Flashcards in Chapter 4. Deck (73):
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Bacteria
Bacteria - simple, single-celled organisms, DNA not enclosed, Prokaryotic, peptidoglycan cell wall, binary fission (split into 2 equal parts), contain flagella
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Distinguish a genus from a specific epithet.
a genus: Capitalized and
a specific epithet (species): not capitalized
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Archaea
prokaryotic, peptidoglycan cell wall, found in extreme environments; pathogenic in humans
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Fungi
Eukaryotic, nucleus containing DNA, uni/multi cellular, photosynthesis, chitin cell wall, sexually or asexual repoduction
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Protozoa
nicellular, eukaryotic, move using pseudopods, flagella or cilia, photosynthesis, sexual/asexual reproduction
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Algae
eukaryotic, photosynthetic, unicellular, cellulose cell wall.
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Viruses
acellular, simple, one type of nucleic acid, must have host to survive.
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Multicellular Animal Parasites/Helminths
eukaryotic, (flat/round worms)
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Which groups of microbes are prokaryotes?
Bacteria and archaea
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Which are eukaryotes?
Algae, Fungi, Protozoa
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What are the three domains?
Bacteria, Archaea, Eukarya
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Explain the importance of observations made by Hooke and van Leeuwenhoek.
He discovered life's smallest structural units called 'cells'; discovered live microorganisms
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What is the cell theory?
all living things are composed of cells
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Compare spontaneous generation and biogenesi
Belief that some forms of life could arise spontaneously from nonliving matter;
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What evidence supported spontaneous generation?
Redi's experiment with one covered and one uncovered meat jar producing maggots proved that this could not occur spontaneously
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Identify the contributions to microbiology made by Needham,
1
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Compare and contrast the overall cell structure of prokaryotes and eukaryotes.
Compare: both contain nucleic acids, proteins, lipids, and carbs; same chemical reactions to metabolize food, build proteins, and store energy.
Contrast: structure of cell walls and membrane, and absence of organelles
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What is the main feature that distinguishes prokaryotes from eukaryotes?
Prokaryotes: DNA not enclosed, singular arranged chromosomes, DNA not associated with histones, lack membrane-enclosed organelles, cell wall contain polysaccharide peptidoglycan, divide by binary fission
Eukaryotes: DNA in nucleus, muti chromosomal, histones, membrane-enclosed organelles, cell wall simple, mitosis
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Identify the three basic shapes of bacteria.
coccus- round, bacillus- rod shaped, spiral- spiral
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How would you be able to identify streptococci through a microscope?
strepto- chains, cocci- round
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Describe the structure and function of the glycocalyx.
sugar coat surrounding a cell. made of viscous (sticky), gelatinous polymer that is externa to the cell wall. composed of polysaccharide, polypeptide, or both.
-organized and firmly attached to cell wall: capsule
-unorganized and loosely attached: slime layer
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Why are bacterial capsules medically important?
they protect the cell from phagocytosis by the cells of the host. this is bad because it makes the bacteria able to cause disease in the host
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Differentiate flagella, axial filaments, fimbriae, and pili.
Flagella: prokaryotic cells; long filamentous appendages that propel bacteria
Axial filaments: found on spirochetes; bundles of fibrils that arise at the ends of the cell beneath an outer sheath and spiral around the cell/spiral motion
Fimbriae: involved in forming biofilms; help bacteria adhere to epithelial surfaces
Pili: motility and DNA transfer (conjugation)
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How do bacteria move?
Flagella, Axial filaments, fimbriae, and pili
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Compare and contrast the cell walls of gram-positive bacteria, gram-negative bacteria, acid-fast bacteria, archaea, and mycoplasmas.
Gram positive: many layers of peptidoglycan, thick, rigid structure; contain teichoic acids
Gram negative: thin layer of peptidoglycan, outer membrane made of lipopolysaccharides, lipoproteins, and phospholipids.
Acid-fast bacteria: high concentration of hydrophobic waxy lipid (mycolic acid), thin layer of peptidoglycan
Archaea: may have no cell wall, or unusual walls of polysaccharides and proteins- no peptidoglycan.
Mycoplasmas: no cell wall
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Why are drugs that target cell wall synthesis useful?
Bacterial cell walls are made of different material as Eukaryotic cells
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Differentiate protoplast, spheroplast, and L form.
Protoplast: a gram-positive bacterium or plant cell treated to remove the cell wall
Spheroplast: gram-negative bacterium treated to damage the cell wall; spherical cell
L form: prokaryotic cell that lack a cell wall; can return to walled state
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How do protoplasts differ from L forms?
L forms can return to a walled state
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compare and contrast overall cell structure of prokaryote and eukaryote cells
prokaryote:
-one singular chrosome, not in a membrane
-no histones (naked DNA)
-no membrane bound organelles
-peptidoglycan cell walls if bacteria
-pseudomerian cell walls if archaea
-divide by binary fission
eukaryote:
-paired chromosomes, in nuclues
-histones around dna
-membrane bound organelles
-polysaccharide cell walls
-mitotic spindle
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what is the main feture that distinguishes prokaryotes from eukaryotes?
the nucleus!
