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MCDB 1B (B)
plant physiology- Dr. Finklestein's lectures
154
Biology
Undergraduate 2
03/15/2011

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Term
atrium
Definition
receives blood from body and pumps it to ventricle
Term
ventricle
Definition
more muscular, responsible for pumping blood to body
Term
atrioventricular (AV) valves
Definition
prevent backflow of blood into atria when the ventricles contract
Term
cardiac cycle
Definition
contraction of 2 atria, followed by contraction of 2 ventricles and then relaxation
Term
systole
Definition
when ventricles contract
Term
diastole
Definition
when ventricles relax
Term
pacemaker cells
Definition
can initiate action potentials without stimulation of the nervous system
Term
sinoatrial node
Definition
primary pacemaker, located at junction of superior vena cava and right atrium
Term
atrioventricular node
Definition
stimulated by depolarization of atria, generates action potentials that are conducted to ventricles via Bundle of His, fibers that then spread out ventricular muscle mass as Purkinje fibers
Term
erythrocytes
Definition
red blood cells, generated by stem cells in bone marrow
Term
erythropoietin
Definition
hormone regulating red blood cell production, released by kidneys in response to insufficient oxygen (hypoxia)
Term
platelet
Definition
tiny fragment of cell, no organelles, lots of enzymes and chemicals for blood clotting
Term
Starling's forces
Definition
responsible for for water movement across capillary walls

-blood pressure squeezes water and small solutes out of the capillaries
-osmotic pressure pulls water back into the capillaries
Term
Frank-Starling law
Definition
if cardiac muscle cells are stretched, as they are when the volume of returning blood increases, they contract more forcefully
Term
thoracic ducts
Definition
lymphatic vessels that empty into large veins at the base of the neck (lymphatic vessels return interstitial fluid to the blood)
Term
artherosclerosis
Definition
hardening of the arteries
Term
thrombus
Definition
intravascular blood clot, caused when platelets stick to the plaque
Term
myocardial infarction
Definition
heart attack
Term
embolus
Definition
piece of thrombus that breaks loose --> embolism
Term
stroke
Definition
embolism in brain causes cells around it to die
Term
precapillary sphincters
Definition
smooth muscle cuffs that shut off blood supply to the capillary bed
Term
hyperemia
Definition
excess blood, caused by increased metabolism of a tissue
Term
baroreceptors
Definition
stretch receptors, monitor changes in blood pressure and composition
Term
excretory systems
Definition
maintain volume, concentration, and composition of extracellular fluids, and excrete wastes
Term
osmoconformers
Definition
marine invertebrates equilibrate their EC fluid osmolarity with ocean water
Term
osmoregulators
Definition
maintain EC fluid osmolarities much lower than seawater
Term
ammonia
Definition
highly toxic, most common nitrogenous waste
Term
ureotelic
Definition
animals that excrete urea (humans!), results in large loss of H2O
Term
uricotelic
Definition
animals that excrete nitrogenous wastes mostly as uric acid
Term
protonephridium
Definition
flame cell and tubule together (flatworms)
Term
nephron
Definition
functional unit of the kidney (main excretory organ of vertebrates)
Term
estivation
Definition
state of low metabolic activity and low water turnover
Term
afferent arteriole
Definition
blood enters glomerular capillaries
Term
efferent arteriole
Definition
blood leaves glomerulus
Term
peritubular capillaries
Definition
deliver substances into renal tubule cells that they will secrete into urine and carry away substances these cells absorb from the urine
Term
Bowman's capsule
Definition
encloses the glomerulus
Term
podocytes
Definition
cells of capsule in direct contact with glomerular capillaries
Term
renal pyramids
Definition
ends of branches of ureter, make up internal core (medulla) of kidney
Term
cortex
Definition
outer layer of medulla, granular
Term
proximal convoluted tubule
Definition
initial segment of renal tubule
Term
loop of Henle
Definition
in medulla, when tubule makes a hairpin turn and ascends back to the cortex
Term
collecting duct
Definition
where distal convoluted tubules of many nephrons join
Term
vasa recta
Definition
peritubular capillaries run into medulla in parallel with loops of Henle and collecting ducts, forming a vascular network
Term
countercurrent multiplier
Definition
responsible for concentrating ability of mammalian kidney
Term
aquaporins
Definition
class of membrane proteins that form water channels (highly permeable regions of kidney)
Term
renin
Definition
causes angiotensin to form:
-constricts efferent renal arterioles
-constricts peripheral blood vessels all over body
-stimulates aldosterone (sodium reabsorption of kidney ^)
-stimulates thirst in brain
Term
atrial natriuretic peptide
Definition
