in semester practice exam questions Flashcards
one piece of evidence that supports the hypothesis that animals are related to choanoflagellates is that
the inner cavity of sponges, the spongocoel, is lined by cells that resemble choanoflagellates
stinging cells of cnidarians are called
cnidocytes
the digestive system of cnidarians is called a gastrovascular cavity because it
distributes nutrients, oxygen and wastes to different regions of the body
animals w a distinct head region, an anterior brain, and displaying forward, directed locomotion in some part of their life have the following form of body symmetry
bilateral symmetry
3 embryonic germ layers are
endoderm, mesoderm, ectoderm
the trypanosoma brucei species complex contains species that are:
a. Flagellated protistans (SCEs same thing)
b. Parasites of the blood of mammals;
c. Cause the disease nagana in domestic cattle in Africa;
d. Able to invade the central nervous system of their infected hosts;
e. All of a-d above.
all of the above
coccidians are apicomplexans responsible for many diseases of many animals including chickens. Coccidians:
a) infect cells in GI tract
b) produce a cyst, called the oocyst, that protects the organisms in the external environment
c) display asexual and sexual reproduction in its life cycle
d) all of the above
all of the above
members of the apicomplexan genus babesia are important pathogens of cattle. Cattle become infected with babesia when:
an infected cattle tick injects babesia parasites w saliva into the bovine
in comparison to animal cells, plant cells lack:
a) flagella and cilia
b) centrosomes
c) centrioles
d) lysosomes
e) all of the above
all of the above
the organism thought to be the closest living relatives of the animals (metazoans) belong to a clade known as the
choanoflagellates
form of interspecific association where one organism lives inside another organism and first derives benefit from the association while causing harm to the second is called;
parasitism
form of body symmetry associated w directed locomotion and cephalization is
bilateral symmetry
viruses that cause the diseases dengue, zika and yellow fever are transmitted to humans by
mosquitoes
- Which of the following statements about viruses is NOT correct?
a. Viruses are metabolically inert outside the host cell;
b. Viruses possess only one type of nucleic acid;
c. Viruses multiply by binary fission; agree - hijack host cell metabolism and resources to replicate themselves
d. Viruses cannot produce their own energy or macromolecules;
e. In their most basic form, viruses consist of nucleic acid surrounded by a protein coat;alive
c) they don’t multiply by binary fission
to answer: are viruses alive? which of the following is most important to consider
viruses have the genetic potential to replicate and evolve
which of the following organelles are NOT components of animal cells
nuclei, central vacuoles, centrioles, flagella, cilia
central vacuoles
members of phylum cnidaria are
diploblastic metazoans, displaying radial symmetry and bearing stinging cells called cnidocytes
the theory to explain the origin of eukaryote life is
endosymbiosis theory
for feeding, members of the phylum porifera
draw water into internal cavity, the spongoceol, water passes through specialized channels in their bodies under the action of chaonocytes
which of the following is not a component of the eukaryotic nucleus or its membrane: histones, nuclear pores, DNA, endoplasmic reticulum
endoplasmic reticulum
in the process of exocytosis, molecules pass through these organelles in the following sequence
endoplasmic reticulum, golgi apparatus, secretory or transport vesicles, external plasma membrane
Which of the following statements is correct?
