Download Bio 250 Exam 4: Immunology and Virology - Questions and Answers and more Exams Biology in PDF only on Docsity!
Bio 250 Latest and Modernised Exam 4
with Answers.
T cells main function - Correct Ans: ✔✔bind to antigens on macrophages and initiate adaptive immunity
T cells develop in - Correct Ans: ✔✔the thymus
lymphoid organs - Correct Ans: ✔✔-lymphoid stem cells
-lymphocytes
-B cells
-lymph nodes
-other secondary lymphoid organs (tonsils, adenoids, and appendix)
main purpose of lymphoid stem cells - Correct Ans: ✔✔produce lymphocytes and natural killer cells
B cells main function - Correct Ans: ✔✔make antibodies
B cells are made up of - Correct Ans: ✔✔mature lymphocytes
B cells develop where - Correct Ans: ✔✔bone marrow tissue
lymph nodes main function - Correct Ans: ✔✔trap organisms from local tissue
lymph nodes are found where - Correct Ans: ✔✔where lymphatic vessels converge (armpits and mucosal regions of gut and respiratory tract)
interfaces between body and environment - Correct Ans: ✔✔skin
lung
GI tract
genitourinary tract
oral cavities
skin has a protective layer of - Correct Ans: ✔✔keratin
keratin is produced from - Correct Ans: ✔✔keratinocytes
sebum - Correct Ans: ✔✔oily substance produced by sebaceous glands
sebum inhibits bacteria via - Correct Ans: ✔✔acidic pH
important skin defenses - Correct Ans: ✔✔keratinocytes and SALT lymphoid system
chemical barriers between human and environment - Correct Ans:
✔✔-acid pH of stomach
-lysozymes
-superoxide radicals
-defensins
defensin - Correct Ans: ✔✔Small, positively charged peptide, produced by animal tissues, that destroys the cell membranes of invading microbes
are defensins important to innate or adaptive immunity - Correct
Ans: ✔✔innate
lysozymes degrade - Correct Ans: ✔✔cell walls of gram+ bacteria
defensins are produced by - Correct Ans: ✔✔small, positively charged peptides produced by animal tissues
MAMPs (microbe-associated molecular patterns) are recognized by -
Correct Ans: ✔✔Toll-like receptors (TLRs)
Binding of MAMPs triggers - Correct Ans: ✔✔release of chemical signal molecules that activate innate and adaptive immune mechanisms
inflammation - Correct Ans: ✔✔critical innate defense that provides a way for phagocytic cells normally confined to the bloodstream to enter infected areas within tissues
cardinal signs of infection - Correct Ans: ✔✔-redness
-warmth
-pain
-swelling/edema
-altered function of state
vasoactive factors - Correct Ans: ✔✔leukotrienes, macrophages, and cytokines
leukotrienes function - Correct Ans: ✔✔Act on blood vessels of the microcirculation, increasing blood volume and capillary permeability to help deliver WBCs to the area
macrophage function - Correct Ans: ✔✔secrete small protein molecules called cytokines
macrophages engulf - Correct Ans: ✔✔microorganisms then release vasoactive factors that increase vascular permeability
cytokines main function - Correct Ans: ✔✔communication between cells
how does body attempt to "wall off" inflammation site - Correct
Ans: ✔✔forming a granuloma
Is phagocytosis specific or non-specific? - Correct Ans: ✔✔non- specific
opsonization - Correct Ans: ✔✔coating antigen with IgG antibodies and complements
how do some bacteria survive phagocytosis - Correct Ans: ✔✔-can live within toxic phagolysosome
-triggering apoptosis of host cell
-too slippery to grab
life span of neutrophil - Correct Ans: ✔✔7 days
inflammation subsides as - Correct Ans: ✔✔neutrophils undergo apoptosis and macrophages clean it up
normal healthy adult oral temp - Correct Ans: ✔✔36-38 C
heat sensors located - Correct Ans: ✔✔throughout skin and large organs and along the spinal cord
wheres the thermoregulatory center - Correct Ans:
✔✔hypothalamus
heat produced as consequence of - Correct Ans: ✔✔metabolic rxns
fever temp - Correct Ans: ✔✔above 38C (100F)
pyrogens - Correct Ans: ✔✔substances that cause fever by stimulating prostaglandin production
disadvantages of fever - Correct Ans: ✔✔-discomfort for patient
-if fever is too high (43C/107.5F), it can cause irreversible brain damage
advantages of fever - Correct Ans: ✔✔-puts many microbes outside of their temp "comfort zone"
-reduces iron availability to bacteria
-slower growth of pathogen allows body's immune system time to subdue the infection before its too late
Viruses infect which taxonomic groups? - Correct Ans: ✔✔All of them
Do viruses contain RNA or DNA? - Correct Ans: ✔✔They can contain either
bacteriophage - Correct Ans: ✔✔A virus that infects bacteria
how do most bacteriophages infect bacteria - Correct Ans: ✔✔insert their genome into the host cell
what is plaque - Correct Ans: ✔✔clear spot against a lawn of bacterial cells
what are plaques used for in a lab - Correct Ans: ✔✔used to observe phages and count each individual virion
tobacco mosaic virus host range - Correct Ans: ✔✔wide range of plant species
tobacco mosaic virus infection results - Correct Ans: ✔✔-mottled leaves
-stunted growth
transmission - Correct Ans: ✔✔process of reaching and infecting a new host
T/F: Different viruses have the same mechanisms and efficiencies of
transmission - Correct Ans: ✔✔False, diff viruses have diff mechanisms and efficiencies of transmission
