Biology Exam 2

Chemicals, secreted by soil fungi, which inhibit the growth of bacteria, are known as -----?


A prokaryote that obtains carbon and energy by ingesting prey is a(n) -------.

Heterotroph and Chemotroph

Which of the following extremophiles might researchers most likely use as a model for the earliest organisms on Earth?

An anaerobic Archaean species

What is the characteristic feature of the Chlamydiales phylum?

Parasitic life cycle

Your run an osteology lab, where students are able to study the bone structure of various species. To produce clean bones, you introduce insects and bacteria to remove all remaining flesh. Which bacteria would be the best purchase for your lab?


One of the fish in your aquarium dies. Adding which protist to the water would allow you to avoid flushing the dead fish by speeding its decay?

A water mold

Which of the following eukaryotic lineages contains many species that lack functioning mitochondria?


You are given an unknown organism to identify. It is unicellular and heterotrophic. It is motile, using many short extensions of the cytoplasm. It has well-developed organelles and two nuclei, one large and one small. This organism is most likely to be a ----.


Protists and bacteria are grouped into different domains because..

Protists have a membrane-bounded nucleus, which bacterial cells lack

Which of the following best describes the leading hypothesis on the origin of the nucleus?

The nucleus was formed through infolding of the plasma membrane

All fungi are


Fungi with hyphae

Are adaptive for rapid directional growth to new food sources

Some fungal species can kill herbivores while feeding off of sugars from its plant host. What type of relationship does this fungus have with its host?


Which of the following is an important role for fungi in the carbon cycle?

Fungi release fixed carbon back to the environment for other plants and photosynthetic organisms to utilize

Some fungi have been instrumental in the development of human culture, including ----- in the phylum ---- as they have been in use for hundreds of years in producing beer and bread

Yeasts; Ascomycota

Actinobacteria (b)

Common in soil and freshwater habitats Cells found as rods or filamentsSome form chains or branching chains called mycelia ChemoheterotrophsUse a varity of organic electron donors and oxygen as an electron acceptor Several are parasitesSome Fix nitrogen Cause TB and leprosyProduce antibiotics- streptomycin, neomycin, tetracycline, and erthromycin

Chlaymdiea (b)

Common in hosts cells of many vertebratesFound in clustersVery small (as small as some viruses)Chemoheterophs All species live as parasites' inside host cells Can produce ATP by electron transport The STD caused by chlamydia trachmatis can lead to ectopic pregnancy and infertility

Cyanobacteria (b)

Common in lakes, rives, oceans Filaments, spheres, spirals Individual cells, chains, or coloniesSome contain heterocysts where nitrogen fixation occurs Photoautotrophs Involved in nitrogen fixationForm symbiotic relationships with fungi called lichens and with protists, sponges, and legume plants Responsible for the origin of Earth's oxygen rich atmosphereSome involved in harmful algal blooms Provide much of the nitrogen used by other organisms

Firmicutes (b)

Common in the human gut Most are rods or spheres Many form chains or clusters of four cells One group produces a cell wall made of cellulose Some produce a durable resting stage called endospore Chemoheterotrophs Some fix nitrogen Some perform anoxygenic photosynthesis Some can use hydrogen gas as an electron donor Members of this group cause anthrax, botulism, tetanus, gangrene, strep throat Bacillus thuringiensis produces BT toxin, an important insecticide Some are used in yogurt and cheese production

Proteobacteria (b)

Common in aquatic environments and as pathogens Diverse morphology Rods, spheres, spiralsSome form colonies that aggregate into a fruiting body and produce reproductive spores at their tips Most are heterotrophs or chemoautotrophs Some contain bacteriochlorophyll and obtain energy through photosynthesis E.coli and Agrobacterium are often used in biotechnologyMembers of this group cause cholera, food poisonings, plague, dysentery, typhus

Spirochaetes/ Spirochetes (b)

Common in the guts of animals and as pathogens Cork-screw shapeFound as individual cells Flagella are found inside cells and cause cells to move in a spiral fashionChemoheterotrophs Produce ATP via fermentation Can thrive in anaerobic conditions Members of this group are responsible for leptospirosis, syphilis, and Lyme diseaseCork-screw like movement enables cells to burrow into host tissue

Crenarchaeota (Eocytes) (a)

Common in sulfur-rich hot springs, acidic environments, and deep-ocean sediments Rods, spheres, filaments, and discs Flagella are common Some produce protein fibers that help attach to sulfur granules One species produces a glycoprotein cell wall Chemoheterotrophs and chemolithoautotrophs Use sulfur, hydrogen gas, Fe^2+ as electron donors Some make ATP only by fermentation May be the only life-forms in extremely hot, high-pressure, acidic environments

Euryarchaeota (a)

Diverse habitats (human gut, highly acidic and alkaline environments, deep-ocean sediments) Rod, spheres, filaments, spirals, and disics Found as chains or clustersFlagella are common Some lack cell wall Chemoheterotrophs and chemolithoautotrophs Many produce methane as a by-product of respiration Some members found near abandoned mines and produce acids that pollute streams Methanogens (found in guts of mammals and swamps) add billions of tons of methane to the atmosphere each year

