bio test 1

fossil evidence of eukaryotes dates back to

1.5 BYA

prokaryote:

a cell lacking a membrane-bounded nucleus or membrane-bound organelles

pseudomurien:

a component of the cell wall of archaea; it is similar to peptidoglycan in structure and function but contains different components

peptidoglycan:

a component of the cell wall of bacteria, consisting of carbohydrate polymers linked by protein cross-bridges

endospore:

a highly resistant, thick-walled bacterial spore that can survive harsh environmental stress, such as heat or desiccation, and then germinate when conditions become favorable

which of the following would be an example of a biomarker

a hydrocarbon found in an ancient rock layer

flagellum:

a long, threadlike structure protruding from the surface of a cell and used in locomotion

virion:

a single virus particle

plasmid:

a small fragment of extrachromosomal DNA, usually circular, that replicates independently of the main chromosome, although it may have been deprived from it

the cell wall in both gram + and gram- cells is

a target for antibiotics that affect peptidoglycan synthesis

lytic cycle:

a viral cycle in which the host cell is killed (lysed) by the virus after viral duplications to release viral particles

lysogenic cycle:

a viral cycle in which the viral DNA becomes integrated into the host chromosome and is replicated during cell reproduction. Results in vertical rather than horizontal transmission

what kind of pathogen would retain its ability to cause infections after being treated with powerful proteolytic chemicals that would destroy all proteinaceous material?

a viroid

the SARS outbreak is an example of

a virus jumping from one species to another

a microbiologist suspects a strain of staphyloccus aureus is resistant to methicillin. what would be the best approach to test this suspicion?

add methicillin to the growth plates

retrovirus:

an RNA virus. When a retrovirus enters a cell, a viral enzyme (reverse transcriptase) transcribes viral RNA into duplex DNA, which the cell's machinery then replicates and transcribes as if it were its own

autotroph:

an organism able to build all the complex organic molecules that it requires as its own food source, using only simple inorganic compounds

heterotroph:

an organism that cannon derive energy from photosynthesis or inorganic chemicals, and so must feed on other plants and animals, obtaining chemical energy by degrading their organic molecules

analyze the following statements and choose the one that most accurately supports the endosymbiotic theory

antibiotics that inhibit protein synthesis in bacteria can have the same effect on mitochondria

virus:

any of a group of complex biochemical entities consisting of genetic material wrapped in protein; viruses can reproduce only within living host cells

viroid:

any of a group of small, naked RNA molecules that are capable of causing plant diseases, presumably by disrupting chromosome integrity

phages are viruses that can infect?

bacteria

farmers often practice crop rotation to help enrich agricultural fields. why are beans and other legumes often used in rotations?

bacteria in legume root nodules are nitrofiers

why are children often told that if they eat too much candy their teeth will fall out?

bacteria use the sugar to make ATP, this fermentation process produces acids as a bi-product

the difficulty designing a single flu vaccine that will work forever is that influenza

both mutates and can be recombined to form new viruses

the varying degrees of resistance to HIV in populations has been suggested to be related to the patterns of smallpox outbreaks over human history. this explanation hinges on

both viruses using the same receptor to bind to host cells

choose all of the following that exhibit an alternation of multicellular generations

brown algae; red algae

ulcers and tooth decay do not appear related, but in fact both

can be due to bacterial infection

if a cell contains a pellicle, it

can change shape readily

prokaryotes participate in the global cycling of

carbon and nitrogen

the disease tuberculosis is

caused by a bacterial pathogen

when food is scarce, cells of this organism communicate with each other to form a multicellular slug

cellular slime molds

examine the life cycle of cellular slime molds, and determine which feature affords the greatest advantage for surviving food shortages

cellular slime molds produce spores when starved

which is most likely the ancestor of animals

choanoflagellates

sponges (phylum porifera) are animals that possess feeding cells called collar cells. these cells have a central flagellum surrounded by a collar of microvilli. The collar filters organic material out of the water column. Which protist shares a more recent common ancestor with the poriferans?

choarioflagellates

all ___ have two very different types of nuclei within their cells, small micronuclei and larger macronuclei.

ciliates

the horizontal transfer of DNA using a plasmid is an example of

conjugation

the 3 domains of life

consist of 3 different basic cell types

organisms that are characterized by being unicellular, photosynthetic, and having double shells made of silica?

diatoms

choose all of the following that are photosynthetic

diatoms; dinoflagellates

DNA is not found in this organelle

endoplasmic reticulum

when bacteria are exposed to nutrient-poor conditions they form thick-walled structures that contain the chromosome and a small amount of cytoplasm. these structures are called?

endospores

which of the following is a common in animal viruses but NOT in bacteriophage?

