Ch. 37 Plant Form & Function Flashcards
indeterminate growth
grow throughout their lives
herbivore
plant eaters
carnivore
meat eaters
photosynthesis
process by which energy from sunlight is transformed into sugar
6CO2 + 6H2O ——–> C6H12O6
anabolic, endergonic, CO2 requiring process
anabolic pathway
any set of chemical reaction that synthesizes large molecules from smaller ones
- requires input of energy
catabolic pathway
any set of chemical reaction that breaks down large/complex molecules into smaller ones
- releases energy
endergonic
a chemical reaction that requires an input of energy to occur
∆G > 0
exergonic
a chemical reaction occurs spontaneously
- releases heat
- increases entropy
∆G < 0
chloroplast
organelle where photosynthesis takes place
- bounded by a double membrane
- chlorophyll found here
- found in plants & photosynthetic protists
things found in chloroplast
(1) starch
(2) amino acid
(3) fatty acid
(4) purine
(5) pyrimidine synthesis
thylakoid
membrane-bound network of flattened sac-like structures inside a plant chloroplast
thylakoid function
converting light energy to chemical energy
grana
(plural - granum)
a stack of thylakoid discs
chlorophyll
any of several closely related green pigments that absorb light during photosynthesis
- found in chloroplasts
- Mg+ in the center
stroma
fluid-filled space between the thylakoids & inner membrane
chlorophyll pigment
pigments that harvest energy (photons) by absorbing certain wavelengths
important wavelengths
(1) blue 420nm
(2) red 660nm
why are plants green?
the green wavelength is reflected off the plant
green chlorophyll during the fall
greatly reduced, revealing other pigments
(ie) leaves are red/orange/yellow instead of green
starting materials of photosynthesis
(1) sunlight
(2) carbon dioxide
(3) water
(4) other resources
reactions in photosynthesis
(1) light-dependent reaction
(2) Calvin cycle reaction
light-dependent reaction
produce O2 from H2O
water splits to form oxygen gas & then H+ is transferred to the electron carrier NADP+, forming NADPH
Calvin cycle
produce sugar from CO2
uses electrons from light-dependent reaction & the potential energy in ATP to reduce CO2 to make sugars
redox reaction
transfer of 1 or more electrons from one reactant to another
- types: oxidation & reduction
oxidation
loss of electrons from an atom or molecule during redox reaction
6H2O ——-> 6O2
how oxidation occurs
(1) donation of an electron to another atom or molecule
(2) the shared electrons in covalent bonds moving farther from the atomic nucleus
reduction
gain of electrons by an atom or molecule during redox reaction
6CO2 ———> C6H12O6
how reduction occurs
(1) accepting an electron from another atom or molecule
(2) the shared electrons in covalent bonds moving closer to the atomic nucleus
products of light-dependent reaction
ATP
NADPH
reactants of light-dependent reaction
energy from solar power (photons)
reactants of Calvin Cycle
ATP
NADPH
products of Calvin Cycle
sugar (glucose)
possible routes for electron flow
(1) cyclic flow
(2) noncyclic electron flow
cyclic electron flow
path of electron flow in which excited electrons of PSI are transferred back to PQ (start of ETC) instead of associating wtih PSII
- occurs in thylakoid membrane
- uses PSI only
- P700 reaction center - chlorophyll a
- generates ATP only
noncyclic electron flow
path of electron flow in which electrons pass from PSII through an ETC to PSI to create NADPH
- occurs in thylakoid membrane
- uses PSII and PSI
- P680 reactionn center (PSII) - chlorophyll a
- P700 reaction center (PSI) - chlorophyll a
- uses electron transport chain (ETC)
- generates O2, ATP & NADPH
chemiosmosis
an energetic coupling mechanism whereby energy stored in an electrochemical proton gradient is used to drive an energy-requiring process such as production of ATP
chemiosmosis facts
(1) powers ATP synthesis
(2) located in thylakoid membrane
(3) uses ETC & ATP synthase (enzyme) to make ATP
(4) photophosphorylation
photophosphorylation
addition of phosphate to ADP to make ATP
carbon fixation
(Calvin Cycle)
process of converting gaseous CO2 into an organic molecule
- often associated with photosynthesis
- requires 6 turns
- uses 18 ATP and 12 NADPH
location of carbon fixation
stroma
reactants of carbon fixation
(1) ATP
(2) NADPH
(3) CO2
products of carbon fixation
glucose
photorespiration
a series of light-driven chemical reactions that consumes oxygen and releases CO2
- undoes photosynthesis
when does photorespiration occur?
