Test 2 vocab Flashcards
photosythesis
the process that converts solar engery into chemicl energy
autotrophs
organisms that obtains organic food molecules without eating anything derived from other organisms
producer
an organism that produces organic molecules from CO2 and other inorganic molecules by harnessing light energy or by oxidizing inorganic chemicals
heterotrophs
organisms that obtain their organic material from other organisms
consumer
an organism that depends on photoautotrophs for food and O2
redox reaction
a chemical reaction involving the complete or partial transfer of one or more electrons from one reactant to another
reduction
the complete or partial addition of electrons from a substance involved in a redox reaction
oxidizing agent
the electron acceptor
oxidation
the complete or partial loss of electorns from a substance involved in a redox reaction
reducing agent
the elctron donor
endergonic reaction
a nonspontaneous chemical reaction, in which free energy (energy available to do work) is absorbed from the surrounding (anabolic)
mesophyll
the interior tissue of a leaf composed of mesophyll cells that contains chloroplasts and other organelles
stomata
microscopic pores found in the epidermis of leaves and stems that carry out gas exchange between environment and the interior of the plant
chloroplasts
pigment containing organelles in plant cells
thylakoid
flattened membranous sac in the chloroplast
chlorophyll
a green pigment that absorbs light energy to drive sythesis of organic molecules
grana
thylakoid stacked columns
stroma
a dense fluid within the choloplast surrounding the thylakoid sacs
photophosphorylation
the process of generating ATP from ADP and phosphate by means of chemiosmosis, using a H+ gradient generated across the thylakoid
photolysis
light provides energy for enzymes to split H2O into hydrogen and oxygen and excited electorns
carbon fixation
incorporating CO2 into organic molecules
nature of sunlight
light is a form of electormagnetic energy (radiation)
electromagnetic radiation
energy that exhibits wavelike behavior
wavelength
the distance between crests of electromagnetic waves
visible light
a small part of the electromagnetic spectrum (the entrie range of radiation) consisting of wavelengths (including those that drive photosynthesis) that produce colors we can see
color spectrum acronym
ROY G BIV
photons
light also behaves as though it consists of discrete particles
pigments
substances that absorb visible light
chlorophyll a
primary photosynthetic pigment because directly starts the light reactions
accessory pigments
chlorophyll b, carotenoids (xanthophylls and carotens)
chlorophyll b
absorbs wavelengths in indigo-blue and orange = broadens the spectrum used for photosynthesis
carotenoids
absorb wavelengths in the violet and blue green light
photosystem
photounit located in the thylakoid membranes that carries out the light reaction
reaction-center complex
a type of protein complex holding a special pair of chlorophyll a molecules
primary electron acceptor
a molecule in the reaction center that accepts excited electrons and is reduced as a result
light-harvesting complexes
pigment molecules (chlorophyll a, chlorophyll b, and carotenoids) bound to proteins
photosystem II (PSII)
functions first (the numbers reflect order of discovery) and is best at absorbing a wavelength of 680 nm
photosystme I (PSI)
is best at absorbing a wavelength of 700 nm
linear electron flow
the primary route of electron flow during light reactions of photosynthesis tha tinvolves both photosystems and produces ATP and NADPH using light energy
chemiosmosis
energy coupling mechansim that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP
cyclic electron flow
uses only photosystem I and produces ATP, but not NADPH
Calvin Cycle
- occurs in the stroma
- builds sugar from smaller molecules by using ATP and the reducing power of electrons carried by NADPH
glyceraldehyde 3- phospate (G3P)
carbon enters the cycle as CO2 and leaves as a sugar
photorespirations
a metabolic pathway that consumes oxygen and ATP, releases carbon dioxide, and decreases photosynthetic output.
