Exam 2: Cell Structure Flashcards
Cell theory
to be considered alive, an organism must have cell structure
cell structure
- genetic information (DNA)
- plasma membrane (separates internal and external environments; maintains internal environment)
- cytoplasm (internal environment, carries out metabolic activities )
If something is not living will antibiotics have an effect on it?
examples of things antibiotics do not work on
no
prions and viruses
complex molecules that can affect cell activity can be confused with living organisms. But they lack some or all requirements for ______
cell structure
prion
infectious protein with no cellular components
- can not make antibiotics against them
3 ways prions can occur
- hereditary - genetic
- acquired - infectious/iatrogenic
- sporadic - unknown case, no known risk factors
Why is it so hard to denature prions?
they are heat shock proteins
Viruses
- contain DNA or RNA
- do NOT have a cell membrane or internal metabolic activity
- categorized by type of genetic material they contain
In a virus how is genetic material contained?
in a protein capsid and may have an outer lipid/protein envelope
Do viruses have a life cycle?
no
Viruses do not have metabolism so…
no process to interrupt with antibiotics
What do viruses need in order to carry out replication?
living cells
Cycles that occur in infected cells all have a______ som have a _____
lytic cycle
lysogenic component
lysogenic component
produce viral proteins that insert viral material into the host material to stay there until it comes to go into the lytic stage
chicken pox replication
- get directly lytic
- some peripheral nerve cells will go lysogenic years later and you can get a virus going from lysogenic to lytic and that is when you would get shingles
- you can follow line of the peripheral nerve that has the outbreak, not all over the skin
- can have many outbreaks of shingles
Basic steps to virus replication/infectious cycle
adsorption penetration production of early viral proteins replication of viral genetic material production of late viral proteins assembly of viral particles release of particles/lyse or budding
Lysogenic modification
early viral proteins insert viral DNA into host DNA and shuts down
Retrovirus modification
reverse transcriptase produces viral DNA from viral RNA template
like with HIV
adsorption
it has to stick
it recognizes a receptor on a target cell, has spike proteins
binding tricks cell into penetration
penetration
get release of genetic material
budding vs lyse
budding - little pieces break off like a slow leak
lyse - complete burst
Lytic DNA viruses
adenoviruses
Lysogenic DNA viruses
HPV
Herpes simplex
epstein barr
varicella zoster
RNA lytic viruses
rubella
influenza
ebola
covid
RNA lysogenic viruses
HIV
Application: Spike Proteins
- spike proteins can activate host immune response
H and N spike proteins
Antigenic drift
occurs continuously resulting in small mutations (slower, smaller)
variants
Antigenic shift
major, abrupt change in spike proteins
new variants
if big enough it can jump to other hosts (bats to humans)
How can antigenic drift be handled by the immune system through cross-protection but may after time evade the immune response?
if there is a big enough change the antibodies you have may no longer be effective
Basic structure of prokaryotes/bacteria
- genetic material (singular, circular, double stranded DNA)
- cytoplasm
- cell membrane
Prokaryotes also have ___ and may have_______
have: cell wall
may have:
plasmids, pili, fimbriae, flagella, capsule, endospore
plasmids
extrachromosomal circular DNA that may have info for antibiotic resistance
- info to share DNA with other bacteria
Pili
connecters
bacteria come together to make this to put DNA through it
fimbriae
help stick to surface
capsule
protection outside cell wall
encloses endospore
endospores
help survive harsh conditions
Gram + cell wall
thick peptidoglycan, thin LPS
stains purple
Gram - cell wall
higher LPS content, small amount of peptidoglycan
stains pink
How can antibiotics affect bacterial cells
- interference with cell wall
- blocking ribosome activity
- blocking DNA synthesis
Examples of antibiotics that affect peptidoglycan synthesis?
- cephalosporins
- penicillins
Antibiotics that bind ribosomes
tetracyclines and macrolides
Antibiotics that block DNA synthesis
quinolines and sulfonamides
If one antibiotic type does not work you can try another, for example…
if you get immune to tetracycline
eukaryotic cells
have compartmentalization
- organelles
- regions to adjust pH
Nucleus
protects DNA
initiates replication
carries out transcription
Nuclear envelope
Nuclear Plasm
envelope: double membrane
nuclear plasm: cytoplasm in nucleus, enzymes stop replication and transcription
Nucleolus
Chromatin
nucleolus: RNA synthesis, only seen in interphase
chromatin: loose, open to transcription happening
Rough ER
carries out translation
modifies proteins
attached to nucleus (if rip out nucleus you also rip out rough ER)
has ribosomes on it
Translating mRNA on a membrane vs in the cytoplasm
if being made on membrane you have something to do on membrane, can become a membrane bound transport molecule, part of organelles surrounded by membrane in cell
either encased, embedded, or have to go through membrane
Golgi Apparatus
modifies, activates, packages proteins
- has a cis and trans surface (directional traffic)
- if enzyme needs to be clipped to be activated that happens here
- embedded as pump protein it would be here so it would end up in vesicles
Smooth ER
lipid synthesis, drug detoxification
- attached to rough ER and nucleus so it would come out if one ripped out
Mitochondria
- site of aerobic respiration
- double membrane: specialized pH, 2 regions with diff pH within the mitochondria
- intermembrane space - pump all H so lower pH than in matrix
Who is mitochondrial DNA from?
only your mother!
Ribosomes are closer to _____ ribosomes than the ones in the cytoplasm of a _____
prokaryotic
eukaryote
F complex
Matrix
F complex: oxidative phosphorylation
Matrix: krebs cycle
folded internal membrane
enzymatic activity with steroidal genesis
Application Ischemia and Mitochondria
Ischemia: lack of oxygen - hypoxia in the cell
mitochondria are of critical concern during conditions of hypoxia or toxin exposure
Degree of cell injury is dependent on:
severity: how low of an O2 level
duration: how long is cell without O2
Type of cell: some have higher O2 demand
genetic variation in individuals (some handle it better)
