CH9 transport systems in dicotyledonous plants

Question 1

Why do plants need transport systems

Answer 1

• high metabolic demands
• Size
• Surface area to volume ratio

Question 2

Why do plants have high metabolic demands

Answer 2

• cells of green part of plant make own glucose and oxygen by photosynthesis
• Internal and underground parts of plant do not photosynthesise
• Need oxygen and glucose transported to them, and waste products removed
• Hormones and mineral ions need to be transported

Question 3

What do dicotyledonous plants make

Answer 3

• seeds that contain two cotyledons

Question 4

What is a cotyledon

Answer 4

• An organ that acts as a food store for the developing embryo plant and forms first leaves when seed germinates

Question 5

Function of xylem

Answer 5

• transport of water and mineral ions
• Support

Question 6

Structure of xylem

Answer 6

• long hollow structures made by several columns of cells fusing together end to end
• Thick waller xylem parenchyma pack around xylem vessels, storing food and containing tannin deposits
• Xylem fibres are long cells with lignified secondary walls that provide extra mechanical strength

Question 7

Function of phloem

Answer 7

• transports food in the form of organic solutes around the plant

Question 8

Structure of phloem

Answer 8

• phloem sieve tubes are made of many cells joined end to end to form a long, hollow structures made
• Area between the cells becomes perforated to form sieve plates
• Companion cells are closely linked to xylem and act as life support system