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mcat bio textbook > ch. 5 > Flashcards

ch. 5 Flashcards

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1
Q

what are viruses and what is important to note

A

they are obligate intracellular parasites that relies on host cell machinery to reproduce. IT IS NOT ALiVE

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2
Q

what is the structure of a virus

A

they have nucleic acid genome surrounded by a protein shell called capsid. they have a collar under the capsid with a sheath acting as its body. tail fibers for mobility and a base plate under the sheath.

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3
Q

what kind of genetic info can a virus have?

A

single/double stranded DNA or RNA

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4
Q

a virus that infects bacteria is called a

A

bacteriophage

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5
Q

what is an effect from the virus using host machinery to replicate

A

VIRUS GENOME CANNOT GET BIGGER BUT new offspring can include host dna from using their stuff

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6
Q

how does virus inject genome into host cell

A

it uses atp to contract and inject the host with its genome through its base plate

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7
Q

what do animal viruses and plant virus not have in common? hint: a structure

A

animal viruses have envelopes that surrounds the virus made up of the hosts cells membrane so it doesnt get attacked by immune system, plant viruses and bacteria viruses are NAKED

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8
Q

how is the envelope acquired

A

through budding: coming out of the host cell from the inside

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9
Q

bacteriophages have two life cycles but have the same start: describe the first few common steps and state the two different cycles

A

the first step: virus binds to outside of host cell through attachment
second step: injects its viral genome through penetration/eclipse
-after this, the virus will either go through lytic or lysogenic cycle

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10
Q

lytic cycle of bacteriophages

A

the host cell machinery starts to transcribe/translate viral genome with a early gene that creates hydrolase: an enzyme that degrades host genome. the new viral dna gets encapsulated with capsid and a late gene creates lysozyme that breaks down cell wall and virus babies burst out host cell KILLING it

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11
Q

lysogenic cycle of bacteriophages

A

once genome is inside host cell, the virus is called prophage and the host is called lysogen. the prophage stays silent while the genome gets replicated and new viruses are release while the host cell does its own thing. once prophage gets activated, it excises itself from host genome and enters lytic cycle

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12
Q

lytic vs lysogenic

A

lytic immediately kills host cell while lysogenic allows the cell to live while it creates more viruses until the prophage gets activated to then go into the lytic cycle

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13
Q

transduction

A

when host DNA thats with viral genome codes for a new trait not found in previous host cell

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14
Q

how do animal viruses choose and enter cells?

A

they choose cells with their specific receptors and then endocytose itself into the cell and release genome

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15
Q

animal viruses can go through what cycles?

A

they can do the lytic, lysogenic, or productive cycle: similar to lytic cycle but doesnt kill host and leaves by budding

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16
Q

dormant form of viral genome in host cell is called

A

provirus

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17
Q

rna + viruses

A

they must encode for RNA dependent RNA POL (AND DONT NEED TO CARRY IT ITSELF). they are single stranded that act just like mRNA and it creates -RNA strand to complement it.

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18
Q

rna - viruses

A

they must carry and encode RNA dependent RNA pol therefore they dont need hosts cell machinery. the - rna strand is used as a temp for mRNA and the RNA pol will make the + strand

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19
Q

retroviruses

A

they are + RNA that go through lysogeny and integrate as provirus. they must encode reverse transcriptase to make DNA from RNA using the RNA pol thats encoded in its own genome

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20
Q

doublestranded DNA viruses characteristics

A

often encode enzymes required for dntp synthesis and DNA replication. these viruses have big genomes and need their own enzymes for make their dntp if host cell doesnt have it readily available.

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21
Q

subviral particles

A

infectious agents that are smaller and more simple

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22
Q

prions

A

misfolded versions of a protein that already exists and they cause good proteins to misfold as well.

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23
Q

prions are responsible for? how do you get them?

A

transmissible spongiform encephalopathies that degrade the NS and are ALWAYS fatal. very resistant to chemicals and temp. you can get them by eating them or them being genetically linked