Thaumarchaeota (a)

Common in fresh and salt water habitats and soilRod ShapedFound as individial cells Chemolithautotrophs Use ammonia as a source of energy and produce nitrite as a by-productOnly a dew members of the group have been observedVery abundant in oceans One member lives as an endosymbiont in marine sponges

Amoebozoa (p)

Lobose amoebas, cellular slime molds, plasmodial slime molds Lack cell walls; flexible and dynamic cell membranesDisplay amoeboid movement with cytoplasmic streaming Both asexual and sexual reproduction Cellular slim molds are haploid dominant Plasmodial slime molds are diploid dominant Slime molds influence nutrient cycling by feeding on microorganisms Dictyostelium discoideum is ued as a model organism for cell biology

Opisthokonta (p)

Choanoflagellate, animals, and fungiSingle celled to large multicellularSome with cell walls some without Most produce motile cells as part of their life cycle Both sexual and asexual Choanoflagellates are the closet living relatives to animals Fungi play a large role as decomposersAnimals play a large role as consumers

Excavata (p)

Parabasalids, diplomonads, eugelnidsExcavated feeding groove on side of cell Most swim via flagella Diplomonads have two nuclei Many euglenids are photosynthetic Primarily asexual reproduction Sexual reproduction has been observed in only a few membersTrichomonas causes trichomoniasis Giardia is responsible for giardiasis Euglenids are abundant in freshwater plankton

Rhizaria (p)

Formainiferans, actinopods, chlorarachniophytesLack cell walls, but many have a shell-like covering Move by amoeboid motion via slender pseudopodia Asexual reproduction is common, but sexual reproduction is possible Meiosis does produce haploid gametes that fuse to form a diploid individual Many display alternation of generations Shells of dead foraminiferans form extensive sediments on the ocean bottom and can form limestones Presence of certain shells can be used to data rocks during petroleum exploration

Plantae (p)

Glacucophyte algae. red algae, green algae, land plants Algae can be unicellular, colonial, multicellularContain chloroplasts Cell walls composed of cellulose Algae produce flagellated cells Both asexual and sexual reproduction Some algae and all land plants exhibit alternation of generations Primary producers in most ecosystem Agar is derived from cell walls of red algae Some red algae aid in development of coral reefs

Alveolata (p)

Ciliates, dinoflagellates, apicocomplexans Contain vesicles called alveoli that support the plasma membrane Move by cilia or flagella Some apicomplexans move by amoeboid motion Both asexual and sexual reproduction Dinoglagellates are photosynthetic, and some are bioluminescent Apricomplexans are parasites responsible for several diseases

Stramenopila (p)

Water molds, diatoms, brown algaeContain flagella with hollow projections Diatoms and brown algae contain chloroplasts Diatoms form ornate glass-like shells Both asexual and sexual reproduction Many exhibit diploid-dominant life cycles Brown algae display alternation of generations Phytopthora infestans caused the Irish potato famine Diatoms are important primary producers Giant kelp forests form habitats for a wide variety of animals

Microsporidia (f)

1300All are parasites of animal cells, especially in insects or fish Enter host cell through polar tube (which microsporidian shoots into host cells) Some appear to reproduce only asexually. Others produce various types of sexual spores Some infect several hosts to complete life cycle Many species can infect humans but cause serious infections only in patients with a compromised immune system Some are pest in honeybee and silkworm colonies

Chytrids (f)

Aquatic; common in fresh water750 Many decompose platns by digesting cellulose Mutualistic chytrids live in guts of cows, deer, and other mammals and help digest plant material Parasitic chytrids infect many species of plants and animals The only fungi that produce motile cells-both their spores and gametes swim via flagella Most exhibit alternation of generations Some are parasites of mosquitoes and are being studied as a biological control agent Batrachochytrium dendrobatids is largely responsible for declines in amphibian populations worldwide

Zygomycetes (f)

Food molds1050Many are saprophytes and live on plant debris Some parasitize other fungi, insects, or spiders Asexual reproduction is very common; asexual sporgangia produce spores Sexual reproduction involves fusion of hypae and formation of zygosporangium and sexual sporangia Several species often seen growing on bread and soft fruits Some are used in production of steroids, pigments, alcohols, and fermented foods

Glomeromycota (f)

200 Form mutualualistic associations with plant roots in the form of arbuscular mycorrhizal fungi Most produce large spores Difficult to grow and study Sexual reproduction has not been documented Play large roles in the ecology of prairies and tropical forests

Basidiomycota (f)

Club fungi: mushrooms, boletes, stinkhorns, puffballs, brackets32,000 Decompose wood by producing lignin peroxidase Some form ectomycorrhizal associations with tree roots Smut and rust fungi are plant parasites Produce haploid spores in club-shaped basidia Basidia of mushroom forming species line gills found under the cap Mushroom used as food, toxic, hallucinogenic Ectomycorrhizal basidiomycetes enhance growth of hardwoods and softwoodsSmuts and rusts cause serious economic damage to crop plants

