Cell Bio Basics

gsafsaf's version from 2015-05-26 16:07

Cell death + injury

Question Answer
What is pyknosis?irreversible nuclear chromatin condensation
What is karyorrhexis? nuclear fragmentation
What is fibrinoid necrosis? Immune-mediated vascular damage
What tissue(s) undergoes fibrinoid necrosis?Blood vessels
What initiates fatty necrosis?Activation of lipases
What tissue(s) undergoes fatty necrosisPancreas
What results in caseous necrosis?Systemic fungal infxn
What disease process displays caseous necrosis?TB
What is observed in tissues undergoing caseous necrosis?Gelatinous + viscous liquid mass
What is observed in tissues undergoing coagulative necrosis?Gelatinous substance in dead tissue
What tissue(s) undergoes coagulative necrosis? Heart, kidney, liver under low oxygen conditions aka infarctions
What is observed in tissues undergoing liquefactive necrosis?Viscous liquid mass
What tissue(s) undergo liquefactive necrosis?Brain
What disease states display liquefactive necrosis?Bacterial abscesses + Pleural effusions
What disease states display wet gangrenous necrosis?Bacterial infxns
What tissue(s) undergoes wet gangrenous necrosis?Extremities
What disease states display dry gangrenous necrosis?Ischemia
What tissue(s) undergoes dry gangrenous necrosis?Toes & feet
What tissue(s) undergoes red infarcts?Liver, lungs, intestine - Loose tissues w collaterals
What cell process do red infarcts follow?re-perfusion
What tissue(s) undergoes pale infarction?Heart, spleem, kidney - Solid tissues w a single blood supply
What are some mediators of Acute inflammationNeutrophils, IL-1, IL-6, TNFa, Histamine, Serotonin, Bradykinin
What do fibroblasts require in order to lay down collagen?Vit. C
What do metalloproteinases require in order to remodel tissue during healing process? zinc
What are some mediators of chronic inflammationMacrophages + Lymphocytes
What are granulomas?Clusters of macrophages in chronically inflamed tissue; Multinucleated giant cells
What mediates "rolling"?Selectins, IL-1, IL-2, TNFa
What mediates "tight binding"?LFA-1 (integrin on leukocyte) + ICAM-1 (on endothelial cells)
What mediates diapedesis?PECAM-1 (on monocytes+platelets+junctions btwn endothelial cells)
What mediates "migration"?Neutrophil chemotactic factors - C5a, IL-8, LTB4, Kallikrenin
What occurs 1-3 days post tissue injury? (after hemorrhage, clotting, acute inflammation)?Macrophage infiltration; granulation tissue; vascular endothelial cells; epithelialization
What occurs weeks-months post tissue injury?Collagen production (Type III then Type I)
HypertrophyEach individual cell gets bigger - ex: myometrium during pregnancy
HyperplasiaIncreased number of cells - ex: glandular tissue of breast during female puberty
MetaplasiaReversible; in response to ongoing stressor, local stem cells induced to make new cell type (not x differentiated cell --> y differentiated cell)
Examples of metaplasiaCiliated columnar trachea and bronchi in smokers -> squamous; Barrett esophagus; squamous --> columnar; response to chronic GERD
AtrophyReduced size of individual cells + reduced number of cells

