Bio 2601 midterm 2
Epidermis - answer-wood part of the root (outside)
Endodermis - answer-Contains the casparian band
surrounds vasculature
Vascular tissue types - answer-- phloem
- xylem
- endodermis
- pericylce/cambium
Xylem - answer--dead cells at maturity
-translocates water and nutrients from roots to shoots (unidirectional)
-tracheids and vessels
tracheids - answer-long and skinny
lots of pores so vertical and lateral water transfer
cell walls fortified
vessels - answer-short and fat
phloem - answer-living cells connected through sieve plates
transports products of photosynthesis and signalling molecules between source and sink tissues
(bidirectionally)
individual cells can't transport both ways
Sieve element cells - answer-has mitochondria, plastids, smooth ER
under high turgor pressure (lots of solutes)
need companion cells
companion cells - answer-function in loading and unloading of sieve elements
fully functional cells
lots of energy for photosynthesis
sieve plates - answer-holes in cell walls between sieve elements
covered by smooth ER
Water potential - answer-osmotic (solute) potential + pressure potential + gravitational potential
water moves toward more negative (lower) pressure
Osmotic potential - answer-measure of solute concentrations on either side of the membrane and
resulting water movement
move from high to low
pressure potential - answer-cell walls allow plants to experience internal pressure that may be different
from the internal pressure in surrounding cells
, gravitational potential - answer-impacts the higher you get
negligible between cells
turgor pressure - answer-positive pressure
found in living cells
pushes water out of a cell
tension - answer-negative pressure
found in dead cells - xylem
pulls water into a cell
leaf pressure - answer-low because of evaporation
overall negative water potential (-2 MPa)
root pressure - answer-higher pressure
water potential near zero (-0.1 MPa)
negative leaf pressure pulls water up from roots
Bulk flow from roots to shoost - answer-generated by a very large negative gradient
needs continuous connection to allow cohesive properties of water to move water
negative hydrostatic pressure at surface of mesophyll cells - answer-generated by evaporation of water
from leaves
as curvature decreases, hydrostatic pressure gets more negative
Cavitation - answer-low pressure in xylem makes water want to be a vapour
water in xylem is meta-stable
bubble can form at nucleating site
Efficiency to safety ranking - answer-oak > maple > spruce
Symplast loading - answer-diffusion-driven
pressure potential drives
flow of sugars through plasmodesmata
apoplast loading - answer-active transport into companion cells
requires ATP to cross cell wall and membrane
builds up sugars in phloem
polymer trapping - answer-mechanism used to increase sugar concentration
Phloem loading - answer-may be symplastic or apoplastic
Root tip - answer-where growth takes place
where xylem and vasculature differentiate
not very permeable
Epidermis - answer-wood part of the root (outside)
Endodermis - answer-Contains the casparian band
surrounds vasculature
Vascular tissue types - answer-- phloem
- xylem
- endodermis
- pericylce/cambium
Xylem - answer--dead cells at maturity
-translocates water and nutrients from roots to shoots (unidirectional)
-tracheids and vessels
tracheids - answer-long and skinny
lots of pores so vertical and lateral water transfer
cell walls fortified
vessels - answer-short and fat
phloem - answer-living cells connected through sieve plates
transports products of photosynthesis and signalling molecules between source and sink tissues
(bidirectionally)
individual cells can't transport both ways
Sieve element cells - answer-has mitochondria, plastids, smooth ER
under high turgor pressure (lots of solutes)
need companion cells
companion cells - answer-function in loading and unloading of sieve elements
fully functional cells
lots of energy for photosynthesis
sieve plates - answer-holes in cell walls between sieve elements
covered by smooth ER
Water potential - answer-osmotic (solute) potential + pressure potential + gravitational potential
water moves toward more negative (lower) pressure
Osmotic potential - answer-measure of solute concentrations on either side of the membrane and
resulting water movement
move from high to low
pressure potential - answer-cell walls allow plants to experience internal pressure that may be different
from the internal pressure in surrounding cells
, gravitational potential - answer-impacts the higher you get
negligible between cells
turgor pressure - answer-positive pressure
found in living cells
pushes water out of a cell
tension - answer-negative pressure
found in dead cells - xylem
pulls water into a cell
leaf pressure - answer-low because of evaporation
overall negative water potential (-2 MPa)
root pressure - answer-higher pressure
water potential near zero (-0.1 MPa)
negative leaf pressure pulls water up from roots
Bulk flow from roots to shoost - answer-generated by a very large negative gradient
needs continuous connection to allow cohesive properties of water to move water
negative hydrostatic pressure at surface of mesophyll cells - answer-generated by evaporation of water
from leaves
as curvature decreases, hydrostatic pressure gets more negative
Cavitation - answer-low pressure in xylem makes water want to be a vapour
water in xylem is meta-stable
bubble can form at nucleating site
Efficiency to safety ranking - answer-oak > maple > spruce
Symplast loading - answer-diffusion-driven
pressure potential drives
flow of sugars through plasmodesmata
apoplast loading - answer-active transport into companion cells
requires ATP to cross cell wall and membrane
builds up sugars in phloem
polymer trapping - answer-mechanism used to increase sugar concentration
Phloem loading - answer-may be symplastic or apoplastic
Root tip - answer-where growth takes place
where xylem and vasculature differentiate
not very permeable
