#2 BIOL 2051 EXAM 1

what are the five fundamental lab steps for processing microbial samples?

inoculation, incubation, isolation, inspection and identification

what type of media would be used to test drinking water for the quantity of viable bacteria?

enumeration media

what is a medium?

nutrient substrate prepared for growing microorganisms

what is a culture that was previously pure but is now tainted with an unwanted microbe?

contaminated culture

what is the purpose of using transport media?

to preserve the viability of fragile microbes during transit

what is a medium that contains substances that inhibit the growth of certain microbes while permitting the growth of others?

selective

what type of medium is supplemented with complex components like blood or serum to support the growth of fastidious species?

enriched medium

what type of medium is designes to distinguish between different microbes by causing visible change in response to their metabolic reactions?

differential medium

what type of media is used specifically to determine the effectiveness of antimicrobial agents?

assay media

a bacterial cell acquires a plasmid containing a gene for tetracycline resistance. for the cell to produce the resistance protein, which of its native cellular machineries are essential?

RNA polymerase for transcription and 70S ribosomes for translation

what is the process called for the generation of the electron beam in a standard transmission electron microscope is acheived by heating a tungsten filament until it emits electrons?

thermionic emission

what domain do animalia, fungi, and plantae all belong to?

eukarya

the observation that mitochondria and chloroplasts divide by binary fission, a process independent of host cell mitosis, supports the endosymbiotic theory. what does this observation imply about these organelles?

they retain a replication mechanism characteristic of their prokaryotic ancestors

prior to Carl Woese three domain system discovery with the analysis 16S rRNA, what were archaea generally classified as?

an unusual group of bacteria often called arachaebacteria

what is a key feature in eurkarya that is absent in bacteria?

the presence of a membrane bound nucleus

bacillus anthracis cells initiate sporulation rather than continue vegetative growth as a critical survival response. what triggers this process?

depletion of essential nutrients in the environment

a core difference between prokaryotic and eukaryotic cell division is the handling of the primary genome. binary fission lacks the complex steps of mitosis, such as nuclear envelope breakdown, because...

prokaryotic DNA is not contained within a nucleus

a key event in the history of life was the endosymbiotic origin of mitochondria. this event is an example of vertical transmission if...

the symbiont is passed down to daughter cells during host cell division

if an organism is single celled, lacks a nucleus, but has a unique ether-linked lipid membrane, what domain would it be classified under?

archaea

if a microscope has a resolution limit of 0.2um, how far apart do the objects have to be for the microscope to distinguish as two seperate points?

250 nm

if a new drug is developed that inhibits the function of 80s ribosomes, would it be a good choice for treating a bacterial infection?

no because it would be ineffective against the 70s ribosomes of bacteria and would be highly toxic to the human host

a pathogenic bacterium's ability to evade the host immune system is a key virulence factor. the presence of a polysaccharide capsule contributes to this evasion primarily by...

inhibiting complement activation and phagocytosis by macrophages

a patient is diagnosed with a viral infection. A physician correctly decides not to prescribe ciprofloxacin, an antibiotic that targets bacterial DNA gyrase. the treatment is ineffective because viruses...

do not contain DNA gyrase and are unaffected by its inhibition

a patient with bacterial pneumonia is treated with penicillin, a β-lactam antibiotic. a second patient with viral influenza receives no antibiotics. the differential treatment is based on the fact that...

β-lactams inhibit peptidoglycan synthesis which is an essential process for bacteria but absent in the acellular influenza virus

what is a bacteria with a single flagellum at each pole described as?

amphitrichous

what is a defining characteristic of eukaryotic cells that is absent in prokaryotic cells?

a membrane delimited nucleus

what cellular process would be affected most by a drug that disrupts the polymerization of actin?

cell crawling and changes in cell shape

what is an example of autophagy?

eukaryotic cell degrading a warn out mitochondrion or other organelle

what is a key difference between prokaryotic and eukaryotic ribosomes?

prokaryotic ribosomes are 70s while eukarytoic cytoplasm ribosomes are 80s

what type of organisms possesses a nucleus and mitochondria but lacks a peptidoglycan cell wall?

plasmodium - a protozoan

an antibiotic that specifically targets 70s ribosomes would be affective against what type of organism?

mostly bacterial pathogens

why are bacterial endospores formed?

in response to a nutrient limitation or harsh environmental conditions

in a chloroplast, the light-dependent reactions occur in the ______, while the Calvin cycle occurs in the ______

thylakoid membranes, stroma

in a eukaryotic cell, proteins destined for secretion out of the cell are synthesized by...

ribosomes attached to the rough ER

in prokaryotes, a high metabolic rate is often supported by an increased surface area from...

extensive infoldings of the plasma membrane

what do lysosomes contain to achieve intracellular digestion?

hydrolytic enzymes that are active at low pH

mesosomes, invaginations of the prokaryotic plasma membrane, are now largely considered to be...

artifacts generated during the chemical fixation process for electron microscopy

what are the polysaccharide chains in peptidoglycans cross linked by?

peptide bonds

plasmolysis, the shrinking of the plasma membrane away from the cell wall, would occur if a bacterium is placed in a...

hypertonic solution

what are polyribosomes complexes of?

multiple ribosomes attached to a single mMRNA molecule

what region of the cytoplasm is the bacterial chromosome located?

nucleoid

the cell walls of fungi are primarily composed of ______, while those of plants are primarily composed of ______

chitin, cellulose

the germination of a bacterial endospore is best described as....

the breaking of endospore's dormant state

the lipid portion of lipopolysaccharide (LPS), known as Lipid A, is medically significant because it acts as an _____

endotoxin

the nucleolus is the primary site for the synthesis of...

ribosomal RNA (rRNA) and ribosome subunits

what is the purpose of gas vacuoles in certain aquatic bacteria?

regulate buoyancy to maintain an optimal position in the water column

what is the primary function of nuclear pores?

regulate the transport of molecules between the nucleus and the cytoplasm

what is the process of cellular self-digestion where the lysosomes digest worn out organelles?

autophagy

what is the purpose of meiosis?

produce four genetically different haploid daughter cells

the resistance of endospores to heat, radiation, and chemicals is partly due to...

a dehydrated core and protective spore coats