decreases reabsorption of sodium in kidney --> more pee
Term
taproot
Definition
primary root developing from radicle of eudicots
Term
adventitious roots
Definition
arriving from outside, form fibrous root system (composed of numerous thin roots that are all roughly equal in diameter)
Term
prop roots
Definition
help support aboveground growth
Term
phytomers
Definition
repeating modules of nodes, internodes, and axillary buds)
Term
node
Definition
where leaf attaches to stem
Term
internode
Definition
interval of stem between 2 nodes
Term
axillary buds
Definition
form in angle where each leaf meets the stem (axil)
Term
petiole
Definition
stalk that attaches blade to the stem
Term
tonoplast
Definition
vascular membrane, pumps solutes into vacuole
Term
middle lamella
Definition
thin layer between walls of 2 daughter cells
Term
protoblast
Definition
living contents of plant cell
Term
secondary cell wall
Definition
deposit more cellulose when cell expansion stops
Term
lignin
Definition
put in secondary cell wall, strong, waterproof, resistant to digestion
Term
plasmodesmata
Definition
ER of adjacent cells connected by these cytoplasm-filled canals
Term
meristems
Definition
clusters of undifferentiated cells at tips of root and shoot, will orchestrate all postembryonic development and allow plant to form organs throughout its lifetime
Term
suspensor
Definition
supporting structure, formed by uneven distribution of cytoplasm within zygote
Term
cotyledons
Definition
seed leaves
Term
dermal tissue system
Definition
epidermis, single cell layer
Term
cuticle
Definition
secreted by epidermal cells, limits H2O loss, reflects solar radiation, serves as barrier against pathogens
Term
ground tissue system
Definition
makes up most of plant body (storage, support, photosynthesis)
Term
parenchyma
Definition
cells have large vacuoles and thin walls
Term
collenchyma
Definition
modified to provide flexible support
Term
sclerencyma
Definition
support, often die for support
Term
fibers
Definition
rigid wood support, long bundles
Term
sclereids
Definition
pack densely, make pears gritty, in nut's shell, some seed coats
Term
vascular tissue system
Definition
plant's plumbing or transport system
Term
tracheary elements
Definition
conducting cells, must die before they function
Term
vessel elements
Definition
flowering plants have this, laid down end-to-end, secrete lignin, create smooth tube for H2O flow
Term
sieve tube elements
Definition
phloem cells, form sieve tubes
Term
initials
Definition
cells that perpetuate meristems
Term
apical meristems
Definition
orchestrate primary growth
Term
lateral meristem
Definition
orchestrate secondary growth
Term
primary meristems
Definition
tissues of primary plant body
Term
cortex
Definition
thick layer of relatively unspecialized cells, storage depot
Term
endodermis
Definition
innermost layer of the cortex
Term
stele
Definition
vascular cylinder
Term
pericycle
Definition
tissue within which lateral roots arise, can contribute to secondary growth, exports ions into xylem cells
Term
pith
Definition
stores carbohydrate reserves
Term
vascular bundle
Definition
contains xylem and phloem
Term
mesophyll
Definition
middle of the leaf, zone of photosynthetic parenchyma tissue
Term
vascular cambium
Definition
cylindrical tissue consisting predominantly of elongated cells that divide frequently
Term
bulk flow
Definition
movement of solution from region of higher pressure potential to lower
Term
apoplast
Definition
fast lane for water and ions to pass into the xylem, consists of cell walls and intercellular spaces, unregulated
Term
symplast
Definition
slow lane for water and ions to pass to the xylem, passes through continuous cytoplasm connected by plasmodesmata
Term
Casparian strip
Definition
distinguishes ground tissue from endodermis, forms water-repelling belt
Term
root pressure
Definition
pressure exerted by the root tissues that would force liquid up the xylem
Term
transpiration
Definition
water diffuses through stomata to outside leaf
Term
translocation
Definition
movement of carbohydrates and other solutes through the plant in the phloem
Term
companion cells
Definition
linked to sieve tube elements, provide them with life support
Term
soil solution
Definition
mineral nutrients dissolve in water as ions within soil, touch roots
Term
macronutrients
Definition
calcium, nitrogen, magnesium, sulfur, potassium, phosphorus
Term
horizons
Definition
recognizable horizontal layers of soil
Term
liming
Definition
adding lime to soil, increases availability of Ca to plants
Term
humus
Definition
dark-colored, organic soil component, comes from dead organic matter
Term
mycorrhizae
Definition
association of fungi with roots
Term
mycelium
Definition
multicellular fungus
Term
strigolactones
Definition
compounds produced by plant roots that stimulate rapid growth of fungal hyphae toward the root
Term
nodules
Definition
root structures that house nitrogen-fixing bacteria
Term
rhizobia