C4 plants
plants in which the calven cycle is preceded by reactions that incorporate CO2 into a 4-C compound, the end product of which supplies CO2 for the calvin cycle
bundle sheath cell
in C4 plants, a type of photosythetic cell arranged into tightly packed sheaths around the veins of a leaf. have different anatomical arrangement from C3 plants cells to ensure optimal carbon fixation
CAM plants
use crassulacean acid metabolism (CAM) to fix carbon (e.g. pineapple)
herbaceous
non woody whose aerial parts die back to the ground at the end of the growing season. These plants do not produce secondary tissue. Have stems with primary growth
woody
aerial parts (trees and shrubs) persist all year. produces hard lignified secondary tissue (cell walls of secondary tissues (vascular and cork cambiums) conatin lignin. Have stems with primary and secondary growth
annuals
herbaceous plants that grow, reproduce, and die in one year or less
biennials
herbaceous plants that take two years to complete their life cycle
perennials
herbaceous or woody plants that have the potential to live for more than two years
deciduous
shed their leaves each year
evergreen
shed their leaves over a long period of time
shoot system
- the above ground part of the plant
- carries out photosythesis and reproduction
- replies on water and minerals absorbed by the root system
- consists of a vertical stem that bears leaves and reproductive structures
root system
- the portion of the plant below ground
- functions include: anchorage, storage, mineral and water absorption, and reprodution
- consists of roots and root
organ
collection of two or more tissues that perform a specific function
leaves
flattened organs of photosynthesis usually attached to the stem
leaf blade
the board, flat portion of the leaf
petiole
the stalk that attaches the blade to the stem
stem
organ of a plant that provides structural support, conduction, and production of new stem tissues
node
area on a stem where on or more leaves are attached
internode
the stem segments between nodes
buds
dormant embryonic shoots
axillary (lateral) bud
a structure that has the potential to form a lateral shoot (branch); develops in a leaf axil (the angle between the stem and petiole)
apical (terminal) bud
is located at the tip of a stem and causes elongation of a yong shoot; when dormant (not actively growing)covered and protected by an outer layer of bud scales which are modified leaves
root
organ that branches forming a network that anchors the plant firmly in place and absorbs water and dissolved minerals
root hair
thin tubular extension of a root epidermal cell that INCREASES the ABSORPTIVE CAPACITY of roots
taproot system
a root system consisting of a prominent main root with smaller lateral root branching off it
fibrous root system
a root system consisting of serveral adventitious roots of approximately equal size that arise from the base of the stem
tissue
a collection of two or more cells that perfom a specific function
ground tissue
composed most of the plant body
cortex
- a cylinder of ground tissue that may contain parenchyma, collenchyma, and sclerenchyma cells
- ground tissue external to the vascular tissue in stems
pith
ground tissue internal to the vascular tissue in stems
endodermis
innermost layer of cortex that regulates passage of substance from soil into vascular cylinder via the Casparian strip
cells
- basic structural and functional unit
- plant cells structures
- chlorophyll for photosynthesis
- cell walls around the cell membrane
parenchyma
cells are enlongated or spherical with a large central vacuole
collenchyma
cells are elongated grouped in strands, living at maturity, and will often have chlorophyll
sclerenchyma
cells are rigid with primary and secondary cell walls that function in support
fibers
long pointed cells with thick pitted cell walls with rather small lumen
sclereids
- usually occur in small cluter or a solitary cell
- cell walls are thicker than fibers. shape is often cubical but may be quite variable
vascular tissue system
conducting system that extends throughout the plant body
xylem
- tissue that conducts water and solutes (dead at maturity)
- usually the upper part of the a vein
- conducts water and dissolved minerals
phloem
- tissue that conducts sugar
- conducts dissolved sugars
- usually confined to lower part of a vein
tracheids
- are found in the xylem of all vascular plants
- long, pointed cells that have joined, overlapping ends and pits between the cells for water exchange
- gymnosperms (cone bearing plant) have only tracheids and no vessel members
vessel elements
