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