

• ferments sugar or amino acids

• found in soil, lake sediments, decaying vegetation

• causitive agent of botulism

botulism

a paralytic illness caused by a nerve toxin produced by C. botulinum

types of botulism

1. foodborne

2. wound

3. inadvertent: accidental overdoes of botulinum toxin

4. infant: caused by consuming spores or bacteria, which germinate in the intesting and release toxin (honey)

5. adult intestinal colonization: caused by consuming spores, which germinate in the intestine and release toxins

purpose of Acetylcholine (Ach)

causes muscles to contract

how does a toxin act on Ach

toxin blocks snare proteins (which is important for release of ach) from guiding Ach to the nerve membrane

what occurs when a muscle is relaxed

paralysis

8 known toxins

ABCDEFG and F/A

symptoms of botulism

• can occur between 4-36 hours after exposure

• double vision

• blurred vision

• drooping eyelids

• slurred speech

• difficulty swallowing

• dry mouth

• muscle weakness

• infants will appear lethargic, feed poorly, are constipated, have a weak cry, and poor muscle tone

what could occur if botulism is left untreated

symptoms may progress to cause paralysis of respiratory muscles and airway obstructions- death

Justinus Andreas Christian

conducted experiments on humself, ate small amounts of bad sausage and documented thesigns and symptims of botulism

treatments for botulism

• needs to be caught early

• treated with an antitoxin that blocks the action of the toxin circulating in the blood

• antitoxin myst come from CDC

• antibiotics if from wound

• may require several months in hospital

• patients who survive will have fatigue and shortness of breath for years

botulism prevention

• boil home canned food before eating

• when in doubt throw it out

glycocalyx in eukaryotic cells

sticky carbohydrates extending from animal plasma membrane, bound to proteins and lipids in membrane, strengthens cell surface, attaches cells together, cell-cell recognition

what causes movement

flagella and cilia make it move or beat, propel cell through water

pseudopods

• contain cytoplasm

• used for cellular locomotion (move cell membrane around, pushes proteins to one side

flagella

few and long

cilia

many and short

microtubules

long hollow tubes made up of a protein called tubulin,

what powers eukaryotic flagella

atp

what causes a flagellum to bend

sliding of microtubules relative to eachother

proton motor force

powers bacteria

which of the following correctly describes a difference between bacterial and eukaryotic flagella

bacterial flagella are powered by a proton motor force, while eukaryotic flagella use atp

eukaryotic cell wall

• simpler than bacteria

• consists of polysaccharide

  • plants- cellulose

  • fungus- chitin-N-acetylglucosamine (NAG)

  • yeast- glucan, mannan

what do eukaryotes lacking a cell wall contain

some kind of protective layer

protozoa

flexible outer protein covering called a pellicle

which of the following correctly describes a differnce in cell wall omposition between eukaryotes and bacteria

yeast cell walls contain glucan and mannan, while bacterial cell walls contain peptidoglycan made of N-acetylglucosamine and N-acetylmuramic acid

eukaryotic vs prokaryotic plasma membrane

• similar function and structure

• different proteins in membrane

eularyotic plasma membrane components

• contain carbs- attachment sites for bacteria

• contains sterols- increase resustance to osmotic lysis

eukaryotic plasma membrane

• selectively permeable

• simple diffusion

• facilitative diffusion

• osmosis

• active transport

• endocytosis

endocytosis

1. phagocytosis

2. pinocytosis

3. receptor mediated endocytosis

phagocytosis

pseudopods extend and engulf particles

pinocytosis

membrane folds inward, bringing in fluid and dissolved substances

receptor mediated endocytosis

binding to a recpetor then membrane folds in on itself

which of the following transport mechanisms is found only in eukaryotic cells and not bacterial cells

endocytosis

cytoplasm

• semifluid, gelatinous, nutrient matrix

• cytoplasm is where most metabolic reactions occur

• provides support, shape, and assists in transport of substances

• contains storage granules and a variety of organelles

major difference with eukaryotic cytoplasm

eukarytoic has complex internal structure consisting of small rods

ribosome subunits

40s+60s- found membrane bound attaches to ER and free in the cytoplasm

80s- found as free ribosomes suspended in the cytosol, and attached to outside of endoplasmic reticulum

which of the following statements correctly compares the bacterial and eukaryotic ribosomes

bacterial ribosomes are 70s and eukaryotic ribosomes are 80s, with differences in subunit composition and sensitivity to antibiotics

what does the nucleus contain

contains chrmosomes

ER

transport network

golgi complex

membrane formation and secretion

lysosome

• digestive enzymes

• membranous sac with acid environment

• have hydrolytic enzymes (work well in acid environment

• can digest bacteria and other molecules withough harming cytoplasmic components of the cell

vacuole

brings food into cells and provides support

mitochondrion

• cellular respiration produces ATP molecules

• stores energy

• powers cell

• # present in cell depends on cells activities

• have their own ribosomes (70s)

