functions and structures

Question 1

why do plants require a transport system?

Answer 1

• to ensure all cells receive a strong supply of the nutrients they require
• especially important as a plant must be able to transport substances up their stem (against gravity)

Question 2

relate the structure of the xylem to its function

Answer 2

• long, continuous columns made of dead tissue, allowing transportation of water
• contain pits, allowing water to move sideways between vessels
• thickened with a tough substance known as lignin, providing structural support

Question 3

relate the structure of the phloem to its function

Answer 3

• living tissue
• sieve tube elements transport sugars around the plant
• companion cells designed for active transport of sugars into tubes
• plasmodesmata allow flow of substances between cytoplasm of different cells

Question 4

describe the structure and function of the vascular system in roots, draw this

Answer 4

• consists of xylem and phloem
• ‘drill’ like structure
• xylem is arranged in an ‘X’ shape to provide resistance against force
• phloem in four different sections around the xylem
• surrounded by endodermis, a water supply
• (refer to images)

Question 5

describe the structure and function of the vascular system in the stem, draw this

Answer 5

• consists of xylem and phloem
• xylem on the inside of the bundle to provide support and flexibility, phloem on the outside
• the cambium layer contains meristem cells that produce new xylem and phloem tissue when required
• (refer to images)

Question 6

describe the structure and function of the vascular system in the leaves

Answer 6

• consists of xylem and phloem, forms the midrib and veins
• network of vasculature veins
• involved in transport and support
• xylem is located on top of the phloem