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identify the three basic shapes of bacteria
-baccilus- rod shaped
-coccus- spherical
-sprial: spirillum (one kink), vibro(comma shaped), spirochete (multiple kinks)
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arrangements of bacteria
pairs- di
clusters- staph
chains- strep
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how would you be able to identify streptococci through a microscope
- it would look like a chain of spheres under the microscope
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describe the structure and function of the glycocalyx in prokaryotic cells
-outside the cell wall
-usually sticky and firmly attached
-organized= capsule, prevents phagocytosis
-unorganized= slime layer, allows cells to attatch, protects against dehydration, nutrient loss and antibiotics
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flagella
flagella
-outside the cell wall
-made of chains of protein flagellin
-attached to a protein hook
-anchored to the wall and membrane by the basal body- gram negative have 2 pairs , postive have 1 pair
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Pili
pili
-used for reproduction, sends copies of DNA to another cell
-1 or 2 per cell
-provide gliding and twitching motility
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fimbriae
-allow attachment
-found in gram positive cells
-anchor cells to something so they can invade
-lots per cell
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axial filaments
-also called endoflagella
-in spirochetes
-anchored to one end of the cell
-rotation causes cell to move
-located inside of the cell
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how do bacteria move?`
running and tumbling by flagella
-running- bacteria moves in one direction for a lenght of time
-tumbles- periodic, abrupt, random changes in direction
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the bacteria cell wall
complex & semiridiged
-made of peptidoglycan (polymer made up of NAG and NAM during a dehydration syntehsis reaction)
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gram positive vs gram negative cell wall
positive:
-up to 25 layers of peptidoglycan
-nag and nam backbone linked together with polypeptides (amino acids)
-teichoic acid forms beams that go up and down to hold the structure together
-side chains up and down, cross bridges across
-stacked on top of membrane
negative:
-one layer of peptioglycan
-doesn't contain and cross bridges or side chains, no peptide bonds
-sandwiched between two membranes
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how does the gram stain work on the cells
gram positive
-alcohol dehyrdates the peptiodglycan
-crystals dont leave
gram negative
-alcohol dissolves outer membrane and leaves holes in peptidoglycan, crystals wash out
-lysosomes effect cross bridges, so they only effect postive
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acid fast bacteria cell walls
-like gram positive
-wazy lipid bound to peptidoglycan, prevents uptake of dyes
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mycoplasmas vs archaea cell wall
mycoplasmas:
-lack cell walls
-sterols in plasma membrane
archaea:
-wall less or walls of pseudomurine( lack NAM and d amino acid)
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differentiate protoplast, spheroplast, and l form
*result from damage to the cell wall
protoplast- wall less gram positive cell
spheroplast- wall less gram negative cell
* both susceptible to osmotic lysis( burst in pure water )
L form- wall less cells that swell into irregular shapes
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describe the structure, chemistry, and functions of the prokaryotic plasma membrane
-consist primarly of phospholipids
-lipid bilayer- produces and repairs cell wall, just inside cell wall
-peripheral proteins- proteins just inside bilayer
-intergral proteins- intergrated in cell wall
-transmembrane- across membrane
-selective permebility- allows passage of some molecules
-important to the breakdown of nutrients and the production of energy
-contains enzymes capable of catalyzing the chemical reactions that break down the nutrients and produce atp
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which agents can cause injury to the bacterial plasma membrane?
-alcochols, quaternary ammonium( detergents), and antibiotics causes leakage of cell contents
-takes off outer membrane layer
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forms of passive transport
*doesn't require energy
simple diffusion:
-movement of a solute from high to low concentration
-nonpolar substances are easy to diffuse
-happens until equilibrium is reached
facilitated diffusion:
-solutes combines with a transporter protein in the membrane
-polar substances use this
osmosis:
-the movemnt of water from high to low concentration
-use aquaporins- water channels
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active transport
*requires a transporter protein and atp
-ions, amino acids, simple sugars
-goes against concentration gradient
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identify the functions of the nucleoid and ribosomes in prokaryotic cells
nucleiod:
-contains a single, long, continuous, circular arranged thread of dna-- bacterial chromosome
-some bacteria also have small circular double stranded dna molecules called plasmids--plasme membrane proteins, can be transfered from cell to cell
ribosomes:
-sites of protein synthesis
-composed of 2 subunits, consists of protein and a type of rna- rRNA
-called 70s ribosomes
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where is the dna located in a prokaryotic cell
dna in prokaryotic cells are found in the nucleiod
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what is the general function of inclusions
reserve deposits, generally cells and accumulate certain nutrients and use them when the environment is deficient
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identify the function of four inclusions
1. metachormatic granules- large inclusions called volutin- reserve of inorganic phosphate that can be used in the synthesis of ATP
2. polysaccharide granules- consists of glycogen and starch
3. lipid inclusions- polymer poly b and acid
4. sulfur granules- genus thiobacillus, use sulfur for energy
5. carboxysomes- enzymes ribulose, photosnthetic bacteria use CO2 as source of carbon and require this enzyme
6. gas vacuoles- hollow cylinders covered by protein. maintain buoyancy so that cells can remain at a depth of water
7. magnetosomes- inclusions of iron oxide
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describe the functions of endospores, sporulation, and endospore germintaion
endospores- resting cells, resistant to desiccation, heat, and chemicals. highly durable dehydrated cells with thick walls, found in gram positive bacteria
sporulation- endospore formation with a vegetative cell, takes several hours. forms spore around DNA of cell
endospore germination- endospore returning to its vegetative state, triggered by physical or chemical damage to the endospore coat
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under what conditions do endospores form?
