Miss Lee - Plant Transport

Question 1

Why do plants require a transport system?

Answer 1

• A transport system ensures that all the cells of a plant receive a sufficient amount of nutrients e.g. water, minerals, sugars to live.
• Plants have a relatively small surface area:volume ratio but have a high metabolic rate.
• This is achieved by the combined action of xylem tissue and phloem tissue.

Question 2

What is a Cotyledons

Answer 2

Cotyledons are organs that act as food stores for the developing embryo.

Question 3

What are Dicots

Answer 3

Dicots are plants that make seeds that contain 2 cotyledons

Question 4

What are the 2 main groups of dicots

Answer 4

1) Herbaceousdicots(non-woody stem) e.g. daisies

2) Woody dicots e.g. oak

Question 5

What is the vascular system in plants

Answer 5

A plant has a series of transport vessels running through the roots, stems, and leaves

Question 6

What are Herbaceous dicots vascular systems are made up of

Answer 6

Herbaceous dicots vascular systems are made up of 2

types of transport vessels; Xylem and Phloem.

Question 7

How are they arranged together in a vascular system

Answer 7

They are arranged together in vascular bundles in the stem, roots, and leaves

Question 8

What are xylem vessels

Answer 8

• Long continuous columns of dead cells
• Transports water and mineral ions from root→shoot→leaves.
• One direction movement only(upwards)
• Also provide structural support (cell wall composed of lignin)

Question 9

What are phloem vessels

Answer 9

• Living tissue
• Transports food(organic solutes e.g. sucrose) from leaves to the rest of the plant (translocation).
• Transport is bidirectional (solutes can move up and down a plant)

Question 10

Why do plants need a transport system

Answer 10

• SA:V Ratio:
• As the size of an plant increases, its surface area to volume ratio decreases.
• This means it has relatively less surface area available for substances to diffuse through, so the rate of diffusion may not be fast enough to meet its cells requirements.
• Large plants therefore cannot rely on diffusion alone to supply their cells with substances such as food and oxygen and to remove waste products.
• This is why they require specialised transport systems.

Question 11

What are the three plant processes

Answer 11

Photosynthesis, respiration and active transport

Question 12

What is photosynthesis

Answer 12

plants producing glucose, through sunlight

Question 13

What is respiration in a plant

Answer 13

plants supplying energy

Question 14

Why does active transport happen in a plant

Answer 14

energy required to move and transport substances

Question 15

What are the two transport systems

Answer 15

Translocation and transpiration

Question 16

What is the transpiration system

Answer 16

• The movement of water molecules and dissolved minerals ions
• Xylem vessels
• Passive process

Question 17

What is translocation

Answer 17

• The movement of sugars (Sucrose) & amino acids
• Phloem vessel – sieve & companion cells
• Active process

Question 18

What is the vascular bundle

Answer 18

• Xylem and Phloem are arranged in vascular bundles in the roots, stems and leaves.
• There is a layer of cambium in between xylem and phloem, that is meristem cells which are involved in production of new xylem and phloem tissue
• Vasculartissueisdistributedthroughouttheplant
• Vascular tissue is made up of xylem and phloem tissue
• As well as the transport of substances the vascular bundle has structural support purposes

Question 19

What does the vascular bundle in the roots look like and why is it different

Answer 19

• This provides a ‘drill’ like structure
• This enables the plant to push down into the root
• Xylem tissues is the strongest so is in the centre – X structure
• Phloem in four separate sections

Question 20

What does the Vascular Bundle in the leaf look like and differentiate from the other vascular bundles

Answer 20

• Xylem is located on top of the phloem

* Thisonlyappliestodicotyledonousplants,other plants types have a different structure – you don’t need to know these

Question 21

What does the Vascular Bundle in the Stem look like and why is it different

Answer 21

• Xylem is located on the inside – in non-wooded plants
• This provides additional support to the stem
• The cambium layer contains meristem cells

Question 22

How many and what different types of cell build up the xylem tissues

Answer 22

4 types of cell 
• Xylem vessels
• Tracheids (not found in herbaceous dicots) 
• Parenchyma
• Fibres

Question 23

Xylem tissue adaptations

Answer 23

1 ) Xylem vessels are very long , tube - like structures formed from cells ( vessel elements ) joined end to end .
2 ) There are no end walls on these cells , making an uninterrupted tube that allows water to pass up through the middle easily .
3 ) The cells are dead , so they contain no cytoplasm .
4 ) Their walls are thickened with a woody substance called lignin , which helps to support the xylem vessels and stops them collapsing inwards . Lignin can be deposited in xylem walls in different ways , e.g. in a spiral or as distinct rings ,
5 ) The amount of lignin increases as the cell gets older .
6 ) Water and ions move into and out of the vessels through small pits in the walls where there’s no lignin .

Question 24

How many and what different types of cell build up the phloem tissues

Answer 24

Phloem tissue is composed of 4 different types of tissue:
• Sievetubeelements 
• Companioncell
• Parenchyma
• Fibres

Question 25

What are the sieve tube elements adaptations in the phloem

Answer 25

1 ) These are living cells that form the tube for transporting solutes through the plant .
2 ) They are joined end to end to form sieve tubes .
3 ) The ‘ sieve parts are the end walls , which have lots of holes in them to allow solutes to pass through .
4 ) Unusually for living cells , sieve tube elements have no nucleus , a very thin layer of cytoplasm and few organelles
5 ) The cytoplasm of adjacent cells is connected through the holes in the sieve plates .

Question 26

What are the adaptations in the companion cells in the phloem

Answer 26

1 ) The lack of a nucleus and other organelles in sieve tube elements means that they can’t survive on their own . So there’s a companion cell for every sieve tube element .
2 ) Companion cells carry out the living functions for both themselves and their sieve cells . For example , they provide the energy for the active transport of solutes .

Question 27

What is a herbaceous dicotyledonous plant

Answer 27

herbaceous dicotyledonous plant is a plant which has vascular bundles