Exam 2 Flashcards
Assimilation
CO2 in
Transpiration
H2O out
Leaf Modifications
protection, support, storage, nitrogen acquisition
Leaf Limitations
avoid excessive water loss, pathogen entry, herbivory, and excessive carbon costs
Internal Leaf Structure
Epidermis + cuticle, trichomes, stomata, palisade parenchyma, spongy parenchyma, aerenchyma
Bundle Sheath
fibers around the veins (sometimes)
Bundle Sheath Extension
supportive fibers above and below (sometimes)
Xylem on ______ side and phloem on ______ side
upper, lower
Simple Leaf
has a blade of just one part
Compound Leaf
has a blade divided into several individual parts
External Leaf Structure
leaf blade, dorsal (abaxial), ventral (adaxial), petiole
Leaf Blade
flat, light-harvesting portion (lamina)
Abaxial (dorsal)
blade’s lower side
Adaxial (ventral)
upper side of the leaf
Petiole
leaf stalk that connects the laminate to the stem, allows leaves to flutter, keeps leaves from shading each other
Sessile
small, or long and narrow leaves with no petiole, trap water, tightly packed
Veins
bundles of vascular tissue
Dicot Veins
occur in netted pattern of reticulate venation
Monot Veins
parallel venation, long and strap shaped
Palmately Compound
with all leaflets attached at the same point
Pinnately Compound
with leaflets attached individually along the rachis
Compound Leaf Adaptations
flex in wind, prevent tearing, increased air turbulence, increase heat removal, CO2 uptake, pests spread less quickly
Smaller Leaflets
thinner boundary layer = more gas exchange = more CO2 uptake and more cooling
Trichomes
shade on the upper, prevent rapid air movement, slowing water loss, secretions
Succulent
thick, fleshy, reduced surface-to-volume ratios, favoring water conservation, few air spaces
Sclerophyllous
sclerenchyma as a layer below the epidermis and in the bundle sheets
Bud Scales
small modified leaves that form tight layer around the stem tip, waxy, tough
Spines
modified leaves of axillary buds, needle-shaped projections, protective and made primarily of fibers
Tendrils
sense contact with objects, coil around objects and use them for support, grow indefinitely
Traps
poor in nitrates, laminate is tubular and secretes a watery digestive fluid, active and passive
Plants need water for _____.
Transport
Water Potential
A measure of the potential energy associated with water, water is pulled through a plant
Plasmolysis
cells are flaccid, dehydrated
0 MPa
leaf completely soaked in pure water
-2 MPa
regular day, air is a little dry, plant is little dry
-4 MPa
air/soil is very dry and soil may be salty
-10 MPa
extremely dry/salty
LMA
leaf mass per unit area (thickness)
Embolism
air bubble blocking water transport in a treachery element
Cavitation
formation of embolism
C13
not preferred
C12
preferred
Root Functions
attach plant to substrate, absorb water/minerals, produce hormones, carbohydrate storage, defense, parasitism
Dicot Roots
a single large taproot that develops from the radicle, numerous lateral roots or branch roots, fibrous root system, secondary growth
Monocot Roots
no secondary growth, adventitious roots
Root Cap
closest to the root meristem, forms files of cells that are pushed forward, constantly regenerating
Apical Meristem
includes mitotically inactive central region (quiescent center)
Zone of Elongation
region beyond the meristematic region, most dividing has stopped, cells are enlarging, tissues begin to differentiate, most cells aren’t mature yet
Zone of Maturation
produce root hairs growing outward, increase the root’s surface area, short-lived
Symplast
plasmodesmata connect protoplasts
Apopolast
all intercellular space and cell walls together
Endodermis
innermost layer of cortical cells differentiates into a cylinder, “gatekeeper”
Casparian Strips
control the minerals that enter the xylem, the “gate”, cut off the apoplectic pathway, forcing symplastic transport of substances
Which statement about root hairs is NOT true?
