4.2.2 - Plant Stems

Question 1

What Are The Function Of The Xylem Tissues In A Plant?
(2 Points)

Answer 1

~ Transports dissolved minerals and water around the plant.

~ Structural support.

Question 2

What Do The Walls Of The Xylem Vessels Contain?

Answer 2

Lignin.

Question 3

What Does Lignin Enable?

Answer 3

The vessels to withstand the pressure created by the moving column of water.

Question 4

What Are Xylem Vessels Formed By?

Answer 4

Dead cells with open ends.

Question 5

What Don’t Xylem Vessels Contain & Why?
(2 Points)

Answer 5

~ No cytoplasm or any organelles.

~ So they don’t slow down the flow of water.

Question 6

What Are The ‘Pits’?

Answer 6

Small regions in the walls of the xylem that are not lignified.

Question 7

What Do They Pits Allow In Terms Of The Xylem Vessel?

Answer 7

Lateral movement of water and minerals between xylem vessels.

Question 8

Do Xylem Vessels Have End Plates?

Answer 8

No.

Question 9

What Do Sclerenchyma Fibres Provide?

Answer 9

Structural support.

Question 10

What Are The Sclerenchyma Fibres Made Up Of?

Answer 10

Dead cells with a hollow lumen and end walls.

Question 11

What Do The Walls Of The Sclerenchyma Fibres Contain?
(2 Points)

Answer 11

~ Lignin but don’t have pits.

~ More cellulose compared to other plant cells.

Question 12

What Is The Function Of The Phloem Tissue?

Answer 12

~ Transport food substances and nutrients from leaves to storage organs.

Question 13

What Direction Does The Transport Of The Substances In Phloem Tissues Occur?

Answer 13

Up and down the plant, which is known as translocation.

Question 14

Do Phloem Tissues Have Any Structural Support In The Plant?

Answer 14

No.

Question 15

What Are Phloem Tissues Made Up Of?

Answer 15

Living cells.

Question 16

Phloem Tissue Is Made Up Of Many Different Cell Types, What Are These Cell Types?
(3 Points)

Answer 16

~ Sieve tube elements.

~ Companion cells.

~ Parenchyma cells.

Question 17

What Are Parenchyma Cells?

Answer 17

Helps with plant storage.

Question 18

What Do The Sieve Tube Elements Do?

Answer 18

Line up end to end to form a continuous tube.

Question 19

What Is The Structure Of Sieve Tube Elements?
(4 Points)

Answer 19

~ Have sieve plates with sieve pores.

~ Cellulose cell wall.

~ No nucleus, vacuole or ribosomes.

~ Thin cytoplasm.

Question 20

One Structure Of The Sieve Tube Elements Is ‘Have Sieve Plates With Sieve Pores’, What Does This Mean?

Answer 20

Allows for the continuous movement of the organic compounds.

Question 21

One Structure Of The Sieve Tube Elements Is ‘Cellulose Cell Wall’, What Does This Mean?

Answer 21

Strengthens the wall to withstand high pressure.

Question 22

One Structure Of The Sieve Tube Elements Is ‘No Nucleus, Vacuole Or Ribosomes’, What Does This Mean?

Answer 22

Maximises the space for translocation.

Question 23

One Structure Of The Sieve Tube Elements Is ‘Thin Cytoplasm’, What Does This Mean?

Answer 23

Reduces friction to facilitate the movement of the substances.

Question 24

What Are Companion Cells Associated With?

Answer 24

Sieve tube elements.

Question 25

What Is The Role Of A Companion Cell?
(2 Points)

Answer 25

~ Controls the metabolism of their associated sieve tube member.

~ They play a role in loading and unloading of sugars into the sieve tube elements.

Question 26

What Is The Structure Of Companion Cells?
(4 Points)

Answer 26

~ Nucleus and other organelles present.

~ Transport proteins in plasma membrane.

~ Large numbers of mitochondria.

~ Plasmodesmata.

Question 27

One Structure Of The Companion Cell Is ‘Nucleus & Other Organelles Present’, What Does This Mean?

Answer 27

Provides metabolic support to sieve tube elements and helps with the loading and unloading of substances.

Question 28

One Structure Of The Companion Cell Is ‘Transport Proteins In Plasma Membrane’, What Does This Mean?

Answer 28

Moves substances into and out of the sieve tube elements.

Question 29

One Structure Of The Companion Cell Is ‘Large Numbers Of Mitochondria’, What Does This Mean?

Answer 29

To provide ATP for the active transport of substances into or out of the companion cell.

Question 30

One Structure Of The Companion Cell Is ‘Plasmodesmata’, What Does This Mean?

Answer 30

Link to the sieve tube elements to allow for substances to move between them.

Question 31

In A Stem Where Are The Xylem Vessels Located?

Answer 31

Middle of the stem.

Question 32

In A Stem Where Are The Phloem Tissues Located?

Answer 32

Towards the outside of the stem.