week 1 Flashcards
ABC Transporters and example
ATP Binding Cassett
Active transport–needs ATP
EX: CFTR (cystic fibrosis conductance regulator)- acts as a chloride ion channel. Flows down [] gradient, does not pump.
ω-6 fatty acids (essential)
Linoleic acid (18:2)– PUFA (polyunsaturated fatty acid)
Arachidonic acid
ω-3 fatty acids (essential)
α-linoleic acid (18:3)– PUFA (polyunsaturated fatty acid)
EPA and DHA
Homeostasis
Maintenance of a stable internal environment despite external variances.
Positive feedback and examples
Amplify the original disturbance. Has a definitive endpoint.
Ex: birth, ejaculation, ovulation.
Negative feedback and example
Action taken to prevent further change.
Ex: blood glucose level. Blood glucose too high, beta-cells sense, secrete insulin, glucose re-uptake.
Steady state
Maintenance of a state that does not change with time, requires Energy.
Ex: ECF[Na+]>ICF[Na+]
Equilibrium
No net energy is transfered between two compartments.
Both compartments have same amount of free energy.
Nucleus
DNA is sequestered in the nucleus.
Ribosomes and 2 types
Made in the nucleolus and enters cytoplasm.
Site of protein synthesis (translation)
- Membrane-bound ribosomes
- Free ribosomes
Membrane-bound ribosome
Attached to RER
Produce:
lysosomal proteins
secreted proteins
plasma membrane proteins
Ribosome->ER->Golgi-> lysosome, secretion, plasma membrane
Free ribosomes
Unattached to membrane.
Nucleus
Mitochondria
Cytosol
Peroxisomes
Rough ER (RER)
Protein synthesis for plasma membrane, lysosome, or secretion.
Smooth ER (SER)
Lipid metabolism, detoxification (liver), sequester calcium (muscle)
Golgi apparatus
Complex of flatten, membrane-enclosed cisternae.
- Post-translational modifications
- Sorting
- Packaging
rER & Golgi Transport
COP-I coated vesicles: Retrograde. CGN to rER.
COP-II coated vesicle: Anterograde.
rER to CGN.
Lysosome
Digestive organelle. Intracellular digestion of macromolecules.
Mannose 6-Phosphate (M6P)
M6P receptor in TGN recognize lysosomal enzyme and transport to lysosomes.
Lysosomal storage disease (LSD)
Caused by mutation from mutations in genes that encode lysosomal enzymes. Accumulation of undigested products. Cell death.
*Impacts neurons and CNS.
Ex: Tay-Sachs Disease
Deficiency of HEXA (beta-hexosaminidase A, alpha-subunit)
Accumulation of GM2 ganglioside
Mitochondria
Generate ATP.
Double stranded circular DNA.
Inner membrane=oxidative reactions, synthesize ATP, regulate metabolite transport.
Intermembrane space= cytochrome c (programmed cell death)
Outer membrane= porins
Mitochondrial diseases
Affects tissues that require large amounts of ATP.
Leber hereditary optic neuropathy
Myoclonic epilepsy with ragged red fibers (MERRF)
Peroxisomes and diseases
Degrade toxic reactive oxygen molecules
Important for fat metabolism.
Synthesized by free cytoplasmic ribosomes.
Ex: Zellweger Syndome
Nucleolus
Site of ribosome production.
RNA transcription and ribosomal subunit assembly.
Nuclear envelope
Inner nuclear membrane- stabilizes the nuclear envelope.
Outer nuclear membrane- continuous with the rER. Cytoplasmic surface has ribosomes.
Nuclear pore complex (NPC)
For transport between nucleus and cytoplasm.
Spans inner and outer membrane.
Chromatin structure (2 types)
Chromosomes in various degree of uncoiling.
Euchromatin- lightly stain. Less condensed. More transcriptionally active!
Heterochromatin-densely stain. More condensed. Less transcriptionally active.
Lysosomal degradation (3 types)
- Phagocytosis
- Endocytosis
- Autophagy (Self eating. Turnover of organelles for new ones)
Intracellular inclusions
Cytoplasmic or nuclear structures formed from metabolic products of the cell.
Pigments
- Lipofuscin
- Hemosiderrin
- Melanin
Glycogen (store glucose)
Lipid (energy store and source of short carbon chains for membrane synthesis)
Cytoskeleton protein filaments
- Actin filaments
- Microtubules
- Intermediate filaments
Acts as tracks for motor proteins to move material within the cell.
Actin filaments
Anchorage
Structural core of microvilli and stereocillia
Intermediate filament
Resist sheer force
Keratins Vimentin Neurofilaments Lamins Beeded filaments
Microtubules
Cilia
Flagella
Centrioles
Centrosome
Centrosome
Organizes microtubules. Initiates microtubule formation. Contains a pair of centrioles.
Cilia
Microtubule-based, hair like strucutre.
9+2 arrangement
Pair of dynein arms
Anchored to cell via basal body.
Primary cilia
Sensory antennae -photoreceptors -chemoreceptors -mechanoreceptors 9+0 arrangement
Microtubule motors
Dynein– moves toward (-)
ie cilia and flagella
Kinesin– moves toward (+)
Cell movement
Protrusion-driven by actin polymerization
Attachment
Contraction
*Actin motor
Membrane protrusion structures (3)
Filopodia (finger like projections)
Lamellipodia (sheet-like)
Pseudopodia (3D projection)
Neutrophil migration
Extravasation
- rolling
- activation
- adhesion
- transendothelial migration
Chemotaxis
Membrane lipid (3)
Cholesterol-decreases fluidity. Intercalates between phospholipids.
Glycolipid-outer monolayer. contain sugar.
Phospholipid-most abundant
Phospholipids (5)
Phosphatidylserine Phosphatidylethanolamine Phosphatidylcholine Phosphatidylinositol Sphingomyelin
2 major classes of membrane protein
Lipids
Proteins-integral and pheripheral
Integral membrane proteins (6)
- Pumps/carrier/transporters
- Receptors
- Linkers
- Channels
- Enzymes
- Structural proteins
Glycocalyx
Carbohydrate rich zone at cell surface.
Cell-cell recognition
Lectins
Protection
Microenvironment of cell surface
Vesicular trafficking (3)
- Constitutive secretory pathway
- regulated secretory pathway
- lysosomal pathway
Endocytosis (3)
Receptor mediated (cargo specific, clathrin dependent)
pinocytosis (non specific, clathrin independent)
phagocytosis (clathrin independent, actin dependent)
Exocytosis (2)
Regulated (secretory cells ie endocrine, exocrine, neurons)- may be stored until needed
Constitutive (substance continuously delivered to plasma membrane)
