micro exam 2 Flashcards
bacterial transformation
uptake of naked dna by cell and incorporation of dna into genome
S strain injected vs R strain
S– pathogenic (killed mice); R transformed to living S
F plasmid
conjugative plasmid; transfer copies of themself during conjugation
HGT (horizontal gene transfer)
genes transferred between species thru cell contact
DNA transferred to recipient
exogenote
genome of recipient
endogenote
recipient cell is partially diploid due to transfer
merozygote
Auxotroph
requirement for nutritional source in complete medium
Phototroph
growth in minimal medium
E colie genetic cross
two strains with different nutritional requirements
on minimal medium
1/10^7 colonies obtained
F factor
F+ x F-
usually : F+ strain have extra chromosomal DNA element carrying genes for sex pilus and plasmid transfer
F factor conjugation
pilus between F+ and F- and then retracts
F+ == Type IV secretion apparatus
rolling circle mechanism transferred to f-
F+ and F- mating
cope of F factor transferred but does not get integrated into chromosome
Hfr donor strains (high frequency of recombinants)
F- not converted to F+ but high efficiency
Donor is Hfr strain; mating: conjugation
have F strain in choromosome
Hfr conjugation
transfer function (tra) still functions
transferred to F- cell
–direction depends on orientation of F factor
–takes 100min
– interrupted enables mapping
–F factor last to be transferred that why its rarely converted to F+
Time of entry depends on
genetic distance
Hfr mapping
based on transfer rate and interruption
F’
loop out causes this creation
when F factor leaves host incorrectly (reversed)
some of F factor left in host
takes chromosomal genes with it
can be a merozygote
Transduction
type of HGT
mediated by viruses
Prophage
insert genome into bacterial genome
lysogenic
some bacterial genes can be incorporate by errors
Antony van Leewenhoek
-dutch draper
Discovered:
bacteria
sperm cells
blood cells
protists
Chromalveolata supergroup has:
Alveolata
Stramenopila
Alveolata has:
dinoglagellatas
ciliophora (ciliates)
apicomlexa (aplicoplexans)
Cilia
-9 outer tubules (1 completes, 1 incomplete)
-2 complete core tubules
-dynein arms (walks In the - direction)
Ameoboze super group:
Eumycotozoa
Eumycotozoa has
Myxogastria
Dictyostelia
Dictyosteium discoideum
“slime molds”
–model organism
feeds on bacteria and yeast
uni and multi cellular depending on nutrients
cAMP
cycloic adenosine monophosphate
Archaeplastida
Chloroplastida
Chloroplastida
green algae
fresh/salt water, soils
RuBisCO
Ribulose-1,5-bisphosphate carboxylase oxygenase
most abundant protein on earth
catalyzes addition of CO2 to ribulose 1,5 bisphosphate (CO2 fixation)
fungi
molds and yeasts
molds: filamentous hyphae– mycelium (mass of hyphae
secrete exoenzymes to digest insoluble matter, absorb solubilized nutrients
sexual and asexual
mycology
study of fungi
mycotoxicity
study of fungal toxins
mycoses
disease by fungi
saprophytes
decompose dead organisms
mycorrhizae
associated with plant roots
lichens
associated with algae or cyanobacteria
fungi importance
-decomposers
-industrial fermentations (food and beverages, steroids and drugs)
-research
-detrimental impact – diseases
yeasts
unicellular fungi
asexually by budding
sexually by spores
filamentous molds (2)
hyphae and mycelium
hyphae
filaments of a mold
coenocytic (many nuclei in cell)
septae to isolate compartments if ruptured
dimorphism
fungi can change from mold (Y) to yeast
yeast in host and filamentous outside
fungi nutrition and metabolism
saprophytes
chemoorganoheterotrophs
aerobic (some facultative anaerobes)
==obligate anaerobic fungi in rumen of cattle
fungi reproduction
asexual::
- yeast: division by fission or budding
- filamentous fungi: extension of hyphae (spore production but asexual)
sexual ::
=union of nuclei by sexual spores (zygospore, ascospores, or basidiospores)
uredinomycetes and ustilaginomycetes
plant pathogens causing rust and smuts
(ure can be in humans as well)
Lambda phage
genome – 48000 bp
packed as linear DNA replicated as circular
hexagon head and one straight tail
phage entry through spike
virulence vs lysogeny for lambda
v: replication, synthesis, assembly &
lysis
l: For lambda, DNA is inserted into att
sites on the bacterial chromosome. DNA is
then replicated as the bacteria replicates
establistment of lysogenic vs lytic cycle
high cll/clll levels : lysogenic
low levels cll/clll and high Cro levels: lytic
cll/clll cause transcription of
Pi and Pre and cI inhibit Pr and Pl
maintenance of lysogenic
cI inhibits Pr and Pl but activates Prm
what is the cII protein for
(protected from
degradation by cIII)
activates expression
of cI and genes
required for
integration
what is Cro protein for?
