Studied by 20 people
viruses, antimicrobial resistance, levels of defense, leukocytes and formed elements
describe the brief structure of a virus
protein coat surrounding genetic material
what is the genetic material of viruses
DNA or RNA
T or F: a virus can contain both DNA and RNA
false; they never have both
how does a virus attach to a host
binds to surface proteins on the host cell using it’s own attachment proteins
define host range
the limited number of host cells that a virus can infect
T or F: viruses have a wide host range
false; they have a narrow host range
describe why viruses have a narrow host range
different host species may lack the surface proteins that a virus can use for attachment
name the protein shell that encloses the viral genome
capsid
T or F: the capsid is the outermost layer of all viruses
false; some viruses have membranous envelops that surround capsids
some viruses have membranous envelops that surround capsids. where do these envelops come from?
derived from host cell membranes
where do the molecules of viral envelopes come from
both viral and host cell molecules
what is the first step in the viral life cycle
virus attached to host and enters
what happens to the protein coat when a virus enters a host cell
the coat is shed
when a virus enters a host cell, what 2 things does it release
viral genome and capsid proteins
what happens to the viral genome once it has been released into a host
the host’s enzymes replicate it
end result of a host’s enzymes replicating the viral DNA?
viral mRNA is produced, and then the host cell ribosomes will use it to make more capsid proteins
what is the last step in the viral life cycle
viral genomes and capsid proteins self-assemble into new virus particles, and then the virus will exit the cell to infect other hosts
what cells does HIV target
T cells of the immune system
what type of virus is HIV
retrovirus
define retrovirus
a virus that changes DNA of the host cells by introducing it’s own DNA into the host
what disease does HIV cause
AIDS
what does AIDS stand for
acquired immunodeficiency syndrome
does HIV have an RNA or DNA genome
RNA
which enzyme does HIV use within a host to copy its RNA genome into DNA
reverse transcriptase
describe what HIV does after it enters a T cell (the whole process)
it releases its RNA, reverse transcriptase makes viral DNA, viral DNA goes into the nucleus, and now the DNA of the host is completely corrupted
what happens to a T cell once it’s genome has been corrupted by viral DNA (from HIV RNA)
the whole cell is destroyed
what do bactericidal antibiotics do
kill bacteria
what do bacteriostatic antibiotics do
stop bacterial growth
T or F: bacteriostatic antibiotics kill bacteria
false; they only stop their growth
list the 3 main antibiotic targets in bacteria
cell wall or membranes, machineries that make DNA and RNA, machinery that produce proteins
describe why antibiotic targets in bacteria won’t harm a human host
the targets are either absent in hosts or structurally different in hosts, so the antibiotics will only harm bacteria
when does antimicrobial resistance occur
when the microbes evolve mechanisms that protect them from the effects of antimicrobials
T or F: antimicrobial resistance is a naturally occurring process
true
describe the whole process of antibiotic resistance
non-resistant bacteria divide, but a few of them will acquire a mutation. some mutations make the bacterium drug resistant. when the drug is given, only the resistant ones will survive. these resistant ones will then continue to divide and thrive
list the 2 broad groups of immunity
innate and adaptive
the 1st and 2nd lines of defense belong to which branch of immunity
innate
the 3rd line of defense belongs to which branch of immunity
adaptive
which is faster to react: innate or adaptive immunity
innate
which is slower to react: innate or adaptive immunity
adaptive
which is specific: innate or adaptive immunity
adaptive
which is non-specific: innate or adaptive immunity
innate
briefly, what is the first line of defense
external body membranes (skin and mucosae)
briefly, what is the second line of defense
antimicrobial proteins, phagocytes, and other cells
what is the hallmark of the second line of defense (hint: something we can see)
inflammation
briefly, what is the third line of defense
the attack of foreign substances. involved leukocytes
why is the adaptive defense system referred to as specific
involves B cells, which make antibodies. antibodies will be specific to whichever antigen is present
when do we acquire innate immunity
we’re born with it
explain why the innate defense system is non-specific
it protects us from a broad range of pathogens
list two ways the skin protects us from pathogens in the 1st line of defense
acid mantle, keratin
how does the acid mantle of skin protect us from pathogens
skin secretions (sweat and sebum) make the skin acidic, which inhibits bacterial growth. there are also bactericidal chemicals present
how does keratin of the skin protect us from pathogens
provides resistance against acids, alkalis, and bacterial enzymes
list 8 associated elements/categories of mucous membranes in the 1st line of defense (hint: think of which mucous membranes there are, now think of what factors they possess that aids in protection)