Definition
fix nitrogen in mutualistic association with roots of legumes
Term
bacteroids
Definition
form of bacteria that can fix nitrogen
Term
nitrifiers
Definition
bacteria that oxidize ammonia to nitrate through process of nitrification
Term
haustoria
Definition
absorptive organs that invade the host and tap into vascular tissues in the root or stem
Term
hemiparasites
Definition
can photosynthesize, but derive H2O and mineral nutrients from living bodies of other plants
Term
holoparasites
Definition
completely parasitic and do not photosynthesis
Term
radicle
Definition
embryonic root
Term
imbibition
Definition
uptake of water (begins seed germination process)
Term
genetic screen
Definition
technique to identify genes involved in plant signal transduction pathway; must create a collection of mutants and identify those individuals likely to have a defect in the pathway being studied
Term
coleoptile
Definition
cylindrical sheath a few cells thick that protects the delicate shoot as it pushes through the soil
Term
apical dominance
Definition
apical buds inhibit the growth of axillary buds --> growth of single main stem with minimal branching (controlled by auxin)
Term
parthenocarpy
Definition
fruit formation without fertilization
Term
acid growth hypothesis
Definition
proteins pumped into cell wall, lowering pH --> polysaccharides adhere to each other less strongly --> cell expansion
Term
brassinosteriod
Definition
stimulates cell elongation, pollen tube elongation, and vascular tissue differentiation, inhibits root elongation
Term
blue-light receptors
Definition
mediate the effects of higher-intensity blue light
Term
phytochrome
Definition
mediates the effects of red light
Term
phototropin
Definition
blue-light receptor protein, absorbs blue light --> changes shape
Term
zeaxanthin
Definition
blue-light receptor, works with phototropin in the light-induced opening of stomata
Term
cryptochromes
Definition
absorb blue and UV light, affect seedling development and flowering
Term
etoliated
Definition
elongated stem, pale yellow folded leaf, and protective hook, occurs in seedling before it reaches the light
Term
Pfr
Definition
triggers seed germination, shoot development after etoliation, and flowering
Term
monoecious
Definition
"one house" male and female flowers on same plant
Term
dioecious
Definition
plants have male only or female only flowers
Term
embryo sacs
Definition
female gametophytes, develop in megasporangia
Term
pollen grains
Definition
male gametophytes, develop in microsporangia
Term
suspensor
Definition
supports embryo by pushing it into endosperm
Term
vivipary
Definition
premature germination
Term
annuals
Definition
complete lives in 1 year, after flowering, put lots of energy into seeds and fruits
Term
inflorescence
Definition
orderly cluster of flowers
Term
photoperiodism
Definition
control of an organism's responses by the length of day or night
Term
short-day plants
Definition
flower only when day is shorter than a critical maximum
Term
florigen
Definition
transmissible signal traveling from leaf when exposed to light to plant to induce flowering
Term
vernalization
Definition
when the environmental signal for flowering is cold temperature
Term
vegetative reproduction
Definition
asexual reproduction, involves stems, leaves, and roots instead of flowers
Term
apomixis
Definition
asexual production of seeds (flowers produced just to reproduce asexually)
Term
light reactions
Definition
convert light energy into chemical energy in the form of ATP and the reduced electron carrier NADPH
Term
dark reactions
Definition
use ATP, NADPH, and CO2 to produce carbohydrate
Term
absorption spectrum
Definition
light absorbed by a purified pigment vs. wavelength
Term
action spectrum
Definition
plot of the biological activity of an organism as a function of the wavelengths of light to which it is exposed
Term
carotenoids
Definition
accessory pigments, appear deep yellow
Term
phycobilins
Definition
absorb yellow-green, yellow, and orange wavelengths
Term
antenna systems
Definition
light-harvesting complexes, how pigments in photosynthetic organisms are arranged
Term
noncyclic electron transport
Definition
produces NADPH and ATP
Term
cyclic electron transport
Definition
produces only ATP
Term
photosystem I
Definition
uses light energy to pass an excited electron to NADP+, reducing it to NADPH
Term
photosystem II
Definition
uses light energy to oxidize water molecules, producing electrons, protons, and O2
Term
photophosphorylation
Definition
electron transport is coupled to the transport of protons across the thylakoid membrane, resulting in a proton gradient across the membrane
Term
Calvin cycle processes
Definition
fixation- of CO2, catalyzed by rubisco, product is 3PG

reduction- of 3PG to G3P

regeneration- of the CO2 acceptor, RuBP
Term
photorespiration
Definition
consumes O2 and releases CO2 bc it occurs only in the light
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