BIO FINAL EXAM PART 4:CH 36:-3-6 Plant Bulk transport (xylem and phloem)

Question 1

Bulk flow via Xylem transport:

What is Xylem sap?

Answer 1

Carries dissolved minerals from roots the the leaves via bulk flow.

Question 2

The water transport puzzle

Answer 2

Trees are tall and water moves fast

Question 3

Capillary action

Answer 3

water sticks to the side of thin tubes and pulls up.
height of water

Question 4

Gutation

Answer 4

exudation of water droplets

Question 5

During the day the xylem is under neg or pos pressure?

Answer 5

Negative pressure during the day

Question 6

Cohesion
Transpiration
Tension

Answer 6

Cohesion= water is polar & is sticky due to H-bonding
Transpiration= water evaporates from leaves
Tension= transpiring molecules pull up the next one

Question 7

Caviation

Answer 7

formation of water vapor pockets

Question 8

Transpiration- cohesion-tension mechanism

Answer 8

driven by the movement of xylem sap against gravity

Question 9

Bulk flow is driven by

Answer 9

water potential differences at opposites ends of xylem tissues.
and by transpiration that does not require energy

Question 10

Transpiration rates increase by

Answer 10

sunny, warm, dry and windy conditions

Question 11

The plant will wilt if

Answer 11

uptake and transport are not sufficient to replace the lost water

Question 12

Transpiration also protects leaves from

Answer 12

overheating by lowering internal temps through evaporative cooling (sweating)

Question 13

Sunny vs. Shaded leaves stomate density

Answer 13

Sunny leaves have a lot of stomates. Shaded leaves have fewer stomates

Question 14

Guard cells and how they open and close based on changes in turgor pressure

Answer 14

Turgid (stiff)= guard cells bow outwards and the pore opens
Flaccid= guard cells become less bowed and the pore closes.

Question 15

Phloem =

Answer 15

source to sink

Question 16

Phloem sap flows

Answer 16

from sources where pressure is HIGH to sinks that are LOW

Question 17

Phloem sap via bulk flow is driven by

Answer 17

postive pressure calles pressure flow

Question 18

What is translocation?

Answer 18

living cells that transport sugars transported through the phloem.

Question 19

Pressure flow hypothesis predicts

Answer 19

Sap near sugar sources should have HIGHER sugar content than phloem sap near sinks.

Question 20

Symplasts is responsible for

Answer 20

dynamic changes in plant transport via phloem

Question 21

Plasmodesmata can open or close in response to

Answer 21

turgor pressure, cytosolic Ca2+ levels or pH

Question 22

Plasmadesmata can close when transitioning from

Answer 22

SINK to SOURCE