Term
| unique structural features of plants (5) |
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Definition
-photosynthesis
-transgenic plants
-secondary metabolites
-plant hormones (ethylene and auxin)
-movement |
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Term
| unique structural features of plant cells (6) |
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Definition
-cell wall
-chlorophlasts (cpDNA)
-large vacuoles
-plasmodesmata
-polyploidy
-self-fertilization possible |
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Term
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Definition
| the cytoplasm of one plant cell is continuous with the cytoplasm of its neighbor and unifies most of the plant into a continuum (gap junction) |
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Term
| most abundant membrane on earth |
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Definition
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Term
| thylakoid membrane does what? |
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Definition
| converts the energy of sunlight into chemical energy |
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Term
| most important reaction on earth |
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Definition
| carbon fixation by means of Rubisco in the calvin cycle |
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Term
| most abundant protein on earth |
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Definition
| Rubisco (50% of all protein in a leaf) |
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Term
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Definition
-transgenes are inserted into a plasmid which is then exposed to the host cell, which it infects with the help of Agrobacterium.
-antibiotic resistance (kanamycin or gentamycin) is linked to the transgene.
-transformation is done on the shoot or leaf tissues that forms a callus when grown on agar medium |
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Term
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Definition
| a mass of dividing, undifferentiates cells formed at the cut end of the shoot (meristem) |
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Term
| plant that glows in the dark |
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Definition
| tobacco expressing a firefly gene (luciferase) |
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Term
| medicinal use of transgenic plants |
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Definition
| expressing antigens in fruits -- vaccination by eating (ex: hepatitis) |
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Term
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Definition
special chemicals that aren't used for cellular metabolism. they may attract pollinators and/or repel predators
-usually stored in the large vacuoles
-humans commercially use these, ie fungicide, rodenticides, etc. |
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Term
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Definition
-defense molecule produced by willow trees
-active ingredient of aspirin
-functions in "systemic acquired resistance" to pathogens like viruses
-functions as a hormone to signal unexposed areas of a plant that infection is underway |
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Term
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Definition
-promotes stem elongation, adventitious root initiation, and fruit growth
-inhibit lateral bud outgrowth and leaf abscission |
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Term
| plant hormones - ethylene |
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Definition
promotes fruit ripening and leaf abscission
-ethylene is a gas
-causes an increase in its own production
-inhibits stem elongation and gravitropism |
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Term
| signal transduction pathway of ethylene |
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Definition
-produces effects through two membrane proteins (ETR1 and EIN2)
-ETR1 = ethylene receptor
-EIN2 = membrane protein that acts through second messenger to activate a transcription factor (EIN3)
-EIN3 turns on the genes that produce ethylene's effect |
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Term
| signal transduction of ethylene = absent versus present |
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Definition
-absent: active CTR1 represses EIN2
-present: 1) ethylene activates ETR1 (protein kinase) 2) this inactivates CTR1 3) EIN2 can now bind a 2nd messenger to activate EIN3 |
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Term
| indoleacetic acid (IAA)/ auxins and phototropism |
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Definition
-most important auxin
-Darwin and son conducted experiments on this and found that photoreceptors are in the coleoptile tip, but bending takes place in the growing region below the tip (ergo a signal must pass from the tip to the growing region)
-coleoptile tip produces hormone that diffuses down the stem
-if tip is removed, growth stops. if the tip is replaced, growth resumes.