• circular DNA

chloroplast

photosynthesis

peroxisome

oxidation of fatty acids; destroys H2O2

centrosome

consists of protein fibers, centrioles, important for cell division

nuclear envelope

encolses the nucleus, covered in pores

pore complex

regulates entry and exit of proteins and RNAs as well as large complexes of macromolecules

shape of eukaryotic DNA

linear

which of the following compares bacterial and eukaryotic genomes

bacterial genomes are usually a single DNA molecule, while eukaryotic genomes consist of multiple linear chromosomes housed in a nucleus

endosymbiont theory

• people with more energy have more mitochondria

• double membranes

• contain ribosomes producing their own proteins

• circular DNA

• grow independent within cell

endosymbiosis

examples of bacteria living inside of a host, losing genes that are important for survival outside of host

tsetse flies

has mircobial partners that it does life with

• wigglesworthia- cant live outside of fly and cant be cultured

• sodalis glossinidius- can be cultured

which of the following best supports the endosymbiosis theory explaining the origin of mitochondria and chloroplasts in eukaryotic cells

all of the above

harmful eukaryotic microorganim

protozoa- can cause significant disease in humans

harmful effects of protozoa

• small amount needed to cause disease

• can be intracellular or extracellular

• unable to withstand drying- cant be free in environment

• anthropod vectors- need a host

protozoa

unicellular, free living, found in soil and water

more animal like than plant like

nonphotosynthetic eukaryotic organism

how are protozoa characterized

motility

• divided into groups based on their methods of locomotion

Amebae

protozoa that move by means of pseudopodia

ciliates

protozoa that move by means of hairliike cilia

flagellates

protozoa that move by means of whiplike flagella

which of the following correctly matches a group of protozoa with its method of locomotion

flagellates- move using whiplike flagella

disease caused by protozoa

• amoeboid- entamoeba histolytica

• falagelalated protozoans- giardia, trypanosomiasis

• ciliated protozoans- balantidium

• spore-forming protozoans- malaria

helminth

type of parasite, usually spread in microscopic form (round worms, flatworms)

taeniasis

infects humans who eat raw of undercooked infected meat

mycology

study of fungi

examples of fungi

yeasts, molds, and fleshy fungi(mushrooms)

characteristics of fungi

• cell walls made of chitin

• cell membranes contain ergosterols

• some are unicellular, while others grow as multicellular filaments call hyphae

fungal spores

• help classify fungi, theyre either asexual or sexual (unlike bacterial spores)

• can be harmful to breathe in 

where is yeast found

• in soil and water

• in the skins of many fruits and vegetables

• on humans

mycosis

infection

hyphae

branching filaments

dimorphic

fungal pathogens cycle between hyphae and yeast like

true pathogens

infect typically healthy hosts

dermatophytes

true pathogens, infect hair skin and nails, infections are like ring worm

which of the following statements about fungal infections (mycoses) is TRUE

Mycoses are more common in individuals who are immunocompromised or on long term antibiotics

who is at risk for fungal infections

those who use antibiotics for a long time, and are immunocompromised

Which of the following statements correctly compares membrane characteristics between bacteria and eukarya

bacterial membranes contain a high abundance of structural proteins, while eukaryotic membranes contain fewer

what makes something a good antibacterial target?

• cell wall

• selective

• proteins

• ribosomal sub units

• gram positive

bacteriostatic

prevent bacterias from growing , target bacterial protein synthesis and metabolic pathways

bactericidal

kill bacteria, tend to target bacterial cell walls or cell membranes and nucleic acids

what kills normal microbiota

bactericidal drugs

which of the following statements correctly distinguishes bactericidal from bacteriostatic agents

bactericidal agents directly kill bacteria while bacteriostatic agents inhibit bacterial growth and replicaton

antibacterial agents

used to treat bacterial disease

antibiotics

a substance produced by a microorganism that kills or inhibits the growth of other microorganisms

semisythetic antibiotics

antibiotics that have been chemically modified to kill a wider variety of pathogens or reduce side effect

narrow spectrum activity

a smal or narrow range of different microbial types they affect

broad spectrum activity

affect a wider range of both gram negative and gram positive bacteria

antibiotics often target

• peptidoglycan sythesis

• membrane integrity

• DNA synthesis

• transcription

• folic acid synthesis

• ribosome function

beta lactams

peptidoglycan synthesis inhibitors

penicillin (bactericidal) natural

narrow spectrum of activity, susceptible to beta lactames

characteristics of beta lactams

• semisythetic

• stable in acidic environments- has side chain that helps it survive stomach acidity

• more readily abosrbed

• more readily absorbed 

• less susceptible to deactivation

what do beta lactams target

transpeptidases- enzyme that fuzes peptide bonds

Non-beta-lactam

• glycopeptides (vancomycin)

• effective against gram-positive organisms

• preffered treatment for clostrodium difficile

vancomycin and B-lactam antibiotics are similar in what way?

they both prevent peptide side chain cross linking in peptidoglycan

steps in developing resistance in bacteria

1. target alterations: altering the drugs target

2. drug inactivation: bacteria may produce enzymes that inactivate the drug

3. reducing drug concentrations: limiting drug entry or pumping drugs out of cells

intrinsic resistance

natural resistance to antimicrobial drugs, makes certain pathogens harder to eliminate