Phloem

Question 1

What are the types of phloem?

Answer 1

sieve cells and sieve tube elements

Question 2

What does phloem do?

Answer 2

transports sugars to different parts of plants for storage or use

Question 3

How do the types of phloem differ?

Answer 3

sieve cells are more narrow, linear, with tapering ends, and do not possess companion cells unlike sieve tubes

Question 4

Which type of phloem evolved first

Answer 4

Sieve cells

Question 5

Which type of phloem is more efficient?

Answer 5

sieve tubes, evolving later on, is more efficient

Question 6

How do phloem differ from xylem?

Answer 6

phloem cells are alive

Question 7

what are sieve plates?

Answer 7

plates found in sieve tubes that have pores to move materials

Question 8

What kind of transport does it take to load sugars into phloem?

Answer 8

active transport

Question 9

What organelles are found in sieve tubes?

Answer 9

mitochondria due to the need to produce energy for active transport

Question 10

What organelles are found in companion cells?

Answer 10

nucleus

Question 11

What do companion cells do?

Answer 11

regulates most of the function of regulating sugar transport into the sieve cells.
sugars is first loaded into the companion cells, then to the sieve tube

Question 12

What is a vascular bundle?

Answer 12

bundle of phloem and xylem

Question 13

Why must the phloem be near xylem?

Answer 13

in order to flush sugar down, water is needed- which is taken from the xylem

Question 14

How is water taken from the xylem to the phloem?

Answer 14

diffusion/ osmosis

Question 15

What are source cells?

Answer 15

where photosynthesis and sugar formation occurs

Question 16

What kind of sugars is transported in the plant, and why?

Answer 16

sucrose, as it is more stable than glucose

Question 17

Why kind of transport is necessary for the movement of sucrose from the source to the companion cell and why?

Answer 17

active transport is needed because sucrose is lower in the source cell compared to the companion cell

Question 18

What are sink cells?

Answer 18

where the sugar products is stored, as phloem moves it from the source cell, often roots or fruits

Question 19

What happens to sucrose as it travels in the phloem?

Answer 19

as the sucrose travels to the sink cell, the sucrose is diluted due to the amount of water drawn from the xylem

Question 20

How does the water return to the xylem?

Answer 20

water is eventually drawn back into the xylem due to reversing water pressure

Question 21

What is the sucrose stored as?

Answer 21

starch

Question 22

What are P proteins?

Answer 22

used as a mechanism for plants to stop “bleeding”
secreted by companion cells to clog up broken phloem

Question 23

How can you distinguish xylem from phloem?

Answer 23

xylem have vessels which can be identified due to their large size
they often have thicker cell walls than phloem

Question 24

How can phloem be found?

Answer 24

phloem doesn’t have much lignin, so don’t stain like xylem

Question 25

What do fibers do for vascular bundles?

Answer 25

supports the phloem

Question 26

What are cambium cells?

Answer 26

actively dividing cells which form new phloem and xylem

Question 27

what is a stele?

Answer 27

vascular tissues of stems and roots

Question 28

How does vascularities differ in leaves?

Answer 28

they branch into vascular bundles

Question 29

What is a vascular cylinder?

Answer 29

stele of root in angiosperms