they form under harsh environments, form spores around DNA. cell dies off and DNA remains protected. can lye dormant for several years
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differentiate prokaryotic and eukaryotic flagella
prok- double membrane, give cells movement. made up of the filliment- flagillan, the hook,and the basal body- rod with a series of rings
euk- structures that extend from the cell, anchored to plasma membrane by basal body- consists of the 9+2 array of microtubles- made of tubulin
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difference between eukaryotic flagella and cillia
cell walls
prok- made of peptidoglycan, can be gram positive or gram negative
-complex and ridgid
euk- much more simple, algae- cellulose, fungi-chitin, yeast- glucan and mannan
glycocalyx
prok- slime layer or capsules
euk- layer of material containing sticky carbs
-strenghtens cell surface, helps attach cells together, contributes to cell to cell recognition
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compare and contrast prok and euk plasma membranes
-very similar in function and basic structure, different in types of proteins found in the membranes
euk- contain carbs, which serve as attachment sites for bacteria and as receptor sites that assume a role in cell to cell recognition
-contain sterols
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euk endocytosis
-segment of the plasma membrane surrounds a particle or large molecule, encloses it, and brings it into the cell
three types:
1. phagocytosis-pseudopods extend and engulf particles
2. pinocytosis- membrane folds inward, brings in fluid and dissolves substances
3.receptor-mediated endocytosis- substance binds to receptors in the membrane, when binding occurs, membrane folds inward. one way viruses can enter cell
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compare and contrast prok and euk cytoplasm
euk-contains a complex internal structure, consisting of exceedingly small rods and cylinders. they form the cytoskeleton
-important enzymes are located in organelles
prok- enzymes are free floating in cytoplasm
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compare the structure and function of euk and prok ribosomes
both- protein synthesis
prok- called 70s ribosomes, made up of 50s and 30s free floating
euk- somewhat larger and denser than prok, called 80s ribosomes made up of 60s and 40s subunits. can be free floating or attached to the rough er
*because of the differences, microbiol cells can be killed by antibiotics without harming the host cells
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endoplasmic reticulum
extensive network of flattened membranous sacs/tubules called ccisterne
-rough: continous with nuclear envelope. studded with ribosomes. factory for synthesizing secretory proteins and membrane molecules
-smoth: network of membrane tubules. contains unique enzymes. synthesizes phospholipids and fats and sterols
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golgi complex
proteins synthesized in rough er transported to golgi. modified and trasnported to the plasma membrane or are stored
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lysosomes
formed in the golgi. contain 40 different kinds of digestive enzymes. single membrane and lack interal structure
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vacuoles
space/ cavity in cytoplasm. derived from golgi. temporary storage. helps bring food into cell. store wastes and poisions. take up water
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mitochondria
double membrane. provides enormus surface area for chemical rreactions for chemical reactions. powerhouse of the cell- ATP production. 70s ribisomes.
-machinery for replicate, transcribe, and translate info incoded by their DNA--can reproduce on their own
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chloroplasts
algae and gree plants. photosynthesis. contain thylakoids and 70 ribisomes
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peroxisomes
from by the divison of preexisting peroxisomes. contain enzymes that can oxidize various organic substances
-protects other parts of cell from hydrogen peroxide
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centrosome
organizing center for mitioc spindles- pericentriolar material
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discuss evidence that supports the endozymbiotic theory of euk evolution
theory- larger bacterial cells lost their cell walls and engulfed smaller bacteria cells
-both mitochondria and chloroplasts resemble bacterian size and shape.
-contain circular DNA and can reprodce on their own
-ribosomes in them resemble prok. ribosomes .
-same antibiotics that inhibit protein synthesis in ribosomes in bacteria also inhibit protein synthesis in mito. and chloro.
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compare the structure of euk. nuclues and prok. nucleiod
euk nucleus- spherical, largest structure of the cell, contains almost all DNA
-surrounded by a double membrane nuclear envelope with nuclear pores for communication
-DNA wrapped in histones
prok nuleoid- single circular DNA-bacterial chromosome and plasmids.
-no histones or nuclear envelope
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compare the structure and function of euk and prok ribosomes
both- protein synthesis
prok- called 70s ribosomes, made up of 50s and 30s free floating
euk- somewhat larger and denser than prok, called 80s ribosomes made up of 60s and 40s subunits. can be free floating or attached to the rough er
*because of the differences, microbiol cells can be killed by antibiotics without harming the host cells
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