module 3 - 9.1 transport systems in plants

Question 1

why do plants need water?

Answer 1

• maintains turgidity of cells, stops wilting/ flaccidity
• used for photosynthesis

Question 2

how do plants transport water up the stem?

Answer 2

transpiration - cohesion tension theory

Question 3

what other substances do plants need?

Answer 3

• mineral ions (nitrates) to build amino acids
• glucose
• sulphur
• fertilisers (nitrate, phosphate, potassium)

Question 4

why do metabolic demands require the need of a transport system?

Answer 4

plants are multicellular so require lots of energy for reactions

Question 5

why does size require the need of a transport system?

Answer 5

plants need to move things over distances

Question 6

why does SA:V require the need of a transport system?

Answer 6

• small SA as its multicellular
• root hair cells & leaves increase SA

Question 7

why do plants need transport systems?

Answer 7

• larger plants don’t have a large enough SA:V to take in what they need
• they’ve developed specialised tissues for transporting water & nutrients to all cells

Question 8

what are the plants called that have specialised transport systems?

Answer 8

vascular plants

Question 9

what materials do plants exchange and transport?

Answer 9

• carbon dioxide
• oxygen
• water
• organic nutrients
• inorganic ions

Question 10

what is photosynthesis?

Answer 10

plants producing glucose through sunlight

Question 11

what is respiration?

Answer 11

plants supplying energy

Question 12

what is active transport?

Answer 12

energy required to move/ transport substances

Question 13

what are the two transport systems?

Answer 13

• transpiration systems
• translocation systems

Question 14

what is the transpiration system?

Answer 14

• movement of water molecules & dissolved mineral ions
• passive process
• xylem vessels
• unidirectional

Question 15

what is the translocation system?

Answer 15

• movement of sugars (sucrose) & amino acids
• active process
• phloem vessels
• bidirectional and seasonal

Question 16

what is the vascular bundle?

Answer 16

• vascular tissue throughout the plant - made of xylem and phloem tissue
• vascular bundle can transport substances & has structural support

Question 17

what is the vascular bundle like in the ROOTS?

Answer 17

• provides ‘drill’ like structure that enables plant to push down into roots
• xylem tissue is in the center - strongest (X structure)
• phloem in 4 sections

Question 18

what type of cells are meristems and what do they form in the roots?

Answer 18

• undifferentiated cells
• form new xylem and phloem tissues

Question 19

what is the vascular bundle like in the LEAF?

Answer 19

• xylem located on top of phloem
• only applies to dicotyledonous plants

Question 20

what is the vascular bundle like in the STEM?

Answer 20

• xylem is located on the inside (in non-wooded plants)
• provides additional support to stem
• cambium layer contains meristems

Question 21

what is the structure of a phloem vessel?

Answer 21

• thin layer of cytoplasm in sieve tube element
• dense cytoplasm of companion cell
• plasmodesmata links companion cell cytoplasm and sieve tube element
• large nucleus
• mitochondria

Question 22

what is the structure of a xylem vessel?

Answer 22

• hollow tube (no cytoplasm)
• thick lignified walls
• non-lignified pit
• region where end cell wall has been lost

Question 23

what do spirals of lignin running around the lumen of the xylem help with?

Answer 23

lignin reinforces xylem vessels so they don’t collapse under transpiration pull