RNA synthesis

Question Answer
RNA polymerase Iproduces 18S, 5.8S, 28S rRNA
RNA polymerase Irestricted to the nucleolus
RNA polymerase IIproduces mRNA
RNA polymerase IIproduces snRNA
RNA polymerase IIproduces miRNA
RNA polymerase IIthe most highly regulated RNA polymerase
RNA polymerase IIIproduces tRNA
RNA polymerase IIIproduces 5S rRNA
18S rRNA, 5.8S, 28S rRNAform essential ribosomal components
mRNAtranslated by ribosomes to form specific proteins
snRNAinvolved in mRNA splicing & txn regulation
snRNPsSmall nuclear ribonucleicproteins that combine w unmodified pre-mRNA to form a spliceosome
snRNPsremove introns from pre-mRNA as a part of post-transcriptional modification, occurring in the nucleus
miRNAcauses gene silencing via translation arrest or mRNA degradation
tRNAadaptor molecule linking codons w specific AAs; binding codon charges this form of RNA, and its binding to mRNA is facilitated by elongation factors
5S rRNAessential component of 60S ribosomal subunit; its genes are located outside the nucleolus
Nucleolusinvolved in transcribing rRNA + the maturation and assembly of ribosomal subunits
Ribosomal protein componentssynthesized in the cytoplasm and transported into the nucleolus for further assembly
Malignant cellshave a large number of active rRNA genes + prominent nucleoli
UAA, UAG, UGAStop codons
Releasing factorsWhen the ribosome encounters a stop codon, these bind to the ribosome so that it disintegrates and lets go of the formed polypeptide chain
TATA promoter regionapprox. 25 bp upstream from the gene's coding region

Regulators of cell cycle

Question Answer
p21binds to cyclin-CDK complexes to inactivate them
p27binds to cyclin-CDK complexes to inactivate them
p21binds to cyclin-CDK complexes to inactivate them
p53controls p21 activation
CDK that couples w Cyclin DCDK4
CDK that couples w Cyclin ECDK2
CDK that couples w Cyclin ACDK2
CDK that couples w Cyclin BCDK1
Cyclin-CDK complex that initiates G2->MCyclin A-CDK2
Cyclin-CDK complex that initiates mitosis prophaseCyclin B-CDK1
Cyclin-CDK complex that initiates G1->SCyclin D-CDK4
Cyclin-CDK complex that phosphorylates RbCyclin D-CDK4
E2FReleased from phosphorylated Rb, synthesizes S phase components


Question Answer
RERSynthesis of proteins destined for outside the cell
Cytosolic ribosomesSynthesis of cytosolic/organelle proteins
RERSite of N-linked glycosylation
Nissl bodiesRER of neurons; synthesize enzymes + peptide neurotransmitters
Smooth ERSite of steroid synthesis and detoxification
COP-IIAnterograde trafficking; RER -> Golgi
COP-IRetrograde trafficking; Golgi -> RER
ClathrinCoats trans Golgi; transports hydrolases to lysosomes; helps PM w/ endocytosis
GolgiCellular "post-office"; distribution of proteins and lipids to PM, lysosomes, secretory vesicles; post-translational modification of proteins + proteoglycans
Smooth ERhepatocytes and adrenal cortex are rich in them
Nissl bodiesfound in DENTRITES, but not axons
GolgiN-linked (asparagine) & O-linked (serene + threonine) glycosylation
GolgiM-6-Phosphorylation of lysosomal enzymes
Golgisulfation of sugars + tyrosine
Sarcoplasmic reticulumSpecialized ER in muscle cells; stores calcium and regulates muscle contraction
Peroxisomeß-oxidation of very long chain + branched chain fatty acids
PeroxisomeSynthesis of plasmalogens (myelin phospholipids)
PeroxisomeSite of oxidase + catalase metabolism of ethanol (+ other toxic substances)

Intermediate filaments

Question Answer
CytokeratinEpithelial cells
Desminmuscle cells (smooth, skeletal, cardiac)
Glial fibrillary acid proteins (GFAP)Astrocytes, schwann cells, other neuroglia
NeurofilamentsAxons within neurons
Nuclear lamins Nuclear envelope and DNA within
VimentinConnective tissue (fibroblasts, leukocytes, endothelium) support cellular membranes, keep certain organelles fixed in cytoplasm
VimentinStain to identify sarcoma
CytokeratinStain to identify carcinoma
DesminStain to identify rhabdomyosarcoma/leiomyosarcoma
NeurofilamentsStain to identify neuroblastoma
Glial fibrillary acid proteins (GFAP)Stain to identify glioblastoma
Nuclear laminsMutations lead to progeria, muscular dystrophies

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