- vessel may be three or four feet long or only inches long
- cells join end to end with their end walls dissolved out or with holes forming perforation plates
- a stack of vessel elements is called a vessel
sieve-tube elements
cells that join end to end to form long sieve tubes. conducting elements of the phloem that transport sugars from the leaves to the rest of the plant
sieve plates
are the porous end walls that allow fluid to flow between cells along the sieve tube
companion cells
cells connect to sieve-tube cells
dermal tissue system
provides a covering for the plant body
epidermis
outer covering of herbaceous plants
epidermal cells
living cells that lack chloroplasts and are usually elongated
cuticle
waxy over the epidermal cells eterior walls restricting water loss from plant surface
stomata
two guard cells (bean-shaped and their shape will change as they gain or lose turgidity; pore is open when guard cells are turgid and closed when they are not)
trichomes
epedermal outgrowths that a single or multicellular
periderm
protective layer in woody plants that forms the outer bark in older stems and roots after the epidermis splits and is lost
cork
cork cells on the outside that are dead at maturity and have a water proof material (suberin)
cork cambium
layer of dividing cells below the cork
indeterminate growth
a plant can grow throughout its life
determinate growth
some plants organs cease to grow at a certain size
meristem
special regions of the plant body where cell division occurs and cells undergo differentiation (embryonic tissue that allows for indeterminate growth
apical meristems
located at the tip of roots and shoots and at the axillary buds of shoots
primary growth
an increase in stem and root length (taller)
stoot apical meristem (SAM)
located at the tip, terminal bud, of each branch
leaf primordia
tissue that develops into new leaves
root apical meristem (RAM)
located at the tip of each root
zone of cell division
includes the RAM and cap. new root cells are produced here
zone of elongation
is behind the zone of cell division, pushes the root deeper into the soil. this is where most growth occurs as cells elongate. specialization begins here
zone of differentiation or maturation
is behind the zone of elongation. this is where the cells become completely differtiated and mature
lateral meristems
areas of localized cell division on side of a plant that give rise to secondary tissue
vascular cambium
single layer of undifferentiated parenchyma cells that adds layers of vascular tissue called secondary zylem (wood) to its interior and secondary phloem to its exterior
bark
the plant tissue located outside the vascular cambium
simple leaf
- a leaf with a single blade; type of complexity
- entire: no indentations/smooth edges
- lobed: deep indentations (sinuses)
- toothed: serrated edges, very shallow indentations
- undulated: wavy margins
compound leaf
- a blade is divided into two or more leaflets; type of complexity
- palmatet: the leaflet diverege from a single point
- pinnate: the leaflets are arranged along an axis
- doubly compound leaf: the blad consists of multiple leaflets AND each leaflets is divided into smaller leaflets
alternate (leaf arrangement)
one leaf at each node
whorled (leaf arrangement)
three or more leaves grow at each node
opposite (leaf arrangement)
two leaves grow at each node
parallel (venation patterns)
veins run parallel (monocots)
pinnately netted (venation patterns)
major veins branching off in succesion along the entire length of a midvein (central vein)
palmately netted (venation patterns)
several major veins radiating out from one point
trichomes
hair-like structures covering the epidermis of many leaves
mesophyll
- photosynthetic ground tissue in a leaf, that is sandwiched between the upper and lower epidermis
- dicots has two distic layers
- the palisade mesophyll
- the spongy mesophyll
palisade mesophyll
the upper part of the leaf; primary function is photosynthesis
spongy mesophyll
in th elower part of the leaf; the loose arrangement allows for gas exchange
rhizomes
a horizontal underground stem that bears buds and often serves as a storage organ and means of asexual reproduction
tubers
thickened end of a rhizome that is fleshy and enlarged for food storage
bulbs
fleshy undergound bud that consist of a short stem with fleshy leaves
stolons (runners)
above ground horizontal stems with long internodes often have buds that develop into separate plants
herbaceous
non woody plant whose aerial parts die back to the ground at the end of the growing season
woody