-hormone is IAA |
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Term
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Definition
lateral distribution of auxins
-when light strikes a coleoptile from one side, the auxins move to the shaded side and the growth on that side is increased so the plant bends toward the light |
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Term
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Definition
also involves lateral redistribution of auxins
-if a shoot is tipped over, the auxins move to the lower side and cause faster growth there so the seedling bends back upward
-auxins move downward in response to gravity to compensate and make the plant grow up
-Roots respond to auxin in the opposite way so they can grow down |
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Term
| how do auxins promote growth? |
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Definition
they act on cell walls, particularly on cellulose
-for the cell wall to expand, it has to loosen and new cellulose microfibrils need to be deposited
-auxin activates proton pumps that cause the release of protons from the cytoplasm into the cell wall space
-expansins are activated by protons and modify hydrogen bonding between polysaccharides. enzymes then cleave the sugars and allow the cell wall to expand
recap:
1)auxin increases proton pump activity
2) protons go from cytoplasm to cell wall space, making it acidic
3)expansins separate microfibrils from crosslinking polysaccharides
4) cleaving allows microfibrils to slide
5) cells can elongate
-cellulose molecules from parallel association. microfibrils are composed of about 250 parallel cellulose molecules. networks of microfibrils connected by smaller polysaccharidic bridges make cell walls rigid |
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Term
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Definition
-use family of cryptochromes and phytochromes as photoreceptor molecules involved in transduction
-the photoreceptor that initiates phototropism is phototropin
-when it absorbs blue light, phototropin initiates a signal transduction pathway leading auxin redistribution, proton secretion, and the plant grows toward the light
-plants also hace receptors for red light called phytochromes that regulate responses to light like seed germination and control of flowering |
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Term
| movement in plants (thigmotropism) |
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Definition
-rapid movement can occur when there is rapid loss of turgor within PULVINI, which are specialized motor organs at the leaf joint
-stimulation causes pulvini cells to lose K+ and the water leaves the cells via osmosis |
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Term
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Definition
| deMairan's experiment using mimosa (1729) showed engogenous biological clocks. showed daily rhythms of "sleep movements" of leaves |
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Term
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Definition
CNS : astrocytes, oligodendrocytes
PNS: Schwann cells
glia outnumber neurons 10:1.
-responsible for supporting neurons and the formatino of myelin |
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Term
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Definition
| combination of diffusion and repulsion/attraction based on charges |
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Term
| how do ions cross the cell membrane? |
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Definition
1)ATP-dependent pumps (move against gradient)
2) ion channels (move with gradient) |
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Term
| resting membrane potential |
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Definition
more negative on inside, -70mV
-changes in charge distribution due to ion flow happen via gated channels.
2 types of changes:
1)graded potentials
2)action potentials |
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Term
| origin of resting potential |
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Definition
1) ATP-dependent ion pumps create concentration gradient
2) plasma membrane is differentially permeable to those ions (more permeable to K+ and Na+ than to Cl-) |
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Term
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Definition
| E(ion)=62log[ion]in/[ion]out mV |
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Term
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Definition
E(Na)= +52 mV
E(k) = -92 mV |
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Term
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Definition
Vm-E(ion)
Vm = strength of electrical gradient
E(ion) = strength of concentration gradient
-larger driving force --> faster rate
-more channels --> faster rate
-at rest: Na+ and K+ flow in equilibrium because Na+ has a high driving force but few channels and K+ has a low driving force but many channels |
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Term
| saltatory conduction of APs |
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Definition
| action potentials only occur at the nodes of Ranvier where voltage gated channels are clustered |
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Term
| electrical synaptic transmission |
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Definition
-occurs through gap junction
-gap junctions (aka connexons) are made of 6 connexin subunits that form a membrane pore which lines up its neighboring cell's pore and connects the cytoplasm of the two |
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Term
| chemical synapse: transmitter release/excitation-secretion coupling |
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Definition
1. AP causes Ca++ channels in presynaptic to open
2. calcium flows and triggers fusion of vesicles with synaptic cleft
3. transmitters release and bind to receptors in postsynaptic |
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Term
| cardiac adrenergic receptor |
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Definition
metabotropic
-G-protein coupled pathway, activation of PKA leads to phosphorylation of a Ca++ channel.