how is HIV transmitted - Correct Ans: ✔✔blood or sexual contact
Is measles or HIV more efficient - Correct Ans: ✔✔Measles
Host range - Correct Ans: ✔✔particular group of host species that a virus can infect
tissue tropism - Correct Ans: ✔✔range of tissue types that a virus can infect
What is influenza's tissue tropism - Correct Ans: ✔✔respiratory epithelium tissue
rabies' tissue tropism - Correct Ans: ✔✔nervous tissue
Reasons why it is hard to make antiviral agents - Correct Ans: ✔✔- hard to discover
-severe side effects
-mutate quickly
Do viruses or bacteria mutate faster - Correct Ans: ✔✔viruses
what usually kills viruses - Correct Ans: ✔✔immune system
what generates a viral progeny - Correct Ans: ✔✔loss of individual identity
What is a virus that has an icosahedral capsid - Correct Ans:
✔✔herpes
Under what pressure is Herpes' DNA packed - Correct Ans: ✔✔high pressure
How does high pressure assist with viral infection - Correct Ans:
✔✔the pressure drives viral DNA into host nucleus
What are spike proteins - Correct Ans: ✔✔envelope bristles that are encoded in the virus
What do spike proteins plug onto - Correct Ans: ✔✔capsid
main function of spike protein - Correct Ans: ✔✔enable virus to attach and infect the next host cell
tegument - Correct Ans: ✔✔proteins expressed during infection of a host cell and then packaged in the virion during envelope formation
Examples of filamentous viruses - Correct Ans: ✔✔-tobacco mosaic virus
-animal viruses like ebola
What type of virus more often causes fatal disease of humans and
related primates - Correct Ans: ✔✔filamentous virus
Structure of tailed bacteriophage - Correct Ans: ✔✔-head
-neck
-tail
in which structure of a bacteriophage will you find icosahedral
protein package - Correct Ans: ✔✔head
which bacteriophage structure contains DNA - Correct Ans: ✔✔head
Which bacteriophage structure channels nucleic acids into the host
cell - Correct Ans: ✔✔neck
which bacteriophage structure is the "injector" - Correct Ans:
✔✔tail
how does the bacteriophage "injector" work - Correct Ans: ✔✔- penetrates the host cell envelope
-releases pressure within head which propels DNA into host cytoplasm
what type of genome is in viroids - Correct Ans: ✔✔circular, single stranded RNA genome
are viroids a virus - Correct Ans: ✔✔no
Why do viroids have circular DNA - Correct Ans: ✔✔allows them to avoid breakdown from host RNAse enzymes
prions - Correct Ans: ✔✔infectious agents w/ no nucleic acid
what do aberrant proteins arise from - Correct Ans: ✔✔preexisting cell
are prions a virus - Correct Ans: ✔✔no
what well-known disease do prions cause - Correct Ans: ✔✔mad cow disease
antigenic drift - Correct Ans: ✔✔a population of viruses whose mutant proteins are no longer recognized by host antibodies
what causes antigenic drift - Correct Ans: ✔✔rapid mutation and evolution
levels of virus evolution - Correct Ans: ✔✔-host community
-viral species population
-individual organism
what are the classification levels of viruses - Correct Ans: ✔✔-capsid form
-envelope
-host range
-type of genome
two capsid forms - Correct Ans: ✔✔icosahedral and filamentous
What does the Baltimore model classify for? - Correct Ans: ✔✔-RNA v DNA
-Single v Double stranded
-How they generate mRNA
Does poliovirus (influenza) have DNA - Correct Ans: ✔✔nope
How does single-stranded DNA viruses replicate - Correct Ans:
✔✔requires host DNA polymerase to generate complementary DNA strand
how does double-stranded DNA viruses replicate - Correct Ans:
✔✔requires a viral RNA-dependent RNA polymerase to generate mRNA by transcribing directly from RNA genome
what occurs during exit and transmission - Correct Ans: ✔✔progeny virions must exit the host cell and then reach new host cells to infect
what type of bacteriophages are important to human intestine -
Correct Ans: ✔✔enteric bacteriphages
Steps of inert phage particles penetrating the bacterial cell - Correct
Ans: ✔✔-phage injects its genome through cell envelope into cytoplasm
-sheath of phage neck tube contracts, bringing the head near the cell surface
-pressure of spooled DNA is released, expelling DNA into cell
-Phage capsid remains outside attached to the cell surface
-replicative cycle of phage genome then occurs
-retains host DNA for potential lysogeny
empty capsid nickname - Correct Ans: ✔✔ghost
lysis - Correct Ans: ✔✔rupture of host cell
lysogeny - Correct Ans: ✔✔process in which the phage genome becomes integrated in the genome of the host cell
lytic infection - Correct Ans: ✔✔after phage inserts its DNA into the cell, the phage genes are expressed by host cell RNA polymerase and ribosomes
burst size - Correct Ans: ✔✔number of virions released
virulent phages - Correct Ans: ✔✔phage that reproduce entirely in lytic cycle
temperate phages - Correct Ans: ✔✔phages that can undergo lysogeny or lysis
prophage - Correct Ans: ✔✔integrated phage DNA
phage+host DNA= prophage
what must happen for lysis to occur - Correct Ans: ✔✔prophage must direct its own excision from host genome
Does the viral genome integrate into the host genome during lytic or
lysogenic cycle - Correct Ans: ✔✔lysogenic
what triggers lytic burst - Correct Ans: ✔✔events that threaten host cell survival
