Draw a labelled diagram of the structure of a chloroplast as seen with an electron microscope.

Describe how water is carried by the transpiration stream.

Explain how flowering is controlled in long-day and short-day plants.

Award [1] for each of the following clearly drawn and correctly labelled. Label lines must be unambiguous in terms of what they are indicating.
double/inner and outer membrane/envelope – shown as two concentric continuous lines close together;
granum/grana – shown as a stack of several disc-shaped subunits;
(intergranal) lamella – shown continuous with thylakoid membrane;
thylakoid – one of the flattened sacs;
stroma;
(70S) ribosomes/(circular) DNA / lipid globules / starch granules / thylakoid space;

transpiration is water loss (from plant) by evaporation;
flow of water through xylem from roots to leaves is the transpiration stream;
evaporation from spongy mesophyll cells;
replaced by osmosis from the xylem;
(diffusion of water vapour) through stomata;
water lost replaced from xylem / clear diagram showing movement of water from xylem through cell(s) (walls) to air space;
water pulled out of xylem creates suction/low pressure/tension; transpiration pull results;
water molecules stick together/are cohesive;
due to hydrogen bonding/polarity of water molecules;
xylem vessels are thin (hollow) tubes;
adhesion between water and xylem due to polarity of water molecules;
creates continuous column/transpiration stream;

flowering affected by light;
phytochrome;
exists in two (interconvertible) forms/P_fr and P_r;
P_r (red absorbing/660 nm) converted to P_fr (far-red/730 nm absorbing) in red or day light;
sunlight contains more red than far red light so P_fr predominates during the day;
gradual reversion of P_fr to P_r occurs in darkness;
P_fr is active form / P_r is inactive form;
in long-day plants, flowering induced by dark periods shorter than a critical length / occurs when day is longer than a critical length;
enough P_fr remains in long-day plants at end of short nights to stimulate flowering;
P_fr acts as promoter of flowering in long-day plants;
short-day plants induced to flower by dark periods longer than a critical length/days shorter than a critical value;
at end of long nights enough P_fr has been converted to P_r to allow flowering to occur;
P_fr acts as inhibitor of flowering in short-day plants;

Diagrams were variable in quality. The poorest were very unclear and labelling was often inaccurate. The double membrane, grana, stroma and thylakoid were most often correctly labelled. The connection between the thylakoid and intra-lamellar membrane was often not shown.

Failing to close lines when drawing membranes was also problematic. In some cases thylakoids were coloured in obscuring connections.

The importance of adhesion and cohesion was covered well, although these were not often related to the molecular properties of water.

It was the process of transpiration and the resultant force created that was less often mentioned or just given a brief treatment, losing marks for many candidates. Commonly, how water moves from soil into the root was detailed.

Phytochrome was known about and that it exists in 2 interconvertible forms. A number showed evidence of memory of facts but with lack of understanding because details were confused and terms interchanged.