biology 103 final exam review-pearson questions (9)

clostridium perfringens, a bacterium responsible for food poisoning, can divide in just 10 minutes under optimum conditions. assuming this generation time and that five c. perfringens cells have landed on a platter of chicken wings that is not being kept refrigerated at a picnic: how many cells of c. perfringens will there be in the platter after 2 hours?

20,480 after 12 generations (of 10 minutes each), the five initial cells will have given rise to 20,480. this is why it is important to keep food at high or cold temperatures that will discourage bacterial growth.

a bacterium living in an underground septic tank thrives by absorbing organic compounds from decomposing wastes. what is it?

a chemoheterotroph

dinoflagellates are best described as...

a clade of protists including unicellular autotrophs, heterotrophs, and mixotrophs

alginates are used in many everyday products, including toothpaste and soap. when added to water, they form a thick gel that binds or emulsifies liquids. alginates come from a group of multicellular stramenopiles that have one pigment that masks all others and therefore gives these organisms a distinctive, dark color. alginates are derived from...

brown algae

prokaryotes are classified into...

domain bacteria and domain archaea

the bacterium bacillus thuringiensis can withstand heat, dryness, and toxic chemicals that would kill most other bacteria. this indicates that it is probably able to form _____

endospores these are thick-walled, extremely resistant structures produced by some gram-positive bacteria, including members of the genus bacillus

some american soldiers serving in iraq have become infected with a skin disease caused by a protist called leishmania, which is transmitted by sand flies. the leishmania organism bears flagella with a unique crystalline rod structure. one of its life stages is squiggly and worm-like in appearance, much like its relative in the same group, trypanosoma. leishmania belongs to the group __________.

excavata leishmanias are closely related to trypanosomes and euglenoids

compost piles create an intense heat source and would therefore be suitable environments for _______________

extreme thermophiles

what evolutionary adaptations might the pesticide-eating bacteria have that allow them to be useful in this context? they likely...

fed on molecules with a chemical structure similar to pesticides

you take a 1-mL sample of pond water and add it to a colorless, viscous media in a small petri dish. when you place it under your dissecting microscope, you see three organisms. two are struggling to move efficiently through the media, while the third moves more quickly. you attribute the faster movement to the third organism's...

flagella

which of the following might typically be caused by bacteria?

food poisoning most food poisoning results from toxins produced by bacteria in food; sometimes, bacteria from food establish an infection in the victim's digestive tract

barry marshall and his collaborators showed that...

helicobacter pylori bacteria cause chronic gastritis and stomach ulcers

if you were just diagnosed with a serious bacterial disease, which of these would predict the most positive outcome for treatment? the disease was acquired...

in a remote, sparsely populated area where the bacteria have not been exposed to antibiotic drugs

which example below presents a misconception about how antibiotic resistance develops?

individual bacteria and viruses become immune to antibiotics after they are exposed to them. eventually the antibiotics are useless antibiotics have no effect on viruses, so this is one common misconception. more importantly, antibiotic resistance arises over several bacterial generations as resistant bacteria flourish and vulnerable strains die out. although they are usually rare, the resistance traits are often present before the antibiotic is first used

unlike archaean and eukaryote cell walls, bacterial cell walls contain a unique substance called...

peptidoglycan

______________ are heterotrophic protists; ____________ are photoautotrophic protists

protozoans; algae

there is a good chance you will eat carrageenan today and that you will eat nori at some point in your life, if you haven't already. In either case, you will be eating a product of...

red algae

suppose that in 1990, fungal treatment was added to stream water contaminated from a textile mill. the toxins in the water tend to lower pH levels, and scientists wanted to study how adding the fungal treatment affected stream pH levels. pH levels were recorded every year for five years. results indicated that the acidity of the stream water decreased from pH 2.5 in the first year to pH 5.9 by the fifth year. scientists concluded that...

the fungal treatment had a positive effect on detoxifying the stream water

which of the following statements regarding ulva is true?

ulva, a green algae, has a complex life cycle with alternation between multicellular diploid and haploid generations

multicellular organisms evolved from three different ancestral lineages: stramenopiles, unikonts, and archaeplastids. of these, fungi and animals evolved from two different lineages of ________, and land plants are ________

unikonts; archeaplastids

prokaryotic cell walls function...

to prevent the cell from bursting in a hypotonic environment.

which group served as the control group in the experiment?

3

chemoautotrophic bacteria obtain their carbon from ___________ and their energy from _____________

CO2; reactions involving inorganic chemicals

a. which time point on the graph shows when the antibiotic was first added? b. which three statements may correctly explain why the population size increases after time point C?

a. B b. -the few drug-resistant bacteria in the population reproduced, quickly leading to a large drug- resistant population -between time points C and D, drug-resistant bacteria were reproducing faster than non-drug resistant bacteria were dying -bacteria that acquired a mutation that conferred drug- resistance had a growth advantage over non-resistant bacteria

two diseases that represent high-priority threats as biological weapons today are...

anthrax and botulinum

the largest group of prokaryotes is the _____________, which obtain both energy and carbon from _____________

chemoheterotrophs; organic molecules

which option would provide evidence for the role of endosymbiosis in the origin of eukaryotes?

chloroplasts and mitochondria have their own DNA and reproduce by binary fission

some current research efforts are investigating whether or not ________, a group of prokaryotes with the ability to produce oxygen as a by-product of photosynthesis, can be used as a source of renewable energy by converting sunlight into electricity

cyanobacteria

protists include...

multiple clades of eukaryotes

scientists have warned doctors of the danger of their increasing use of antibiotics for treating minor illnesses. they are concerned because ___________

strains of bacteria that are resistant to these drugs will become more widespread a previously existing or new mutation that happens to be beneficial can increase in frequency in a bacterial population very rapidly. if a single individual in the population harbors a mutation that renders it resistant to an antibiotic, there may be millions of resistant bacteria a day after antibiotic treatment begins