BIOL353 flashcards

Mechanism = how a function works now (firefly: luciferase makes light). Origin = how/why it evolved (sexual selection for mate attraction).

ATP, O2, luciferin. NOT light (light is the product).

Acclimation = reversible change in an individual (days-months; lab = acclimation, field = acclimatization). Adaptation = genetic change over generations.

Evolutionary (acute < chronic < developmental < evolutionary).

Acute, chronic, evolutionary, developmental, biological clocks.

More UNsaturated fatty acids (keeps membranes fluid) AND change enzyme amount/isoforms.

Warm = more SATURATED. Cold = more UNsaturated (kinked tails keep fluidity).

Conformer: internal environment follows the outside. Regulator: keeps it steady despite outside changes.

One genotype capable of multiple phenotypes (e.g., exercise gives bigger heart, lower resting HR).

It sets the RATE of biological processes.

8 units = about 50% of the low value. Substantial variation among individuals.

Shifts the group AVERAGES, but individual distributions still OVERLAP.

Higher LDH activity: makes more lactic acid per time (faster anaerobic ATP).

Octopus photoreceptors point TOWARD light, direct signal to brain. Fish/vertebrate photoreceptors point AWAY from light, signal through integrating neurons first.

Enzyme, channel, transporter, receptor, structural.

Permits diffusion of solutes (ion channels) or osmosis of water (aquaporins) through the membrane.

Voltage, stretch, phosphorylation, ligand.

Ligand-gated, G-protein coupled, enzyme-linked, intracellular.

Tight (block paracellular diffusion), desmosome (hold cells together), gap (connexins, diffusion between cells).

High Na+ and Cl- outside; high K+ and anionic proteins (A-) inside.

3 Na+ out, 2 K+ in (active transport).

K+ leak channels (K+ leaks out, leaving net negative interior).

BOTH active transport AND passive diffusion.

Kinase phosphorylates kinase phosphorylates kinase: one signal triggers many downstream molecules.

It amplifies signals and often sits at rate-limiting or branch-point reactions, setting the pace or branch.

Inversely related. High affinity = LOW Km (saturates faster).

Hyperbolic = independent binding sites. Sigmoid = cooperative multiple sites.

Passive transport of water across a membrane.

Body fluids saltier than water, so water enters by osmosis and fish make lots of dilute urine.

Lower the activation energy.

Separation of positive and negative charges.

Open, closed, closed.

Depolarization to threshold. Then all-or-none.

Higher FREQUENCY of spikes (spike train). Amplitude stays the same.

Voltage-gated Na+ channels open, Na+ rushes in.

K+ out through voltage-gated K+ channels. Undershoot = K+ channels still open. Na+ channels need to recover from inactivation.

Depolarization opens Na+ channels, Na+ enters, more depolarization opens more Na+ channels.

Makes membrane more negative, away from threshold.

Current through a SINGLE channel.

ALL ionic currents across the membrane.

Blocks K+ channels, leaving only the Na+ inward current.

Insulates the axon and increases conduction speed.

Schwann cells (PNS) and oligodendrocytes (CNS).

Metabolic support between capillaries and neurons, take up neurotransmitter, regulate extracellular ions.

Phagocytes; the immune cells of the CNS.

Afferent = to CNS. Efferent = from CNS to targets. Interneuron = within CNS.

Dendrites (input), soma (integration), axon (conduction), presynaptic terminal (output).

Gray = cell bodies, synapses, unmyelinated processes. White = tracts of myelinated axons.

Graded potentials only; fine for short axons.

Nervous = fast, precise, targeted. Endocrine = slow, widespread, prolonged.

Specialized site of contact between a neuron and another neuron or effector.

Electrical (gap junctions). Then ionotropic, then metabotropic.

Ionotropic: receptor IS a channel, fast. Metabotropic: G-protein/second messengers, slow, can excite, inhibit or other.

EPSP depolarizes toward threshold. IPSP hyperpolarizes away from threshold.

Temporal = same pathway over time. Spatial = different pathways at once.

AP arrives, voltage-gated Ca2+ channels open, Ca2+ triggers vesicle release, transmitter binds receptors, removed by degradation or reuptake.

Acetylcholinesterase.

Ionotropic ligand-gated channel: Na+ in (K+ out), excitatory (NMJ).

Metabotropic: G-protein itself opens a K+ channel (no second messenger). Slows the heart.

G-protein, adenylyl cyclase, ATP to cAMP, protein kinase, phosphorylation cascade. Raises heart rate.

DAG activates protein kinase C. IP3 releases Ca2+ from the ER.

