Test Review Questions Flashcards
Describe characteristics unique to plants
Multicellular autotrophs (differential cells that form variety of tissues and self-feeding) that experiences alternation of generations (diploid and haploid generations = sporophytes and gametophyte phases)
Why evolution of plants was important to diversification of animals before/during Cambrian period (550 million yrs ago)
Plants provided shelter, habitats, and food for animals (diversity leads to diversity)
What challenges did plants face when transitioning from water to land?
Plants faced challenges in acquiring nutrients and transport (in terms of reproduction and how sperm cells had tails to swim in water not to travel on land)
describe 5 morphological evolutionary adaptions of plants that helped them adapt to living on land
Leaves- increase surface area for photosynthesis
cuticles- waxy covering that prevents water loss
stomata- small openings on underside of leaf that regulate water movement
roots- anchors plant to soil and absorbs nutrients
vascular tissues- transports water and mineral throughout the plant
What has been the general evolutionary trend of the sizes of gametophytes and sporophytes?
The sizes of gametophytes has decreased (gotten smaller, and smaller, and smaller over time) while the size of sporophytes has increased. Initial plants were dominantly gametophytes, but now sporophytes are really large (dominant) and the gametophyte is reduced to being inside the pollen
What is most diverse lineage of plants?
Flowering plants (angiosperms)
Why was the evolution of flowering plants important in the diversification of terrestrial animals?
Diversity leads to diversity
–> flowering plants coevolved with pollinators which led to diversification of predators, etc…
three differences between monocots and eudicots that you could use to identify them
Monocots have single cotyledon, vascular tissue is parallel in leaves, and the vascular bundles are scattered
Eudicots have 2 or more cotyledons, their vascular tissue is in branching patterns in leaves, and they have a ring of vascular bundles
angiosperms vs gymnosperms
Angiosperms include flowering plants and have seeds enclosed w/in fruit. They also have vessel elements that transport water throughout the plant
Gymnosperms are seed plants (cones) w/out fruit or flowers. They have tracheids as their main water conducting cells
Why are ferns not a seed plant even though they grow tall and have a vascular system?
Ferns do not have seeds, and therefore reproduce using spores (making them not a seed plant)
How can you determine if young trees are sprouting from roots or an underground stem?
Stems will have nodes or auxiliary buds where new branches can form, where roots will have a root system, but will lead to the stem growing above ground
5 ways leaves are modified for different purposes
Needles, bulbs, thorns, succulents, floating leaves
2 ways stems are modified for different purposes (not to support leaves)
cactus (storage of water and photosynthesis), green stems (photosynthesis), swollen rhizomes (storage, ex.potato)
Why is a potato a stem growing underground and not a root?
A potato is a swollen rhizomes, in which the “eyes” are the auxiliary buds where new branches can form
3 similarities between a plant cell and an animal cell
Both eukaryotic cells with nucleus, endomembrane systems, rely on mitochondria to make most of their ATP, and reproduce by mitosis
3 structures found in plant cells not found in animal cells
cell wall, chloroplasts, and amyloplasts
3 types of tissue systems in plants
dermal tissue, ground tissue, and vascular tissue
What type of cell tissue system in a leaf would mesophyll and bundle sheath cells belong to?
ground meristem
what is a meristem?
cells that actively divide throughout their lives and their daughter cells can differentiate into different cell types (like stem cells)
which type of primary meristem would a guard cell come from?
protoderm –> dermal tissue
Why are parenchyma cells usually alive at maturity?
Parenchyma cells have an important function of forming mesophyll cells and being available to form into a new plant (so they must be alive)
Why can xylem cells be dead at maturity, but not the phloem (especially companion cells)
Xylem cells participate in passive transport of water and act as a straw/tube so they do not need to be alive, where the phloem transports metabolites from leaves and loading into phloem is an active process (requires E) so they have to be alive
What is the evolutionary trade-off in angiosperms for having vessel elements in addition to tracheids?
vessel elements allow for faster movement of water throughout the cell allowing for faster growth, but leave the plant more susceptible to freezing and drought stress
How would you distinguish a stem between a monocot or dicot?
Monocot stems have scattered vascular bundles where dicot (eudicot) stems have vascular bundles in a ring (they also have trichomes but the monocot stems do not)
Why is the vascular bundle inside the endodermis located in the middle of a root rather than near the epidermis like in a stem?
the endodermis acts as a barrier that controls ion uptake
How would the lateral meristem of a cottonwood being damaged (preventing the cells from dividing) affect tree growth?
secondary growth would no longer happen, so the plant would not be able to gain width or girth.
Where does primary growth occur in a stem?
apical meristem
What’s the difference between a primary and secondary bud?