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24
Q

viroids

A

viral like things that consist of a circular short piece of RNA

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25
cell theory by hooke
1. all living organisms are made up of one or more cells and their products 2. cells are the monomer for organisms 3. new cells come from preexisting cells
26
prokaryotes include what type of organisms
bacteria , archea, and blue green algae
27
living organisms are classified through what? whats the biggest division of this system? what three ____ exist?
they are classified through taxonomy and domain is the biggest and it divides into bacteria, archae, and eukarya
28
each eukarya breaks into what sections
animalia, plantae, and fungi
29
bacteria have what inside their cytoplasm
they have no membrane bound organelles, they have ribosomes but they are not membrane bound where they translate mRNA into a polyribosome
30
bacteria have what other thing made up of genome besides its own DNA
plasmid: circular piece of ds-DNA that is much smaller than main DNA, they are extra chromosomal genetic material
31
what can bacteria do with plasmid
they can go through conjugation where two bacteria swap genetic info (plasmid) to each other
32
round shape is called what plural and singular
plural: cocci singular: coccus
33
rod shapes is called what plural and sungular
plural: bacilli singular: bacillus
34
spirial shapes
plural: spirochete or spirilla singular: spirochete or spirillum
35
what is stronger cell wall or cell membrane? what is cell wall made up of?
cell wall is more rigid therefore resistant to lysis. cell walls are made up of peptidoglycan
36
bacteria that stains dark purple are
gram +
37
bacteria that stains light pink color
gram -
38
what differentiates gram + and gram - from each other besides the color staining
gram (+) have a thicker cell wall while gram (-) have thinner layer but with another layer and the space between those two is called the periplasmic space
39
how can gram (-) beat antibiotics
the periplasmic space allows the degradation of antibiotics
40
endotoxins
arent inherently poisonous but our immune system has a very strong response to it. lysis of gram (+) bacteria can cause septic shock
41
exotoxins
very toxic and found in both gram - and gram + and these toxins allows to outcompete other bacteria
42
what is bacterial capsule?
AKA glycocalyx , a layer of sugar goo surrounding the cell and often the whole colony. it stops the immune system from killing it and helps with sticking to surfaces
43
what helps with bacterial mobility? what do you call a bacteria with many of these
flagella and a bacteria with multiple is called motile.
44
monotrichous
one flagellum at the end
45
amphitrichous
flagella at both ends
46
peritrichous
multiple flagella
47
the flagellum can be broken down into what parts
1. filament: attached to the body 2. hook: connects filament to the basal structure 3. basal structure: contains number of rings that anchor the flagellum to the outer and inner membrane and rotates rod to move
48
how do bacterial flagellum move?
by using proton gradient as energy
49
chemotaxis
bacterial motion towards attractants or away from toxins and it is dependent on chemoreceptors
50
what are pili
long projections on bacterial surface that can attach it to different surfaces, there are also sex pili that attaches male and female to make conjugation bridge
51
what are mesophiles? thermophiles? psychrophiles?
meso: moderate temp lovers, thermophiles: heat lovers psychro: cold lovers
52
autotroph? heterotroph? chemo? photo?
auto: uses co2 as carbon source hetero: relies on organic material for co2 chemo: gets energy from chemicals photo: gets energy from sun
53
environment where bacteria grow is called ? and putting it on a plate is called?
the environment is called the medium and its usually agar on a petri dish, putting it on the dish is called plating.
54
one spot of bacteria is called? a dense growth of bacteria is called?
one spot is a colony, a dense growth is called a lawn.
55
minimal medium means? wild type means?
minimal medium means it only has glucose and agar. wild type bacteria are bacteria that have all characteristics normal to that species
56
what is a plaque? what is doubling time?
a plaque is a clear area in the lawn. doubling time is the time it takes for a population to double its number
57
auxotroph bacteria cannot survive what
on minimal medium because it cant synthesize a molecule to live.
58
bacteria that need oxygen to live are
obligate aerobes
59
bacteria that dont need oxygen are
anaerobes
60
facultative anaerobes
use O2 when around but dont need it, they make more energy with oxygen present
61
tolerant anaerobes
can grow with o2 present but doesnt use it
62
obligate anaerobe
poisoned by o2
63
fermentation vs respiration
respiration is glucose catabolism using o2 while fermentation is the same but with out o2 and can make lactic acid or ethanol
64
what is anaerobic respiration
glucose metabolism with electron transport and oxidative phosph. without using o2 as electron acceptor, it can use so4- or no3-
65
bacteria usually divide through
binary fission: making an identical copy of itself
66
conjugation between bacteria can do what
increate genetic variability as through the conjugation bridge, bacteria can swap genetic info
67
bacterial growth is
exponential which means the log of the population get linear hence log phase
68
transformation
if pure DNA is sitting around, a bacteria can absorb it
69
after the log phase, what occurs
the bacteria that wasnt previously growing go through lag phase where cell division doesnt grow even in ideal conditions
70
after the log phase, what other thing can occur besides lag phase?
stationary phase where cells dont divide due to lack of nutrients,
71
the maximum population during stationary phase is called
carrying capacity
72
what bacteria can make endospores? what are endospores?
some gram + bacteria can make endospores when in unfavorable conditions and it holds genetic info and are very environmentally resistant
73
metabolic reactivation of an endospore is called what
germination
74
in conjugation, the male has what f factor? what occurs to female after conjugation?
male has F+ factor and transfers F factor to female. once females receive the f factor, they become male.
75
how do archaea differ from bacteria
they lack peptidoglycan in cell wall and live in extreme environment
76
parasite bacteria
they can either be obligate (need a host) or facultative (replicate in or out of a cell). they create damage to host cell
77
symbiotic bacteria
bacteria that coexists with host and both bacteria and host have a benefit.
78
Gram (-) bacteria have an extra membrane that helps evade antibiotics, what is this membrane made of?
Lipoprotein

mcat bio textbook (10 decks)

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