- genetic information (DNA) - plasma membrane (separates internal and external environments; maintains internal environment) - cytoplasm (internal environment, carries out metabolic activities )

- contain DNA or RNA - do NOT have a cell membrane or internal metabolic activity - categorized by type of genetic material they contain

Exam 2: Cell Structure Flashcards by Angie Broga

Cell theory

to be considered alive, an organism must have cell structure

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cell structure

genetic information (DNA)
plasma membrane (separates internal and external environments; maintains internal environment)
cytoplasm (internal environment, carries out metabolic activities )

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If something is not living will antibiotics have an effect on it?
examples of things antibiotics do not work on

prions and viruses

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complex molecules that can affect cell activity can be confused with living organisms. But they lack some or all requirements for ______

cell structure

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prion

infectious protein with no cellular components

- can not make antibiotics against them

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3 ways prions can occur

hereditary - genetic
acquired - infectious/iatrogenic
sporadic - unknown case, no known risk factors

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Why is it so hard to denature prions?

they are heat shock proteins

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Viruses

contain DNA or RNA
do NOT have a cell membrane or internal metabolic activity
categorized by type of genetic material they contain

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In a virus how is genetic material contained?

in a protein capsid and may have an outer lipid/protein envelope

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Do viruses have a life cycle?

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Viruses do not have metabolism so…

no process to interrupt with antibiotics

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What do viruses need in order to carry out replication?

living cells

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Cycles that occur in infected cells all have a______ som have a _____

lytic cycle

lysogenic component

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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

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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

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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

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Lysogenic modification

early viral proteins insert viral DNA into host DNA and shuts down

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Retrovirus modification

reverse transcriptase produces viral DNA from viral RNA template
like with HIV

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adsorption

it has to stick
it recognizes a receptor on a target cell, has spike proteins
binding tricks cell into penetration

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penetration

get release of genetic material

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budding vs lyse

budding - little pieces break off like a slow leak

lyse - complete burst

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Lytic DNA viruses

adenoviruses

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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)