Connexons (6 connexin subunits each) form channels connecting cytoplasm of adjacent cells.

Long-lasting increase in EPSP amplitude after tetanic (strong, repeated) stimulation; hippocampus.

One motor neuron contacts one muscle fiber; ACh on nicotinic receptors.

Blocks ACh receptor sites.

AMPA and NMDA (ionotropic, excitatory) plus metabotropic mGlu.

Ionotropic inhibitory (GABA-A, GlyR). GABA-B is metabotropic.

Preganglionic ACh (nicotinic), postganglionic norepinephrine (adrenergic). Short pre, long post.

ACh at BOTH synapses (nicotinic then muscarinic). Long pre, short post.

Less stretch, weaker afferent signal. Medulla raises sympathetic, lowers parasympathetic: HR, contractility, vasoconstriction up.

Carotid sinus and aortic arch.

Medulla. Sense PaCO2/pH in CSF. CO2 up lowers pH, signaling up, ventilation up.

Carotid and aortic bodies. Sense LOW PO2, plus pH and PaCO2 in plasma.

Suprachiasmatic nucleus (SCN).

CLOCK/BMAL1 activate period gene, PER builds up and pairs with CRY, PER/CRY inhibit CLOCK/BMAL1, PER degrades, cycle restarts.

Air currents move filiform hairs; sensory neurons fire; interneurons excite motor neurons (3 elements: sensory, inter, motor).

Large somatosensory representation (touch), small visual area.

Conversion of stimulus energy into an electrical signal.

Photoreceptors, sweetittermami taste, vertebrate smell. (Mechano, thermo, vestibular, auditory, salt/sour are ionotropic.)

CNS knows the sense by WHICH axon carries the signal.

Tonic = slowly adapting (Merkel, Ruffini). Phasic = rapidly adapting (Meissner; Pacinian is extremely phasic, spikes only at onset/offset).

Toward = depolarize (excited). Away = hyperpolarize.

Hair cell bending (stereocilia against the tectorial membrane).

High frequency = base (oval window end). LOW frequency = APEX.

Semicircular canals = rotation. Utricle/saccule = linear motion and gravity.

cGMP high, binds Na+ channels, channels open, cell depolarized (dark current).

Rhodopsin activated, transducin, phosphodiesterase breaks down cGMP, channels close, cell HYPERpolarizes.

Opsin + retinal. Light changes retinal 11-cis to all-trans.

A rhodopsin-based photoreceptor cell (prototype eye).

Na+ enters cation channels, directly depolarizing the cell (type I cells).

G-protein coupled receptors (type II cells). Sour = type III.

Odorant, G-protein, adenylyl cyclase, cAMP opens cation channel (Na+, Ca2+), depolarizes.

Rods = monochromatic (dim light). Cones = color.

Steroid (cholesterol); peptide (amino acids); amine (amino acids): catecholamines, thyroid, melatonin.

Neuron that releases hormone into blood. Transduces neural signal into endocrine signal.

Paracrine = neighboring cells, autocrine = same cell (no blood). Hormone = blood, distant targets.

Vasopressin (= ADH) and oxytocin, MADE in the hypothalamus. Vasopressin and ADH are the SAME hormone.

TSH, ACTH, GH, LH, FSH, prolactin (MSH in some animals).

Capillaries linking hypothalamus to anterior pituitary; releasing/inhibiting hormones arrive undiluted.

Medulla: epinephrine/norepinephrine. Cortex: glomerulosa = aldosterone; fasciculata = glucocorticoids; reticularis = androgens.

Synthesized at ribosomes (ER), proinsulin, C-peptide cleaved in Golgi, stored in vesicles, released by exocytosis on demand.

Glucose and insulin rise, glucagon falls.

Amino acids rise; insulin AND glucagon both rise; glucose about flat.

Each opposes insulin alone; together they synergize (glucose stays high).

Vasopressin up (water reabsorption), aldosterone up (Na+ reabsorption), renin-angiotensin up. Raises volume and pressure.

Binds receptor, cAMP/PKA, AQP-2 vesicles fuse to apical membrane, water reabsorbed. Less ADH = fewer AQP-2 = more dilute urine.

Low BP: juxtaglomerular cells release renin, angiotensin I, ACE makes angiotensin II (vasoconstriction, thirst, ADH, aldosterone).

Released by stretched atria. Inhibits Na+ reabsorption, vasopressin and renin: lowers volume and pressure.

Fat cells insulin-sensitive in fall (store fat), insulin-resistant in winter den (burn fat), sensitive again in spring.

