Plant Transport Systems

Question 1

Why do multicellular organisms require transport systems?

Answer 1

Multicellular organisms have a small surface area to volume ratio therefore diffusion cannot occur fast enough to supply the raw materials to the whole cell. This means they have transport systems to carry the raw materials to the sites of their diffusion

Question 2

Why do plants require transport systems for water?

Answer 2

To get the water from its roots into its leaves

Question 3

Upper epidermis

Answer 3

A transparent layer which allows sunlight to pass through to the cells below

Question 4

Palisade mesophyll

Answer 4

Closely packed cells which contain many chloroplasts - the site of photosynthesis

Question 5

Spongy mesophyll

Answer 5

A layer that contains many air spaces where gases can diffuse into and out of cells. These cells also carry out photosynthesis

Question 6

Guard cells

Answer 6

Two cells which control the opening of the stomata

Question 7

Stomata

Answer 7

Pores on the underside of the leaf which allow gas exchange

Question 8

Vein

Answer 8

Contains a vascular bundle composed of xylem and phloem which are two transport systems

Question 9

Lower epidermis

Answer 9

Underside of the leaf

Question 10

State the structures involved in transport of water in plants

Answer 10

Root hair cells, xylem

Question 11

Describe the process of osmosis in plants.

Answer 11

-The water enters the plant through its roots which contain specialised cells called root hair cells. These cells have long extensions that increase the surface area of the cell allowing it to absorb more water and dissolved minerals

-Once inside inside the plant, water and minerals move up from through roots to the leaves in the stem in narrow tubes called xylem. Xylem are hollow tubes made of dead cells, they gave rings of lignin which stop the tubes closing under the pressure of water

Question 12

Describe the structure and function of the xylem

Answer 12

Structure : hollow tubes made of dead cells, they have rings of lignin which top the tube closing under the pressure of the water

Function : transport water from the bottom to the top of the leaf

Question 13

Name environmental factors which increase the rate of transpiration in plants

Answer 13

-Increased wind speed
-Increased temperature
-Increased surface area
-Increased humidity

Question 14

Why do plants require a transport system for sugar?

Answer 14

To transport the sugar from the leaves to all cells

Question 15

State the structures involved in the transport of sugar in plants

Answer 15

Phloem:
Composed of a sieve tube with sieve plates and companion cells
Transport all around the plant
Transports sugar

Question 16

How do plants obtain water?

Answer 16

A plant obtains water through its roots, roots contain specialised cells called root hair cells.

These cells increase the surface are in which the plant can absorb water and nutrients from the soil

Question 17

How do plants transport water and minerals?

Answer 17

Water is transported from the roots to other parts of the plant through dead Xylem vessels.

These dead xylem vessels (lignified) contains rings of lignin. This allows the xylem vessel to withstand the pressure changes as water moves throughout the plant

Question 18

Describe the process of transpiration

Answer 18

Transpiration is the movement of water through the plant. Water evaporates from the stomata in the leaf, this causes pressure changes within the plant meaning more water is drawn through the plant from the roots back into the leaves

Question 19

Describe how sugar is transported around the plant

Answer 19

Sugar is transported up and down the plant in living phloem tissue.

Phloem cells have sieve plates and associated companion cells to allow sugar to be transported to all parts of the plant

Question 20

How is the rate of transpiration measured using a mass potometer?

Answer 20

Change in mass (g)
Divide by the number of minutes (experiment run for)