(1) when there are high O2 and low CO2 concentrations inside plant cells
(2) when stomata must be kept closed to prevent dehydration
plants that use photorespiration
(1) C4 plants
(2) CAM plants
CAM plants
(crassulacean acid metabolism)
a variant type of photosynthesis in which CO2 is fixed and stored in organic acids at night when stomata are open and then released to feed the Calvin cycle during the day when stomata are closed
- helps reduce water loss and CO2 loss by photorespiration
C4 plants
perform C4 photosynthesis
- carbon fixation & the Calvin cycle occur in separate cells
C4 plant facts
(1) live in hot, moist environments
(2) 15% of plants: grasses, corn, sugarcane
(3) divides photosynthesis equally
(4) light reaction - mesophyll cells
(5) Calvin cycle - bundle sheath cells
(6) reactions separated in space
CAM plant facts
(1) live in hot, dry environments
(2) 5% of plants: cactus & ice plants
(3) stomates closed during day
(4) stomates open during the night
(5) light reaction occurs during the day
(6) Calvin cycle occurs when CO2 is present
(7) reactions separated in time
nonvascular plant
(bryophytes) plants that lack vascular tissue
- do not make seeds
vascular tissue
specialized group of cells that conduct water or dissolved nutrients throughout the plant body
seedless vascular plant
plants that have well-developed vascular tissue
- do not make seeds
seed
a plant reproductive structure consisting of an embryo
- stores nutritive tissue
- surrounded by a tough protective layer (seed coat)
seed plant
plants that have vascular tissue
- make seeds
gymnosperm
a vascular plant that makes seeds but does not produce flowers
- form 5 lineages
angiosperm
a flowering vascular plant that produces seeds within mature ovaries (fruits)
- form a single lineage
plant tissue systems
(1) root system
(2) shoot system
(3) leaf
(4) dermal tissue
(5) ground tissue
(6) vascular tissue
(7) secondary growth
root system
belowground portion of plant
function of root system
(1) anchor plant
(2) take in water/nutrients from soil
shoot system
aboveground portion of plant
- repeating series of nodes, internodes, leaves and buds
- does not increase in size over time
- grows through plant lifetime
- responds to changes in environment conditions
- grows in directions that maximize chances of capturing light
function of shoot system
harvest light & carbon dioxide from the atmosphere to produce sugars
taproot
a large, vertical main root of a plant’s root system
lateral root
a plant root that extends horizontally from another root
herbaceous plants
seed plants without woody tissue
perennial
describing a plant whose life cycle normally lasts for more than one year
- root preserved even if fire destroys the aboveground plant
phenotypic plasticity
form can change in response to environmental conditions
adventitious root
a root that develops from a plant’s shoot system instead of from the plant’s root system
(ie) corn plants
prop root
type of adventitious root that helps brace individuals in windy weather
(ie) corn plants)
pneumatophore
specialized lateral roots that function in gas exchange
(ie) mangrove
contractile root
roots that shorten to pull the organism deeper into the soil
(ie) roots of onion
stem
vertical, aboveground structures that make up the shot system of plants
node
part of the stem where leaves or leaf buds are attached
internode
segments in between nodes
leaf
appendage that projects from the stem laterally
- FCN: photosynthetic organs
axillary bud
bud that forms where leaves attach to the stem
- may develop into lateral branch
branch
lateral extension of the shoot system
apical bud
bud at the tip of a stem or branch where growth occurs to length the stem or branch
stolon
stems that run (horizontal) over the soil surface
- produce new stems at nodes
(ie) strawberries
rhizome
stems that grow underground horizontally
- produce new individuals at noeds belowground
(ie) corn
tuber
rhizomes modified to store carbohydrates belowground
(ie) potatoes
thorn
stems that protect the plant from herbivore
blade
expanded portion of leaf
petiole
stalk of a leaf
leaf morphological diversity
(1) leaves may be compound
(2) leaves can be needle-like
(3) blades may vary in size & shape
compound leaves
leaves with blades that are divided into series of leaflets
doubly compound leaves
leaves where the leaflets are divided more than once
function of needle-like leaves
smaller surface area —-> reduce likehood of water loss through transpiration
transpiration
loss of water from aboveground plant parts
- occurs primarily through stomata
types of leaf arrangement
(1) opposite
(2) whorl
(3) alternate
(4) basal
sun leaf
leaves with a relatively small surface area, which reduces water loss in areas of the body where light is abundant
shade leaf
relatively large and broad leaves
- provide high surface area that maximizes absorption of rare photons
types of modified leaves
(1) spine
(2) succulents
(3) tendrils
(4) floral mimics / poinsetta leaves
(5) traps / carnivory leaves
(6) onion bulbs
spine
modified leaves that protect the stem
onion bulb
specialized for storing nutrients
- carb rich
succulent
thick leaves that store water
(ie) aloe leaves
tendril
modified leaflets or leaves that enable the plant to climb
(ie) peas
meristem
population of undifferentiated cells that retain the ability to undergo mitosis and produce new cells
- equivalent to stem cells
apical meristem
meristem located at the tip of each root & shoot
primary growth
growth process where an increase in the length of stems and roots due to the activity of apical meristems
trichome function
*depends on species
1) keep leaf surface cool by reflecting sunlight
2) reduce water loss by forming a dense mat that limits transpiration
3) provide barbs, or store toxic compounds that thwart herbivores
4) trap & digest insects