A. They remain alive for the duration of the plant’s life.
B. They increase the surface area of the root.
C. They excel at water absorption.
D. They increase the acidity of the soil.
E. They form in the zone of maturation.
D. They increase the acidity of the soil.
Lateral Roots
some cells of the pericycle divide to form a small root primordial and organize into a root apical meristem
Monocots v. Dicots
Monocots
- 1 cotyledon
- fibrous root system
- scattered bundles
- vessels in a circle
- parallel leaf veins
Dicots
- 2 cotyledons
- taproot
- bundles in a circle
- one bundle root
- branching veins
Storage Roots
provide long-term storage for carbohydrates that accumulate during summer photosynthesis, less viable for foragers, more stable
Prop Roots
adventitious roots that grow extensively throughout the air, stabilize stems, brace against wind/water
Buttress Roots
tall, plate-like roots of some tropical tress, upper side grows more rapidly than other parts, brace support
Aerial Roots
orchids, grow on trees, roots dangle, specialized epidermis called vela men
Mycorrhizae
symbiotic associations between the roots of seed plants and soil fungi, fungi gain carbohydrates, fungal hyphae aid the plant in water uptake
Root Growth Limiting Factors
plants lack enzymes for nitrogen-fixation
Haustoria
roots of parasitic plants, penetrate host’s epidermis, cortex, and xylem
Wrinkled Peach Mushroom
oozes red liquid
Ophiocordyceps
parasitic zombie fungus
Beefsteak Mushroom
meat substitute
Giant Puff Ball
huge, white, up to two feet, edible
Truffle
round, dark brown, grows underground, exchanges substances through roots with trees
Chicken of the Woods
orange-yellow fan shaped, meaty texture
Witch’s Butter
parasite of a parasite, edible, temperate and tropical regions
Lobster Mushroom
bright orange, warped, parasitic, meaty, North America
Lion’s Mane
grows on dying trees, spores, rich in thiamine
Jack O Lantern Mushroom
Mediterranean, bright orange bioluminescent metabolites, contains toxins
Where does plant biomass come from?
Carbon Dioxide
Light Reactions
Produce ATP and NADPH
Calvin Cycle
Fix CO2 into sugars
Photosynthesis takes place in the _________.
chloroplast
Chlorophyll
main pigment in plants
Beta-Carotene
Orange
Chlorophyll b
Blue
Chlorophyll A
Red
Absorption Spectra
wavelengths of light that are absorbed
Action Spectra
plot of biological activity as a function of wavelength
What color(s) should “grow lights” be?
A. Green
B. Blue
C. Red
D. Red & Blue
E. Green & Blue
Red and Blue
Why is it advantageous to have both
chlorophyll a and b (and other accessory
pigments)?
It allows plants to absorb a wider range of light wavelengths from the sun
Xanthophylls
yellow pigments
Anthocyanins
red, purple, blue fruits
Antenna Complex
light harvesting complex, group of pigment molecules embedded within proteins to capture light
Cytochromes
intrinsic membrane proteins with heme cofactor (iron)
Plastoquinones
transport electrons short distances, hydrocarbon tail
Plastocyanin
small protein with Cooper, travel short distance along membrane surface
PSI
light absorbed -> transfer energy -> excited e- given to Fd -> e- too ferredoxin -> NADPH is stable goes to Calvin
PSII
phaeophytin -> Q -> plastoquininone -> Cato b6/f -> plastocyanin -> PSI
The oxygen that you breathe is
coming from:
A. H2O
B. CO2
B. CO2
Cyclic electron transport produces extra:
A. ATP
B. NADPH
C. O2
D. H2O
E. none of these
A. ATP
Rubisco
Ribulose 1,5 Bisphosphate Carboxylase Oxygenase
Calvin Cycle
- Carbon Fixation
- Reduction
- Regeneration
Carbon Fixation
Rubisco sticks CO2 on a 3C sugar
Reduction
ATP and NADPH are used to turn the sugar into PGAL
Regeneration
More ATP is needed to turn some of PGAL back into RUBP
Both the light reactions and the Calvin Cycle
a. synthesize ATP.
b.use NADPH.
c. rely on electron transport.
d.occur in the chloroplast.
e. fix CO2
b.use NADPH.
The electrons that get excited by light and ultimately
transfer light energy to power the production of ATP and
NADPH in photosynthesis come from :
A. Photons
B. H2O
C. CO2
D. O2
B. H2O
Thought experiment: If the lights are turned off, what will you
measure in terms of CO2 uptake?
A. Positive photosynthesis (CO2 uptake)
B. Zero photosynthesis (no CO2 uptake or release)
C. Negative photosynthesis (CO2 release)
C. Negative photosynthesis (CO2 release)
Light Response Curve
A component is limiting when photosynthesis would go faster if only we had more, first part is light limiting, second CO2 is limiting
C3 Plants
most plants, first sugar product has 3 carbons
C4 Plants
increase the CO2 concentration around Rubisco, higher Co2 compared to O2 reduces photorespiration, better in high temperatures, separating carbon capture and sugar production in SPACE
As the concentration of CO2 rises in the atmosphere, would you
expect photorespiration to be more or less common in plants?
A. More
B. Less
C. Depends on the plant
B. Less
CAM
separating carbon capture and sugar production in TIME, cope with limited water
SPAC
Soil-Plant-Atmosphere Continuum (root uptake, xylem transport, leaf water loss)
Root Uptake
More Negative Water Potential
Xylem Transport
Water moves through xylem conduits, cohesion and adhesion