a. Point mutations are always lethal to cells and organisms
b. Point mutations always result in changes in coded amino acids
c. Point mutations can sometimes produce changes in coded amino acids in proteins
d. Point mutations occur in proteins
point mutations can sometimes produce changes in coded amino acids in proteins
which is NOT an autotroph:
photosynthetic alga
photosynthetic bacterium
symbiotic ciliate in rumen of sheep
tree
symbiotic ciliate in the rumen of a sheep
mutualism is a form of symbiotic relationship in which
one organism lives in or on another organism, both benefit
giardia parasites transit between hosts through
feacal-oral transmission, a cyst stage of parasite passes w feces of an infected host and new host infected by ingesting those cysts
apicomplexa is a clade of single cell eukaryotes, the name apicomplexa refers to:
the presence in the cell of an apical complex that is used to invade host cells
which of following displays radial symmetry; planarian, fish, hydra, haemonchus
hydra
ruminant mammals lack enzymes for digesting cellulose from plant material, in order to derive nutrition they rely on
endosymbiotic ciliates and prokaryotes in the rumen able to digest cellulose
amoebae move through their environment by means of
pseudopodia
the anatomical plane that runs perpendicular to the longitudinal axis of the body or limb is the
transverse plane
viruses should be considered alive because
they possess genes, replicate and evolve
which of the following is NOT used to classify viruses into taxonomic groups:
-type of nucleic acid
-shape of capsid
-envelope or lock of
-replication
-genome sequence/organization
-pH, temp
-type of disease caused by virus
type of disease caused by virus
list principles of the modern cell theory
- all known living things made from cells
- all cells arise from pre-existing cells
- the cell is the basic structural and functional unit of all living things
- cells contain heredity info which is passed from cell to cell during cell division
- all cells have basically the same chemical composition
- all energy flow of life occurs within cells
outline major steps of serial endosymbiosis theory of origins of eukaryotes
- ancestral prokaryote cell underwent infoldings of plasma membrane; gave rise to endomembrane components including nucleus and endoplasmic reticulum
- this cell then engulfed other bacterial cells that evolved into other organelles such as mitochondria
- later engulfed photosynthetic bacteria that evolved to be chloroplast
characteristics of metazoa
- multicellular eukaryotes
- cell differentiation (different cells have different function)
- cell-cell cooperation (symbiotic)
- ingestive heterotrophs (gain nutrients from other organims)
- motile
- homeostasis (consistent body environment)
- diploidy (meiosis at reproduction)
- have embryonic stage
Write a short account of how the African trypanosome Trypanosoma brucei directly and indirectly affect human populations in Africa.
African Trypanosoma directly affects the human population by causing Sleeping sickness in humans. This results in CNS diseases, coma, and death. It can also indirectly reduce the human population by causing Nagana disease in domestic animals. This causes a decline in productivity in meat, milk, and labor which lead to poverty and starvation
describe the 3 ways animal may develop disease from fungi
-can produce a toxin that can be absorbed or ingested
-can be pathogenic
-produce hypersensitivity or allergy
discuss how genetic variation can occur in bacteria (4 ways)
- mutation,
- transformation (take up foreign DNA from environment),
- conjugation (plasmid gene transfer),
- transduction: gene transfer between cells by phage (virus)
describe autotrophic
organism that can produce its own nutrients by producing energy from light, water, CO2 or other chemicals
describe eukaryotes
group of organisms with eukaryotic cells,
contain a mitochondria/ chloroplast another organelles bound by a plasma membrane, have DNA bound in nuclear envelope
how do the agents of african trypanosomiasis avoid being killed by their host when they are in the blood stream? what is molecular mechanism
variant surface glycoproteins (thick dense protein coat)
their VSG is not recognized by the host and they can go undetected by immune system, they can periodically switch switch to another active VSG in order to stay undetected
what are two pieces of evidence for the endosymbiosis theory
mitochondria have their own DNA and genomic sequence shows similarity between mitochondria and some prokaryotes
also endosymbiosis happens today!! (mixotricha paradoxa in termites)
how do the following move
a) giardia
b) sperm cell of cattle
c) antamoeba histolyca
d) apicomplexan baesia
e) mutualistic eukaryotes of rumen
a) 8-10 flagella
b)a single posterior flagellum
c) pseudopodia
d) cytoskeletal elements beneath plasma membrane
e) cilia
describe the 3 morpholgies of fungi
1) multicellular filamentous fungi that form microscopic fruiting bodies such as mould
2) multicellular filamentous fungi that form macroscopic fruiting bodies such as mushrooms
3) single celled yeast
describe using examples how commensal bacteria can cause opportunist infections
commensals can become pathogenic when they gain access to abnormal location, or infects a host with diminished immune status (immunosuppressed, disease, normal gut flora disturbed ie from meds etc)
example us fusobacterium necrophorum commensal of the rumen but when transfers to liver of cattle becomes pathogenic and cause hepatic abscesses
describe structure and function of bacterial cell wall
contains peptidoglycan, maintains cell shape, provide physical protection, prevents osmotic bursting
gram positive: thick wall of peptidoglycan
gram negative; thin wall of peptidoglycan and contains lipopolysaccharide (endotoxin)
name characteristics of living organisms
-contain water,
-composed of elements: C,O,H,N,P,S among other
-all life is carbon based
-all share common atomic and molecular theme
which of the following is not a feature of the prokaryotic cell
-presence of histones
-ribosomes
-DNA
-cell wall
presence of histones
what is the trophozoite stage of giradia
the active feeding stage of the life cycle of this parasite
are apicomplexa exclusively intracellular
yes
Which of the following statement is NOT an accepted theory of the origin of viruses?
