Plants have developed efficient methods for transport and for synthesis of foods.

Xylem	Phloem
a transports water/mineral ions	sucrose/sugars/amino acids/organic/carbon compounds/products of photosynthesis/food
b from roots to leaves	from source/leaves to sink/roots
c dead/no membranes/no organelles	living/membranes present/some organelles
d no cross/end walls/hollow/continuous tubes	sieve plates/perforated walls/separate elements
e flow due to low pressures/tension/suction	flow due to high pressure/pressure gradient
f thicker walls	thinner walls
g lignified walls/gives support/forms wood	does not provide support/strength
h wider lumen	narrower lumen

a. Light-dependent reactions produce ATP/reduced NADP; 1 mark

b. ATP generated by chemiosmosis/by photophosphorylation/by ATP synthase; 1 mark

c. Reduced NADP produced by/using electrons from Photosystem I; 1 mark

$$\text{RuBP} + \text{CO}_2 \rightarrow \text{glycerate 3-phosphate} \quad \text{(in light independent reactions)}$$

1 mark

e. Glycerate 3-phosphate reduced to triose phosphate (in light independent reactions); 1 mark

f. ATP/reduced NADP used in the light-independent reactions; 1 mark

g. Reduced NADP provides electrons/hydrogen / to reduce (glycerate 3-phosphate)

OR

Reduced NADP used to convert glycerate 3-phosphate to triose phosphate; 1 mark

h. ATP provides energy (for reduction of glycerate 3-phosphate); 1 mark

i. ATP needed to regenerate RuBP; 1 mark

j. ATP/reduced NADP run out in darkness; 1 mark

k. Calvin cycle only possible with light/in the day/is indirectly dependent on light; 1 mark

Outline how the properties of water make it an ideal transport medium in plants.

a. polarity of water; 1 mark b. hydrogen bonds between water molecules; 1 mark
c. cohesion between water molecules/water molecules stick together; 1 mark d. cohesion allows tensions/low pressures/transpiration pull/movement upward/against gravity; 1 mark e. adhesion to cellulose/cell walls generates tensions/pull (in xylem) 1 mark

OR

adhesion to xylem walls/vessel walls causes capillary rise/upward movement; 1 mark

f. solvent for many substances / many substances dissolve; 1 mark g. liquid at most temperatures experienced by plants / liquid so can flow; 1 mark

Polarity of water and/or hydrogen bonding can be shown in an annotated diagram.