3.1.3 a and b transport systems

Question 1

why do multicellular plants need transport systems?

Answer 1

metabolic demands- substances need transporting all around the plant eg glucose, oxygen , carbon dioxide, hormones
size- some plants live a long time so they grow to be very big and substances need to be transported from the tips of the roots to eh leaves of the plants and diffusion would take too long and isn’t efficient enough
surface area to volume ratio- small so can’t rely on diffusion alone

Question 2

what are dicotyledonous plants?

Answer 2

have 2 place where seeds are arranged- 2 cotyledons

Question 3

where is the vascular bundle in a stem and why is it there?

Answer 3

around the edge to give it strength and support

Question 4

where is the vascular bundle in the root and why is it there?

Answer 4

in the middle to help the plant withstand the tugging strains that result when the stem and leaves are blown in the wind

Question 5

where is the vascular bundle in the dicot leaf and why?

Answer 5

in the midrib of the leaf to help support the structure of the leaf

Question 6

where is the xylem and phloem in the vascular bundle in the stem?

Answer 6

phloem on the outside and xylem on the inside

Question 7

where is the xylem and phloem in the vascular bundle in the root?

Answer 7

xylem in the x shape in the middle and phloem in four dots around it

Question 8

where is the xylem and phloem in the vascular bundle in the leaf?

Answer 8

xylem on top and phloem below

Question 9

what is the function of the xylem?

Answer 9

to transport water and mineral ions up from the roots and for support

Question 10

what is xylem made from?

Answer 10

dead cells and lignin

Question 11

what is the function of the lignin?

Answer 11

lignin breaks down the organelles in the cells that make the xylem and make them waterproof

Question 12

how is lignin laid down in the walls of the xylem vessels?

Answer 12

it forms rings, spirals or solid tubes which have lots of small unlignified areas called bordered pits

Question 13

what are bordered pits?

Answer 13

where water leaves the xylem and moves into other cells of the plant

Question 14

what are phloem made from?

Answer 14

living tissue

Question 15

what is the function of the phloem?

Answer 15

to transport sugars and amino acids needed for respiration around the plant

Question 16

what is the main transporting vessel of the phloem?

Answer 16

sieve tube elements

Question 17

what is in the area between sieve cells?

Answer 17

sieve plates which let the phloem contents flow through

Question 18

what is linked to the sieve tube cell?

Answer 18

companion cells

Question 19

what are companion cells linked to the sieve tube cells by?

Answer 19

plasmodesmata

Question 20

what are the cell contents of the companion cells?

Answer 20

have nuclei and all other common organelles

Question 21

what is the function of the companion cells?

Answer 21

very vatic cells which function as a life support system for the sieve tube elements
carry out metabolic processes needed by the sieve tube elements

Question 22

what else makes up the phloem?

Answer 22

phloem fibres- cell wall is lignin, empty, provides mechanical strength and support and is imbedded within the phloem
parenchyma- cellulose cell wall, plays a role in storage and transport within the phloem, unspecialised and gives turgidity

Question 23

what is the difference between xylem tracheids and vessels?

Answer 23

tracheids are unicellular, narrower lumen, ends are tapering or oblique and closed
vessels are multicellular and larger, broader lumen due to less lignified walls, ends are rounded and open