a) Viruses evolved from escaped pieces of host cell DNA such as plasmids or transposons
b) Viruses evolved from ribosomal RNA in primordial time
c) Viruses evolved from degenerate unicellular life forms
d) Viruses evolved from complex molecules of protein and nucleic acid independently to the evolution of host cells
Viruses evolved from ribosomal RNA in primordial time
what is NOT a component of viruses: capsid, capsule, envelope, nucleic acid
capsule
from list below select all that apply to phylum cnidaria:
bilateral symmetry
radial symmetry
triploblastic development
diploblastic development
trues tissues
radial symmetry, diploblastic development, true tissues
heterotrophic organism is one that
sources energy from organic compounds
what are the various physical and chemical characteristics of a microbe that contribute to its pathogenicity
virulence factors
pathogenicity principles
fomites
none of above
virulence factors
how is the malaria parasite transmitted between humans
bite of tick
bite of mosquito
through fecal contamination of food
bite of mosquito
common method of reproduction in yeast is
fusion
budding
fragmentation
fission
budding
which are following characteristics of life; select all that apply
all known living entities composed of elements that include COHNPS
all living entities contain water
all known living organisms evolved from viruses and prions
all known life is silicon based
all known live is carbon based
all known living entities composed of elements that include COHNPS
all living entities contain water
all known life is carbon based
single celled eukaryotes in which the cell possesses a single posterior flagellum belong to clade commonly called the
opisthokonts
cells contain heredity info that is passed from cell to cell during ______
cell division
true or false the apicomplexa use locomotory organelles called flagella to move through their environment
false
Locomotion; no visible apparatus for locomotion; move by gliding motility, apical complex secretes organelles and molecules from anterior end, flow along body + cell cytoskeleton= movement
Rely on flow of medium for most movement (ex blood flow)
ciliates typically posses two nuclei, a micronucleus and a macronucleus
true
list the characeristics of a metazoa
-cell cell differentiation
-multicellular eukaryotes
-cell cell cooperation
-diploidy
-have an embryonic stage
-motile
-ingestive heterotrophic
-homeostasis
Why is the disease African trypanosomiasis considered a One Health issue? In your answer note how the parasitic organism responsible for African trypanosomiasis causes disease in its hosts.
-able to express 1000s of distinct proteins called variant surface glycoproteins (VSGs) allows them to go undetected by the immune system, they can periodically switch switch to another active VSG in order to stay undetected
one health issue as it harms humans directly and indirectly
kills humans by causing sleeping sickness; gets in the bloodstream and invades CNS results in coma and death
kills animals via nagana disease, kills millions of cows a year, decreases meat and milk production , protein shortages
describe three differences between bacteria and fungi
prokaryotes vs eukaryotes
binary fission vs budding/ sexual reproduction
cell walls composed of chitin versus peptidoglycan
motility
describe conjugation
plasmid gene transfer via direct contact
endosymbiosis theory
Cell membrane infolded in a bacterial cells
This infolded membrane eventually surrounded the nuclear material
This advanced cell w endo-membranes engulfed the other bacterial cells
These internal cells eventually became organelles-mitochondria
Other cells engulfed (ex photosynthetic bacteria) other cells became other organelles like chloroplasts
how do virus particles leave the host cell once they are assembled
lysis of cell causing cell death, often cause disease