activates the
expression of genes
required for
replication,
assembly and lysis
and represses cI
general dna packaging
prohead –> motor –> package motor complete with dsDNA in and ATP used –> scaffold proteins discarded –> packaging motor head discarded –> mature virion
pi dna packaging has
terminase complex + cos site –> translocation –> cos Binding –> terminal cos cleavage
In holin what protein helps control the time of lysis
P35
CRISPR stands for
clustered regularly interspaced short palindromic repeats
CRISPR is and does
Short RNA-based defense systems in bacteria
and archaea
* Provide immunity against viruses, plasmids or
other mobile genetic elements
CRISPR three phases
Adaptation, crRNA Biogenesis,
Invader Silencing
CRISPR loci features:
- Leader AT-rich, not conserved
- Repeat – 23 – 50 nt, number of repeats is variable
- Spacer – share sequence identity to fragments of plasmids or
phages - cas genes – CRISPR associated genes
phage titering
The number of phages in a given solution is
determined using “plaque forming units” (PFU)
icosahedron
symmetry virus
one way is 5, 3, and 2 fold
double stranded DNA
herpesviridae,
poxviridae
single stranded dna
Phage M13
double stranded rna:
reoviridae
(+) stranded rna
retroviridae, picornaviridae…
coronavirus
(-) stranded
filoviridae, rhabdoviridae
viral lifecyle
attachment (adsorption)
entry
synthesis
assembly
release
entry types
fusion (spike binds to receptor on host)
endocytosis
HSV 1 vs HSV 2 – herpes
1: cold sores
2: genital
HSV exit
The virus assembles at the inner nuclear
membrane (INM)
* Buds through INM and fuses with the outer
nuclear membrane (ONM)
– Releases a naked capsid into the cytoplasm
* The naked capsid buds into the Golgi where it is
modified
* The modified, enveloped virus exits the cell when
the Golgi vesicle fuses with the plasma
membrane (exocytosis).
HIV (+) strand RNA statistics
1.12 people in US infected
30-40K new infections every year
what does HIV infect
CD4+ cells which express on cell surface of `immune cells
gag –
in hiv genome
encodes gag polyprotein
* Gag broken down to: Matrix, Capsid, Nucleocapsid
pol -
in hiv genome
encodes Pol polyprotein
* Pol broken down to: Reverse Transcriptase, Integrase & Protease
env –
in HIV genome
– encodes gp160 polyprotein
* Gp160 broken down to gp120 and gp41 by protease
retrovirus
Rna virus that is replicated in a cell using reverse transcriptase
-RNA dependent DNA polymerase
-RNase H activites which degrades RNA-DNA duplexes
in cytoplasm
HIV integration
dsDNA HIV is bound by integrase
translocated into nucleus
integrate viral genome into hosts
HIV transcription
RNA transcribed into nucleus to create the +RNA genome for viral packaging and smaller transcripts for proteins
HAART
highly active anti-retroviral therapy
what is HAART?
drug cocktail?:
entry: enfuvirtide
reverse transcriptase: tenovir (NRTI) or efavirenz (NNRTI)
integrase: raltegravie
protease: darunavir
Influenza virus
disease
prevalence: 10-20%
incdince ~36 per 100
Neuraminidase
digests sialic acids present on the outside of cells
This is what Tamiflu binds to and inhibits
Hemagglutinin
binds to sialic acids on host
cells
