transport in plants

Question 1

why do plants needs a transport sytem

Answer 1

-high metabolic demand
cells make thier own glucose and o2 in photosynthesis

size - grow to a large size and substances need to be transported from root to leaf
long diffusion pathway so diffusion alone isn’t sufficient
-surface AREA-Leaves have large SA:V stem and roots taken inot account small SA:V

Question 2

what are plants that make two cotyledons in their seeds known as ?

Answer 2

dicotyledons

Question 3

what is cotyledons ?

Answer 3

food storage organ for the developing embryo plant

Question 4

what are twp types of dicotyledenous plants known as?

Answer 4

Herbaceous dicotyledons -soft tissue , short life cycle
- woody Dicotyledons - hard lignified , long life span

Question 5

what are the components of vascualr bundle ?

Answer 5

• phloem
  cambium
  -xylem

Question 6

where are the vascualr bundle found in stem

Answer 6

• around the edge to give strength and support

Question 7

whera are the vascular bundles found in roots ?

Answer 7

found in the middle
- to help the plant withstand the tugging strains as stem leaves blown in the wind

Question 8

where are the vascular bundles foun in the leaves

Answer 8

• in the midrib of dicot leaf -main vein
  supports the structure of the leaves
• small branching veins - spread through help in transport and support

Question 9

what is the function of xylem tissue ?

Answer 9

transport of water and minerals , unidirectional

Question 10

what are the structure of xylem?

Answer 10

• made of xyelm vessels and xyelm parenchyma
• xyelm vessels are: dead cells stacked end to end forming a tube
• no end walls #
• no cell surface membrane no organelles
  hollow

Question 11

state the function of spiral band and lignin and explain why it is important

Answer 11

-strengthens cell wall prevents from collapsing
- waterproofs the wall prevents water loss
- allows flexibility prevents stems from breaking

Question 12

what is the function of bordered pits no lignin

Answer 12

• allows lateral mov of water out of the xylem vessel to get to other cells or bypass blockage

Question 13

what is the function of phloem?

Answer 13

transport sucros and assimilates
from source to sink

Question 14

describe structure of phloem ?

Answer 14

sieve tube elements , cells stacked end to end
- end walls perforated giving sieve plates - allowing sucrose to go through
-no nucleus ,few organelles
litlle cytoplasm found at the edge of the cells
COMPANION CELLS
-contains all organelles
-active cells
linked to sieve tube elements by plasmodesmata
SCEROIDS/SCHELERA PARENCHYMA
supporting fibres around thecsieve tube elements .