Flashcards in Final 1 Deck (80):
Cells isolated directly from a particular tissue that do not survive many passages in culture
Primary cultures aging and dying
Modified cell line that is the result of alterations in normal cell cycle control mechanisms such as those that occur during cancer
What does low-speed centrifugation result in
Whole cells, nuclei, cytoskeletons
What does medium-speed centrifugation result in?
Mitochondria, lysosomes, peroxisomes
What does high-speed centrifugation result in?
Microsomes, small vesicles
What does very high-speed centrifugation result in?
Ribosomes, viruses, large macromolecules
Uses positively charged beads to separate negatively charged molecules
Uses porous beads that allow larger molecules to flow through
Uses beads with covalently attached substrate to bind to correct enzyme molecules
What is SDS-PAGE separate molecules based on?
Charge to mass ratio
Why is SDS-PAGE mainly based on mass?
Protein uniformly coated with SDS which denatures the protein
Uses a stable pH gradient to separate molecules based on pH
Cut DNA so that there are sticky ends
4 steps of PCR
Heat to separate strands, hybridization of primers, add free nucleotides, DNA synthesis
Use double-stranded plasmid DNA vector to overexpress protein
Recombinant protein production
2 ways to obtain contrast in light microscopy
White light, green light
4 types of light microscopy
Bright field, phase contrast, DIC, dark field
Used to cut tissue into thin sections for use under a microscope
Dye that binds to negatively charged compounds like nucleic acid
Dye that binds to protein
2 ways to overcome out of plane light
Computationally-image deconvolution, optically-confocal microscope
Acquire images above and below focal plane of interest
Only illuminate the focal plane of interest
4 super resolution microscopy techniques
SIM, STED, STORM, PALM
4 functions of protein molecules that span the lipid bilayer
Transport of specific molecules through membrane, catalyzing membrane-associated reactions, structural links to ECM, receptors to detect chemical signals in environment
The tail of a phospholipid is
The head of a phospholipid is
Molecule that has both a hydrophilic, polar end and a hydrophobic, non-polar end
Where are new lipid molecules primarily synthesized?
Cytoplasmic leaflet of membrane
How do lipid molecules travel to the ECM-side of the membrane if flip-flops are so rare?
4 movements of phospholipid molecules
Lateral diffusion, flexion, rotation, flip-flop
Phase transition of a lipid bilayer occurs at lower temperatures if what 2 characteristics of the phospholipids are seen?
Short hydrocarbon chains, many double bonds
Lipid found in large amounts in PM that has rigid, plate like steroid ring
What is the main function of cholesterol in a membrane?
Immobilizes regions of hydrocarbon chains, making them less deformable and less permeable to small molecules
Sugar-containing lipid molecules found exclusively on noncytosolic side of PM
What kind of structures do self-associated glycolipids form?
3 functions of glycolipids
Protect cell surface, regulate membrane potential, cell recognition and adhesion
Enzymes that cleave phospholipids in specific locations
Main way that phospholipid composition is changed quickly
Removing or modifying certain lipid headgroups
Storage form for fatty acids primarily found in adipocyes
During apoptosis, this phospholipid rapidly tranlocates to the extracellular monolayer to serve as a signal for the destruction of the cell
4 types of membrane proteins
Transmembrane, Located entirely within cytosol, located entirely on outer surface, bound to either face by noncovalent interactions
Computational method to predict membrane spanning alpha helical segments
Added to a membrane to isolate membrane proteins from the lipid bilayer
Used to monitor movements of proteins or lipids in membranes
Molecules that can diffuse readily through the lipid bilayer
Small, hydrophobic molecules, small, uncharged polar molecules
Molecules that cannot diffuse readily through lipid bilayer
Where is the concentration of sodium ten times higher?
2 major classes of membrane transport proteins
Bind to a specific solute to be transported and undergo conformational changes to move the bound molecules across the membrane
Interact with solute weakly, forming an aqueous pore that extends across the membrane
What determines the direction of transport of single, uncharged molecules
What determines the direction of transport of a molecule if it carries a charge?
Concentration gradient and electrical potential difference across the membrane
3 ways to accomplish active transport
Coupled carriers, ATP-driven pumps, light-driven pumps
4 types of ATP-driven pumps
P-type, ABC, V-type, F-type
3 types of coupled carriers
Uniporter, symporter, antiporter
Example of P-type pump
SR Ca2+ pump
Na-K pump transports how many Na's and K's
3 Na, 2 K
2 transporters that an epithelial cell uses to ingest glucose
Na+-glucose symporter, Na-K pump to reestablish sodium concentration levels
2 important features of ion channels
Ion selectivity, not continuously open - gated
3 stimuli that affect the opening of ion channels
Change in voltage across a membrane, mechanical stress, binding of ligand
Situation in which there is no net flow of ions across a membrane
Resting membrane potential
What is primarily responsible for generation of a membrane potential
K+ leak channel
Amino acids lining the pore a channel that are arranged in such a way that they provide energetically favorable interactions with a particular ion
Conformational changes within the subunits of a channel that rearrange the location of the transmembrane domains to restrict access to the opening of a pore
K+ channel is a _____ of identical subunits
Cl- channel is a _____
How is ion passage blocked in aquaporins?
Energetically disfavoring removal of ion's hydration shell
Part of a nerve that conducts signals away from the body towards distant target
Shorter branches that project from a nerve, providing enlarged surfaces for the reception and detection of signals
How is an action potential triggered?
Depolarization of PM which causes voltage-gated Na+ channels to open
How are action potentials propagated?
Na+ channels open in a wave down a nerve
How does a nerve maintain unidirectional action potentials
Na channels are inactivated and K+ channels become activated, so the cell is overwhelmed by K+
How is a membrane repolarized after an action potential?
K+ channels reset the membrane by moving potassium of of the neuron
Compound the helps conduct nerve impulses faster
Non-myelinated regions of a nerve
Node of Ravier
3 excitatory neurotransmitters
Acetylcholine, glutamate, serotonin