Lecture 3 Flashcards Preview

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Flashcards in Lecture 3 Deck (106):
1

Prokaryotes

(pro=before) DNA is not enclosed w/in membrane, chromosome is singular&circular, no membrane could organelles, single celled organisms only

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Chromosome of prokaryotes exists w/ in ...

specific region of cell called nucleoid

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Eukaryotes

(eu=true) DNA is contained w/in membrane bound nucleus, DNA is arranged as multiple chromosome, organelles are present and membrane bound

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Eukaryotes can either her..

single celled or multicellular

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Eukaryotes include..

protists, fungi, plants, animals (multicellular)

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Morphology means

shape

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3 bacterial morphology

-coccus
-bacillus
-spirillum

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Coccus

spherical (ex: streptococcus pyogene also known as strep throat)

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Bacillus

rods (ex: escherichia coli also known as E.coli)

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Spirillum

spiral (ex: treponema pallidum causes syphilis)

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Glycocalyx

(sugar coat) gelatinous, sticky polymer, secreted from the prokaryote onto outside of cell wall. varied (some bugs make them other don't)

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Glycocalyx can be composed of either..

polysaccaride, protein or both

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When glycocalyx is made only of sugar its called an..

extracellular polysaccaride

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Glycocalyx capsule is when substance of glycocalyx..

is firmly attached to cell wall and organized

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Glycocalyx slime layerwhen substance of glycocalyx

is disorganized and only loosely attached to cell wall

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Capsules contribute to organisms virulence

by protecting from phagocytosis, and against dehydration (holds nutrients inside cell)

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Virulence

ability to cause disease

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Capsule stickiness allows the organism to..

adhere to and colonize host cells

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Certain organisms such as Bacillus anthracis ca only cause disease if they are..

encapsulated

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Extracellular polysaccarides

allows the bacterium to survive by attaching to diff surfaces w/in microbes environment

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Cons of extracellular polysaccarides to other bacteria, catheters, implants, teeth, plant roots, water pipes etc..

this quality allows the bacterium to attach to them and thrive (hard to get rid of)

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Flagella

found on some prokaryotic cells, long filamentous and used for motility, need been to be produced, move in cork screw motion

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3 primary parts of flagella

-filament
-hook
-basal body

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Filament of flagella

composed of circular flagellin protein forming helix around hallow core, not covered by sheath

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Hook of flagella

made of different protein than the flagella, attached to basal body

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Basal body of flagella

Anchors the flagellum to plasma membrane and cell wall

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Flagellar arrangements

-peritrichous
-monotrichous
-lophotrichous
-ampthitrichous

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Peritrichous

flagella distrbuted over entire cell surface, multiple flagella

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Monotrichous

single polar flagella

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Lophotrichous

2 or more flagella at 1 or both ends of the cell. can describe multiple types of flagellar arrangements

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Amphitrichous

tuft of flagella at each cell end

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Flagellar proteins are used to differentiate ..

in between strings of diff bacteria

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Flagella can rotate either..

clockwise or counterclockwise

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Flagellar movement depends on..

energy production

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Run/swim

movement in one direction for continuous period of time

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Tumbles

abrupt or random changes in direction, result when flagella changes its direction

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Taxis

move away dangerous environments and toward favourable environments

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Chemotaxis

movement toward chemical stimulus

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Phototaxis

movement toward light stimulus

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Pili and fimbriae

hair like appendages (stick to walls to reproduce) that are shorter, thinner than flagella and not used for motility, found in many gram - bacteria (never +)

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Pili/frimbriae on prokaryotes are wither

bacteria(gram - or +) or archaea

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Frimbriae

Bacterial cell can contain a few to hundreds, can be all over or only at poles

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Frimbriae enables the bacterial cell to..

adhere to surfaces and other bacterial cells

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Frimbriae allows bacterium to..

adhere and colonize, w/o frimbriae colonization cannot occur and disease doesn't occur

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Pili

longer than frimbriae, only 1-2 per cell

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Conjugation

pili filaments join 2 bacterial cells in order to transfer DNA in between them, direct port of passage for info

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Bacterial cell wall

semi-rigid, complex and semi permeable, provides cell shape, prevents cell rupture, important means of classifying bacteria

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Bacterial cell wall is composed of the polysaccharide..

peptidoglycan

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Peptidoglycan

polysaccarides composed of repeating disaccharides, very unique

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Peptidoglycan chains are..

-layered on top of on another
-liked together by short polypeptides (creating lattice and strong cell wall resistant to osmotic changes)

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Disaccharide unit is composed of..

