Cells 🧫 Flashcards
Nucleolus
Ribosomal RNA synthesis (all subunits except 5S)
Mitochondrion
Semi-autonomous (own genes; independent replication via binary fission)
Outer/inner membrane//inter membrane space//cristae//matrix
ETC + ATP synthase = oxidative phosphorylation —> power
Release ETC enzymes = initiate apoptosis
Golgi
Stacked membranous discs
Further processing of proteins (+carbs/P/S/FA tails/specific signal sequence)
Re-package vesicles and ship out (intra/extra cellular targets and PM)
CIS vs TRANS GN
R Endoplasmic Reticulum
Contiguous with nuclear envelope; ribosomes for protein translation
S Endoplasmic Reticulum
Contiguous with nuclear envelope but NO ribosomes
Protein transport to Golgi
Lipid Synthesis
Detoxification
Lysosome
Hydrolytic enzymes for breakdown of substrates from endocytosis and cellular waste/old organelles (autophagy)
Enzyme release breaks down cell = autolysis or direct apoptosis
Peroxisome
“Da PPP”
H2O2 breakdown of very long chain fatty acids to shorter long chain fatty acids via B oxidation (also D- amino acids)
Help synthesize phospholipids
Contain some enzymes of Pentose Phosphate Pathway
Centriole
Located in centrosome region
9 TRIPlets of mt @ HOLLOW center
Organizing center for microtubule attachment, migration to opposite poles, organize mitotic spindle for sister chromatid separation during cell division
Intermediate Filaments
Diverse family of proteins, cell type dependent (keratin, desmin)
Cell to cell and cell to ECM adhesion (adherens junctions; desmodomes)
Maintain cellular shape
Tension bearing —> rigid structure
Anchor organelles/synaptic machinery
Microtubule
Hollow tubulin polymers in 9 + 2 doublet arrangement (euk)
Vesicular transport via dynein/kinesins in axons and cell bodies
Movement (cilia — across cell surface) (flagella — cell itself)
Attach to centrioles and chromosomes in mitosis to pull apart sister chromatids at kinetochores
Microfilaments
Polymerized actin rods arranged in bundles and networks
Protect cell integrity
Form cleavage furrow in mitosis (ring of microfilaments contracts in cytokinesis until cells pinch off)
Movement (actin + mysosin + ATP = muscle contraction)
Archaea
Prokaryotes (single cell, non membrane organelles)
Visually like bacteria (single circular chromosome, •/• binary fission/budding, similar structure)
Eukaryotic similarities (start translation with Met, similar RNA pol, histone association)
Many extremophiles (High T/salinity // no light) but many habitats including human body
Alt E sources via inorganic chemosynthesis (N/S)
Plasmid
Extrachromosomal/genomic circular DNA in bacteria
Confer benefit or virulence F such as resistance, toxin production, adhesion, evasion
Episome
Plasmid that can integrate into bacterial genome
Transformation
Integrate foreign to host genome
Frequently from nearby bacterial lysis
Common in gram negative rods
Conjugation
Bacterial sex!(ual) production
Male donor (+) with sex factor (plasmid coding for sex pili formation) forms conjugate bridge with (-) recipient female for UNIdirectional transfer of genomic material including sex factor thereby making (-) become (+) and capable of transferring to other bacteria in the colony
If sex factor integrates into genome, will attempt to transfer entire circular chromosome (bridge will usually fail before total transfer) = Hfr or High frequency recombination, can adapt very quickly
Transduction
Vector transfers bacterial DNA
Typically bacteriophage that releases trapped bacterial DNA into new host cell
Transposons
Insert AND remove from genome
Not limited to prokaryotes
Positive Sense RNA Virus
Single stranded RNA directed translated by host ribosome in cytoplasm
Negative Sense RNA Virus
Single stranded RNA template; must first make complementary strand with VIRAL RNA replicase in host cytosol, then host ribosomes translate
Retrovirus
Enveloped ss RNA with 2 identical RNA molecules that VIRAL RNA transcriptase uses to synthesize ss DNA that integrates into host DNA
May remain dormant in host for multiple replication cycles before environmental factors trigger expression via usual cellular transcription/translation machinery
Examples: HPV and HIV
Lytic Cycle
Abundance of viral progeny produced by host cell leads to cell lysis and no further ability to use cellular machinery
Infected host = virulent
Lysogenic Cycle
Integrated viral DNA is not immediately expressed but remains dormant during multiple cycles of host cell replication until environmental factors cause provirus to leave the genome and begin progeny formation at which point cell is virulent and considered to be in the lyric phase of viral replication