Primary bud (apical) grows the primary shoot where the secondary bud (lateral) provides a backup source of growth for if the primary bud is damaged
In which zone would you expect cellular differentiation in an actively growing root?
Zone of cellular maturation
What type of growth produces wood?
secondary growth
which types of cambium makes the secondary xylem?
vascular cambium
the bark of a tree primarily comes from which type of cambium?
cork cambium
General equation for Photosynthesis?
6CO2 + 6H20 + energy –> C6H12O6 + 6O2
structures in a chloroplast and where light reaction and calvin cycle occur
Light reactions occur in thylakoids
Calvin cycle occurs in stroma
What connects the light rxn and Calvin cycle
Light rxn provides ATP and NADPH for Calvin cycle
Why are plants green
Plants are able to absorb other light spectra (like red and blue) because these
what is source of electrons for photosynthesis?
splitting of water
what is purpose of PSII?
PS II uses light E to split water, supplying e- to the reaction and it responsible for elevating e- to a higher E level so pheophytin can take them
What is purpose of PSI?
PS I re-elevates e- after they flow through the electron transport chain so that they can be taking by ferrodoxin to react with NADP+ reductase to produce NADPH
Why do electrons flow through an electron transport chain (and cytochrome complex) from PSII to PSI?
This electron transport chain contributes to the formation of the electrochemical gradient, which forms ATP
Describe flow of electrons from water to the Calvin cycle
water is split –> electrons are raised in energy level in rxn center of PSII –> pheophytin transports to plastoquinone–> to cytochrome complex –> plastocyanin transports to PS I –> e- raised in energy level –> ferrodoxin transports to NADP+ reductase –> forms NADPH –> electrons with NADPH and ATP go to Calvin cycle
three major steps of Calvin cycle
1) fixation (Rubisco fixes CO2 to RuBP = 3PGA)
2) reduction (ATP, then NADPH reduce 3PGA into G3P (–> 3 Cs leave to form Glucose) and results in ADP and NADP+)
3) Regeneration (Remaining G3Ps are used to make RuBp)
Why is ATP and NADPH needed for the calvin cycle?
ATP and NADPH are vital to the reduction phase of the calvin cycle, which allows 3PGAs to be reduced to G3P which can then make glucose and be used to regenerate RuBp.
why do we generally show the Calvin cycle with 3 CO2s entering?
The calvin cycle is a C3 pathway in which 3 CO2s are needed to be fixed to the 3 RuBps the cycle begins with, and the first stable molecule produced in this cycle is G3P (a 3C molecule)
Does the calvin cycle make glucose?
yes
C4 plants are better adapted to dry environments than C3 plants. What’s the advantage of PEP carboxylase initially fixing carbon dioxide in the mesophyll cells and then using Rubisco to fix carbon in the bundle of sheath cells? What is the cost?
The advantage of using PEP carboxylase to fix RuBp is that it helps mitigate photorespiration, but the cost is that pyruvate will form and then needs to be recharged which means C4 pathways require more energy than C3 pathways
difference between PEP carboxylase, RuBisCo, and Rubp
PEP carboxylase is an enzyme that performs carbon fixation in C4 pathways, has a stronger affinity for CO2 and lacks oxygenase activity, where Rubisco is an enzyme that performs carbon fixation for C3 pathways and has oxygenase activity which results in a loss of efficiency due to photorespiration (fixes oxygen to RuBp).
If initial carbon fixation takes place in the mesophyll cell using RuBisCo, why is this caled a C3 pathway?
because the product of this pathway is a 3C molecule (G3P)
Most abundant enzyme on earth
RuBisCo
Explain how plants move water without using any energy?
the movement of water in plants is a passive process in which the properties of water including cohesion and adhesion, as well as negative pressure created by evapotranspiration pull water to the top of the plant through the water conducting cells (tracheids and vessel elements)
for most plant would water potential be higher in the air or the ground?
water potential is higher in the ground (higher= water molecules can move more freely, lower= less freely) (water flows from high –> low potential so soil > roots > leaves > atmosphere)
how does adding solutes lower water potential?
Adding solutes lowers water potential because water is a polar molecule and solutes attract these molecules and hold them in place (preventing them from moving freely) (like a salt brick)
which structure in the root produces a lateral root?
pericycle
Why does a root force water from the apoplastic route into cell at the endodermis, why not just continue to the vascular tissue? (discuss casperian strip)
water moves faster through apoplast than symplast and the casperian strip (which blocks the apoplastic route) regulates the movement of ions. The casperian strip combined with the endodermis (which also regulates ions) create root pressure that pushes water up the plant