-N-acetyl glucosamine (NAG)
-N-acetyl mermaid acid (NAM)

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Gram positive cell wall contains..

thick layer of peptidoglycan outside of the plasma membrane

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Teichoic acids

only found in gram + organisms, they hold everything together on top of membrane (toothpicks)

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2 forms of teichoic acids

-wall teichoic acids
-lipoteichoic acids

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Wall terichoic acids

extend out from the peptidoglycan (only goes to the peptidoglycan)

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Lipoteichoic acids

connect the plasma membrane to the peptidoglycan (goes all the way to the lipid membrane)

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Gram positive bacteria only have....

one membrane, plasma membrane. no top layer

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Gram negative bacteria contain a..

plasma membrane and outer membrane

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Periplasmic space

space between two membranes. filled w/ periplasmic fluid

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Outer membrane of gram negative cell contains

-lipids (phospholipids)
-proteins
-lipopolysaccharides (LPS)

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Lipopolysaccharides lipid portion ..

toxic, referred to as endotoxin

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Lipopolysaccharide polysaccharide portion..

composed of O sugars used to distinguish gram negative organisms

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First step of gram stain

crystal violet applied, gram +'s and -'s appear purple while only the gram + is actually stained

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Second step of gram stain

add iodine, gram + and gram - are both still purple

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Third step of gram stain

add alcohol (a destain) which disrupts the outer membrane has washes away any crystal violet leaving gram + purple and gram - colorless

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Final step of gram stain

Add safranin (counterstain) which is take up by gram - cells so the gram + are purple still while gram - are now pink

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Peptidoglycan is a common target for both..

host defences (lysozymes in saliva) and chemotherapies (penicillin)

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Plasma membrane composed of .. and provides a barrier in between ...

classic phospholipid bilayer; the intracellular and extracellular environments

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Semi permeable barrier exists in a semi-fluid state where..

fluid enough that membrane proteins are able to move/perform function but sold enough to maintain cell shape

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What disputes the plasma membrane

alcohol

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Cytoplasm composed of ..

75% water (cytozol)

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Cytoplasm contains

amino acids, carbohydrates, nucleotides, enzymes, inorganic ions, nucleiod, ribosome,

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Cytoplasm is ...

aqueous but thick and semi transparent

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Nucleoid

contains bacterial chromosome, no nuclear membrane, may have plasmids

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Plasmids

small circular double stranded DNA molecules

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Plasmids house..

non essential genes which can help bacterium to survive adverse conditions (antibiotic resistance)

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Ribosomes

where protein synthesis occurs, made of protein and ribosomal RNA

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Ribosomes consist of 2 subunits

-50S subunit; large
-30S subunit; small

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50S and 30S subunits come together to form..

70S subunit

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Eukaryotic ribosomes are..

larger and heavier (80S) large subunit is 60S and small subunit is 40S

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Why is it a perfect opportunity for antibiotics to target bacterial ribosomes

to execute selective toxicity, it can target the ribosome and will not cause harm to host cells

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Inclusion bodies

deposits of nutrient granules store for later use, serve basis for identification

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Types of inclusion bodies include:

-sulfur granulesI*
-polysaccharide granules*
-lipid inclusions *
-enzymes
(*important NRG sourcE)

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Endospores are only formed from..

gram POSITIVE

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Endospores

special structures that allow bacterium to resist heat, desiccation, chemicals, and radiation

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Endospore will remain ____ for long periods of time and leave ____ when..

dormant; dormancy; good growth conditions

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Spores

very resilient and some can even survive boiling water for hours making them difficult to get rid of

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Examples of spore forming bacteria include

-bacillus anthracis
-clostridium botulinum

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First step in sporulation

bacterial cell replicates its DNA

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Second step in sporulation

a septum forms diving the cell

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Third step in sporulation

larger compartment engulfs the smaller forming foreshore within the mother cell

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Fourth step in sporulation

peptidoglycan and other protective material forms around forespore (the spore coat)

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Fifth step in sporulation

spore is free from mother cell

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Simple eukaryotes

-protozoa (unicellular)
-fungi (multicellular)
-algae (multi and unicellular)

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Higher eukaryotes

plants and animal

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Eukaryotic flagella and cilia

long and flexible, move in whip like motion, contain protein and cytoplasm, used for motility

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Eukaryotic cell wall

not present in animal cells, structurally simple, composed of singly polysaccharide

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Polysaccharide in algae and plants

cellulose

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Polysaccharide in fungi

chitin

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Eukaryotic plasma membrane

same structure as prokaryotic, contain phospholipids, proteins, sterols

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Sterols

not in prokaryotes, cause eukaryotes membrane to be more rigid

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Eukaryotes are often capable of..

endocytosis which engulfs particles outside cell and brings them inside

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Eukaryotic cytoplasm located within..

boundary of plasma membrane but outside n clear membrane

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Eukaryotic cytoplasm have complex internal structure called a ___ that ..

cytoskeleton; provides support/shape, acts to transport substance though cell, composed of protein filaments

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Membrane bound organelles are..

absent in bacteria, structures w/ specialized function

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Examples of membrane bound organelles..

-nucleus
-mitochondria
-chloroplasts