Transport in Plants 3.3.1

Question 1

Why do plants need a transport system?

Answer 1

• Metabolic demands : many internal and underground parts do not photosynthesise therefore do not make their own glucose or oxygen, so they need transporting to them.
• Plants have a small surface area to volume ratio, therefore they cannot rely on diffusion alone to supply their cells with what they need

Question 2

What is the function of xylem tissue?

Answer 2

Moves water and soluble mineral ions upwards

Question 3

What is the plant transport system composed of?

Answer 3

• Xylem tissue
• Phloem tissue

Question 4

What is the function of the phloem tissue?

Answer 4

Moves assimilates, such as sucrose, up or down

Question 5

What are dicotyledonous plants

Answer 5

They have 2 seed leaves, and have a very characteristic distribution of vascular tissue

Question 6

What is the distribution of vascular tissue in dicotyledonous plants?

Answer 6

• The xylem and phloem make up the vascular bundle, along with other tissues such as sclerenchyma and collenchyma

Question 7

What do the sclerenchyma and collenchyma do?

Answer 7

Give the bundle strength and support

Question 8

Where is the vascular bundle found in the roots?

Answer 8

At the centre, with the xylem in the middle (shape of an X) and the phloem found in between the arms of the X.

Question 9

Why is the vascular bundle positioned the way it is in the roots?

Answer 9

As it provides strength to withstand the pulling forces which the roots are exposed to.

Question 10

What is the layer of cells called surrounding the vascular bundle in the roots?

Answer 10

Endodermis - which contains suberin (a waterproof material in cell walls)

Question 11

What is located just inside of the endodermis?

Answer 11

A layer of meristem cells (able to divide through the pericycle)

Question 12

What are parenchyma cells?

Answer 12

They are located in the cortex and have thin walls and large air spaces, and they often contain numerous starch grains

Question 13

Describe the distribution of the vascular bundle in the stem

Answer 13

The vascular tissue is in bundles towards the outside of the stem
- The xylem is found towards the inside of each vascular bundle and the phloem towards the outside

Question 15

Where is the vascular bundle within the stem, and what is the tissues positioning?

Answer 15

Its in bundles towards the outside of the stem.
- Xylem towards the inside of each vascular bundle
- Phloem towards the outside of each vascular bundle

Question 16

What is located in between the xylem and phloem in the stem?

Answer 16

Cambium, which is a layer of meristem tissue

Question 17

What is located outside the vascular bundle in the stem?

Answer 17

The sclerenchyma fibres

Question 18

What is the function of the sclerenchyma cells?

Answer 18

To provide strength and support, composed of thick-walled cells that are heavily lignified

Question 19

Why does the dissection of plant material require staining?

Answer 19

To view the cell organelles and tissues within the organism, such as the vascular tissue.

Question 20

What is the structure of the xylem and phloem in the leaf?

Answer 20

The vascular bundles form the midrib and veins of a leaf.
Within each vein, the xylem is located on top of the phloem.