Final 1 Flashcards by steve aspery

Cells isolated directly from a particular tissue that do not survive many passages in culture

Primary Culture

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Primary cultures aging and dying

Replicative senescence

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Modified cell line that is the result of alterations in normal cell cycle control mechanisms such as those that occur during cancer

Cell lines

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What does low-speed centrifugation result in

Whole cells, nuclei, cytoskeletons

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What does medium-speed centrifugation result in?

Mitochondria, lysosomes, peroxisomes

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What does high-speed centrifugation result in?

Microsomes, small vesicles

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What does very high-speed centrifugation result in?

Ribosomes, viruses, large macromolecules

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Uses positively charged beads to separate negatively charged molecules

Ion-exchange chromatography

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Uses porous beads that allow larger molecules to flow through

Gel-filtration chromatography

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Uses beads with covalently attached substrate to bind to correct enzyme molecules

Affinity chromatography

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What is SDS-PAGE separate molecules based on?

Charge to mass ratio

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Why is SDS-PAGE mainly based on mass?

Protein uniformly coated with SDS which denatures the protein

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Uses a stable pH gradient to separate molecules based on pH

Isoelectric focusing

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Cut DNA so that there are sticky ends

Restriction endonucleases

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4 steps of PCR

Heat to separate strands, hybridization of primers, add free nucleotides, DNA synthesis

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Use double-stranded plasmid DNA vector to overexpress protein

Recombinant protein production

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2 ways to obtain contrast in light microscopy

White light, green light

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4 types of light microscopy

Bright field, phase contrast, DIC, dark field

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Used to cut tissue into thin sections for use under a microscope

Microtome

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Dye that binds to negatively charged compounds like nucleic acid

Hematoxyln

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Dye that binds to protein

Eosin

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2 ways to overcome out of plane light

Computationally-image deconvolution, optically-confocal microscope

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Acquire images above and below focal plane of interest

Computationally-image deconvolution

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Only illuminate the focal plane of interest

Optically-confocal microscope

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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

Hydrophobic, non-polar

The head of a phospholipid is

Hydrophilic, polar

Molecule that has both a hydrophilic, polar end and a hydrophobic, non-polar end

Amphipathic

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?

Phospholipid translocators

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

Cholesterol

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

Glycolipids

What kind of structures do self-associated glycolipids form?

Lipid rafts

3 functions of glycolipids

Protect cell surface, regulate membrane potential, cell recognition and adhesion

Enzymes that cleave phospholipids in specific locations

Phospholipases

Main way that phospholipid composition is changed quickly

Removing or modifying certain lipid headgroups

Storage form for fatty acids primarily found in adipocyes

Lipid droplets

During apoptosis, this phospholipid rapidly tranlocates to the extracellular monolayer to serve as a signal for the destruction of the cell

Phosphatidylserine

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

Hydropathy analysis

Added to a membrane to isolate membrane proteins from the lipid bilayer

Detergents

Used to monitor movements of proteins or lipids in membranes

FRAP

Molecules that can diffuse readily through the lipid bilayer

Small, hydrophobic molecules, small, uncharged polar molecules

Molecules that cannot diffuse readily through lipid bilayer

Ions

Where is the concentration of sodium ten times higher?

Outside cells

2 major classes of membrane transport proteins

Carrier, channel

Bind to a specific solute to be transported and undergo conformational changes to move the bound molecules across the membrane

Transporter proteins

Interact with solute weakly, forming an aqueous pore that extends across the membrane

Channel proteins

What determines the direction of transport of single, uncharged molecules

Concentration

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

Selectivity filter

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

Channel gating

K+ channel is a _____ of identical subunits

Tetramer

Cl- channel is a _____

Dimer

Water channels

Aquaporins

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

Axon

Shorter branches that project from a nerve, providing enlarged surfaces for the reception and detection of signals

Dendrites

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

Myelin

Non-myelinated regions of a nerve

Node of Ravier

3 excitatory neurotransmitters

Acetylcholine, glutamate, serotonin

2 inhibitory neurotransmitters

GABA, glycine