Plant Physiology

Question 1

Differences b/w plant cell and animal cell?

Answer 1

plants: rigid cell wall (cellulose), chloroplast and mitochondria (ATP), large central vacuole
animal: no cell wall, irregular shape, mitochondria (ATP)

Question 2

plasmodesmata

Answer 2

links cytosols of plant cells together, symplastic pathway, like a giant gap junction (viruses can move through)

Question 3

central vacuole

Answer 3

storage/rigidity

Question 4

chloroplast

Answer 4

light harvesting organelle, photosynthesis

Question 5

primary cell wall

Answer 5

mostly carbs and some protein (polysaccharides>cellulose>protein), hydrophilic from OH groups (allows for stacked polymers), outer most cell wall layer

Question 6

middle lamella

Answer 6

like grout b/w plant cells, outside primary cell wall

Question 7

cellulose microfibril structure

Answer 7

composed of 30-250 linear molecules H bonded together, stacked

Question 8

cell walls + growth

Answer 8

constrict growth, elongation require turgor pressure (water into vacuole), expansion perpendicular to cellulose micro fibrils, older micro fibrils shift in position (cross hatch)

Question 9

secondary cell wall

Answer 9

when cell is done growing, tougher/hydrophobic, regular array of cellulose, impregnated w lignin

Question 10

three paths of movement

Answer 10

symplastic (inside cytosol), apoplastic (space outside PM), and transmembrane pathways

Question 11

2 major organ systems in plants

Answer 11

shoot system and root system

Question 12

node

Answer 12

where branches grow

Question 13

internode

Answer 13

space in between branches

Question 14

3 tissue types

Answer 14

dermal (outer protective), ground (storage, photosynthesis, support), vascular (transport of materials, xylem and phloem)

Question 15

primary growth

Answer 15

vertical, apical/root meristems

Question 16

secondary growth

Answer 16

horizontally, lateral meristems

Question 17

meristems

Answer 17

localized regions of undifferentiated cells

Question 18

plants and stem cells

Answer 18

nearly all live plants act like animal “stem cells”, totipotent

Question 19

flowering plants (dicots vs monocots)

Answer 19

monocots: one leaf, ring of root xylem and ploem, circular vascular bundles in stem, parallel leaf veins, petals in multiples of 3
dicots: two leaves, root phloem/xylem in star, triangle of vascular bundle in stem form ring, net leaf veins, petals in 4 or 5

Question 20

water potential

Answer 20

water potential= solute potential + pressure potential

Question 21

pressure potential

Answer 21

+ or -

+=cell turgor pushes out on cell wall

Question 22

solute potential

Answer 22

= -RT[solute]

always negative, as [solute] increases the solute potential becomes more negative, water follows solute

Question 23

cell turgor

Answer 23

positive pressure, caused by osmotic flow of water into a solute-filled cell

Question 24

hypertonic solution

Answer 24

water leaves cell

Question 25

isotonic solution

Answer 25

water leaves and enters at same rate

Question 26

hypotonic

Answer 26

water enters cell

Question 27

water movement across plant plasma membrane

Answer 27

via aquaporins

Question 28

water/ion uptake in roots

Answer 28

epithelial cell root hairs increase surface area for absorption, travel through symplast/apoplast until they reach endodermis/casparian strip where apoplastic must enter the symplast

Question 29

casparian strip

Answer 29

waxy, prevents apoplastic movement, selective uptake of minerals (against gradient, electrochemical gradient

Question 30

“transpiration-Tension-cohesion mechanism”

Answer 30

movement of water up a plant through xylem

Question 31

transpiration

Answer 31

loss of water out stomata

Question 32

tension

Answer 32

water evaporating produces tension (- pressure), sucking straw

Question 33

cohesion

Answer 33

waters polar natural, water column sticks together

Question 34

xylem cell

Answer 34

tracheids and vessel elements, dead/hollow cells, pits=cavities in secondary cell wall allow movement, secondary cell wall maintains structure

Question 35

how do plants regulate transpiration stream

Answer 35

alter xylem width: diameter of pit micro channels altered by salt (K+) which is regulated by plant, increased K+ increases transpiration stream alter stomatal aperture: guard cells (stoma) regulated by light/low CO2 which open them, high CO2 of lack of water which close them, adding K+ opens stoma

Question 36

nutrients from soil/air

Answer 36

soil: nitrogen, phosphorus, potassium, etc ( structural, catalytic signaling, ion balance) air: all carbon from air

Question 37

action potential in plants

Answer 37

membrane potential=charge difference inside/outside cell, pump H outside cell creates - resting potential, uptake of K reduces negative charge, depolarization (cells become negative)=info transmission venus fly trap/protective responses

Question 38

roles for phloem

Answer 38

carry photosynthates from source to sink

Question 39

cellular respiration

Answer 39

combust glucose to make co2 water and ATP

Question 40

phloem cell

Answer 40

alive, outside VC, translocation of sugar, sieve tube elements connected by plasmodesmata, absent of organelles and kept alive by companion cells

Question 41

pressure flow model

Answer 41

movement of sap relies on pressure not total water potential, bidirectional, positive pressure

Question 42

phloem loading

Answer 42

symplastic: flow from mesophyll to phloem through plasmodesmata apoplastic: active transport using proton pump and SWEET

Question 43

photosynthesis

Answer 43

convert light energy to chemical energy , supports all life (except hydrothermal vents), algae = 50-60%, co2 water and light make sugar water and oxygen 3 reqs: light, pigment to absorb light energy, co2 to fix into sugars (reduction) occurs in leaves: chloroplasts of mesophyll cells

Question 44

chloroplast structure

Answer 44

thylakoids in stack=grana ( light reactions) | stroma = cytosol of chloroplast (dark reactions / calvin cycle

Question 45

chloroplast vs mitochondria

Answer 45

``` mitochondria= catabolism, ATP produced (e trans chain and h gradient), double membrane, NADH, ATP for cellular purposes, plant and animal cells have mitochondria chloroplast = anabolism, ATP produced (e trans chain and h gradient), double membrane, NADPH, ATP used only for sugar ```

Question 46

goal of light reactions

Answer 46

ATP and NADPH (energy and reducing power) for dark reaction building sugars

Question 47

light energy

Answer 47

electromagnetic energy, unit = photon, inversely proportional to wavelength, can raise electron to higher energy, red and blue/violet are best

Question 48

chloroplast pigments

Answer 48

Absorb red and blue light (look green)

Question 49

carotenoids

Answer 49

accessory pigments