aerial parts (trees and shrubs) persist all year. produces hard lignified secondary tissue (cell walls of secondary tissues (vascular and cork cambiums) contain lignin)
sapwood
lighter wood near the periphery. this has functional secondary sylem that does motst of the water and solute transport in the tree
heartwood
dark wood in the center of the tree. cells no longer function since they are filled with resin, gums, pigments, and tannins that block them
annual rings
concentric rings of cells in the secondary zylem
vascular rays
radial files of mostly parenchyma cells that connect the secondary zylem and phloem
hardwoods
the wood of flowering plants that is generally harder than softwoods
softwood
the wood of gymnosperms, lacks fibers, and vessel elements, and is typlically softer
springwood (early wood)
cells in the inner part are usually larger in diameter with thin cell walls to maximize water delivery since they form in the spring when there is more rain
summerwood (late wood)
cells form later (summer) are smaller in diameter have thick-walled cells and contributes more to stem support
flower buds
produce flowers instead of leaves
bud scars
scars left on the side of the stem when bud scales fall
leaf scars
scars left on the stem when leaves fall
bundle scars
scars for vascular bundles left within leaf scars when leaves fal
channel proteins
hydrophilic channel that certain molecules or ions use as a tunnel through the membrane
aquaporins
channel protein that speed up the rate of water transport across the plasma membrane
ion channels
channel proteins which function as gated channels that open and close in response to a stimulus, voltage, or pressure
carrier proteins
proteins that hold onto their passengers and change shape in a way that shuttles them across the membrane
cotransporter proteins
the coupling of “downhill” diffusion of one substance to the “uphill”transport of another against its own concentration gradient
osmosis
the diffusion of free water across a membrane
free water
water molecules not bound to soute or surfaces and thus available to do work
water potential (ψ)
quantity of a physical property that predicts the direction in which water will flow
flaccid
plant cell is one that is limp and a result of losing water
plasmolysis
in hypertonic environments the cytoplasm shrinks and pulls away from the cell wall
turgid
plant cell is one that is very firm and a result of gaining water
xylem sap
water and dissolved minerals in the xylem
transpiration
loss of water vapor from leaves and other aerial parts of plants
guttation
plants exude liquid water in the morning on the tips of edges of leaves
tension-cohesion hypothesis
proposes that the movement of xylem sap is driven by water potential difference created at the leaf end of the sylem by the evaporation of water from leaf cells
tension
negative pressue that pulls water through the xylym
cohesion
linking fo like molecules often by hydrogen bonding
adhesion
clinging of one substande to another
translocation
transport of products of photosynthesis via phloem tissue from leaves to actively growing parts and storage
source
a plant organ that net producer of sugar by photosynthesis or breakdown of starch
sink
a plant organ that is a net consumer or depository of sugar
pressure-flow hypothesis
proposes that building of positive pressure at the source and reduction of that pressure at the sink cause sap to flow from source to sink
companion cells
cells connected to sieve-tube cells
sieve-tube elements
cells that join end to end to form long sieve tubes. conducting elements of the phloem that transport sugars from the leaves to the rest of the plant
adventitious
plant organ that arises from an unusual posistion on a plant
casparian strip
a band of waterproof material around the radial and transverse walls of endodermal root cells
pericycle
outermost layer, which gives rise to lateral roots
apoplastic route
solutes and water travel through everything external to the plasma membrane of a plant cell
symplastic route
solutes and water travel through the continuum of cytoplasm connected by plasmodesmata between cells
transmembrane route
solutes and water travel through both apoplasts and symplasts compartments
prop roots
an aerial adventitious root that arises from the stem and provides additional support for a plant
storage roots
store food and water (ie radish and beets)
buttress roots
brace-like roots at the base of certain trees that provide upright support
pnuematophores
roots thtat extend up out of the water in swamp areas and are thought to provide aeration between the atmosphere and submerged roots