Arginine vasotocin ENHANCES clasping; corticosterone (stress) INHIBITS it.

Fiber (cell) > myofibrils > sarcomeres in series. Sarcomere = smallest unit that shortens.

Thick = myosin. Thin = actin + troponin + tropomyosin.

Myosin heads pull thin filaments, Z discs move together. Filaments don't shorten; I and H bands shrink.

Ca2+ binds troponin, tropomyosin moves, myosin-binding sites on ACTIN exposed; cross-bridges cycle until Ca2+ drops.

ATP binding detaches myosin from actin; hydrolysis re-cocks the head. One cycle = one ATP, about 10 nm.

Rigor, ATP binds/detach, hydrolysis (cocked), binds actin, Pi release and power stroke, ADP release back to rigor.

Motor neuron AP, ACh, muscle AP, T-tubule, DHPR opens ryanodine receptor, SR releases Ca2+, troponin/tropomyosin shift, contraction; AChE ends signal.

Peak active tension at optimal sarcomere length (~2.0-2.25 um). Stretched too far = fewer cross-bridges = less tension.

Maximum shortening velocity at NO load. Max force at zero velocity (isometric).

One motor neuron plus all fibers it innervates. More units = more tension.

Isometric = muscle contracts but load doesn't move. Isotonic = shortens and moves the load.

Higher stimulation frequency adds twitches until fused maximal contraction (tetanus).

Slow, red, many mitochondria and myoglobin, fatigue resistant, low force.

Fast, white, few mitochondria, high force, fatigue quickly (use ATP rapidly).

Fast, red, intermediate fatigue resistance.

Same function, different kinetics (e.g., ATPase speed).

Single-unit: gap junctions, acts as unit (gut, small vessels). Multi-unit: few gap junctions, independent, direct neural control (iris, hair erectors, large arteries).

Skeletal: no / yes / somatic. Smooth: few / no / autonomic. Cardiac: yes / yes / autonomic.

Burst of spindle afferents causes the muscle to contract MORE forcefully.

CPGs initiate AND maintain locomotion; reflexes correct and fine-tune.

Flexion withdraws limb (excites flexors, inhibits extensors). Crossed extension extends the opposite limb for support.

Modified muscle cells that don't contract; stacked in columns so voltages add; evolved independently in 6 vertebrate orders.

ATP lets myosin detach; no Ca2+ keeps tropomyosin blocking so they can't reattach.

An isolated system changes toward greater disorder (entropy). Heat flows hot to cold.

Direct = heat production. Indirect = O2 consumption and/or CO2 production.

RQ = CO2 produced / O2 consumed. Carbohydrates 1.0, proteins 0.83, lipids 0.71.

BMR = resting fasted homeotherm. SMR = same for ectotherm.

Whole-animal rate divided by body weight.

Environmental temperature (plus physical activity). Smaller: meals, size, age, hormones, time of day.

Rise in metabolic rate after eating; proportional to meal size.

Glucose to pyruvate, 2 net ATP, fast, no O2 needed.

Pyruvate reduced to lactate by LDH (regenerates NAD+). Small ATP, fast.

CO2 and H2O (Krebs makes CO2; ETC consumes O2, makes H2O).

Oxygen (becomes water).

Complexes I, III, IV pump H+ into the intermembrane space; ubiquinone and cytochrome c carry electrons; gradient stores energy.

H+ back through ATP synthase = ATP. H+ back through UCP1 = HEAT (less ATP). UCP1: hibernators warming up.

Back to pyruvate, then glucose (gluconeogenesis) or oxidized in Krebs.

Creatine phosphate + ADP gives creatine + ATP (creatine kinase, vertebrates). Arginine phosphate (arginine kinase, invertebrates).

Creatine phosphate first, then anaerobic glycolysis, then aerobic.

Phosphagen: fastest, highest peak, smallest total. Anaerobic glycolysis: fast, high peak, moderate. Aerobic: slow start, moderate peak, high and indefinite total.

Repetitive movements, low force, aerobic metabolism.

Start: anaerobic covers the aerobic lag. End: aerobic stays elevated to clear lactic acid.

Metabolic depression.

Metabolic depression PLUS shell and bone buffer (CaCO3) and store lactate.

Stay active; convert lactate to ethanol (alcohol dehydrogenase), excrete across gills.

O2 regulators first, then conformers (can be fatal).

U-shaped: costly slow, minimum at middle speed, costly fast.

Training raises VO2max and aerobic enzymes (citrate synthase, cytochrome c oxidase).

Chronic exercise (run/swim) raised O2 consumption vs. sit; acute exercise raised it as speed rose.