-cAMP can also bind to and activate ligand-gated Na+ channels
-combined effect increases frequency and strength of contractions of heart muscle |
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Term
| terminating action of neurotransmitters |
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Definition
1. enzymatic degradation (ACh by acetylcholinesterase)
2. diffusion - neuropeptides
3. active transport - biogenic amines and amino acid transmitters |
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Term
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Definition
| organ of Corti contains the hair cells that project into the cochlear duct and attach to the tectoral membrane, sound causes vibration of the basilar membrane which results in the hairs bending |
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Term
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Definition
| G-protein coupled receptor composed of opsin, functions as a chromopore. photon absorption causes retinal isomerization which activated the receptor |
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Term
| transduction in vertebrate photoreceptors |
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Definition
transducin is a heterotrimeric G-protein.
it activates cGMP phosphodiesterase (PDE) which leads to the closure of cGMP gated Na+ channel and membrane hyperpolarization |
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Term
| transduction in vertebrate photoreceptors |
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Definition
transducin is a heterotrimeric G-protein.
it activates cGMP phosphodiesterase (PDE) which leads to the closure of cGMP gated Na+ channel and membrane hyperpolarization |
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Term
| skeletal muscle structure |
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Definition
thick filaments are made of myosin (ATPase)
-thin filaments are composed of actin
-sarcomere = the distance between two Z lines
-I band = light band |
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Term
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Definition
| during contraction, the H bands and I bands decrease in length as the myosin thick filaments pull the actin thin filaments which is anchored by the Z-line toward the M-line |
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Term
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Definition
1) the myosin head is bound to ATP and in its low energy configuration
2) the myosin hydrolyzes ATP to ADP and is in its high energy state
3) the myosin head binds to actin, forming a cross bridge
4) releasing ADP, myosin relaxes back to its low energy configuration
5) binding of a new ATP releases the myosin head from actin and a new cycle begins |
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Term
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Definition
| the myosin binding site on actin is blocked by tropomyosin. When calcium binds to troponin, the tropomyosin shifts and exposes the binding site |
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Term
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Definition
transverse tubules.
-release of calcium is regulated by depolarization of the muscle cell caused by the release of ACh from the motor neuron. the depolarization is carried into the interior of the muscle by the T -tubules, where calcium stored in the endoplasmic reticulum is released |
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Term
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Definition
retina, optic nerve, optic chiasm, lateral geniculate nucleus, superior colliculus, optic radiation, visual cortex
-THALAMUS |
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Term
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Definition
cochlea, dorsal cochlear nucleus, cochlear nerve, ventral cochlear nucleas, nucleus of lateral lemnisci, medial geniculate body, auditory cortex
-THALAMUS |
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Term
| Aphasia, Wernicke's/Broca's |
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Definition
partial or complete loss of language ability
Wernicke's - loss of comprehension of spoken word and difficulty forming meaningful speech
Broca's - inability to speak without loss of comprehension |
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Term
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Definition
inbility to speak
-broca's area is a region of the higher motor cortex |
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Term
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Definition
can articulate just fine, but can't comprehend and tend to make nonsensical statements
-wernicke's area is a region of the association cortex |
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Term
| lateralization of language |
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Definition
| the neural components that are involved in speech are located in the left hemisphere |
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Term
| biological clock in mammals and light |
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Definition
some retinal ganglion cell axons emerge from the optic chiasm and form a retinohypothalamic tract (RHT) which goes to the suprachiasmatic nucleus (SCN) of the hypothalamus
-cutting the optic nerve (in front) of the chiasm causes the rhythm to free run
-cutting the optic tracts (behind) has no effect
-lesions that destroy the SCN abolish daily rhythm activity |
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Term
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Definition
| pressure: greater in arteries, so thicker walls, veins have thinner walls but need valves |
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Term
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Definition
NOS = nitric oxide synthetase (regulated by calcium ions)
-not released by exocytosis (diffuses freely)
-major mechanism of action is direct stimulation of guanylate cyclas in target cells for the production of cGMP |
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