Test Review Questions

Question 1

Describe characteristics unique to plants

Answer 1

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)

Question 2

Why evolution of plants was important to diversification of animals before/during Cambrian period (550 million yrs ago)

Answer 2

Plants provided shelter, habitats, and food for animals (diversity leads to diversity)

Question 3

What challenges did plants face when transitioning from water to land?

Answer 3

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)

Question 4

describe 5 morphological evolutionary adaptions of plants that helped them adapt to living on land

Answer 4

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

Question 5

What has been the general evolutionary trend of the sizes of gametophytes and sporophytes?

Answer 5

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

Question 6

What is most diverse lineage of plants?

Answer 6

Flowering plants (angiosperms)

Question 7

Why was the evolution of flowering plants important in the diversification of terrestrial animals?

Answer 7

Diversity leads to diversity
–> flowering plants coevolved with pollinators which led to diversification of predators, etc…

Question 8

three differences between monocots and eudicots that you could use to identify them

Answer 8

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

Question 9

angiosperms vs gymnosperms

Answer 9

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

Question 10

Why are ferns not a seed plant even though they grow tall and have a vascular system?

Answer 10

Ferns do not have seeds, and therefore reproduce using spores (making them not a seed plant)

Question 11

How can you determine if young trees are sprouting from roots or an underground stem?

Answer 11

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

Question 12

5 ways leaves are modified for different purposes

Answer 12

Needles, bulbs, thorns, succulents, floating leaves

Question 13

2 ways stems are modified for different purposes (not to support leaves)

Answer 13

cactus (storage of water and photosynthesis), green stems (photosynthesis), swollen rhizomes (storage, ex.potato)

Question 14

Why is a potato a stem growing underground and not a root?

Answer 14

A potato is a swollen rhizomes, in which the “eyes” are the auxiliary buds where new branches can form

Question 15

3 similarities between a plant cell and an animal cell

Answer 15

Both eukaryotic cells with nucleus, endomembrane systems, rely on mitochondria to make most of their ATP, and reproduce by mitosis

Question 16

3 structures found in plant cells not found in animal cells

Answer 16

cell wall, chloroplasts, and amyloplasts

Question 17

3 types of tissue systems in plants

Answer 17

dermal tissue, ground tissue, and vascular tissue

Question 18

What type of cell tissue system in a leaf would mesophyll and bundle sheath cells belong to?

Answer 18

ground meristem

Question 19

what is a meristem?

Answer 19

cells that actively divide throughout their lives and their daughter cells can differentiate into different cell types (like stem cells)

Question 20

which type of primary meristem would a guard cell come from?

Answer 20

protoderm –> dermal tissue

Question 21

Why are parenchyma cells usually alive at maturity?

Answer 21

Parenchyma cells have an important function of forming mesophyll cells and being available to form into a new plant (so they must be alive)

Question 22

Why can xylem cells be dead at maturity, but not the phloem (especially companion cells)

Answer 22

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

Question 23

What is the evolutionary trade-off in angiosperms for having vessel elements in addition to tracheids?

Answer 23

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

Question 24

How would you distinguish a stem between a monocot or dicot?

Answer 24

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)

Question 25

Why is the vascular bundle inside the endodermis located in the middle of a root rather than near the epidermis like in a stem?

Answer 25

the endodermis acts as a barrier that controls ion uptake

Question 26

How would the lateral meristem of a cottonwood being damaged (preventing the cells from dividing) affect tree growth?

Answer 26

secondary growth would no longer happen, so the plant would not be able to gain width or girth.

Question 27

Where does primary growth occur in a stem?

Answer 27

apical meristem

Question 28

What’s the difference between a primary and secondary bud?

Answer 28

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

Question 29

In which zone would you expect cellular differentiation in an actively growing root?

Answer 29

Zone of cellular maturation

Question 30

What type of growth produces wood?

Answer 30

secondary growth

Question 31

which types of cambium makes the secondary xylem?

Answer 31

vascular cambium

Question 32

the bark of a tree primarily comes from which type of cambium?

Answer 32

cork cambium

Question 33

General equation for Photosynthesis?

Answer 33

6CO2 + 6H20 + energy –> C6H12O6 + 6O2

Question 34

structures in a chloroplast and where light reaction and calvin cycle occur

Answer 34

Light reactions occur in thylakoids
Calvin cycle occurs in stroma

Question 35

What connects the light rxn and Calvin cycle

Answer 35

Light rxn provides ATP and NADPH for Calvin cycle

Question 36

Why are plants green

Answer 36

Plants are able to absorb other light spectra (like red and blue) because these

Question 37

what is source of electrons for photosynthesis?

Answer 37

splitting of water

Question 38

what is purpose of PSII?

Answer 38

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

Question 39

What is purpose of PSI?

Answer 39

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

Question 40

Why do electrons flow through an electron transport chain (and cytochrome complex) from PSII to PSI?

Answer 40

This electron transport chain contributes to the formation of the electrochemical gradient, which forms ATP

Question 41

Describe flow of electrons from water to the Calvin cycle

Answer 41

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

Question 42

three major steps of Calvin cycle

Answer 42

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)

Question 43

Why is ATP and NADPH needed for the calvin cycle?

Answer 43

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.

Question 44

why do we generally show the Calvin cycle with 3 CO2s entering?

Answer 44

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)

Question 45

Does the calvin cycle make glucose?

Answer 45

yes

Question 46

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?

Answer 46

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

Question 47

difference between PEP carboxylase, RuBisCo, and Rubp

Answer 47

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).

Question 48

If initial carbon fixation takes place in the mesophyll cell using RuBisCo, why is this caled a C3 pathway?

Answer 48

because the product of this pathway is a 3C molecule (G3P)

Question 49

Most abundant enzyme on earth

Answer 49

RuBisCo

Question 50

Explain how plants move water without using any energy?

Answer 50

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)

Question 51

for most plant would water potential be higher in the air or the ground?

Answer 51

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)

Question 52

how does adding solutes lower water potential?

Answer 52

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)

Question 53

which structure in the root produces a lateral root?

Answer 53

pericycle

Question 54

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)

Answer 54

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