envelope

which of the following characteristics is unique to the archaea?

ether-linked phospholipids

DNA replication and gene expression in archaens more closely resemble eukaryotic cells than the same process in bacteria. However, both bacteria and archea are prokaryotic. what does this suggest?

eukaryotic cells shared a more recent common ancestor with archaens than with bacteria cells

pilus (pili):

extensions of a bacterial cell enabling it to transfer genetic materials from one individual to another or to adhere to substrates

determine which feature of the choanoflagellates was likely the most significant for the evolution of animals

flagellum with a funnel-shaped, contractile collar also found in sponges

an experimental chemical has been shown to selectively cleave phosphodiester bonds. How will this affect a virus?

fragment the genome

prior to entry, the ____ glycoprotein of the HIV virus recognizes the ___ receptor on the surface of the macrophage

gp120; CD4

phage conversion in which viruses add genes to a bacterial cell can be considered to be a form of

horizontal gene transfer

the mechanisms of DNA exchange in prokaryotes share the feature of

horizontal transfer of information

which of the following wound not be part of the life cycle of a lytic virus?

integration into the host genome

bacteria lack independent internal membrane systems, but are able to perform photosynthesis and respiration, both of which use membranes. they are able to perform these functions because

invaginations of the plasma membrane can provide an internal membrane surface

trypanosomes are examples of

kinetoplastids

both diplomonads and parabasalids

lack mitochondria

which of the following is typically not associated with prokaryote?

multiple, linear chromosomes

are transformation and transduction the same process?

no, although they both involve gene transfer, the source of genetic material differ.

can a virus be killed?

no, viruses are nonliving and cannot die

which class of drugs would be effective against HIV but not against most other pathogenic viruses?

non-nucleoside reverse transcriptase inhibitors that block reverse transcription

plants cannot fix nitrogen, yet some plants do not need nitrogen from the soil. this is because

of a symbiotic association with a bacterium that can fix nitrogen

what best describes whether a virus is likely to infect a particular cell?

only infect cells with the correct surface receptor

the irish potato famine in the 1840's was caused in large part by a proliferation of a(n)?

oomycote

the function of the apical complex in apicomplexans is to

penetrate host tissue

a process by which a virus may change a benign bacteria into a virulent strain is called

phage conversion

a cell that can use energy from the sun, and CO2 as a carbon source is a

photoautotroph

a high concentration of chlorophyll imbedded in the plasma membrane fold of a newly discovered species of bacteria suggest a?

photoautotrophic matabolism

cell walls of bacteria Z contains high concentrations of phospholipids along with proteisn and relatively low amount of lipopolysaccharide. When bacteria Z is gram stained, it will most likely be colored?

pink

recently a class of infectious proteins with no associated nucleic acid have been identified. they are referred to as?

prions

most viruses form a capsid around their nucleic acid core, the capsid is composed of?

proteins

the idea of a protein that was an infectious agent was heretical because

proteins are not the informational molecules in cells

the use of multiple drugs in HAART to treat AIDS has

reduced the viral level in the bloodstream to undetectable levels

bacterial viruses and animal viruses are similar in that they both

require host functions for some aspect of their life cycle

the reverse transcriptase enzyme is active in which class of viruses?

retroviruses

which of the following is NOT part of a virus?

ribosome

current classification of prokaryotes is based on?

sequencing of proteins, DNA, and RNA

stramenopila are

small hairs on flagella

the marine multicellular protists including the larger brown algae belong to the?

stramenopiles

conjugation:

temporary union of two unicellular organisms, during which genetic material is transferred from one cell to the other; occurs in bacteria, protists, and ceratin algae and fungi

tissue tropism:

the affinity of a virus for ceratin cells within a multicellular host; ex: hepatitis B virus targets liver cells

gram-positive (+) and gram-negative (-) bacteria are characterized by differences in

the cell wall: gram+ have a thick layer of peptidoglycan and gram- have an outer membrane

the drugs used against HIV in AIDS therapy are not effective against the flu because

the proteins targeted by HIV drugs are not found in influenza

host range:

the range of organisms that can be infected by a particular virus

transformation:

the uptake of DNA directly the environment; a natural process in some bacterial species

endosymbiosis:

theory that proposes that eukaryotic cells evolved from a symbiosis between different species of prokaryotes

the products of budding are

two cells, one of which is smaller than the other

plasma from a sick mouse is filtered across a membrane that has a 200 nm pore size. if the filtrate is still infectious when injected into a healthy mouse, then the pathogen is most likely a(n)?

virus

according to the prion hypothesis, the infectious agent for scrapie must have "genetic" information in

the three-dimensional structure of the scrapie prion