Ascomycota (f)

sac fungi: morels, truffles, yeasts, cup fungi, lichen-forming fungi 64,000 Many for ectomycorrhizal associations with tree roots Some form mutualistic associations with photosynthetic algae or bacteria in lichens Some are predatory on protists or nematodes Produce haploid spores in sac-like asci Asci of many species found on fleshy, cup-shaped structures Asexual reproduction in many Lichens are often sensitive to air pollution and are used as bioindicators

Class I Double Stranded DNA dsDNA (V)

Largest group of viruses; 33 families; 142 Virions are enveloped or naked Capsids are icosahedral, helical, or complex4.5-2400 kb genomes, as a single circular or linear molecule or multiple linear molecules Most infect animals or bacteria; fewer infect protists or archaea Not known to infect plants Some genera may coexist with host via lysogeny or latency Genome replicated by a semiconservative mechanism Genome used as template for transcription of mRNA mRNA used to produce viral proteins

Class II Single Stranded DNA ssDNA (V)

9 families, 44 generaMost virions are naked; a few are enveloped Most capsids are icoshedral; a few are helical 1.8-12.5 kb genomes as single or multiple molecules that may be circular or linear Most infect animals; fewer infect bacteria or plantsMarine invertebrates recently identified as hosts Genome replicated via a dsDNA intermediate, where either strand is used in progeny virions dsDNA intermediate used as the template or transcription of mRNA mRNA used to produce viral proteins

Class III Double Stranded RNA dsRNA (V)

12 families, 36 generaMost virions are naked; are envelopedCapids are icosahedral and often have multiple layers 2.7-30 kb genomes as one or more linear molecules Animals, plants, and protists are common hosts Several known to infect hosts across different taxa Viral RNA replicas packaged in virion transcribes mRNA from the dsRNA genomemRNA used as template to make copies of the dsRNA genomemRNA also used to produce viral proteins

Class IV Positive Sense Single Stranded RNA+ssRNA (V)

Largest group of RNA viruses; 32 families, 139 generaVirions are enveloped or naked Most capsids are icosahedral; a few are helical 2.4-31 kb genomes as one or more linear molecules Plants and animals are most common hosts Some can infect vertebrates and arthropods which are used as vectors for transmission Genomic RNA translated to produce a viral RNA replicase Viral replicase makes copies of genomic RNA via dsRNA intermediate Copies of viral genome used to produce polyproteins are generated via cleavage

Class V Negative-Sense Single Stranded RNA -ssRNA (v)

9 families, 42 generaMost virions are enveloped; a few are naked Capsids are helical 10-25 kb genomes as one or more linear molecules Most infect animals; fewer infect plants Not known to infect bacteria or archaea Viral RNA replicase packaged in virion transcribed mRNA from -ssRNA genome Viral replicase makes copies of -ssRNA genomic RNA via dsRNA intermediate mRNA used to produce viral proteins

Class VI Reverse-Transcribing +ssRNA (v)

Smallest group of viruses; only 1 family, 8 generaVirions are enveloped Capsids are icosahedral, byt may be processed to change shape 7-11 kb genomes, as single linear molecules Known to infect only humans and other vertebrates Viral reverse transciptase packaged in virion converts RNA genome to dsDNA which is integrated into host genome Integrated dsDNA transcribed to replicate +ssRNA genome and produce mRNA mRNA used to produce viral proteins

Class VII Reverse Transcribing dsDNA (v)

2 families, 9 generaVirions are enveloped or naked Capsids are icosahedral 3-8.3 kb genomes, as a single circular molecule, often incomplete dsDNA Known to infect only vertebrates and plants Genome used as template for transcription of full-length +ssRNA and mRNA Viral reverse transcriptase converts +ssRNA into dsDNA to replicate genome mRNA used to produce viral proteins

You just discovered a new virus. This virus infects heart muscle, where it causes inflammation, and has a very high mutation rate. Which of the following is the best strategy for finding a treatment for this virus?

Identify the receptor this virus uses and develop a drug that blocks the receptor

When people die from HIV infections, it is usually because they -----.

Have too few T cells to adequately fight infection

Effective antiviral drugs are usually associated with which of the following properties?

Interference with viral replication

A biologists develops a new drug that seems to dramatically slow the onset of symptoms resulting from HIV infection. Close monitoring of HIV-infected cells reveals that the viral proteins are in the form of long polyproteins. The biologist most likely developed a -------> .

Protease inhibitor

Cells were infected with approximately 1000 copies of either virus A or virus B at the 0 time point. At 5-minute intervals, a sample of the virus and cell mixture was removed. The intact cells were removed from the sample, and the number of viruses per milliliter of culture was determined.Using the data in the figure, how long does it take for virus B to go through one lytic cycle?

60 minutes