mucus, nasal hairs, cilia, gastric juice, acid mantle of vagina, tears, saliva, urine
how does mucus of mucous membranes protect us from pathogens
traps microbes in resp. and digestive tracts
how do nasal hairs of mucous membranes protect us from pathogens
filter and trap microbes in the nasal passages
how does cilia of mucous membranes protect us from pathogens
propel mucus away (which contains trapped bacteria) from the nasal cavity/lower resp. passages
how does gastric juice of mucous membranes protect us from pathogens
contains HCl and protein-digesting enzymes that destroy microbes
how does the acid mantle of the vagina of mucous membranes protect us from pathogens
acidity inhibits growth of most bacteria/fungi in the female reproductive tract
how do tears (lacrimal secretions) of mucous membranes protect us from pathogens
continuously lubricate and cleanse eyes. contain lysozyme, which is an enzyme that destroys microbes
how does saliva (lacrimal secretions) of mucous membranes protect us from pathogens
lubricates and cleanses the oral cavity. contains lysozyme, which is an enzyme that destroys microbes
how does urine of mucous membranes protect us from pathogens
acidity inhibits bacterial growth. cleanses the lower urinary tract as it flushes from the body
list 6 mucous membranes of the body
mouth, anus, nose, conjunctiva, urethra, vagina
what is pneumonia
inflammation of the lung tissue
how is pneumonia caused
via anything that damages the lung tissue
list 4 cellular/chemical ways that the body protects itself during the 2nd line of defense
interferon, complement protein, phagocytosis, fever
what is interferon (in 2nd line of defense)
a chemical released by virus-infected cells which helps to increase antiviral defenses
what are complement proteins (in 2nd line of defense)
antimicrobial proteins that cause lysis of invading cells, and it helps trigger inflammation by releasing cytokines
what is phagocytosis (in 2nd line of defense)
the ingestion and digestion of foreign substances
what is fever (in 2nd line of defense)
increase of body temperature to suppress the growth and propagation of pathogens
describe the entire process of how interferons are made and how they work to protect the body during the 2nd line of defense
interferons are made by the host when a virus enters it. interferons are then exocytosed from the host (and host dies) where they will then bind to an un-infected host. binding triggers the synthesis of anti-viral proteins in this uninfected host. now when a virus goes to infect that host cell, the AVPs become active and destroy the invading virus by destroying the mRNA (stops viral replication)
how does a phagocyte identify and attach to a pathogen
it has receptors
describe the entire process of phagocytosis, starting when the phagocyte attaches to a pathogen
attaches to pathogen via receptors. it then forms a pseudopod which encircles it, and then the pathogen is engulfed. lysosomes within the cell will fuse with the vesicle = phagolysosome. lysosomal enzymes and toxic compounds are released into it, which destroys the pathogen. sometimes exocytosis of vesicle contents will occur
define phagolysosome
structure that occurs when a lysosome fuses with a vesicle that contains a pathogen
when does adaptive immunity develop
after exposure to a pathogen
when do opportunistic pathogens arise
when a member of the normal microbiota is introduced to an unusual site in the body
give an example of an opportunistic pathogen in the human body
e coli is beneficial in the colon but can cause disease when found elsewhere
what are the two major groups of leukocytes
granulocytes and agranulocytes
how are granulocytes different from agranulocytes
granulocytes contain cytoplasmic granules whereas agranulocytes do not
what is the mnemonic to remember the order of leukocytes from most abundant to least abundant in the blood
never let monkeys eat bananas
list the leukocytes in order from most abundant to least abundant in the blood
neutrophils, lymphocytes, monocytes, eosinophils, basophils
list the leukocytes that are granulocytes
neutrophils, eosinophils, basophils
list the leukocytes that are agranulocytes
lymphocytes, monocytes
define formed elements
living blood cells of blood
list the formed elements of blood
erythrocytes, leukocytes, platelets
other than formed elements, list the 2 components of blood
plasma, buffy coat
what is plasma
the nonliving fluid matrix of blood
is plasma living or non living
non living
are formed elements living or non living
living
what does the buffy coat contain
leukocytes and platelets
what percentage of blood is the buffy coat
less than 1%
what percentage of blood is erythrocytes
45%
what percentage of blood is plasma
55%
if you spin blood in a centrifuge, list the layers from top to bottom
plasma, buffy coat, erythrocytes
define hematocrit
percent of blood volume that is RBCs
what is the hematocrit value for males (and % error)
47% ± 5%
what is the hematocrit value for females (and % error)
42% ± 5%
compared to RBCs, how big are granulocytes
larger
compared to RBCs, how long do granulocytes live
shorter-lived
shape of RBC nuclei
circular
shape of granulocyte nuclei
lobed
T or F: all granulocytes are phagocytic
true
Note
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