Phloem Transport (Exam 2)

Question 1

phloem movement driven by

Answer 1

hydrostatic pressure

Question 2

Phloem transport cells =

Answer 2

sieve cells & STM (sieve tube members)

Question 3

Phloem transport cells have: (4)

Answer 3

1. ) unlignified cw’s
2. ) are “living” (even tho they lack a nucleus”
3. ) few organelles
4. ) work in concert with other cells
   - sieve cells: albuminous cells
   - STMs: companion cells

Question 4

Phloem transports: (5)

Answer 4

1. ) sugars (primarily sucrose)
2. ) AA’s
3. ) Hormones
4. ) RNA’s
5. ) Solutes

Question 5

sucrose =

Answer 5

glucose + fructose

Question 6

Where is sucrose made

Answer 6

mesophyll cells (in c4 bundle sheath cells)

Question 7

photosynthates are transported:

Answer 7

either symplastically or apoplectically to the phloem transport cells

Question 8

photosynthates must be actively

Answer 8

loaded into transport cells (going against concentration gradient)

Question 9

pressure-flow hypothesis =

Answer 9

movement of phloem solution from source to sink

Question 10

is osmotic pressure in the phloem high or low?

Answer 10

high

Question 11

high osmotic pressure in the phloem at source leads to

Answer 11

a high positive hydrostatic pressure

Question 12

unloading at the sink leads to

Answer 12

a low osmotic pressure & low hydrostatic pressure

Question 13

(source to sink) what leads to phloem movement

Answer 13

the differences in hydrostatic pressure (source to sink)

Question 14

phloem movement goes from

Answer 14

source of cars –> sink of carbs

Question 15

osmotic pressure (Π) of sources vs sinks

Answer 15

Πsource > Πsink

Question 16

hysrostatic pressure (P) of sources vs sinks

Answer 16

Psource > Psink

Question 17

source examples

Answer 17

leaves, roots, starch storage areas (wood ray, pith)

Question 18

sink examples

Answer 18

fruits, meristems, roots, wood, anything thats growing

Question 19

draw phloem movement diagram

Answer 19

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